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+Figure 28.7.1,Anatomy_And_Physio/images/Figure 28.7.1.jpg,"Figure 28.7.1 – Chromosomal Complement of a Male: Each pair of chromosomes contains hundreds to thousands of genes. The banding patterns are nearly identical for the two chromosomes within each pair, indicating the same organization of genes. As is visible in this karyotype, the only exception to this is the XY sex chromosome pair in males. (credit: National Human Genome Research Institute)","Each human body cell has a full complement of DNA stored in 23 pairs of chromosomes. Figure 28.7.1 shows the pairs in a systematic arrangement called a karyotype. Among these is one pair of chromosomes, called the sex chromosomes, that determines the sex of the individual (XX in females, XY in males). The remaining 22 chromosome pairs are called autosomal chromosomes. Each of these chromosomes carries hundreds or even thousands of genes, each of which codes for the assembly of a particular protein—that is, genes are “expressed” as proteins. An individual’s complete genetic makeup is referred to as his or her genotype. The characteristics that the genes express, whether they are physical, behavioral, or biochemical, are a person’s phenotype.","{'5e7951f8-2ebe-441a-ba29-56256b203922': 'Each human body cell has a full complement of DNA stored in 23 pairs of chromosomes. Figure 28.7.1 shows the pairs in a systematic arrangement called a karyotype. Among these is one pair of chromosomes, called the sex chromosomes, that determines the sex of the individual (XX in females, XY in males). The remaining 22 chromosome pairs are called autosomal chromosomes. Each of these chromosomes carries hundreds or even thousands of genes, each of which codes for the assembly of a particular protein—that is, genes are “expressed” as proteins. An individual’s complete genetic makeup is referred to as his or her genotype. The characteristics that the genes express, whether they are physical, behavioral, or biochemical, are a person’s phenotype.', 'b5df4607-9b5a-4f82-a7fa-43f44c9c1b3c': 'You inherit one chromosome in each pair—a full complement of 23—from each parent. This occurs when the sperm and oocyte combine at the moment of your conception. Homologous chromosomes—those that make up a complementary pair—have genes for the same characteristics in the same location on the chromosome. Because one copy of a gene, an allele, is inherited from each parent, the alleles in these complementary pairs may vary. Take for example an allele that encodes for dimples. A child may inherit the allele encoding for dimples on the chromosome from the father and the allele that encodes for smooth skin (no dimples) on the chromosome from the mother.', 'c19f5d8a-e42b-418e-a133-c2b02e0b29c3': 'Although a person can have two identical alleles for a single gene (a homozygous state), it is also possible for a person to have two different alleles (a heterozygous state). The two alleles can interact in several different ways. The expression of an allele can be dominant, for which the activity of this gene will mask the expression of a nondominant, or recessive, allele. Sometimes dominance is complete; at other times, it is incomplete. In some cases, both alleles are expressed at the same time in a form of expression known as codominance.', '43f30d40-14a3-41ab-bb9d-dcdc77559e8b': 'In the simplest scenario, a single pair of genes will determine a single heritable characteristic. However, it is quite common for multiple genes to interact to confer a feature. For instance, eight or more genes—each with their own alleles—determine eye color in humans. Moreover, although any one person can only have two alleles corresponding to a given gene, more than two alleles commonly exist in a population. This phenomenon is called multiple alleles. For example, there are three different alleles that encode ABO blood type; these are designated IA, IB, and i.', '21c79aa3-993d-4eb2-a232-e9b0c80571cc': 'Over 100 years of theoretical and experimental genetics studies, and the more recent sequencing and annotation of the human genome, have helped scientists to develop a better understanding of how an individual’s genotype is expressed as their phenotype. This body of knowledge can help scientists and medical professionals to predict, or at least estimate, some of the features that an offspring will inherit by examining the genotypes or phenotypes of the parents. One important application of this knowledge is to identify an individual’s risk for certain heritable genetic disorders. However, most diseases have a multigenic pattern of inheritance and can also be affected by the environment, so examining the genotypes or phenotypes of a person’s parents will provide only limited information about the risk of inheriting a disease. Only for a handful of single-gene disorders can genetic testing allow clinicians to calculate the probability with which a child born to the two parents tested may inherit a specific disease.'}"
+Figure 28.7.2,Anatomy_And_Physio/images/Figure 28.7.2.jpg,"Figure 28.7.2 – Random Segregation: In the formation of gametes, it is equally likely that either one of a pair alleles from one parent will be passed on to the offspring. This figure follows the possible combinations of alleles through two generations following a first-generation cross of homozygous dominant and homozygous recessive parents. The recessive phenotype, which is masked in the second generation, has a 1 in 4, or 25 percent, chance of reappearing in the third generation.","Because of the random segregation of gametes, the laws of chance and probability come into play when predicting the likelihood of a given phenotype. Consider a cross between an individual with two dominant alleles for a trait (AA) and an individual with two recessive alleles for the same trait (aa). All of the parental gametes from the dominant individual would be A, and all of the parental gametes from the recessive individual would be a (Figure 28.7.2). All of the offspring of that second generation, inheriting one allele from each parent, would have the genotype Aa, and the probability of expressing the phenotype of the dominant allele would be 4 out of 4, or 100 percent.","{'bac86291-a46e-4c2a-9fcc-c7b0c712f258': 'Our contemporary understanding of genetics rests on the work of a nineteenth-century monk. Working in the mid-1800s, long before anyone knew about genes or chromosomes, Gregor Mendel discovered that garden peas transmit their physical characteristics to subsequent generations in a discrete and predictable fashion. When he mated, or crossed, two pure-breeding pea plants that differed by a certain characteristic, the first-generation offspring all looked like one of the parents. For instance, when he crossed tall and dwarf pure-breeding pea plants, all of the offspring were tall. Mendel called tallness dominant because it was expressed in offspring when it was present in a purebred parent. He called dwarfism recessive because it was masked in the offspring if one of the purebred parents possessed the dominant characteristic. Note that tallness and dwarfism are variations on the characteristic of height. Mendel called such a variation a trait. We now know that these traits are the expression of different alleles of the gene encoding height.', '51263e42-cf11-4190-aa80-2f1c5093b28f': 'Mendel performed thousands of crosses in pea plants with differing traits for a variety of characteristics. And he repeatedly came up with the same results—among the traits he studied, one was always dominant, and the other was always recessive. (Remember, however, that this dominant–recessive relationship between alleles is not always the case; some alleles are codominant, and sometimes dominance is incomplete.)', '8d841c32-8ba8-40e3-84ef-0dc6a70af9c3': 'Using his understanding of dominant and recessive traits, Mendel tested whether a recessive trait could be lost altogether in a pea lineage or whether it would resurface in a later generation. By crossing the second-generation offspring of purebred parents with each other, he showed that the latter was true: recessive traits reappeared in third-generation plants in a ratio of 3:1 (three offspring having the dominant trait and one having the recessive trait). Mendel then proposed that characteristics such as height were determined by heritable “factors” that were transmitted, one from each parent, and inherited in pairs by offspring.', 'f19b3056-ba03-4123-8bf8-f2f8194c1f5e': 'In the language of genetics, Mendel’s theory applied to humans says that if an individual receives two dominant alleles, one from each parent, the individual’s phenotype will express the dominant trait. If an individual receives two recessive alleles, then the recessive trait will be expressed in the phenotype. Individuals who have two identical alleles for a given gene, whether dominant or recessive, are said to be homozygous for that gene (homo- = “same”). Conversely, an individual who has one dominant allele and one recessive allele is said to be heterozygous for that gene (hetero- = “different” or “other”). In this case, the dominant trait will be expressed, and the individual will be phenotypically identical to an individual who possesses two dominant alleles for the trait.', 'b43b1d00-3b76-4d0c-a532-32d2fe40f85d': 'It is common practice in genetics to use capital and lowercase letters to represent dominant and recessive alleles. Using Mendel’s pea plants as an example, if a tall pea plant is homozygous, it will possess two tall alleles (TT). A dwarf pea plant must be homozygous because its dwarfism can only be expressed when two recessive alleles are present (tt). A heterozygous pea plant (Tt) would be tall and phenotypically indistinguishable from a tall homozygous pea plant because of the dominant tall allele. Mendel deduced that a 3:1 ratio of dominant to recessive would be produced by the random segregation of heritable factors (genes) when crossing two heterozygous pea plants. In other words, for any given gene, parents are equally likely to pass down either one of their alleles to their offspring in a haploid gamete, and the result will be expressed in a dominant–recessive pattern if both parents are heterozygous for the trait.', '05615087-feef-40e5-86c0-721ce7df2652': 'Because of the random segregation of gametes, the laws of chance and probability come into play when predicting the likelihood of a given phenotype. Consider a cross between an individual with two dominant alleles for a trait (AA) and an individual with two recessive alleles for the same trait (aa). All of the parental gametes from the dominant individual would be A, and all of the parental gametes from the recessive individual would be a (Figure 28.7.2). All of the offspring of that second generation, inheriting one allele from each parent, would have the genotype Aa, and the probability of expressing the phenotype of the dominant allele would be 4 out of 4, or 100 percent.', '38838748-0c01-4b2a-9227-a6d2a4b05b41': 'This seems simple enough, but the inheritance pattern gets interesting when the second-generation Aa individuals are crossed. In this generation, 50 percent of each parent’s gametes are A and the other 50 percent are a. By Mendel’s principle of random segregation, the possible combinations of gametes that the offspring can receive are AA, Aa, aA (which is the same as Aa), and aa. Because segregation and fertilization are random, each offspring has a 25 percent chance of receiving any of these combinations. Therefore, if an Aa × Aa cross were performed 1000 times, approximately 250 (25 percent) of the offspring would be AA; 500 (50 percent) would be Aa (that is, Aa plus aA); and 250 (25 percent) would be aa. The genotypic ratio for this inheritance pattern is 1:2:1. However, we have already established that AA and Aa (and aA) individuals all express the dominant trait (i.e., share the same phenotype), and can therefore be combined into one group. The result is Mendel’s third-generation phenotype ratio of 3:1.', '36028006-d049-4631-8d10-7d96dfcfd616': 'Mendel’s observation of pea plants also included many crosses that involved multiple traits, which prompted him to formulate the principle of independent assortment. The law states that the members of one pair of genes (alleles) from a parent will sort independently from other pairs of genes during the formation of gametes. Applied to pea plants, that means that the alleles associated with the different traits of the plant, such as color, height, or seed type, will sort independently of one another. This holds true except when two alleles happen to be located close to one other on the same chromosome. Independent assortment provides for a great degree of diversity in offspring.', '24fd5ef9-fabc-4a7f-b41c-1c7b4f4e1e44': 'Mendelian genetics represent the fundamentals of inheritance, but there are two important qualifiers to consider when applying Mendel’s findings to inheritance studies in humans. First, as we’ve already noted, not all genes are inherited in a dominant–recessive pattern. Although all diploid individuals have two alleles for every gene, allele pairs may interact to create several types of inheritance patterns, including incomplete dominance and codominance.', '3b2ee4f8-486a-4a75-9537-d05a6201c824': 'Secondly, Mendel performed his studies using thousands of pea plants. He was able to identify a 3:1 phenotypic ratio in second-generation offspring because his large sample size overcame the influence of variability resulting from chance. In contrast, no human couple has ever had thousands of children. If we know that a man and woman are both heterozygous for a recessive genetic disorder, we would predict that one in every four of their children would be affected by the disease. In real life, however, the influence of chance could change that ratio significantly. For example, if a man and a woman are both heterozygous for cystic fibrosis, a recessive genetic disorder that is expressed only when the individual has two defective alleles, we would expect one in four of their children to have cystic fibrosis. However, it is entirely possible for them to have seven children, none of whom is affected, or for them to have two children, both of whom are affected. For each individual child, the presence or absence of a single gene disorder depends on which alleles that child inherits from his or her parents.'}"
+Figure 28.7.3,Anatomy_And_Physio/images/Figure 28.7.3.jpg,"Figure 28.7.3 – Autosomal Dominant Inheritance: Inheritance pattern of an autosomal dominant disorder, such as neurofibromatosis, is shown in a Punnett square.","In the case of cystic fibrosis, the disorder is recessive to the normal phenotype. However, a genetic abnormality may be dominant to the normal phenotype. When the dominant allele is located on one of the 22 pairs of autosomes (non-sex chromosomes), we refer to its inheritance pattern as autosomal dominant. An example of an autosomal dominant disorder is neurofibromatosis type I, a disease that induces tumor formation within the nervous system that leads to skin and skeletal deformities. Consider a couple in which one parent is heterozygous for this disorder (and who therefore has neurofibromatosis), Nn, and one parent is homozygous for the normal gene, nn. The heterozygous parent would have a 50 percent chance of passing the dominant allele for this disorder to his or her offspring, and the homozygous parent would always pass the normal allele. Therefore, four possible offspring genotypes are equally likely to occur: Nn, Nn, nn, and nn. That is, every child of this couple would have a 50 percent chance of inheriting neurofibromatosis. This inheritance pattern is shown in Figure 28.7.3, in a form called a Punnett square, named after its creator, the British geneticist Reginald Punnett.","{'76d2daa9-dc48-4c5d-b426-555273b44b4b': 'In the case of cystic fibrosis, the disorder is recessive to the normal phenotype. However, a genetic abnormality may be dominant to the normal phenotype. When the dominant allele is located on one of the 22 pairs of autosomes (non-sex chromosomes), we refer to its inheritance pattern as autosomal dominant. An example of an autosomal dominant disorder is neurofibromatosis type I, a disease that induces tumor formation within the nervous system that leads to skin and skeletal deformities. Consider a couple in which one parent is heterozygous for this disorder (and who therefore has neurofibromatosis), Nn, and one parent is homozygous for the normal gene, nn. The heterozygous parent would have a 50 percent chance of passing the dominant allele for this disorder to his or her offspring, and the homozygous parent would always pass the normal allele. Therefore, four possible offspring genotypes are equally likely to occur: Nn, Nn, nn, and nn. That is, every child of this couple would have a 50 percent chance of inheriting neurofibromatosis. This inheritance pattern is shown in Figure 28.7.3, in a form called a Punnett square, named after its creator, the British geneticist Reginald Punnett.', '2b90d12e-5c73-4fbe-89f9-007e90205676': 'Other genetic diseases that are inherited in this pattern are achondroplastic dwarfism, Marfan syndrome, and Huntington’s disease. Because autosomal dominant disorders are expressed by the presence of just one gene, an individual with the disorder will know that he or she has at least one faulty gene. The expression of the disease may manifest later in life, after the childbearing years, which is the case in Huntington’s disease (discussed in more detail later in this section).'}"
+Figure 28.7.4,Anatomy_And_Physio/images/Figure 28.7.4.jpg,Figure 28.7.4 – Autosomal Recessive Inheritance: The inheritance pattern of an autosomal recessive disorder with two carrier parents reflects a 3:1 probability of expression among offspring. (credit: U.S. National Library of Medicine),"An example of an autosomal recessive disorder is cystic fibrosis (CF), which we introduced earlier. CF is characterized by the chronic accumulation of a thick, tenacious mucus in the lungs and digestive tract. Decades ago, children with CF rarely lived to adulthood. With advances in medical technology, the average lifespan in developed countries has increased into middle adulthood. CF is a relatively common disorder that occurs in approximately 1 in 2000 Caucasians. A child born to two CF carriers would have a 25 percent chance of inheriting the disease. This is the same 3:1 dominant:recessive ratio that Mendel observed in his pea plants would apply here. The pattern is shown in Figure 28.7.4, using a diagram that tracks the likely incidence of an autosomal recessive disorder on the basis of parental genotypes.","{'50c5046a-cb4b-48d9-8597-83a941974534': 'When a genetic disorder is inherited in an autosomal recessive pattern, the disorder corresponds to the recessive phenotype. Heterozygous individuals will not display symptoms of this disorder, because their unaffected gene will compensate. Such an individual is called a carrier. Carriers for an autosomal recessive disorder may never know their genotype unless they have a child with the disorder.', '6c160eca-2723-4b6d-9ca2-2c29caf85ecf': 'An example of an autosomal recessive disorder is cystic fibrosis (CF), which we introduced earlier. CF is characterized by the chronic accumulation of a thick, tenacious mucus in the lungs and digestive tract. Decades ago, children with CF rarely lived to adulthood. With advances in medical technology, the average lifespan in developed countries has increased into middle adulthood. CF is a relatively common disorder that occurs in approximately 1 in 2000 Caucasians. A child born to two CF carriers would have a 25 percent chance of inheriting the disease. This is the same 3:1 dominant:recessive ratio that Mendel observed in his pea plants would apply here. The pattern is shown in Figure 28.7.4, using a diagram that tracks the likely incidence of an autosomal recessive disorder on the basis of parental genotypes.', 'b4eb50df-bd6e-455e-9bda-527c92e47eec': 'On the other hand, a child born to a CF carrier and someone with two unaffected alleles would have a 0 percent probability of inheriting CF, but would have a 50 percent chance of being a carrier. Other examples of autosome recessive genetic illnesses include the blood disorder sickle-cell anemia, the fatal neurological disorder Tay–Sachs disease, and the metabolic disorder phenylketonuria.'}"
+Figure 28.7.5,Anatomy_And_Physio/images/Figure 28.7.5.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine),"An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.","{'ce4ae496-4b8d-4fe7-b31b-e9258acd57bf': 'An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.', '6ae46a9d-f4bb-464f-8f8c-3fef2b140f72': 'When an abnormal allele for a gene that occurs on the X chromosome is dominant over the normal allele, the pattern is described as X-linked dominant. This is the case with vitamin D–resistant rickets: an affected father would pass the disease gene to all of his daughters, but none of his sons, because he donates only the Y chromosome to his sons (see Figure 28.7.5a). If it is the mother who is affected, all of her children—male or female—would have a 50 percent chance of inheriting the disorder because she can only pass an X chromosome on to her children (see Figure 28.7.5b). For an affected female, the inheritance pattern would be identical to that of an autosomal dominant inheritance pattern in which one parent is heterozygous and the other is homozygous for the normal gene.', '90c45d87-3097-4fdd-b697-a5c018502449': 'X-linked recessive inheritance is much more common because females can be carriers of the disease yet still have a normal phenotype. Diseases transmitted by X-linked recessive inheritance include color blindness, the blood-clotting disorder hemophilia, and some forms of muscular dystrophy. For an example of X-linked recessive inheritance, consider parents in which the mother is an unaffected carrier and the father is normal. None of the daughters would have the disease because they receive a normal gene from their father. However, they have a 50 percent chance of receiving the disease gene from their mother and becoming a carrier. In contrast, 50 percent of the sons would be affected (Figure 28.7.6).', '0b4a1161-bdc4-4fa0-8155-a5ccfb269daf': 'With X-linked recessive diseases, males either have the disease or are genotypically normal—they cannot be carriers. Females, however, can be genotypically normal, a carrier who is phenotypically normal, or affected with the disease. A daughter can inherit the gene for an X-linked recessive illness when her mother is a carrier or affected, or her father is affected. The daughter will be affected by the disease only if she inherits an X-linked recessive gene from both parents. As you can imagine, X-linked recessive disorders affect many more males than females. For example, color blindness affects at least 1 in 20 males, but only about 1 in 400 females.'}"
+Figure 28.7.5,Anatomy_And_Physio/images/Figure 28.7.5.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine),"An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.","{'ce4ae496-4b8d-4fe7-b31b-e9258acd57bf': 'An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.', '6ae46a9d-f4bb-464f-8f8c-3fef2b140f72': 'When an abnormal allele for a gene that occurs on the X chromosome is dominant over the normal allele, the pattern is described as X-linked dominant. This is the case with vitamin D–resistant rickets: an affected father would pass the disease gene to all of his daughters, but none of his sons, because he donates only the Y chromosome to his sons (see Figure 28.7.5a). If it is the mother who is affected, all of her children—male or female—would have a 50 percent chance of inheriting the disorder because she can only pass an X chromosome on to her children (see Figure 28.7.5b). For an affected female, the inheritance pattern would be identical to that of an autosomal dominant inheritance pattern in which one parent is heterozygous and the other is homozygous for the normal gene.', '90c45d87-3097-4fdd-b697-a5c018502449': 'X-linked recessive inheritance is much more common because females can be carriers of the disease yet still have a normal phenotype. Diseases transmitted by X-linked recessive inheritance include color blindness, the blood-clotting disorder hemophilia, and some forms of muscular dystrophy. For an example of X-linked recessive inheritance, consider parents in which the mother is an unaffected carrier and the father is normal. None of the daughters would have the disease because they receive a normal gene from their father. However, they have a 50 percent chance of receiving the disease gene from their mother and becoming a carrier. In contrast, 50 percent of the sons would be affected (Figure 28.7.6).', '0b4a1161-bdc4-4fa0-8155-a5ccfb269daf': 'With X-linked recessive diseases, males either have the disease or are genotypically normal—they cannot be carriers. Females, however, can be genotypically normal, a carrier who is phenotypically normal, or affected with the disease. A daughter can inherit the gene for an X-linked recessive illness when her mother is a carrier or affected, or her father is affected. The daughter will be affected by the disease only if she inherits an X-linked recessive gene from both parents. As you can imagine, X-linked recessive disorders affect many more males than females. For example, color blindness affects at least 1 in 20 males, but only about 1 in 400 females.'}"
+Figure 28.7.6,Anatomy_And_Physio/images/Figure 28.7.6.jpg,"Figure 28.7.6 – X-Linked Recessive Inheritance: Given two parents in which the father is normal and the mother is a carrier of an X-linked recessive disorder, a son would have a 50 percent probability of being affected with the disorder, whereas daughters would either be carriers or entirely unaffected. (credit: U.S. National Library of Medicine)","X-linked recessive inheritance is much more common because females can be carriers of the disease yet still have a normal phenotype. Diseases transmitted by X-linked recessive inheritance include color blindness, the blood-clotting disorder hemophilia, and some forms of muscular dystrophy. For an example of X-linked recessive inheritance, consider parents in which the mother is an unaffected carrier and the father is normal. None of the daughters would have the disease because they receive a normal gene from their father. However, they have a 50 percent chance of receiving the disease gene from their mother and becoming a carrier. In contrast, 50 percent of the sons would be affected (Figure 28.7.6).","{'ce4ae496-4b8d-4fe7-b31b-e9258acd57bf': 'An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.', '6ae46a9d-f4bb-464f-8f8c-3fef2b140f72': 'When an abnormal allele for a gene that occurs on the X chromosome is dominant over the normal allele, the pattern is described as X-linked dominant. This is the case with vitamin D–resistant rickets: an affected father would pass the disease gene to all of his daughters, but none of his sons, because he donates only the Y chromosome to his sons (see Figure 28.7.5a). If it is the mother who is affected, all of her children—male or female—would have a 50 percent chance of inheriting the disorder because she can only pass an X chromosome on to her children (see Figure 28.7.5b). For an affected female, the inheritance pattern would be identical to that of an autosomal dominant inheritance pattern in which one parent is heterozygous and the other is homozygous for the normal gene.', '90c45d87-3097-4fdd-b697-a5c018502449': 'X-linked recessive inheritance is much more common because females can be carriers of the disease yet still have a normal phenotype. Diseases transmitted by X-linked recessive inheritance include color blindness, the blood-clotting disorder hemophilia, and some forms of muscular dystrophy. For an example of X-linked recessive inheritance, consider parents in which the mother is an unaffected carrier and the father is normal. None of the daughters would have the disease because they receive a normal gene from their father. However, they have a 50 percent chance of receiving the disease gene from their mother and becoming a carrier. In contrast, 50 percent of the sons would be affected (Figure 28.7.6).', '0b4a1161-bdc4-4fa0-8155-a5ccfb269daf': 'With X-linked recessive diseases, males either have the disease or are genotypically normal—they cannot be carriers. Females, however, can be genotypically normal, a carrier who is phenotypically normal, or affected with the disease. A daughter can inherit the gene for an X-linked recessive illness when her mother is a carrier or affected, or her father is affected. The daughter will be affected by the disease only if she inherits an X-linked recessive gene from both parents. As you can imagine, X-linked recessive disorders affect many more males than females. For example, color blindness affects at least 1 in 20 males, but only about 1 in 400 females.'}"
+Figure 28.6.1,Anatomy_And_Physio/images/Figure 28.6.1.jpg,Figure 28.6.1 – Let-Down Reflex: A positive feedback loop ensures continued milk production as long as the infant continues to breastfeed.,"When the infant suckles, sensory nerve fibers in the areola trigger a neuroendocrine reflex that results in milk secretion from lactocytes into the alveoli. The posterior pituitary releases oxytocin, which stimulates myoepithelial cells to squeeze milk from the alveoli so it can drain into the lactiferous ducts, collect in the lactiferous sinuses, and discharge through the nipple pores. It takes less than 1 minute from the time when an infant begins suckling (the latent period) until milk is secreted (the let-down). Figure 28.6.1 summarizes the positive feedback loop of the let-down reflex.","{'0bbc0e55-6312-4a51-9d44-2a59074b35d8': 'The pituitary hormone prolactin is instrumental in the establishment and maintenance of breast milk supply. It also is important for the mobilization of maternal micronutrients for breast milk.', '9c70f88e-e161-4f06-a3ef-d79c0cf944e8': 'Near the fifth week of pregnancy, the level of circulating prolactin begins to increase, eventually rising to approximately 10–20 times the pre-pregnancy concentration. We noted earlier that, during pregnancy, prolactin and other hormones prepare the breasts anatomically for the secretion of milk. The level of prolactin plateaus in late pregnancy, at a level high enough to initiate milk production. However, estrogen, progesterone, and other placental hormones inhibit prolactin-mediated milk synthesis during pregnancy. It is not until the placenta is expelled that this inhibition is lifted and milk production commences.', 'f8ec265d-9229-41e6-a662-ca9347807caf': 'After childbirth, the baseline prolactin level drops sharply, but it is restored for a 1-hour spike during each feeding to stimulate the production of milk for the next feeding. With each prolactin spike, estrogen and progesterone also increase slightly.', '0614c14e-4192-43d7-983f-4da913d4b255': 'When the infant suckles, sensory nerve fibers in the areola trigger a neuroendocrine reflex that results in milk secretion from lactocytes into the alveoli. The posterior pituitary releases oxytocin, which stimulates myoepithelial cells to squeeze milk from the alveoli so it can drain into the lactiferous ducts, collect in the lactiferous sinuses, and discharge through the nipple pores. It takes less than 1 minute from the time when an infant begins suckling (the latent period) until milk is secreted (the let-down). Figure 28.6.1 summarizes the positive feedback loop of the let-down reflex.', 'dbc49d50-e8ca-4b7e-871d-651eef288dc4': 'The prolactin-mediated synthesis of milk changes with time. Frequent milk removal by breastfeeding (or pumping) will maintain high circulating prolactin levels for several months. However, even with continued breastfeeding, baseline prolactin will decrease over time to its pre-pregnancy level. In addition to prolactin and oxytocin, growth hormone, cortisol, parathyroid hormone, and insulin contribute to lactation, in part by facilitating the transport of maternal amino acids, fatty acids, glucose, and calcium to breast milk.'}"
+Figure 28.5.1,Anatomy_And_Physio/images/Figure 28.5.1.jpg,"Figure 28.5.1 – Neonatal Circulatory System: A newborn’s circulatory system reconfigures immediately after birth. The three fetal shunts have been closed permanently, facilitating blood flow to the liver and lungs.","The process of clamping and cutting the umbilical cord collapses the umbilical blood vessels. In the absence of medical assistance, this occlusion would occur naturally within 20 minutes of birth because the Wharton’s jelly within the umbilical cord would swell in response to the lower temperature outside of the mother’s body, and the blood vessels would constrict. Natural occlusion has occurred when the umbilical cord is no longer pulsating. For the most part, the collapsed vessels atrophy and become fibrotic remnants, existing in the mature circulatory system as ligaments of the abdominal wall and liver. The ductus venosus degenerates to become the ligamentum venosum beneath the liver. Only the proximal sections of the two umbilical arteries remain functional, taking on the role of supplying blood to the upper part of the bladder (Figure 28.5.1).","{'6bc17aa7-055a-4ed1-b20b-4390cba77b80': 'The process of clamping and cutting the umbilical cord collapses the umbilical blood vessels. In the absence of medical assistance, this occlusion would occur naturally within 20 minutes of birth because the Wharton’s jelly within the umbilical cord would swell in response to the lower temperature outside of the mother’s body, and the blood vessels would constrict. Natural occlusion has occurred when the umbilical cord is no longer pulsating. For the most part, the collapsed vessels atrophy and become fibrotic remnants, existing in the mature circulatory system as ligaments of the abdominal wall and liver. The ductus venosus degenerates to become the ligamentum venosum beneath the liver. Only the proximal sections of the two umbilical arteries remain functional, taking on the role of supplying blood to the upper part of the bladder (Figure 28.5.1).', 'f0b8c822-4662-406f-b857-2b4d27008206': 'The newborn’s first breath is vital to initiate the transition from the fetal to the neonatal circulatory pattern. Inflation of the lungs decreases blood pressure throughout the pulmonary system, as well as in the right atrium and ventricle. In response to this pressure change, the flow of blood temporarily reverses direction through the foramen ovale, moving from the left to the right atrium, and blocking the shunt with two flaps of tissue. Within 1 year, the tissue flaps usually fuse over the shunt, turning the foramen ovale into the fossa ovalis. The ductus arteriosus constricts as a result of increased oxygen concentration, and becomes the ligamentum arteriosum. Closing of the ductus arteriosus ensures that all blood pumped to the pulmonary circuit will be oxygenated by the newly functional neonatal lungs.'}"
+Figure 28.4.1,Anatomy_And_Physio/images/Figure 28.4.1.jpg,Figure 28.4.1 – Size of Uterus throughout Pregnancy: The uterus grows throughout pregnancy to accommodate the fetus.,"A full-term pregnancy lasts approximately 270 days (approximately 38.5 weeks) from conception to birth. Because it is easier to remember the first day of the last menstrual period (LMP) than to estimate the date of conception, obstetricians set the due date as 284 days (approximately 40.5 weeks) from the LMP. This assumes that conception occurred on day 14 of the woman’s cycle, which is usually a good approximation. The 40 weeks of an average pregnancy are usually discussed in terms of three trimesters, each approximately 13 weeks. During the second and third trimesters, the pre-pregnancy uterus—about the size of a fist—grows dramatically to contain the fetus, causing a number of anatomical changes in the mother (Figure 28.4.1).","{'b2fb8d96-7e2e-4670-b509-0a6a9e9e400c': 'In adults, the gastrointestinal tract harbors bacterial flora—trillions of bacteria that aid in digestion, produce vitamins, and protect from the invasion or replication of pathogens. In stark contrast, the fetal intestine is sterile. The first consumption of breast milk or formula floods the neonatal gastrointestinal tract with beneficial bacteria that begin to establish the bacterial flora.', '0da87c55-885f-4d00-8781-1659d04e4e5e': 'The fetal kidneys filter blood and produce urine, but the neonatal kidneys are still immature and inefficient at concentrating urine. Therefore, newborns produce very dilute urine, making it particularly important for infants to obtain sufficient fluids from breast milk or formula.', 'ba593ae6-a511-429c-9332-b6cd0dd583b9': 'Five criteria—skin color, heart rate, reflex, muscle tone, and respiration—are assessed, and each criterion is assigned a score of 0, 1, or 2. Scores are taken at 1 minute after birth and again at 5 minutes after birth. Each time that scores are taken, the five scores are added together. High scores (out of a possible 10) indicate the baby has made the transition from the womb well, whereas lower scores indicate that the baby may be in distress.', '273124cd-319c-4fe6-beb4-19cf969ed3cd': 'The technique for determining an Apgar score is quick and easy, painless for the newborn, and does not require any instruments except for a stethoscope. A convenient way to remember the five scoring criteria is to apply the mnemonic APGAR, for “appearance” (skin color), “pulse” (heart rate), “grimace” (reflex), “activity” (muscle tone), and “respiration.”', '3fefba63-6303-4aba-bdb1-9eadc9d899fd': 'Of the five Apgar criteria, heart rate and respiration are the most critical. Poor scores for either of these measurements may indicate the need for immediate medical attention to resuscitate or stabilize the newborn. In general, any score lower than 7 at the 5-minute mark indicates that medical assistance may be needed. A total score below 5 indicates an emergency situation. Normally, a newborn will get an intermediate score of 1 for some of the Apgar criteria and will progress to a 2 by the 5-minute assessment. Scores of 8 or above are normal.', '86b4b2a0-822b-4831-8ac9-a704402ef767': 'A full-term pregnancy lasts approximately 270 days (approximately 38.5 weeks) from conception to birth. Because it is easier to remember the first day of the last menstrual period (LMP) than to estimate the date of conception, obstetricians set the due date as 284 days (approximately 40.5 weeks) from the LMP. This assumes that conception occurred on day 14 of the woman’s cycle, which is usually a good approximation. The 40 weeks of an average pregnancy are usually discussed in terms of three trimesters, each approximately 13 weeks. During the second and third trimesters, the pre-pregnancy uterus—about the size of a fist—grows dramatically to contain the fetus, causing a number of anatomical changes in the mother (Figure 28.4.1).'}"
+Figure 28.4.3,Anatomy_And_Physio/images/Figure 28.4.3.jpg,Figure 28.4.3 – Hormones Initiating Labor: A positive feedback loop of hormones works to initiate labor.,"First, recall that progesterone inhibits uterine contractions throughout the first several months of pregnancy. As the pregnancy enters its seventh month, progesterone levels plateau and then drop. Estrogen levels, however, continue to rise in the maternal circulation (Figure 28.4.3). The increasing ratio of estrogen to progesterone makes the myometrium (the uterine smooth muscle) more sensitive to stimuli that promote contractions (because progesterone no longer inhibits them). Moreover, in the eighth month of pregnancy, fetal cortisol rises, which boosts estrogen secretion by the placenta and further overpowers the uterine-calming effects of progesterone. Some women may feel the result of the decreasing levels of progesterone in late pregnancy as weak and irregular peristaltic Braxton Hicks contractions, also called false labor. These contractions can often be relieved with rest or hydration.","{'524b43be-a055-4f6d-b07f-d654cf2796e1': 'Childbirth, or parturition, typically occurs within a week of a woman’s due date, unless the woman is pregnant with more than one fetus, which usually causes her to go into labor early. As a pregnancy progresses into its final weeks, several physiological changes occur in response to hormones that trigger labor.', '6c438b70-906c-4a7c-bd29-444101d492ef': 'First, recall that progesterone inhibits uterine contractions throughout the first several months of pregnancy. As the pregnancy enters its seventh month, progesterone levels plateau and then drop. Estrogen levels, however, continue to rise in the maternal circulation (Figure 28.4.3). The increasing ratio of estrogen to progesterone makes the myometrium (the uterine smooth muscle) more sensitive to stimuli that promote contractions (because progesterone no longer inhibits them). Moreover, in the eighth month of pregnancy, fetal cortisol rises, which boosts estrogen secretion by the placenta and further overpowers the uterine-calming effects of progesterone. Some women may feel the result of the decreasing levels of progesterone in late pregnancy as weak and irregular peristaltic Braxton Hicks contractions, also called false labor. These contractions can often be relieved with rest or hydration.', '635ec6a4-47fe-459e-8cad-24bbb5c57a36': 'A common sign that labor will be short is the so-called “bloody show.” During pregnancy, a plug of mucus accumulates in the cervical canal, blocking the entrance to the uterus. Approximately 1–2 days prior to the onset of true labor, this plug loosens and is expelled, along with a small amount of blood.', '3985d435-ae79-4630-86bc-81666a162e20': 'Meanwhile, the posterior pituitary has been boosting its secretion of oxytocin, a hormone that stimulates the contractions of labor. At the same time, the myometrium increases its sensitivity to oxytocin by expressing more receptors for this hormone. As labor nears, oxytocin begins to stimulate stronger, more painful uterine contractions, which—in a positive feedback loop—stimulate the secretion of prostaglandins from fetal membranes. Like oxytocin, prostaglandins also enhance uterine contractile strength. The fetal pituitary also secretes oxytocin, which increases prostaglandins even further. Given the importance of oxytocin and prostaglandins to the initiation and maintenance of labor, it is not surprising that, when a pregnancy is not progressing to labor and needs to be induced, a pharmaceutical version of these compounds (called pitocin) is administered by intravenous drip.', '879de23d-1534-47c3-8980-b94d27f21267': 'Finally, stretching of the myometrium and cervix by a full-term fetus in the vertex (head-down) position is regarded as a stimulant to uterine contractions. The sum of these changes initiates the regular contractions known as true labor, which become more powerful and more frequent with time. The pain of labor is attributed to myometrial hypoxia during uterine contractions.'}"
+Figure 28.4.4,Anatomy_And_Physio/images/Figure 28.4.4.jpg,"Figure 28.4.4 – Stages of Childbirth: The stages of childbirth include Stage 1, early cervical dilation; Stage 2, full dilation and expulsion of the newborn; and Stage 3, delivery of the placenta and associated fetal membranes. (The position of the newborn’s shoulder is described relative to the mother.)","The process of childbirth can be divided into three stages: cervical dilation, expulsion of the newborn, and afterbirth (Figure 28.4.4).","{'3e3ea78d-a80e-4427-9db5-8577523c6ce3': 'The process of childbirth can be divided into three stages: cervical dilation, expulsion of the newborn, and afterbirth (Figure 28.4.4).', '494d9e30-47db-423a-a677-373cdddf1d2d': 'As you will recall, a developing human is called a fetus from the ninth week of gestation until birth. This 30-week period of development is marked by continued cell growth and differentiation, which fully develop the structures and functions of the immature organ systems formed during the embryonic period. The completion of fetal development results in a newborn who, although still immature in many ways, is capable of survival outside the womb.'}"
+Figure 28.3.1,Anatomy_And_Physio/images/Figure 28.3.1.jpg,Figure 28.3.1 – Sexual Differentiation: Differentiation of the male and female reproductive systems does not occur until the fetal period of development.,"Sexual differentiation does not begin until the fetal period, during weeks 9–12. Embryonic males and females, though genetically distinguishable, are morphologically identical (Figure 28.3.1). Bipotential gonads, or gonads that can develop into male or female sexual organs, are connected to a central cavity called the cloaca via Müllerian ducts and Wolffian ducts. (The cloaca is an extension of the primitive gut.) Several events lead to sexual differentiation during this period.","{'36eed267-0ca8-40fd-80d0-982f6cdacb6e': 'Sexual differentiation does not begin until the fetal period, during weeks 9–12. Embryonic males and females, though genetically distinguishable, are morphologically identical (Figure 28.3.1). Bipotential gonads, or gonads that can develop into male or female sexual organs, are connected to a central cavity called the cloaca via Müllerian ducts and Wolffian ducts. (The cloaca is an extension of the primitive gut.) Several events lead to sexual differentiation during this period.', '4c32e5c6-9121-4617-aa32-05a659cbd1e4': 'During male fetal development, the bipotential gonads become the testes and associated epididymis. The Müllerian ducts degenerate. The Wolffian ducts become the vas deferens, and the cloaca becomes the urethra and rectum.', '493d7f37-74de-4f28-a307-f2c7cfc5ce43': 'During female fetal development, the bipotential gonads develop into ovaries. The Wolffian ducts degenerate. The Müllerian ducts become the uterine tubes and uterus, and the cloaca divides and develops into a vagina, a urethra, and a rectum.'}"
+Figure 28.3.2,Anatomy_And_Physio/images/Figure 28.3.2.jpg,"Figure 28.3.2 – Fetal Circulatory System: The fetal circulatory system includes three shunts to divert blood from undeveloped and partially functioning organs, as well as blood supply to and from the placenta.","The placenta provides the fetus with necessary oxygen and nutrients via the umbilical vein. (Remember that veins carry blood toward the heart. In this case, the blood flowing to the fetal heart is oxygenated because it comes from the placenta. The respiratory system is immature and cannot yet oxygenate blood on its own.) From the umbilical vein, the oxygenated blood flows toward the inferior vena cava, all but bypassing the immature liver, via the ductus venosus shunt (Figure 28.3.2). The liver receives just a trickle of blood, which is all that it needs in its immature, semifunctional state. Blood flows from the inferior vena cava to the right atrium, mixing with fetal venous blood along the way.","{'83db608a-4655-4308-a04d-fb250c0bb676': 'During prenatal development, the fetal circulatory system is integrated with the placenta via the umbilical cord so that the fetus receives both oxygen and nutrients from the placenta. However, after childbirth, the umbilical cord is severed, and the newborn’s circulatory system must be reconfigured. When the heart first forms in the embryo, it exists as two parallel tubes derived from mesoderm and lined with endothelium, which then fuse together. As the embryo develops into a fetus, the tube-shaped heart folds and further differentiates into the four chambers present in a mature heart. Unlike a mature cardiovascular system, however, the fetal cardiovascular system also includes circulatory shortcuts, or shunts. A shunt is an anatomical (or sometimes surgical) diversion that allows blood flow to bypass immature organs such as the lungs and liver until childbirth.', '65257d19-ee64-44e9-8941-5e25ae94e8b4': 'The placenta provides the fetus with necessary oxygen and nutrients via the umbilical vein. (Remember that veins carry blood toward the heart. In this case, the blood flowing to the fetal heart is oxygenated because it comes from the placenta. The respiratory system is immature and cannot yet oxygenate blood on its own.) From the umbilical vein, the oxygenated blood flows toward the inferior vena cava, all but bypassing the immature liver, via the ductus venosus shunt (Figure 28.3.2). The liver receives just a trickle of blood, which is all that it needs in its immature, semifunctional state. Blood flows from the inferior vena cava to the right atrium, mixing with fetal venous blood along the way.', 'fb68ca60-6654-4cda-bbfd-41d8d515c166': 'Although the fetal liver is semifunctional, the fetal lungs are nonfunctional. The fetal circulation therefore bypasses the lungs by shifting some of the blood through the foramen ovale, a shunt that directly connects the right and left atria and avoids the pulmonary trunk altogether. Most of the rest of the blood is pumped to the right ventricle, and from there, into the pulmonary trunk, which splits into pulmonary arteries. However, a shunt within the pulmonary artery, the ductus arteriosus, diverts a portion of this blood into the aorta. This ensures that only a small volume of oxygenated blood passes through the immature pulmonary circuit, which has only minor metabolic requirements. Blood vessels of uninflated lungs have high resistance to flow, a condition that encourages blood to flow to the aorta, which presents much lower resistance. The oxygenated blood moves through the foramen ovale into the left atrium, where it mixes with the now deoxygenated blood returning from the pulmonary circuit. This blood then moves into the left ventricle, where it is pumped into the aorta. Some of this blood moves through the coronary arteries into the myocardium, and some moves through the carotid arteries to the brain.', 'c06548e7-eb05-429a-99e6-6d50d8149c03': 'The descending aorta carries partially oxygenated and partially deoxygenated blood into the lower regions of the body. It eventually passes into the umbilical arteries through branches of the internal iliac arteries. The deoxygenated blood collects waste as it circulates through the fetal body and returns to the umbilical cord. Thus, the two umbilical arteries carry blood low in oxygen and high in carbon dioxide and fetal wastes. This blood is filtered through the placenta, where wastes diffuse into the maternal circulation. Oxygen and nutrients from the mother diffuse into the placenta and from there into the fetal blood, and the process repeats.'}"
+Figure 28.2.1,Anatomy_And_Physio/images/Figure 28.2.1.jpg,Figure 28.2.1 – Pre-Embryonic Cleavages: Pre-embryonic cleavages make use of the abundant cytoplasm of the conceptus as the cells rapidly divide without changing the total volume.,"Following fertilization, the zygote and its associated membranes, together referred to as the conceptus, continue to be projected toward the uterus by peristalsis and beating cilia. During its journey to the uterus, the zygote undergoes five or six rapid mitotic cell divisions. Although each cleavage results in more cells, it does not increase the total volume of the conceptus (Figure 28.2.1). Each daughter cell produced by cleavage is called a blastomere (blastos = “germ,” in the sense of a seed or sprout).","{'adcd4aa1-20f5-4c94-8b67-d96a1006632b': 'Following fertilization, the zygote and its associated membranes, together referred to as the conceptus, continue to be projected toward the uterus by peristalsis and beating cilia. During its journey to the uterus, the zygote undergoes five or six rapid mitotic cell divisions. Although each cleavage results in more cells, it does not increase the total volume of the conceptus (Figure 28.2.1). Each daughter cell produced by cleavage is called a blastomere (blastos = “germ,” in the sense of a seed or sprout).', 'e3a5274a-a737-4396-a40c-c2fd3f944eb4': 'Approximately 3 days after fertilization, a 16-cell conceptus reaches the uterus. The cells that had been loosely grouped are now compacted and look more like a solid mass. The name given to this structure is the morula (morula = “little mulberry”). Once inside the uterus, the conceptus floats freely for several more days. It continues to divide, creating a ball of approximately 100 cells, and consuming nutritive endometrial secretions called uterine milk while the uterine lining thickens. The ball of now tightly bound cells starts to secrete fluid and organize themselves around a fluid-filled cavity, the blastocoel. At this developmental stage, the conceptus is referred to as a blastocyst. Within this structure, a group of cells forms into an inner cell mass, which is fated to become the embryo. The cells that form the outer shell are called trophoblasts (trophe = “to feed” or “to nourish”). These cells will develop into the chorionic sac and the fetal portion of the placenta (the organ of nutrient, waste, and gas exchange between mother and the developing offspring).', 'ed662868-d8f0-4b94-8f8f-37a1e40d6c43': 'The inner mass of embryonic cells is totipotent during this stage, meaning that each cell has the potential to differentiate into any cell type in the human body. Totipotency lasts for only a few days before the cells’ fates are set as being the precursors to a specific lineage of cells.', 'b2bfae9e-75fd-42db-967a-11c5036922ac': 'As the blastocyst forms, the trophoblast excretes enzymes that begin to degrade the zona pellucida. In a process called “hatching,” the conceptus breaks free of the zona pellucida in preparation for implantation.'}"
+Figure 28.2.2,Anatomy_And_Physio/images/Figure 28.2.2.jpg,"Figure 28.2.2 – Pre-Embryonic Development: Ovulation, fertilization, pre-embryonic development, and implantation occur at specific locations within the female reproductive system in a time span of approximately 1 week.","At the end of the first week, the blastocyst comes in contact with the uterine wall and adheres to it, embedding itself in the uterine lining via the trophoblast cells. Thus begins the process of implantation, which signals the end of the pre-embryonic stage of development (Figure 28.2.2). Implantation can be accompanied by minor bleeding. The blastocyst typically implants in the fundus of the uterus or on the posterior wall. However, if the endometrium is not fully developed and ready to receive the blastocyst, the blastocyst will detach and find a better spot. A significant percentage (50–75 percent) of blastocysts fail to implant; when this occurs, the blastocyst is shed with the endometrium during menses. The high rate of implantation failure is one reason why pregnancy typically requires several ovulation cycles to achieve.","{'04a53e5b-54fe-414e-b9d0-4aa1124552a5': 'At the end of the first week, the blastocyst comes in contact with the uterine wall and adheres to it, embedding itself in the uterine lining via the trophoblast cells. Thus begins the process of implantation, which signals the end of the pre-embryonic stage of development (Figure 28.2.2). Implantation can be accompanied by minor bleeding. The blastocyst typically implants in the fundus of the uterus or on the posterior wall. However, if the endometrium is not fully developed and ready to receive the blastocyst, the blastocyst will detach and find a better spot. A significant percentage (50–75 percent) of blastocysts fail to implant; when this occurs, the blastocyst is shed with the endometrium during menses. The high rate of implantation failure is one reason why pregnancy typically requires several ovulation cycles to achieve.', 'f8fc8f56-2368-41ce-abe4-2991a05517ef': 'When implantation succeeds and the blastocyst adheres to the endometrium, the superficial cells of the trophoblast fuse with each other, forming the syncytiotrophoblast, a multinucleated body that digests endometrial cells to firmly secure the blastocyst to the uterine wall. In response, the uterine mucosa rebuilds itself and envelops the blastocyst (Figure 28.2.3). The trophoblast secretes human chorionic gonadotropin (hCG), a hormone that directs the corpus luteum to survive, enlarge, and continue producing progesterone and estrogen to suppress menses. These functions of hCG are necessary for creating an environment suitable for the developing embryo. As a result of this increased production, hCG accumulates in the maternal bloodstream and is excreted in the urine. Implantation is complete by the middle of the second week. Just a few days after implantation, the trophoblast has secreted enough hCG for an at-home urine pregnancy test to give a positive result.', 'e4d7bde5-53a3-41fe-8739-a7163c0ee784': 'Most of the time an embryo implants within the body of the uterus in a location that can support growth and development. However, in one to two percent of cases, the embryo implants either outside the uterus (an ectopic pregnancy) or in a region of uterus that can create complications for the pregnancy. If the embryo implants in the inferior portion of the uterus, the placenta can potentially grow over the opening of the cervix, a condition call placenta previa.'}"
+Figure 28.2.3,Anatomy_And_Physio/images/Figure 28.2.3.jpg,"Figure 28.2.3 – Implantation: During implantation, the trophoblast cells of the blastocyst adhere to the endometrium and digest endometrial cells until it is attached securely.","When implantation succeeds and the blastocyst adheres to the endometrium, the superficial cells of the trophoblast fuse with each other, forming the syncytiotrophoblast, a multinucleated body that digests endometrial cells to firmly secure the blastocyst to the uterine wall. In response, the uterine mucosa rebuilds itself and envelops the blastocyst (Figure 28.2.3). The trophoblast secretes human chorionic gonadotropin (hCG), a hormone that directs the corpus luteum to survive, enlarge, and continue producing progesterone and estrogen to suppress menses. These functions of hCG are necessary for creating an environment suitable for the developing embryo. As a result of this increased production, hCG accumulates in the maternal bloodstream and is excreted in the urine. Implantation is complete by the middle of the second week. Just a few days after implantation, the trophoblast has secreted enough hCG for an at-home urine pregnancy test to give a positive result.","{'04a53e5b-54fe-414e-b9d0-4aa1124552a5': 'At the end of the first week, the blastocyst comes in contact with the uterine wall and adheres to it, embedding itself in the uterine lining via the trophoblast cells. Thus begins the process of implantation, which signals the end of the pre-embryonic stage of development (Figure 28.2.2). Implantation can be accompanied by minor bleeding. The blastocyst typically implants in the fundus of the uterus or on the posterior wall. However, if the endometrium is not fully developed and ready to receive the blastocyst, the blastocyst will detach and find a better spot. A significant percentage (50–75 percent) of blastocysts fail to implant; when this occurs, the blastocyst is shed with the endometrium during menses. The high rate of implantation failure is one reason why pregnancy typically requires several ovulation cycles to achieve.', 'f8fc8f56-2368-41ce-abe4-2991a05517ef': 'When implantation succeeds and the blastocyst adheres to the endometrium, the superficial cells of the trophoblast fuse with each other, forming the syncytiotrophoblast, a multinucleated body that digests endometrial cells to firmly secure the blastocyst to the uterine wall. In response, the uterine mucosa rebuilds itself and envelops the blastocyst (Figure 28.2.3). The trophoblast secretes human chorionic gonadotropin (hCG), a hormone that directs the corpus luteum to survive, enlarge, and continue producing progesterone and estrogen to suppress menses. These functions of hCG are necessary for creating an environment suitable for the developing embryo. As a result of this increased production, hCG accumulates in the maternal bloodstream and is excreted in the urine. Implantation is complete by the middle of the second week. Just a few days after implantation, the trophoblast has secreted enough hCG for an at-home urine pregnancy test to give a positive result.', 'e4d7bde5-53a3-41fe-8739-a7163c0ee784': 'Most of the time an embryo implants within the body of the uterus in a location that can support growth and development. However, in one to two percent of cases, the embryo implants either outside the uterus (an ectopic pregnancy) or in a region of uterus that can create complications for the pregnancy. If the embryo implants in the inferior portion of the uterus, the placenta can potentially grow over the opening of the cervix, a condition call placenta previa.'}"
+Figure 28.2.5,Anatomy_And_Physio/images/Figure 28.2.5.jpg,Figure 28.2.5 – Development of the Embryonic Disc: Formation of the embryonic disc leaves spaces on either side that develop into the amniotic cavity and the yolk sac.,"At the beginning of the second week, the cells of the inner cell mass form into a two-layered disc of embryonic cells, and a space—the amniotic cavity—opens up between it and the trophoblast (Figure 28.2.5). Cells from the upper layer of the disc (the epiblast) extend around the amniotic cavity, creating a membranous sac that forms into the amnion by the end of the second week. The amnion fills with amniotic fluid and eventually grows to surround the embryo. Early in development, amniotic fluid consists almost entirely of a filtrate of maternal plasma, but as the kidneys of the fetus begin to function at approximately the eighth week, they add urine to the volume of amniotic fluid. Floating within the amniotic fluid, the embryo—and later, the fetus—is protected from trauma and rapid temperature changes. It can move freely within the fluid and can prepare for swallowing and breathing out of the uterus.","{'c9d12da9-447f-4452-8897-f5e4d3e70354': 'During the second week of development, with the embryo implanted in the uterus, cells within the blastocyst start to organize into layers. Some grow to form the extra-embryonic membranes needed to support and protect the growing embryo: the amnion, the yolk sac, the allantois, and the chorion.', '0232bba0-8797-4113-9f34-c858215e5ed2': 'At the beginning of the second week, the cells of the inner cell mass form into a two-layered disc of embryonic cells, and a space—the amniotic cavity—opens up between it and the trophoblast (Figure 28.2.5). Cells from the upper layer of the disc (the epiblast) extend around the amniotic cavity, creating a membranous sac that forms into the amnion by the end of the second week. The amnion fills with amniotic fluid and eventually grows to surround the embryo. Early in development, amniotic fluid consists almost entirely of a filtrate of maternal plasma, but as the kidneys of the fetus begin to function at approximately the eighth week, they add urine to the volume of amniotic fluid. Floating within the amniotic fluid, the embryo—and later, the fetus—is protected from trauma and rapid temperature changes. It can move freely within the fluid and can prepare for swallowing and breathing out of the uterus.', 'ceb33528-f00f-4c70-96d2-f997ff746863': 'On the ventral side of the embryonic disc, opposite the amnion, cells in the lower layer of the embryonic disk (the hypoblast) extend into the blastocyst cavity and form a yolk sac. The yolk sac supplies some nutrients absorbed from the trophoblast and also provides primitive blood circulation to the developing embryo for the second and third week of development. When the placenta takes over nourishing the embryo at approximately week 4, the yolk sac has been greatly reduced in size and its main function is to serve as the source of blood cells and germ cells (cells that will give rise to gametes). During week 3, a finger-like outpocketing of the yolk sac develops into the allantois, a primitive excretory duct of the embryo that will become part of the urinary bladder. Together, the stalks of the yolk sac and allantois establish the outer structure of the umbilical cord.', 'da78f602-6c55-457d-85a8-da1f2e2acb1e': 'The last of the extra-embryonic membranes is the chorion, which is the one membrane that surrounds all others. The development of the chorion will be discussed in more detail shortly, as it relates to the growth and development of the placenta.'}"
+Figure 28.2.6,Anatomy_And_Physio/images/Figure 28.2.6.jpg,Figure 28.2.6 – Germ Layers: Formation of the three primary germ layers occurs during the first 2 weeks of development. The embryo at this stage is only a few millimeters in length.,"As the third week of development begins, the two-layered disc of cells becomes a three-layered disc through the process of gastrulation, during which the cells transition from totipotency to multipotency. The embryo, which takes the shape of an oval-shaped disc, forms an indentation called the primitive streak along the dorsal surface of the epiblast. A node at the caudal or “tail” end of the primitive streak emits growth factors that direct cells to multiply and migrate. Cells migrate toward and through the primitive streak and then move laterally to create two new layers of cells. The first layer is the endoderm, a sheet of cells that displaces the hypoblast and lies adjacent to the yolk sac. The second layer of cells fills in as the middle layer, or mesoderm. The cells of the epiblast that remain (not having migrated through the primitive streak) become the ectoderm (Figure 28.2.6).","{'3c09ee70-8866-4b40-a978-15b7b2cfdb73': 'As the third week of development begins, the two-layered disc of cells becomes a three-layered disc through the process of gastrulation, during which the cells transition from totipotency to multipotency. The embryo, which takes the shape of an oval-shaped disc, forms an indentation called the primitive streak along the dorsal surface of the epiblast. A node at the caudal or “tail” end of the primitive streak emits growth factors that direct cells to multiply and migrate. Cells migrate toward and through the primitive streak and then move laterally to create two new layers of cells. The first layer is the endoderm, a sheet of cells that displaces the hypoblast and lies adjacent to the yolk sac. The second layer of cells fills in as the middle layer, or mesoderm. The cells of the epiblast that remain (not having migrated through the primitive streak) become the ectoderm (Figure 28.2.6).', 'dbda7534-b8cc-43dd-bafc-f13909454df1': 'Each of these germ layers will develop into specific structures in the embryo. Whereas the ectoderm and endoderm form tightly connected epithelial sheets, the mesodermal cells are less organized and exist as a loosely connected cell community. The ectoderm gives rise to cell lineages that differentiate to become the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails. Mesodermal cells ultimately become the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm goes on to form the epithelial lining of the gastrointestinal tract, liver, and pancreas, as well as the lungs (Figure 28.2.7).'}"
+Figure 28.2.7,Anatomy_And_Physio/images/Figure 28.2.7.jpg,"Figure 28.2.7 – Fates of Germ Layers in Embryo: Following gastrulation of the embryo in the third week, embryonic cells of the ectoderm, mesoderm, and endoderm begin to migrate and differentiate into the cell lineages that will give rise to mature organs and organ systems in the infant.","Each of these germ layers will develop into specific structures in the embryo. Whereas the ectoderm and endoderm form tightly connected epithelial sheets, the mesodermal cells are less organized and exist as a loosely connected cell community. The ectoderm gives rise to cell lineages that differentiate to become the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails. Mesodermal cells ultimately become the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm goes on to form the epithelial lining of the gastrointestinal tract, liver, and pancreas, as well as the lungs (Figure 28.2.7).","{'3c09ee70-8866-4b40-a978-15b7b2cfdb73': 'As the third week of development begins, the two-layered disc of cells becomes a three-layered disc through the process of gastrulation, during which the cells transition from totipotency to multipotency. The embryo, which takes the shape of an oval-shaped disc, forms an indentation called the primitive streak along the dorsal surface of the epiblast. A node at the caudal or “tail” end of the primitive streak emits growth factors that direct cells to multiply and migrate. Cells migrate toward and through the primitive streak and then move laterally to create two new layers of cells. The first layer is the endoderm, a sheet of cells that displaces the hypoblast and lies adjacent to the yolk sac. The second layer of cells fills in as the middle layer, or mesoderm. The cells of the epiblast that remain (not having migrated through the primitive streak) become the ectoderm (Figure 28.2.6).', 'dbda7534-b8cc-43dd-bafc-f13909454df1': 'Each of these germ layers will develop into specific structures in the embryo. Whereas the ectoderm and endoderm form tightly connected epithelial sheets, the mesodermal cells are less organized and exist as a loosely connected cell community. The ectoderm gives rise to cell lineages that differentiate to become the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails. Mesodermal cells ultimately become the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm goes on to form the epithelial lining of the gastrointestinal tract, liver, and pancreas, as well as the lungs (Figure 28.2.7).'}"
+Figure 28.2.8,Anatomy_And_Physio/images/Figure 28.2.8.jpg,"Figure 28.2.8 – Cross-Section of the Placenta: In the placenta, maternal and fetal blood components are conducted through the surface of the chorionic villi, but maternal and fetal bloodstreams never mix directly.","The maternal portion of the placenta develops from the deepest layer of the endometrium, the decidua basalis. To form the embryonic portion of the placenta, the syncytiotrophoblast and the underlying cells of the trophoblast (cytotrophoblast cells) begin to proliferate along with a layer of extraembryonic mesoderm cells. These form the chorionic membrane, which envelops the entire conceptus as the chorion. The chorionic membrane forms finger-like structures called chorionic villi that burrow into the endometrium like tree roots, making up the fetal portion of the placenta. The cytotrophoblast cells perforate the chorionic villi, burrow farther into the endometrium, and remodel maternal blood vessels to augment maternal blood flow surrounding the villi. Meanwhile, fetal mesenchymal cells derived from the mesoderm fill the villi and differentiate into blood vessels, including the three umbilical blood vessels that connect the embryo to the developing placenta (Figure 28.2.8).","{'5678e08a-b960-4410-a027-c99103de5d5f': 'During the first several weeks of development, the cells of the endometrium—referred to as decidual cells—nourish the nascent embryo. During prenatal weeks 4–12, the developing placenta gradually takes over the role of feeding the embryo, and the decidual cells are no longer needed. The mature placenta is composed of tissues derived from the embryo, as well as maternal tissues of the endometrium. The placenta connects to the conceptus via the umbilical cord, which carries deoxygenated blood and wastes from the fetus through two umbilical arteries; nutrients and oxygen are carried from the mother to the fetus through the single umbilical vein. The umbilical cord is surrounded by the amnion, and the spaces within the cord around the blood vessels are filled with Wharton’s jelly, a mucous connective tissue.', '6523169d-b898-422d-912e-fc994fe7e79e': 'The maternal portion of the placenta develops from the deepest layer of the endometrium, the decidua basalis. To form the embryonic portion of the placenta, the syncytiotrophoblast and the underlying cells of the trophoblast (cytotrophoblast cells) begin to proliferate along with a layer of extraembryonic mesoderm cells. These form the chorionic membrane, which envelops the entire conceptus as the chorion. The chorionic membrane forms finger-like structures called chorionic villi that burrow into the endometrium like tree roots, making up the fetal portion of the placenta. The cytotrophoblast cells perforate the chorionic villi, burrow farther into the endometrium, and remodel maternal blood vessels to augment maternal blood flow surrounding the villi. Meanwhile, fetal mesenchymal cells derived from the mesoderm fill the villi and differentiate into blood vessels, including the three umbilical blood vessels that connect the embryo to the developing placenta (Figure 28.2.8).', '416948f9-3c5b-4354-876c-28ddaa2cf8b7': 'The placenta develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 14–16. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function (Table 28.1 and Figure 28.2.9). It receives blood from the fetus through the umbilical arteries. Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through the umbilical vein. Nutrients and oxygen are transferred from maternal blood surrounding the villi through the capillaries and into the fetal bloodstream. Some substances move across the placenta by simple diffusion. Oxygen, carbon dioxide, and any other lipid-soluble substances take this route. Other substances move across by facilitated diffusion. This includes water-soluble glucose. The fetus has a high demand for amino acids and iron, and those substances are moved across the placenta by active transport.', '2d40b12d-ef2c-4746-8dd9-0e95e71e2038': 'Maternal and fetal blood does not commingle because blood cells cannot move across the placenta. This separation prevents the mother’s cytotoxic T cells from reaching and subsequently destroying the fetus, which bears “non-self” antigens. Further, it ensures the fetal red blood cells do not enter the mother’s circulation and trigger antibody development (if they carry “non-self” antigens)—at least until the final stages of pregnancy or birth. This is the reason that, even in the absence of preventive treatment, an Rh− mother doesn’t develop antibodies that could cause hemolytic disease in her first Rh+ fetus.', 'c1be3a17-df5f-43b0-bd5f-3409d786e9ed': 'Although blood cells are not exchanged, the chorionic villi provide ample surface area for the two-way exchange of substances between maternal and fetal blood. The rate of exchange increases throughout gestation as the villi become thinner and increasingly branched. The placenta is permeable to lipid-soluble fetotoxic substances: alcohol, nicotine, barbiturates, antibiotics, certain pathogens, and many other substances that can be dangerous or fatal to the developing embryo or fetus. For these reasons, pregnant women should avoid fetotoxic substances. Alcohol consumption by pregnant women, for example, can result in a range of abnormalities referred to as fetal alcohol spectrum disorders (FASD). These include organ and facial malformations, as well as cognitive and behavioral disorders.'}"
+Figure 28.2.9,Anatomy_And_Physio/images/Figure 28.2.9.jpg,Figure 28.2.9 – Placenta: This post-expulsion placenta and umbilical cord (white) are viewed from the fetal side.,"The placenta develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 14–16. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function (Table 28.1 and Figure 28.2.9). It receives blood from the fetus through the umbilical arteries. Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through the umbilical vein. Nutrients and oxygen are transferred from maternal blood surrounding the villi through the capillaries and into the fetal bloodstream. Some substances move across the placenta by simple diffusion. Oxygen, carbon dioxide, and any other lipid-soluble substances take this route. Other substances move across by facilitated diffusion. This includes water-soluble glucose. The fetus has a high demand for amino acids and iron, and those substances are moved across the placenta by active transport.","{'5678e08a-b960-4410-a027-c99103de5d5f': 'During the first several weeks of development, the cells of the endometrium—referred to as decidual cells—nourish the nascent embryo. During prenatal weeks 4–12, the developing placenta gradually takes over the role of feeding the embryo, and the decidual cells are no longer needed. The mature placenta is composed of tissues derived from the embryo, as well as maternal tissues of the endometrium. The placenta connects to the conceptus via the umbilical cord, which carries deoxygenated blood and wastes from the fetus through two umbilical arteries; nutrients and oxygen are carried from the mother to the fetus through the single umbilical vein. The umbilical cord is surrounded by the amnion, and the spaces within the cord around the blood vessels are filled with Wharton’s jelly, a mucous connective tissue.', '6523169d-b898-422d-912e-fc994fe7e79e': 'The maternal portion of the placenta develops from the deepest layer of the endometrium, the decidua basalis. To form the embryonic portion of the placenta, the syncytiotrophoblast and the underlying cells of the trophoblast (cytotrophoblast cells) begin to proliferate along with a layer of extraembryonic mesoderm cells. These form the chorionic membrane, which envelops the entire conceptus as the chorion. The chorionic membrane forms finger-like structures called chorionic villi that burrow into the endometrium like tree roots, making up the fetal portion of the placenta. The cytotrophoblast cells perforate the chorionic villi, burrow farther into the endometrium, and remodel maternal blood vessels to augment maternal blood flow surrounding the villi. Meanwhile, fetal mesenchymal cells derived from the mesoderm fill the villi and differentiate into blood vessels, including the three umbilical blood vessels that connect the embryo to the developing placenta (Figure 28.2.8).', '416948f9-3c5b-4354-876c-28ddaa2cf8b7': 'The placenta develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 14–16. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function (Table 28.1 and Figure 28.2.9). It receives blood from the fetus through the umbilical arteries. Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through the umbilical vein. Nutrients and oxygen are transferred from maternal blood surrounding the villi through the capillaries and into the fetal bloodstream. Some substances move across the placenta by simple diffusion. Oxygen, carbon dioxide, and any other lipid-soluble substances take this route. Other substances move across by facilitated diffusion. This includes water-soluble glucose. The fetus has a high demand for amino acids and iron, and those substances are moved across the placenta by active transport.', '2d40b12d-ef2c-4746-8dd9-0e95e71e2038': 'Maternal and fetal blood does not commingle because blood cells cannot move across the placenta. This separation prevents the mother’s cytotoxic T cells from reaching and subsequently destroying the fetus, which bears “non-self” antigens. Further, it ensures the fetal red blood cells do not enter the mother’s circulation and trigger antibody development (if they carry “non-self” antigens)—at least until the final stages of pregnancy or birth. This is the reason that, even in the absence of preventive treatment, an Rh− mother doesn’t develop antibodies that could cause hemolytic disease in her first Rh+ fetus.', 'c1be3a17-df5f-43b0-bd5f-3409d786e9ed': 'Although blood cells are not exchanged, the chorionic villi provide ample surface area for the two-way exchange of substances between maternal and fetal blood. The rate of exchange increases throughout gestation as the villi become thinner and increasingly branched. The placenta is permeable to lipid-soluble fetotoxic substances: alcohol, nicotine, barbiturates, antibiotics, certain pathogens, and many other substances that can be dangerous or fatal to the developing embryo or fetus. For these reasons, pregnant women should avoid fetotoxic substances. Alcohol consumption by pregnant women, for example, can result in a range of abnormalities referred to as fetal alcohol spectrum disorders (FASD). These include organ and facial malformations, as well as cognitive and behavioral disorders.'}"
+Figure 28.2.10,Anatomy_And_Physio/images/Figure 28.2.10.jpg,Figure 28.2.10 – Neurulation: The embryonic process of neurulation establishes the rudiments of the future central nervous system and skeleton.,"Following gastrulation, rudiments of the central nervous system develop from the ectoderm in the process of neurulation (Figure 28.2.10). Specialized neuroectodermal tissues along the length of the embryo thicken into the neural plate. During the fourth week, tissues on either side of the plate fold upward into a neural fold. The two folds converge to form the neural tube. The tube lies atop a rod-shaped, mesoderm-derived notochord, which eventually becomes the nucleus pulposus of intervertebral discs. Block-like structures called somites form on either side of the tube, eventually differentiating into the axial skeleton, skeletal muscle, and dermis. During the fourth and fifth weeks, the anterior neural tube dilates and subdivides to form vesicles that will become the brain structures.","{'6dd61c10-7885-4d10-9517-c991b087395c': 'Following gastrulation, rudiments of the central nervous system develop from the ectoderm in the process of neurulation (Figure 28.2.10). Specialized neuroectodermal tissues along the length of the embryo thicken into the neural plate. During the fourth week, tissues on either side of the plate fold upward into a neural fold. The two folds converge to form the neural tube. The tube lies atop a rod-shaped, mesoderm-derived notochord, which eventually becomes the nucleus pulposus of intervertebral discs. Block-like structures called somites form on either side of the tube, eventually differentiating into the axial skeleton, skeletal muscle, and dermis. During the fourth and fifth weeks, the anterior neural tube dilates and subdivides to form vesicles that will become the brain structures.', '641ecb87-40e7-4621-a83f-a634b2cd4426': 'Folate, one of the B vitamins, is important to the healthy development of the neural tube. A deficiency of maternal folate in the first weeks of pregnancy can result in neural tube defects, including spina bifida—a birth defect in which spinal tissue protrudes through the newborn’s vertebral column, which has failed to completely close. A more severe neural tube defect is anencephaly, a partial or complete absence of brain tissue.', '3b8c5963-dba3-4d33-be33-f58f6f00b883': 'The embryo, which begins as a flat sheet of cells, begins to acquire a cylindrical shape through the process of embryonic folding (Figure 28.2.11). The embryo folds laterally and again at either end, forming a C-shape with distinct head and tail ends. The embryo envelops a portion of the yolk sac, which protrudes with the umbilical cord from what will become the abdomen. The folding essentially creates a tube, called the primitive gut, that is lined by the endoderm. The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.', '9ca108ee-bcb2-4e9b-814f-7dcf40437f4c': 'Within the first 8 weeks of gestation, a developing embryo establishes the rudimentary structures of all of its organs and tissues from the ectoderm, mesoderm, and endoderm. This process is called organogenesis.', 'd8382eb1-3bd2-4699-8d42-2386f3c7f3d4': 'Like the central nervous system, the heart also begins its development in the embryo as a tube-like structure, connected via capillaries to the chorionic villi. Cells of the primitive tube-shaped heart are capable of electrical conduction and contraction. The heart begins beating in the beginning of the fourth week, although it does not actually pump embryonic blood until a week later, when the oversized liver has begun producing red blood cells. (This is a temporary responsibility of the embryonic liver that the bone marrow will assume during fetal development.) During weeks 4–5, the eye pits form, limb buds become apparent, and the rudiments of the pulmonary system are formed.', 'b9533943-beca-40e1-8306-67a16cadee23': 'During the sixth week, uncontrolled fetal limb movements begin to occur. The gastrointestinal system develops too rapidly for the embryonic abdomen to accommodate it, and the intestines temporarily loop into the umbilical cord. Paddle-shaped hands and feet develop fingers and toes by the process of apoptosis (programmed cell death), which causes the tissues between the fingers to disintegrate. By week 7, the facial structure is more complex and includes nostrils, outer ears, and lenses (Figure 28.2.12). By the eighth week, the head is nearly as large as the rest of the embryo’s body, and all major brain structures are in place. The external genitalia are apparent, but at this point, male and female embryos are indistinguishable. Bone begins to replace cartilage in the embryonic skeleton through the process of ossification. By the end of the embryonic period, the embryo is approximately 3 cm (1.2 in) from crown to rump and weighs approximately 8 g (0.25 oz).', '8d47225a-c2de-4c68-9e97-80ca31631b40': 'Fertilization occurs when a sperm and an oocyte (egg) combine and their nuclei fuse. Because each of these reproductive cells is a haploid cell containing half of the genetic material needed to form a human being, their combination forms a diploid cell. This new single cell, called a zygote, contains all of the genetic material needed to form a human—half from the mother and half from the father.'}"
+Figure 28.2.11,Anatomy_And_Physio/images/Figure 28.2.11.jpg,"Figure 28.2.11 – Embryonic Folding: Embryonic folding converts a flat sheet of cells into a hollow, tube-like structure.","The embryo, which begins as a flat sheet of cells, begins to acquire a cylindrical shape through the process of embryonic folding (Figure 28.2.11). The embryo folds laterally and again at either end, forming a C-shape with distinct head and tail ends. The embryo envelops a portion of the yolk sac, which protrudes with the umbilical cord from what will become the abdomen. The folding essentially creates a tube, called the primitive gut, that is lined by the endoderm. The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.","{'6dd61c10-7885-4d10-9517-c991b087395c': 'Following gastrulation, rudiments of the central nervous system develop from the ectoderm in the process of neurulation (Figure 28.2.10). Specialized neuroectodermal tissues along the length of the embryo thicken into the neural plate. During the fourth week, tissues on either side of the plate fold upward into a neural fold. The two folds converge to form the neural tube. The tube lies atop a rod-shaped, mesoderm-derived notochord, which eventually becomes the nucleus pulposus of intervertebral discs. Block-like structures called somites form on either side of the tube, eventually differentiating into the axial skeleton, skeletal muscle, and dermis. During the fourth and fifth weeks, the anterior neural tube dilates and subdivides to form vesicles that will become the brain structures.', '641ecb87-40e7-4621-a83f-a634b2cd4426': 'Folate, one of the B vitamins, is important to the healthy development of the neural tube. A deficiency of maternal folate in the first weeks of pregnancy can result in neural tube defects, including spina bifida—a birth defect in which spinal tissue protrudes through the newborn’s vertebral column, which has failed to completely close. A more severe neural tube defect is anencephaly, a partial or complete absence of brain tissue.', '3b8c5963-dba3-4d33-be33-f58f6f00b883': 'The embryo, which begins as a flat sheet of cells, begins to acquire a cylindrical shape through the process of embryonic folding (Figure 28.2.11). The embryo folds laterally and again at either end, forming a C-shape with distinct head and tail ends. The embryo envelops a portion of the yolk sac, which protrudes with the umbilical cord from what will become the abdomen. The folding essentially creates a tube, called the primitive gut, that is lined by the endoderm. The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.', '9ca108ee-bcb2-4e9b-814f-7dcf40437f4c': 'Within the first 8 weeks of gestation, a developing embryo establishes the rudimentary structures of all of its organs and tissues from the ectoderm, mesoderm, and endoderm. This process is called organogenesis.', 'd8382eb1-3bd2-4699-8d42-2386f3c7f3d4': 'Like the central nervous system, the heart also begins its development in the embryo as a tube-like structure, connected via capillaries to the chorionic villi. Cells of the primitive tube-shaped heart are capable of electrical conduction and contraction. The heart begins beating in the beginning of the fourth week, although it does not actually pump embryonic blood until a week later, when the oversized liver has begun producing red blood cells. (This is a temporary responsibility of the embryonic liver that the bone marrow will assume during fetal development.) During weeks 4–5, the eye pits form, limb buds become apparent, and the rudiments of the pulmonary system are formed.', 'b9533943-beca-40e1-8306-67a16cadee23': 'During the sixth week, uncontrolled fetal limb movements begin to occur. The gastrointestinal system develops too rapidly for the embryonic abdomen to accommodate it, and the intestines temporarily loop into the umbilical cord. Paddle-shaped hands and feet develop fingers and toes by the process of apoptosis (programmed cell death), which causes the tissues between the fingers to disintegrate. By week 7, the facial structure is more complex and includes nostrils, outer ears, and lenses (Figure 28.2.12). By the eighth week, the head is nearly as large as the rest of the embryo’s body, and all major brain structures are in place. The external genitalia are apparent, but at this point, male and female embryos are indistinguishable. Bone begins to replace cartilage in the embryonic skeleton through the process of ossification. By the end of the embryonic period, the embryo is approximately 3 cm (1.2 in) from crown to rump and weighs approximately 8 g (0.25 oz).', '8d47225a-c2de-4c68-9e97-80ca31631b40': 'Fertilization occurs when a sperm and an oocyte (egg) combine and their nuclei fuse. Because each of these reproductive cells is a haploid cell containing half of the genetic material needed to form a human being, their combination forms a diploid cell. This new single cell, called a zygote, contains all of the genetic material needed to form a human—half from the mother and half from the father.'}"
+Figure 28.2.12,Anatomy_And_Physio/images/Figure 28.2.12.jpg,"Figure 28.2.12 – Embryo at 7 Weeks: An embryo at the end of 7 weeks of development is only 10 mm in length, but its developing eyes, limb buds, and tail are already visible. (This embryo was derived from an ectopic pregnancy.) (credit: Ed Uthman)","During the sixth week, uncontrolled fetal limb movements begin to occur. The gastrointestinal system develops too rapidly for the embryonic abdomen to accommodate it, and the intestines temporarily loop into the umbilical cord. Paddle-shaped hands and feet develop fingers and toes by the process of apoptosis (programmed cell death), which causes the tissues between the fingers to disintegrate. By week 7, the facial structure is more complex and includes nostrils, outer ears, and lenses (Figure 28.2.12). By the eighth week, the head is nearly as large as the rest of the embryo’s body, and all major brain structures are in place. The external genitalia are apparent, but at this point, male and female embryos are indistinguishable. Bone begins to replace cartilage in the embryonic skeleton through the process of ossification. By the end of the embryonic period, the embryo is approximately 3 cm (1.2 in) from crown to rump and weighs approximately 8 g (0.25 oz).","{'6dd61c10-7885-4d10-9517-c991b087395c': 'Following gastrulation, rudiments of the central nervous system develop from the ectoderm in the process of neurulation (Figure 28.2.10). Specialized neuroectodermal tissues along the length of the embryo thicken into the neural plate. During the fourth week, tissues on either side of the plate fold upward into a neural fold. The two folds converge to form the neural tube. The tube lies atop a rod-shaped, mesoderm-derived notochord, which eventually becomes the nucleus pulposus of intervertebral discs. Block-like structures called somites form on either side of the tube, eventually differentiating into the axial skeleton, skeletal muscle, and dermis. During the fourth and fifth weeks, the anterior neural tube dilates and subdivides to form vesicles that will become the brain structures.', '641ecb87-40e7-4621-a83f-a634b2cd4426': 'Folate, one of the B vitamins, is important to the healthy development of the neural tube. A deficiency of maternal folate in the first weeks of pregnancy can result in neural tube defects, including spina bifida—a birth defect in which spinal tissue protrudes through the newborn’s vertebral column, which has failed to completely close. A more severe neural tube defect is anencephaly, a partial or complete absence of brain tissue.', '3b8c5963-dba3-4d33-be33-f58f6f00b883': 'The embryo, which begins as a flat sheet of cells, begins to acquire a cylindrical shape through the process of embryonic folding (Figure 28.2.11). The embryo folds laterally and again at either end, forming a C-shape with distinct head and tail ends. The embryo envelops a portion of the yolk sac, which protrudes with the umbilical cord from what will become the abdomen. The folding essentially creates a tube, called the primitive gut, that is lined by the endoderm. The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.', '9ca108ee-bcb2-4e9b-814f-7dcf40437f4c': 'Within the first 8 weeks of gestation, a developing embryo establishes the rudimentary structures of all of its organs and tissues from the ectoderm, mesoderm, and endoderm. This process is called organogenesis.', 'd8382eb1-3bd2-4699-8d42-2386f3c7f3d4': 'Like the central nervous system, the heart also begins its development in the embryo as a tube-like structure, connected via capillaries to the chorionic villi. Cells of the primitive tube-shaped heart are capable of electrical conduction and contraction. The heart begins beating in the beginning of the fourth week, although it does not actually pump embryonic blood until a week later, when the oversized liver has begun producing red blood cells. (This is a temporary responsibility of the embryonic liver that the bone marrow will assume during fetal development.) During weeks 4–5, the eye pits form, limb buds become apparent, and the rudiments of the pulmonary system are formed.', 'b9533943-beca-40e1-8306-67a16cadee23': 'During the sixth week, uncontrolled fetal limb movements begin to occur. The gastrointestinal system develops too rapidly for the embryonic abdomen to accommodate it, and the intestines temporarily loop into the umbilical cord. Paddle-shaped hands and feet develop fingers and toes by the process of apoptosis (programmed cell death), which causes the tissues between the fingers to disintegrate. By week 7, the facial structure is more complex and includes nostrils, outer ears, and lenses (Figure 28.2.12). By the eighth week, the head is nearly as large as the rest of the embryo’s body, and all major brain structures are in place. The external genitalia are apparent, but at this point, male and female embryos are indistinguishable. Bone begins to replace cartilage in the embryonic skeleton through the process of ossification. By the end of the embryonic period, the embryo is approximately 3 cm (1.2 in) from crown to rump and weighs approximately 8 g (0.25 oz).', '8d47225a-c2de-4c68-9e97-80ca31631b40': 'Fertilization occurs when a sperm and an oocyte (egg) combine and their nuclei fuse. Because each of these reproductive cells is a haploid cell containing half of the genetic material needed to form a human being, their combination forms a diploid cell. This new single cell, called a zygote, contains all of the genetic material needed to form a human—half from the mother and half from the father.'}"
+Figure 28.1.1,Anatomy_And_Physio/images/Figure 28.1.1.jpg,"Figure 28.1.1 – Sperm and the Process of Fertilization: Before fertilization, hundreds of capacitated sperm must break through the surrounding corona radiata and zona pellucida so that one can contact and fuse with the oocyte plasma membrane.","As it is swept along the distal uterine tube, the oocyte encounters the surviving capacitated sperm, which stream toward it in response to chemical attractants released by the cells of the corona radiata. To reach the oocyte itself, the sperm must penetrate the two protective layers. The sperm first burrow through the cells of the corona radiata. Then, upon contact with the zona pellucida, the sperm bind to receptors in the zona pellucida. This initiates a process called the acrosomal reaction in which the enzyme-filled “cap” of the sperm, called the acrosome, releases its stored digestive enzymes. These enzymes clear a path through the zona pellucida that allows sperm to reach the oocyte. Finally, a single sperm makes contact with sperm-binding receptors on the oocyte’s plasma membrane (Figure 28.1.1). The plasma membrane of that sperm then fuses with the oocyte’s plasma membrane, and the head and mid-piece of the “winning” sperm enter the oocyte interior.","{'4a4982cf-98af-4f01-b99a-9e73cfb949c4': 'Upon ovulation, the oocyte released by the ovary is swept into—and along—the uterine tube. Fertilization must occur in the distal uterine tube because an unfertilized oocyte cannot survive the 72-hour journey to the uterus. As you will recall from your study of the oogenesis, this oocyte (specifically a secondary oocyte) is surrounded by two protective layers. The corona radiata is an outer layer of follicular (granulosa) cells that form around a developing oocyte in the ovary and remain with it upon ovulation. The underlying zona pellucida (pellucid = “transparent”) is a transparent, but thick, glycoprotein membrane that surrounds the cell’s plasma membrane.', '380035c5-d8fb-4014-9c87-31f6b1cd1515': 'As it is swept along the distal uterine tube, the oocyte encounters the surviving capacitated sperm, which stream toward it in response to chemical attractants released by the cells of the corona radiata. To reach the oocyte itself, the sperm must penetrate the two protective layers. The sperm first burrow through the cells of the corona radiata. Then, upon contact with the zona pellucida, the sperm bind to receptors in the zona pellucida. This initiates a process called the acrosomal reaction in which the enzyme-filled “cap” of the sperm, called the acrosome, releases its stored digestive enzymes. These enzymes clear a path through the zona pellucida that allows sperm to reach the oocyte. Finally, a single sperm makes contact with sperm-binding receptors on the oocyte’s plasma membrane (Figure 28.1.1). The plasma membrane of that sperm then fuses with the oocyte’s plasma membrane, and the head and mid-piece of the “winning” sperm enter the oocyte interior.', 'f4bb0e66-dfd7-44a6-bb52-2e130b740d71': 'How do sperm penetrate the corona radiata? Some sperm undergo a spontaneous acrosomal reaction, which is an acrosomal reaction not triggered by contact with the zona pellucida. The digestive enzymes released by this reaction digest the extracellular matrix of the corona radiata. As you can see, the first sperm to reach the oocyte is never the one to fertilize it. Rather, hundreds of sperm cells must undergo the acrosomal reaction, each helping to degrade the corona radiata and zona pellucida until a path is created to allow one sperm to contact and fuse with the plasma membrane of the oocyte. If you consider the loss of millions of sperm between entry into the vagina and degradation of the zona pellucida, you can understand why a low sperm count can cause male infertility.', '437e1bdf-fe0f-444e-90d4-c299a68ffe70': 'When the first sperm fuses with the oocyte, the oocyte deploys two mechanisms to prevent polyspermy, which is penetration by more than one sperm. This is critical because if more than one sperm were to fertilize the oocyte, the resulting zygote would be a triploid organism with three sets of chromosomes. This is incompatible with life.', 'f8fcd7b7-cba8-4b28-8707-1652faf53736': 'The first mechanism is the fast block, which involves a near instantaneous change in sodium ion permeability upon binding of the first sperm, depolarizing the oocyte plasma membrane and preventing the fusion of additional sperm cells. The fast block sets in almost immediately and lasts for about a minute, during which time an influx of calcium ions following sperm penetration triggers the second mechanism, the slow block. In this process, referred to as the cortical reaction, cortical granules sitting immediately below the oocyte plasma membrane fuse with the membrane and release zonal inhibiting proteins and mucopolysaccharides into the space between the plasma membrane and the zona pellucida. Zonal inhibiting proteins cause the release of any other attached sperm and destroy the oocyte’s sperm receptors, thus preventing any more sperm from binding. The mucopolysaccharides then coat the nascent zygote in an impenetrable barrier that, together with hardened zona pellucida, is called a fertilization membrane.'}"
+Figure 27.3.1,Anatomy_And_Physio/images/Figure 27.3.1.jpg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell.","Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.3.1). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.","{'c6889883-80f0-43c9-a12e-cc13a1d4b25e': 'Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.3.1). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.', 'f4aaa073-841b-45e5-9738-ab323a2d0995': 'The initiation of ovulation—the release of an oocyte from the ovary—marks the transition from puberty into reproductive maturity for women. From then on, throughout a woman’s reproductive years, ovulation occurs approximately once every 28 days. Just prior to ovulation, a surge of luteinizing hormone triggers the resumption of meiosis in a primary oocyte. This initiates the transition from primary to secondary oocyte. However, as you can see in Figure 27.3.1, this cell division does not result in two identical cells. Instead, the cytoplasm is divided unequally, and one daughter cell is much larger than the other. This larger cell, the secondary oocyte, eventually leaves the ovary during ovulation. The smaller cell, called the first polar body, may or may not complete meiosis and produce second polar bodies; in either case, it eventually disintegrates. Therefore, even though oogenesis produces up to four cells, only one survives.', '62fdbda1-a61a-470d-8a14-daa0061ddea7': 'How does the diploid secondary oocyte become an ovum—the haploid female gamete? Meiosis of a secondary oocyte is completed only if a sperm succeeds in penetrating its barriers. Meiosis II then resumes, producing one haploid ovum that, at the instant of fertilization by a (haploid) sperm, becomes the first diploid cell of the new offspring (a zygote). Thus, the ovum can be thought of as a brief, transitional, haploid stage between the diploid oocyte and diploid zygote.', '9822c351-b067-4af4-a12c-d2070c293b0d': 'The larger amount of cytoplasm contained in the female gamete is used to supply the developing zygote with nutrients during the period between fertilization and implantation into the uterus. Interestingly, sperm contribute only DNA at fertilization —not cytoplasm. Therefore, the cytoplasm and all of the cytoplasmic organelles in the developing embryo are of maternal origin. This includes mitochondria, which contain their own DNA. Scientific research in the 1980s determined that mitochondrial DNA was maternally inherited, meaning that you can trace your mitochondrial DNA directly to your mother, her mother, and so on back through your female ancestors.'}"
+Figure 27.3.1,Anatomy_And_Physio/images/Figure 27.3.1.jpg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell.","Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.3.1). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.","{'c6889883-80f0-43c9-a12e-cc13a1d4b25e': 'Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.3.1). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.', 'f4aaa073-841b-45e5-9738-ab323a2d0995': 'The initiation of ovulation—the release of an oocyte from the ovary—marks the transition from puberty into reproductive maturity for women. From then on, throughout a woman’s reproductive years, ovulation occurs approximately once every 28 days. Just prior to ovulation, a surge of luteinizing hormone triggers the resumption of meiosis in a primary oocyte. This initiates the transition from primary to secondary oocyte. However, as you can see in Figure 27.3.1, this cell division does not result in two identical cells. Instead, the cytoplasm is divided unequally, and one daughter cell is much larger than the other. This larger cell, the secondary oocyte, eventually leaves the ovary during ovulation. The smaller cell, called the first polar body, may or may not complete meiosis and produce second polar bodies; in either case, it eventually disintegrates. Therefore, even though oogenesis produces up to four cells, only one survives.', '62fdbda1-a61a-470d-8a14-daa0061ddea7': 'How does the diploid secondary oocyte become an ovum—the haploid female gamete? Meiosis of a secondary oocyte is completed only if a sperm succeeds in penetrating its barriers. Meiosis II then resumes, producing one haploid ovum that, at the instant of fertilization by a (haploid) sperm, becomes the first diploid cell of the new offspring (a zygote). Thus, the ovum can be thought of as a brief, transitional, haploid stage between the diploid oocyte and diploid zygote.', '9822c351-b067-4af4-a12c-d2070c293b0d': 'The larger amount of cytoplasm contained in the female gamete is used to supply the developing zygote with nutrients during the period between fertilization and implantation into the uterus. Interestingly, sperm contribute only DNA at fertilization —not cytoplasm. Therefore, the cytoplasm and all of the cytoplasmic organelles in the developing embryo are of maternal origin. This includes mitochondria, which contain their own DNA. Scientific research in the 1980s determined that mitochondrial DNA was maternally inherited, meaning that you can trace your mitochondrial DNA directly to your mother, her mother, and so on back through your female ancestors.'}"
+Figure 27.3.2,Anatomy_And_Physio/images/Figure 27.3.2.jpg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.","{'9ef0eeb0-668d-4a09-baaa-cb187b8000b1': 'Again, ovarian follicles are oocytes and their supporting cells. They grow and develop in a process called folliculogenesis, which typically leads to ovulation of one follicle approximately every 28 days, along with death to multiple other follicles. The death of ovarian follicles is called atresia, and can occur at any point during follicular development. Recall that, a female infant at birth will have one to two million oocytes within her ovarian follicles, and that this number declines throughout life until menopause, when no follicles remain. As you’ll see next, follicles progress from primordial, to primary, to secondary and tertiary stages prior to ovulation—with the oocyte inside the follicle remaining as a primary oocyte until right before ovulation.', 'ef635e06-6087-4afa-a616-47c5e774518d': 'Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.', 'ef0873de-b183-4660-ae4f-963ab1f2d8a1': 'After puberty, a few primordial follicles will respond to a recruitment signal each day, and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles—now called secondary follicles (see Figure 27.3.2)—increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells—cells that work with the granulosa cells to produce estrogens.', '5fd9f857-78d2-40d4-a6a7-da7b47fb86c6': 'Within the growing secondary follicle, the primary oocyte now secretes a thin acellular membrane called the zona pellucida that will play a critical role in fertilization. A thick fluid, called follicular fluid, that has formed between the granulosa cells also begins to collect into one large pool, or antrum. Follicles in which the antrum has become large and fully formed are considered tertiary follicles (or antral follicles). Several follicles reach the tertiary stage at the same time, and most of these will undergo atresia. The one that does not die will continue to grow and develop until ovulation, when it will expel its secondary oocyte surrounded by several layers of granulosa cells from the ovary. Keep in mind that most follicles don’t make it to this point. In fact, roughly 99 percent of the follicles in the ovary will undergo atresia, which can occur at any stage of folliculogenesis.', '090d8717-063f-491c-8012-3ba00d403013': 'The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.', '6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce': 'As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.', '202e961d-d3d9-4827-b87f-cbd77e344647': 'The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.', 'b5f7bbfe-c23e-4805-b286-ae9832497d8c': 'When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.', '7e248393-a8b1-4449-95f5-2db20d4dc4c4': 'It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.', 'e3fb9b5a-de8b-402e-8728-0d2993bd6050': 'In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.', '9c5b9b26-24e4-4d8c-8e29-210a4f18238c': 'The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.'}"
+Figure 27.3.2,Anatomy_And_Physio/images/Figure 27.3.2.jpg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.","{'9ef0eeb0-668d-4a09-baaa-cb187b8000b1': 'Again, ovarian follicles are oocytes and their supporting cells. They grow and develop in a process called folliculogenesis, which typically leads to ovulation of one follicle approximately every 28 days, along with death to multiple other follicles. The death of ovarian follicles is called atresia, and can occur at any point during follicular development. Recall that, a female infant at birth will have one to two million oocytes within her ovarian follicles, and that this number declines throughout life until menopause, when no follicles remain. As you’ll see next, follicles progress from primordial, to primary, to secondary and tertiary stages prior to ovulation—with the oocyte inside the follicle remaining as a primary oocyte until right before ovulation.', 'ef635e06-6087-4afa-a616-47c5e774518d': 'Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.', 'ef0873de-b183-4660-ae4f-963ab1f2d8a1': 'After puberty, a few primordial follicles will respond to a recruitment signal each day, and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles—now called secondary follicles (see Figure 27.3.2)—increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells—cells that work with the granulosa cells to produce estrogens.', '5fd9f857-78d2-40d4-a6a7-da7b47fb86c6': 'Within the growing secondary follicle, the primary oocyte now secretes a thin acellular membrane called the zona pellucida that will play a critical role in fertilization. A thick fluid, called follicular fluid, that has formed between the granulosa cells also begins to collect into one large pool, or antrum. Follicles in which the antrum has become large and fully formed are considered tertiary follicles (or antral follicles). Several follicles reach the tertiary stage at the same time, and most of these will undergo atresia. The one that does not die will continue to grow and develop until ovulation, when it will expel its secondary oocyte surrounded by several layers of granulosa cells from the ovary. Keep in mind that most follicles don’t make it to this point. In fact, roughly 99 percent of the follicles in the ovary will undergo atresia, which can occur at any stage of folliculogenesis.', '090d8717-063f-491c-8012-3ba00d403013': 'The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.', '6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce': 'As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.', '202e961d-d3d9-4827-b87f-cbd77e344647': 'The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.', 'b5f7bbfe-c23e-4805-b286-ae9832497d8c': 'When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.', '7e248393-a8b1-4449-95f5-2db20d4dc4c4': 'It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.', 'e3fb9b5a-de8b-402e-8728-0d2993bd6050': 'In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.', '9c5b9b26-24e4-4d8c-8e29-210a4f18238c': 'The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.'}"
+Figure 27.3.3,Anatomy_And_Physio/images/Figure 27.3.3.jpg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries.","As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.","{'090d8717-063f-491c-8012-3ba00d403013': 'The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.', '6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce': 'As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.', '202e961d-d3d9-4827-b87f-cbd77e344647': 'The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.', 'b5f7bbfe-c23e-4805-b286-ae9832497d8c': 'When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.', '7e248393-a8b1-4449-95f5-2db20d4dc4c4': 'It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.', 'e3fb9b5a-de8b-402e-8728-0d2993bd6050': 'In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.', '9c5b9b26-24e4-4d8c-8e29-210a4f18238c': 'The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.'}"
+Figure 27.3.3,Anatomy_And_Physio/images/Figure 27.3.3.jpg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries.","As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.","{'090d8717-063f-491c-8012-3ba00d403013': 'The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.', '6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce': 'As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.', '202e961d-d3d9-4827-b87f-cbd77e344647': 'The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.', 'b5f7bbfe-c23e-4805-b286-ae9832497d8c': 'When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.', '7e248393-a8b1-4449-95f5-2db20d4dc4c4': 'It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.', 'e3fb9b5a-de8b-402e-8728-0d2993bd6050': 'In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.', '9c5b9b26-24e4-4d8c-8e29-210a4f18238c': 'The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.'}"
+Figure 27.3.2,Anatomy_And_Physio/images/Figure 27.3.2.jpg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.","{'9ef0eeb0-668d-4a09-baaa-cb187b8000b1': 'Again, ovarian follicles are oocytes and their supporting cells. They grow and develop in a process called folliculogenesis, which typically leads to ovulation of one follicle approximately every 28 days, along with death to multiple other follicles. The death of ovarian follicles is called atresia, and can occur at any point during follicular development. Recall that, a female infant at birth will have one to two million oocytes within her ovarian follicles, and that this number declines throughout life until menopause, when no follicles remain. As you’ll see next, follicles progress from primordial, to primary, to secondary and tertiary stages prior to ovulation—with the oocyte inside the follicle remaining as a primary oocyte until right before ovulation.', 'ef635e06-6087-4afa-a616-47c5e774518d': 'Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.', 'ef0873de-b183-4660-ae4f-963ab1f2d8a1': 'After puberty, a few primordial follicles will respond to a recruitment signal each day, and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles—now called secondary follicles (see Figure 27.3.2)—increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells—cells that work with the granulosa cells to produce estrogens.', '5fd9f857-78d2-40d4-a6a7-da7b47fb86c6': 'Within the growing secondary follicle, the primary oocyte now secretes a thin acellular membrane called the zona pellucida that will play a critical role in fertilization. A thick fluid, called follicular fluid, that has formed between the granulosa cells also begins to collect into one large pool, or antrum. Follicles in which the antrum has become large and fully formed are considered tertiary follicles (or antral follicles). Several follicles reach the tertiary stage at the same time, and most of these will undergo atresia. The one that does not die will continue to grow and develop until ovulation, when it will expel its secondary oocyte surrounded by several layers of granulosa cells from the ovary. Keep in mind that most follicles don’t make it to this point. In fact, roughly 99 percent of the follicles in the ovary will undergo atresia, which can occur at any stage of folliculogenesis.', '090d8717-063f-491c-8012-3ba00d403013': 'The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.', '6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce': 'As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.', '202e961d-d3d9-4827-b87f-cbd77e344647': 'The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.', 'b5f7bbfe-c23e-4805-b286-ae9832497d8c': 'When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.', '7e248393-a8b1-4449-95f5-2db20d4dc4c4': 'It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.', 'e3fb9b5a-de8b-402e-8728-0d2993bd6050': 'In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.', '9c5b9b26-24e4-4d8c-8e29-210a4f18238c': 'The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.'}"
+Figure 27.2.1,Anatomy_And_Physio/images/Figure 27.2.1.jpg,"Figure 27.2.1 – Hormones of Puberty: During puberty, the release of LH and FSH from the anterior pituitary stimulates the gonads to produce sex hormones in adolescents","Puberty is the stage of development at which individuals become sexually mature. As shown in Figure 27.2.1, a concerted release of hormones from the hypothalamus (GnRH), the anterior pituitary (LH and FSH), and the gonads (either testosterone or estrogen) is responsible for the maturation of the reproductive systems and the development of secondary sex characteristics, which are physical changes in the body.","{'108efd25-0f66-451b-8ed6-cd098f9b3640': 'Puberty is the stage of development at which individuals become sexually mature. As shown in Figure 27.2.1, a concerted release of hormones from the hypothalamus (GnRH), the anterior pituitary (LH and FSH), and the gonads (either testosterone or estrogen) is responsible for the maturation of the reproductive systems and the development of secondary sex characteristics, which are physical changes in the body.', 'cffded30-290b-4208-9147-310f21454ec5': 'The first changes begin around the age of eight or nine when the production of LH becomes detectable. The release of LH occurs primarily at night during sleep and precedes the physical changes of puberty by several years. In pre-pubescent children, the sensitivity of the negative feedback system in the hypothalamus and pituitary is very high. This means that very low concentrations of androgens or estrogens will negatively feed back onto the hypothalamus and pituitary, keeping the production of GnRH, LH, and FSH low.', '9b5b2adc-c976-4e04-8130-9b04717446c5': 'As an individual approaches puberty, two changes in sensitivity occur. The first is a decrease of sensitivity in the hypothalamus and pituitary to negative feedback, meaning that it takes increasingly larger concentrations of sex steroid hormones to stop the production of LH and FSH. The second change in sensitivity is an increase in sensitivity of the gonads to the FSH and LH signals, meaning the gonads of adults are more responsive to gonadotropins than are the gonads of children. Because of these two changes, the levels of LH and FSH slowly increase and lead to the enlargement and maturation of the gonads, which in turn leads to secretion of higher levels of sex hormones and the initiation of spermatogenesis and folliculogenesis.', 'ccf7627a-935a-45b3-acd1-b05d648a9382': 'In addition to age, multiple factors can affect the age of onset of puberty, including genetics, environment, and psychological stress. One of the more important influences may be nutrition; historical data demonstrate the effect of better and more consistent nutrition on the age of menarche in the United States, which decreased from an average age of approximately 17 years of age in 1860 to the current age of approximately 12.75 years in 1960, as it remains today. Some studies indicate a link between puberty onset and the amount of stored fat in an individual. This effect has been documented in both sexes. Body fat, corresponding with secretion of the hormone leptin by adipose cells, appears to have a strong role in determining menarche. This may reflect to some extent the high metabolic costs of gestation and lactation. In individuals who are lean and highly active, such as gymnasts, there is often a delay in the onset of puberty.'}"
+Figure 27.1.1,Anatomy_And_Physio/images/Figure 27.1.1.jpg,"Figure 27.1.1 – Vulva: The mons pubis, labia minora, labia majora and vestibule are referred to collectively as the vulva.","The mons pubis is a pad of fat that is located over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of pubic hair-covered skin that extend from the mons pubis to the perineal raphe – the region of skin between the vaginal opening and the anus. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) are medial to the labia majora.  The labia majora and minora naturally vary in shape and size from person to person, and left-right asymmetries are normal and expected. The vestibule is the region between the two labia minora. Therefore, the labia minora protect the mucous membranes and orifices of the urethra and vagina, found in the vestibule. The mons pubis, labia majora, labia minora and vestibule are collectively referred to as the vulva (Figure 27.1.1).","{'06223f44-08ca-4501-9cc2-4fb4fa621cba': 'Different sex steroid hormone concentrations also contribute to the development and function of secondary sexual characteristics. Examples of secondary sexual characteristics due to a predominance of testosterone or estrogen are listed in Table 27.1.', 'd55ba12c-c4f6-40e1-9db6-f679183cb603': 'An increased production of estrogen at puberty typically leads to the development of breast tissue. This is followed by the growth of axillary and pubic hair. A growth spurt typically starts at approximately age 9 to 11, and may last two years or more. During this time, an individual’s height can increase an average of 3 inches a year. The next step in puberty due to estrogen is menarche, the start of menstruation.', '3570cff1-b6b2-4b37-b5bf-8d5b7cb7ecd8': 'An increased production of testosterone leads to growth of the testes, typically the first physical sign of the beginning of puberty, which is followed by growth and pigmentation of the scrotum and growth of the penis. The next step is the growth of hair, including armpit, pubic, chest, and facial hair. Testosterone stimulates the growth of the larynx and thickening and lengthening of the vocal folds, which causes the voice to drop in pitch. The first fertile ejaculations typically appear at approximately 15 years of age, but this age can vary widely across individuals. The prostate normally doubles in size during puberty. A growth spurt occurs toward the end of puberty, at approximately age 11 to 13, and height can increase as much as 4 inches a year. In some individuals, pubertal development can continue through the early 20s.', 'dd636bcb-a9bb-41fb-882a-675fa384d8bc': 'In this section we describe the anatomy at either extreme of the spectrum of sexual anatomical variation. In section 27.2, we will describe the variations of sexual anatomy that occur which are not easily characterized by this binary system of male or female.', '613a9835-d799-4351-aa2c-4d0c5bc7abcc': 'The mons pubis is a pad of fat that is located over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of pubic hair-covered skin that extend from the mons pubis to the perineal raphe – the region of skin between the vaginal opening and the anus. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) are medial to the labia majora.\xa0 The labia majora and minora naturally vary in shape and size from person to person, and left-right asymmetries are normal and expected. The vestibule is the region between the two labia minora. Therefore, the labia minora protect the mucous membranes and orifices of the urethra and vagina, found in the vestibule. The mons pubis, labia majora, labia minora and vestibule are collectively referred to as the vulva (Figure 27.1.1).', 'e84d77e5-03f3-4a66-87d1-84eba1ce272b': 'The superior, anterior portions of the labia minora come together to meet the glans of the clitoris which has an extremely dense network of nerve endings. This is the portion of the clitoris that is partially covered by the prepuce (foreskin) of the clitoris. The clitoris also includes crura or legs (sing.: crus or leg) which are subcutaneous and extend inferiorly, following the contours of the pubic rami. The glans and crura are connected by the body of the clitoris. The glans, crura and body of the clirtoris are made up of corpus cavernosum erectile tissue. In contrast, the bulbs of the vestibule are corpus spongiosum erectile tissue. It is found medial to the crura of the clitoris and surrounds the vaginal and urethral orifices. The non-erect clitoris (including the superficial glans through to the end of the subcutaneous crura) has been recorded to be as long as 9 cm.'}"
+Figure 27.1.3,Anatomy_And_Physio/images/Figure 27.1.3.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity","The vagina (Figure 27.1.3) is a muscular canal (approximately 10 cm long) typically leading to the uterus.  The superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina. The vaginal opening is located between the opening of the urethra and the anus. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body. The opening between the hymen and the vaginal wall can change in size based on the degree in which the hymen is stretched. The membrane will decrease in size due to increased pressure.","{'e9f20932-831a-4d33-baa7-3aba3d0a52b6': 'The vagina (Figure 27.1.3) is a muscular canal (approximately 10 cm long) typically leading to the uterus.\xa0 The superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina. The vaginal opening is located between the opening of the urethra and the anus. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body. The opening between the hymen and the vaginal wall can change in size based on the degree in which the hymen is stretched. The membrane will decrease in size due to increased pressure.', 'b3890ef4-90a3-4b98-99e9-a7d73d27070a': 'The vagina is home to a normal population of microorganisms that help to protect against infection by pathogenic bacteria, yeast, or other organisms that can enter the vagina. In a healthy vagina, the most predominant type of bacteria is from the genus Lactobacillus. This family of beneficial bacterial flora secretes lactic acid, and thus protects the vagina by maintaining an acidic pH (below 4.5). Potential pathogens are less likely to survive in these acidic conditions. Lactic acid, in combination with other vaginal secretions, makes the vagina a self-cleansing organ. Douching (washing out the vagina with fluid) disrupts the normal balance of healthy microorganisms, and increases the risk for infections and irritation. Indeed, the American College of Obstetricians and Gynecologists recommends against douching, and instead recommends allowing the vagina to maintain its normal healthy population of protective microbial flora.', 'cecef381-3789-44fd-acbb-d68ebf70d4b3': 'The ovaries are the gonads (see Figure 27.1.3) located at the distal end of the uterine tubes, close to the fimbriae. They are each about 2 to 3 cm in length, about the size of an almond. The ovaries are supported by the mesovarium, a double fold of peritoneum that is part of the broad ligament. The suspensory ligament is the peritoneum that contains the ovarian blood and lymph vessels. The ovary itself is attached to the uterus via the ovarian ligament.', '8582cb0e-d2e2-4f07-9d31-c658a5f0e7ad': 'The ovary comprises an outer covering of cuboidal epithelium that is superficial to a dense connective tissue covering called the tunica albuginea. Beneath the tunica albuginea is the cortex, or outer portion, of the organ. The cortex is composed of a tissue framework called the ovarian stroma that forms the bulk of the adult ovary.'}"
+Figure 27.1.3,Anatomy_And_Physio/images/Figure 27.1.3.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity","The vagina (Figure 27.1.3) is a muscular canal (approximately 10 cm long) typically leading to the uterus.  The superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina. The vaginal opening is located between the opening of the urethra and the anus. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body. The opening between the hymen and the vaginal wall can change in size based on the degree in which the hymen is stretched. The membrane will decrease in size due to increased pressure.","{'e9f20932-831a-4d33-baa7-3aba3d0a52b6': 'The vagina (Figure 27.1.3) is a muscular canal (approximately 10 cm long) typically leading to the uterus.\xa0 The superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina. The vaginal opening is located between the opening of the urethra and the anus. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body. The opening between the hymen and the vaginal wall can change in size based on the degree in which the hymen is stretched. The membrane will decrease in size due to increased pressure.', 'b3890ef4-90a3-4b98-99e9-a7d73d27070a': 'The vagina is home to a normal population of microorganisms that help to protect against infection by pathogenic bacteria, yeast, or other organisms that can enter the vagina. In a healthy vagina, the most predominant type of bacteria is from the genus Lactobacillus. This family of beneficial bacterial flora secretes lactic acid, and thus protects the vagina by maintaining an acidic pH (below 4.5). Potential pathogens are less likely to survive in these acidic conditions. Lactic acid, in combination with other vaginal secretions, makes the vagina a self-cleansing organ. Douching (washing out the vagina with fluid) disrupts the normal balance of healthy microorganisms, and increases the risk for infections and irritation. Indeed, the American College of Obstetricians and Gynecologists recommends against douching, and instead recommends allowing the vagina to maintain its normal healthy population of protective microbial flora.', 'cecef381-3789-44fd-acbb-d68ebf70d4b3': 'The ovaries are the gonads (see Figure 27.1.3) located at the distal end of the uterine tubes, close to the fimbriae. They are each about 2 to 3 cm in length, about the size of an almond. The ovaries are supported by the mesovarium, a double fold of peritoneum that is part of the broad ligament. The suspensory ligament is the peritoneum that contains the ovarian blood and lymph vessels. The ovary itself is attached to the uterus via the ovarian ligament.', '8582cb0e-d2e2-4f07-9d31-c658a5f0e7ad': 'The ovary comprises an outer covering of cuboidal epithelium that is superficial to a dense connective tissue covering called the tunica albuginea. Beneath the tunica albuginea is the cortex, or outer portion, of the organ. The cortex is composed of a tissue framework called the ovarian stroma that forms the bulk of the adult ovary.'}"
+Figure 27.1.4,Anatomy_And_Physio/images/Figure 27.1.4.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple.","The external features of the breast include a nipple surrounded by a pigmented areola (Figure 27.1.4), whose coloration may deepen due to changes in hormone levels. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterized by small, raised areolar glands that secrete lubricating fluid under certain hormonal conditions.","{'ed91885b-6b0a-4247-8abf-98e077d5521f': 'The external features of the breast include a nipple surrounded by a pigmented areola (Figure 27.1.4), whose coloration may deepen due to changes in hormone levels. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterized by small, raised areolar glands that secrete lubricating fluid under certain hormonal conditions.', '0ac6c4e0-7777-417d-8ced-985f153a1378': 'Breast milk is produced by the mammary glands, which are modified sweat glands. The milk itself exits the breast through the nipple via 15 to 20 lactiferous ducts that open on the surface of the nipple. These lactiferous ducts each extend to a lactiferous sinus that connects to a glandular lobe within the breast itself that contains groups of milk-secreting cells in clusters called alveoli (see Figure 27.1.4). The clusters can change in size depending on the amount of milk in the alveolar lumen. Once milk is made in the alveoli, stimulated myoepithelial cells that surround the alveoli contract to push the milk to the lactiferous sinuses. From here, milk can be drawn through the lactiferous ducts by suckling. The lobes themselves are surrounded by fat tissue, which determines the size of the breast; breast size differs between individuals and does not affect the amount of milk produced. Asymmetry in breast size within an individual is expected and normal. Increased levels of hormones can lead to further development of the mammary tissue and enlargement of the breasts. Supporting the breasts are multiple bands of connective tissue called suspensory ligaments that connect the breast tissue to the dermis of the overlying skin.'}"
+Figure 27.1.4,Anatomy_And_Physio/images/Figure 27.1.4.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple.","The external features of the breast include a nipple surrounded by a pigmented areola (Figure 27.1.4), whose coloration may deepen due to changes in hormone levels. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterized by small, raised areolar glands that secrete lubricating fluid under certain hormonal conditions.","{'ed91885b-6b0a-4247-8abf-98e077d5521f': 'The external features of the breast include a nipple surrounded by a pigmented areola (Figure 27.1.4), whose coloration may deepen due to changes in hormone levels. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterized by small, raised areolar glands that secrete lubricating fluid under certain hormonal conditions.', '0ac6c4e0-7777-417d-8ced-985f153a1378': 'Breast milk is produced by the mammary glands, which are modified sweat glands. The milk itself exits the breast through the nipple via 15 to 20 lactiferous ducts that open on the surface of the nipple. These lactiferous ducts each extend to a lactiferous sinus that connects to a glandular lobe within the breast itself that contains groups of milk-secreting cells in clusters called alveoli (see Figure 27.1.4). The clusters can change in size depending on the amount of milk in the alveolar lumen. Once milk is made in the alveoli, stimulated myoepithelial cells that surround the alveoli contract to push the milk to the lactiferous sinuses. From here, milk can be drawn through the lactiferous ducts by suckling. The lobes themselves are surrounded by fat tissue, which determines the size of the breast; breast size differs between individuals and does not affect the amount of milk produced. Asymmetry in breast size within an individual is expected and normal. Increased levels of hormones can lead to further development of the mammary tissue and enlargement of the breasts. Supporting the breasts are multiple bands of connective tissue called suspensory ligaments that connect the breast tissue to the dermis of the overlying skin.'}"
+Figure 27.1.5,Anatomy_And_Physio/images/Figure 27.1.5.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.","The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.","{'42667063-0ec1-4111-a68f-f604b64a6306': 'The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.', 'dd6833c8-ce00-472d-86ce-8f2309110740': 'During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.', '0d72d1fc-4a46-425f-bb04-e5107260ef96': 'Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).', '006e541c-249b-4407-a787-f4fd04e747ae': 'Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.', '03f125b6-25ba-42f3-9860-72c610ca9258': 'As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.', 'feecdf0d-980a-493b-bc0d-474f5626d372': 'The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.', '284b2bb8-2827-4a8a-9988-36cbb7255d8b': 'As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.'}"
+Figure 27.1.7,Anatomy_And_Physio/images/Figure 27.1.7.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.,"The testes (singular = testis) are the gonads which produce both sperm and androgens, such as testosterone, and are active throughout the sexual lifespan. The testes are spherical in shape, each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.1.7). They are surrounded by two distinct layers of protective connective tissue (Figure 27.1.6). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer (similar to the visceral and parietal serous membranes of the pericardium, peritoneum, and pleura). Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a fetus secreting testosterone, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.","{'a1c80393-d6d2-40cb-95f4-4c8b5e5479e5': 'The testes (singular = testis) are the gonads which produce both sperm and androgens, such as testosterone, and are active throughout the sexual lifespan. The testes are spherical in shape, each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.1.7). They are surrounded by two distinct layers of protective connective tissue (Figure 27.1.6). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer (similar to the visceral and parietal serous membranes of the pericardium, peritoneum, and pleura). Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a fetus secreting testosterone, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.', '17b8acf2-c22f-40f6-b16a-50c2df103ca5': 'The tightly coiled seminiferous tubules form the bulk of each testis. Within the tubules are developing sperm cells. From the lumens of the seminiferous tubules, sperm move into the straight tubules (or tubuli recti), and from there into a fine meshwork of tubules called the rete testes. Sperm leave the rete testes, and the testis itself, through the 15 to 20 efferent ductules that cross the tunica albuginea.', 'a5fa6c8c-138b-435f-b55c-75802a12c59a': 'Inside the seminiferous tubules are six different cell types. These include supporting cells called sustentacular cells, as well as five types of developing sperm cells called germ cells. Germ cell development progresses from the basement membrane—at the perimeter of the tubule—toward the lumen.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.'}"
+Figure 27.1.6,Anatomy_And_Physio/images/Figure 27.1.6.jpg,"Figure 27.1.6 – Anatomy of a Testis: This sagittal view shows seminiferous tubules, the site of sperm production. Formed sperm are transferred to the epididymis, where they mature. They leave the epididymis during an ejaculation via the ductus deferens.","From the lumen of the seminiferous tubules, the immotile sperm are surrounded by testicular fluid and moved to the epididymis (plural = epididymides), a coiled tube attached to the testis where newly formed sperm continue to mature (see Figure 27.1.6) Though the epididymis does not take up much room in its tightly coiled state, it would be approximately 6 m (20 feet) long if straightened. It takes an average of 12 days for sperm to move through the coils of the epididymis, with the shortest recorded transit time in humans being one day. Sperm enter the head of the epididymis and are moved along predominantly by the contraction of smooth muscles lining the epididymal tubes. As they are moved along the length of the epididymis, the sperm further mature and acquire the ability to move on their own. The more mature sperm are then stored in the tail of the epididymis (the final section) until ejaculation occurs.","{'fb4e33fc-ee4b-49a7-8135-c1fd3e217c24': 'From the lumen of the seminiferous tubules, the immotile sperm are surrounded by testicular fluid and moved to the epididymis (plural = epididymides), a coiled tube attached to the testis where newly formed sperm continue to mature (see Figure 27.1.6) Though the epididymis does not take up much room in its tightly coiled state, it would be approximately 6 m (20 feet) long if straightened. It takes an average of 12 days for sperm to move through the coils of the epididymis, with the shortest recorded transit time in humans being one day. Sperm enter the head of the epididymis and are moved along predominantly by the contraction of smooth muscles lining the epididymal tubes. As they are moved along the length of the epididymis, the sperm further mature and acquire the ability to move on their own. The more mature sperm are then stored in the tail of the epididymis (the final section) until ejaculation occurs.'}"
+Figure 27.1.5,Anatomy_And_Physio/images/Figure 27.1.5.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.","The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.","{'42667063-0ec1-4111-a68f-f604b64a6306': 'The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.', 'dd6833c8-ce00-472d-86ce-8f2309110740': 'During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.', '0d72d1fc-4a46-425f-bb04-e5107260ef96': 'Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).', '006e541c-249b-4407-a787-f4fd04e747ae': 'Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.', '03f125b6-25ba-42f3-9860-72c610ca9258': 'As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.', 'feecdf0d-980a-493b-bc0d-474f5626d372': 'The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.', '284b2bb8-2827-4a8a-9988-36cbb7255d8b': 'As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.'}"
+Figure 27.1.7,Anatomy_And_Physio/images/Figure 27.1.7.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.,"The testes (singular = testis) are the gonads which produce both sperm and androgens, such as testosterone, and are active throughout the sexual lifespan. The testes are spherical in shape, each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.1.7). They are surrounded by two distinct layers of protective connective tissue (Figure 27.1.6). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer (similar to the visceral and parietal serous membranes of the pericardium, peritoneum, and pleura). Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a fetus secreting testosterone, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.","{'a1c80393-d6d2-40cb-95f4-4c8b5e5479e5': 'The testes (singular = testis) are the gonads which produce both sperm and androgens, such as testosterone, and are active throughout the sexual lifespan. The testes are spherical in shape, each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.1.7). They are surrounded by two distinct layers of protective connective tissue (Figure 27.1.6). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer (similar to the visceral and parietal serous membranes of the pericardium, peritoneum, and pleura). Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a fetus secreting testosterone, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.', '17b8acf2-c22f-40f6-b16a-50c2df103ca5': 'The tightly coiled seminiferous tubules form the bulk of each testis. Within the tubules are developing sperm cells. From the lumens of the seminiferous tubules, sperm move into the straight tubules (or tubuli recti), and from there into a fine meshwork of tubules called the rete testes. Sperm leave the rete testes, and the testis itself, through the 15 to 20 efferent ductules that cross the tunica albuginea.', 'a5fa6c8c-138b-435f-b55c-75802a12c59a': 'Inside the seminiferous tubules are six different cell types. These include supporting cells called sustentacular cells, as well as five types of developing sperm cells called germ cells. Germ cell development progresses from the basement membrane—at the perimeter of the tubule—toward the lumen.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.'}"
+Figure 27.1.5,Anatomy_And_Physio/images/Figure 27.1.5.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.","The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.","{'42667063-0ec1-4111-a68f-f604b64a6306': 'The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.', 'dd6833c8-ce00-472d-86ce-8f2309110740': 'During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.', '0d72d1fc-4a46-425f-bb04-e5107260ef96': 'Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).', '006e541c-249b-4407-a787-f4fd04e747ae': 'Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.', '03f125b6-25ba-42f3-9860-72c610ca9258': 'As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.', 'feecdf0d-980a-493b-bc0d-474f5626d372': 'The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.', '284b2bb8-2827-4a8a-9988-36cbb7255d8b': 'As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.'}"
+Figure 27.1.5,Anatomy_And_Physio/images/Figure 27.1.5.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.","The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.","{'42667063-0ec1-4111-a68f-f604b64a6306': 'The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.', 'dd6833c8-ce00-472d-86ce-8f2309110740': 'During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.', '0d72d1fc-4a46-425f-bb04-e5107260ef96': 'Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).', '006e541c-249b-4407-a787-f4fd04e747ae': 'Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.', '03f125b6-25ba-42f3-9860-72c610ca9258': 'As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.', 'feecdf0d-980a-493b-bc0d-474f5626d372': 'The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.', '284b2bb8-2827-4a8a-9988-36cbb7255d8b': 'As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.'}"
+Figure 27.1.5,Anatomy_And_Physio/images/Figure 27.1.5.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen.","The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.","{'42667063-0ec1-4111-a68f-f604b64a6306': 'The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.', 'b3e45d07-8916-40ca-bdc9-6e347225e129': 'The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.', '07c21a2c-0489-46ba-99ef-1321e7ed5530': 'The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.', 'dd6833c8-ce00-472d-86ce-8f2309110740': 'During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.', '0d72d1fc-4a46-425f-bb04-e5107260ef96': 'Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).', '006e541c-249b-4407-a787-f4fd04e747ae': 'Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.', '03f125b6-25ba-42f3-9860-72c610ca9258': 'As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.', 'feecdf0d-980a-493b-bc0d-474f5626d372': 'The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.', '284b2bb8-2827-4a8a-9988-36cbb7255d8b': 'As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.'}"
+Figure 26.5.1,Anatomy_And_Physio/images/Figure 26.5.1.jpg,Figure 26.5.1 – Symptoms of Acidosis and Alkalosis: Symptoms of acidosis affect several organ systems. Both acidosis and alkalosis can be diagnosed using a blood test.,"Normal arterial blood pH is restricted to a very narrow range of 7.35 to 7.45. A person who has a blood pH below 7.35 is considered to be in acidosis (actually, “physiological acidosis,” because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal. Acidosis has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued (Figure 26.5.1). A person who has a blood pH above 7.45 is considered to be in alkalosis, and a pH above 7.8 is fatal. Some symptoms of alkalosis include cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting. Both acidosis and alkalosis can be caused by either metabolic or respiratory disorders.","{'d5b0766f-2495-406d-9a48-52eeda457fc5': 'At approximately age 25, the prostate gradually begins to enlarge. This enlargement does not usually cause problems; however, abnormal growth of the prostate, or benign prostatic hyperplasia (BPH), can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, such as a frequent and intense urge to urinate, a weak stream, and a sensation that the bladder has not emptied completely. The number of individuals with BPH increases dramatically with age. Treatments for BPH attempt to relieve the pressure on the urethra so that urine can flow more normally. Mild to moderate symptoms are treated with medication, whereas severe enlargement of the prostate is treated by surgery in which a portion of the prostate tissue is removed.', '6401bf5a-f187-4e45-aa5d-b426ade56750': 'Another common disorder involving the prostate is prostate cancer. According to the Centers for Disease Control and Prevention (CDC), prostate cancer is one of the most common cancers. However, some forms of prostate cancer grow very slowly and thus may not ever require treatment. Aggressive forms of prostate cancer, in contrast, involve metastasis to vulnerable organs like the lungs and brain. There is no link between BPH and prostate cancer, but the symptoms are similar. Prostate cancer is detected by a medical history, a blood test, and a rectal exam that allows physicians to palpate the prostate and check for unusual masses. If a mass is detected, the cancer diagnosis is confirmed by biopsy of the cells.', '4004a27e-d4f4-43fa-a674-02044fc274cd': 'The terms sex and gender are often used interchangeably, but these terms have different contexts and meanings. Gender is socially constructed and operates as a way to identify and categorize certain behavioral, cultural, and psychological traits as belonging to specific groups of people. Sex is a biological construct that refers to the structural, functional and behavioral characteristics of living beings determined by sex chromosomes. Although the sexual system is often described as a binary of male and female, in reality there is a spectrum of anatomical and chromosomal variation found in the human population including intersex as well as genitalia considered ambiguous at birth. In addition, sexual anatomy has a long history of surgical intervention such a circumcision, vasectomy, tubal ligation and more recently, sex reassignment surgery.\xa0 Sexual anatomy has typically been described using only heterocentric language and binary sexual identity, with an assumption that sex only occurs between a cis-gendered man and woman, for the purpose of reproduction, making it one of the least inclusive and representative topics found in anatomy textbooks. In this chapter, we attempt to present anatomy and physiology in ways that incorporate more lived experiences, rather than only what exists at the binary extremes.', '2676a251-7248-4ea5-828d-be35a056bf23': 'Normal arterial blood pH is restricted to a very narrow range of 7.35 to 7.45. A person who has a blood pH below 7.35 is considered to be in acidosis (actually, “physiological acidosis,” because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal. Acidosis has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued (Figure 26.5.1). A person who has a blood pH above 7.45 is considered to be in alkalosis, and a pH above 7.8 is fatal. Some symptoms of alkalosis include cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting. Both acidosis and alkalosis can be caused by either metabolic or respiratory disorders.', 'bf36e036-bc99-401d-afb4-19fa0bd581dd': 'As discussed earlier in this chapter, the concentration of carbonic acid in the blood is dependent on the level of CO2 in the body and the amount of CO2 gas exhaled through the lungs. Thus, the respiratory contribution to acid-base balance is usually discussed in terms of CO2 (rather than of carbonic acid). Remember that a molecule of carbonic acid is lost for every molecule of CO2 exhaled, and a molecule of carbonic acid is formed for every molecule of CO2 retained.'}"
+Figure 26.4.1,Anatomy_And_Physio/images/Figure 26.4.1.jpg,Figure 26.4.1 – The pH Scale: This chart shows where many common substances fall on the pH scale.,"Proper physiological functioning depends on a very tight balance between the concentrations of acids and bases in the blood. Acid-balance balance is measured using the pH scale, as shown in Figure 26.4.1. A variety of buffering systems permits blood and other bodily fluids to maintain a narrow pH range, even in the face of perturbations. A buffer is a chemical system that prevents a radical change in fluid pH by dampening the change in hydrogen ion concentrations in the case of excess acid or base. Most commonly, the substance that absorbs the ions is either a weak acid, which takes up hydroxyl ions, or a weak base, which takes up hydrogen ions.","{'d9a5ba77-19fe-4a03-ac7c-03a7a43dbaa5': 'Various compensatory mechanisms exist to maintain blood pH within a narrow range, including buffers, respiration, and renal mechanisms. Although compensatory mechanisms usually work very well, when one of these mechanisms is not working properly (like kidney failure or respiratory disease), they have their limits. If the pH and bicarbonate to carbonic acid ratio are changed too drastically, the body may not be able to compensate. Moreover, extreme changes in pH can denature proteins. Extensive damage to proteins in this way can result in disruption of normal metabolic processes, serious tissue damage, and ultimately death.', '0b829977-5b05-48ad-aa48-380276947931': 'Proper physiological functioning depends on a very tight balance between the concentrations of acids and bases in the blood. Acid-balance balance is measured using the pH scale, as shown in Figure 26.4.1. A variety of buffering systems permits blood and other bodily fluids to maintain a narrow pH range, even in the face of perturbations. A buffer is a chemical system that prevents a radical change in fluid pH by dampening the change in hydrogen ion concentrations in the case of excess acid or base. Most commonly, the substance that absorbs the ions is either a weak acid, which takes up hydroxyl ions, or a weak base, which takes up hydrogen ions.'}"
+Figure 26.4.3,Anatomy_And_Physio/images/Figure 26.4.3.jpg,"Figure 26.4.3 Conservation of Bicarbonate in the Kidney. Tubular cells are not permeable to bicarbonate; thus, bicarbonate is conserved rather than reabsorbed. Steps 1 and 2 of bicarbonate conservation are indicated.","Bicarbonate ions, HCO3–, found in the filtrate, are essential to the bicarbonate buffer system, yet the cells of the tubule are not permeable to bicarbonate ions. The steps involved in supplying bicarbonate ions to the system are seen in Figure 26.4.3 and are summarized below:","{'c998a7b8-94f1-42e8-8c55-9e162e33412a': 'The renal regulation of the body’s acid-base balance addresses the metabolic component of the buffering system. Whereas the respiratory system (together with breathing centers in the brain) controls the blood levels of carbonic acid by controlling the exhalation of CO2, the renal system controls the blood levels of bicarbonate. A decrease of blood bicarbonate can result from the inhibition of carbonic anhydrase by certain diuretics or from excessive bicarbonate loss due to diarrhea. Blood bicarbonate levels are also typically lower in people who have Addison’s disease (chronic adrenal insufficiency), in which aldosterone levels are reduced, and in people who have renal damage, such as chronic nephritis. Finally, low bicarbonate blood levels can result from elevated levels of ketones (common in unmanaged diabetes mellitus), which bind bicarbonate in the filtrate and prevent its conservation.', 'bf77bb34-3266-4398-89ed-9a46ba5ba56b': 'Bicarbonate ions, HCO3–, found in the filtrate, are essential to the bicarbonate buffer system, yet the cells of the tubule are not permeable to bicarbonate ions. The steps involved in supplying bicarbonate ions to the system are seen in Figure 26.4.3 and are summarized below:', 'd3e5cc21-194d-4441-91a5-53356e452d1a': 'It is also possible that salts in the filtrate, such as sulfates, phosphates, or ammonia, will capture hydrogen ions. If this occurs, the hydrogen ions will not be available to combine with bicarbonate ions and produce CO2. In such cases, bicarbonate ions are not conserved from the filtrate to the blood, which will also contribute to a pH imbalance and acidosis.', '17a7d3b1-25b3-4c17-8f62-c13f59b601b2': 'The hydrogen ions also compete with potassium to exchange with sodium in the renal tubules. If more potassium is present than normal, potassium, rather than the hydrogen ions, will be exchanged, and increased potassium enters the filtrate. When this occurs, fewer hydrogen ions in the filtrate participate in the conversion of bicarbonate into CO2 and less bicarbonate is conserved. If there is less potassium, more hydrogen ions enter the filtrate to be exchanged with sodium and more bicarbonate is conserved.', '3b83413e-c493-476a-af12-b2360ffc46b4': 'Chloride ions are important in neutralizing positive ion charges in the body. If chloride is lost, the body uses bicarbonate ions in place of the lost chloride ions. Thus, lost chloride results in an increased reabsorption of bicarbonate by the renal system.', 'bd27d976-2857-4598-acf7-41473c322fcf': 'The body contains a large variety of ions, or electrolytes, which perform a variety of functions. Some ions assist in the transmission of electrical impulses along cell membranes in neurons and muscles. Other ions help to stabilize protein structures in enzymes. Still others aid in releasing hormones from endocrine glands. All of the ions in plasma contribute to the osmotic balance that controls the movement of water between cells and their environment.', '14fa0ce1-2020-4083-ba27-bba4e7052f51': 'Electrolytes in living systems include sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium, copper, zinc, iron, manganese, molybdenum, copper, and chromium. In terms of body functioning, six electrolytes are most important: sodium, potassium, chloride, bicarbonate, calcium, and phosphate.'}"
+Figure 26.2.1,Anatomy_And_Physio/images/Figure 26.2.1.jpg,Figure 26.2.1 – A Flowchart Showing the Thirst Response: The thirst response begins when osmoreceptors detect a decrease in water levels in the blood.,"Drinking water is considered voluntary. So how is water intake regulated by the body? Consider someone who is experiencing dehydration, a net loss of water that results in insufficient water in blood and other tissues. The water that leaves the body, as exhaled air, sweat, or urine, is ultimately extracted from blood plasma. As the blood becomes more concentrated, the thirst response—a sequence of physiological processes—is triggered (Figure 26.2.1). Osmoreceptors are sensory receptors in the thirst center in the hypothalamus that monitor the concentration of solutes (osmolality) of the blood. If blood osmolality increases above its ideal value, the hypothalamus transmits signals that result in a conscious awareness of thirst. The person should (and normally does) respond by drinking water. The hypothalamus of a dehydrated person also releases antidiuretic hormone (ADH) through the posterior pituitary gland. ADH signals the kidneys to recover water from urine, effectively diluting the blood plasma. To conserve water, the hypothalamus of a dehydrated person also sends signals via the sympathetic nervous system to the salivary glands in the mouth. The signals result in a decrease in watery, serous output (and an increase in stickier, thicker mucus output). These changes in secretions result in a “dry mouth” and the sensation of thirst.","{'7b366118-4642-4e10-9ae7-7bafaeeb42b2': 'Osmolality is the ratio of solutes in a solution to a volume of solvent in a solution. Plasma osmolality is thus the ratio of solutes to water in blood plasma. A person’s plasma osmolality value reflects his or her state of hydration. A healthy body maintains plasma osmolality within a narrow range, by employing several mechanisms that regulate both water intake and output.', 'f3236012-7154-4cd8-a302-659c199e78d7': 'Drinking water is considered voluntary. So how is water intake regulated by the body? Consider someone who is experiencing dehydration, a net loss of water that results in insufficient water in blood and other tissues. The water that leaves the body, as exhaled air, sweat, or urine, is ultimately extracted from blood plasma. As the blood becomes more concentrated, the thirst response—a sequence of physiological processes—is triggered (Figure 26.2.1). Osmoreceptors are sensory receptors in the thirst center in the hypothalamus that monitor the concentration of solutes (osmolality) of the blood. If blood osmolality increases above its ideal value, the hypothalamus transmits signals that result in a conscious awareness of thirst. The person should (and normally does) respond by drinking water. The hypothalamus of a dehydrated person also releases antidiuretic hormone (ADH) through the posterior pituitary gland. ADH signals the kidneys to recover water from urine, effectively diluting the blood plasma. To conserve water, the hypothalamus of a dehydrated person also sends signals via the sympathetic nervous system to the salivary glands in the mouth. The signals result in a decrease in watery, serous output (and an increase in stickier, thicker mucus output). These changes in secretions result in a “dry mouth” and the sensation of thirst.', 'b1c734fd-d701-4cec-9db1-1258b6670e9a': 'Decreased blood volume resulting from water loss has two additional effects. First, baroreceptors, blood-pressure receptors in the arch of the aorta and the carotid arteries in the neck, detect a decrease in blood pressure that results from decreased blood volume. The heart is ultimately signaled to increase its rate and/or strength of contractions to compensate for the lowered blood pressure.', '30295370-6e27-49b8-8e26-19eb18df25d9': 'Second, the kidneys have a renin-angiotensin hormonal system that increases the production of the active form of the hormone angiotensin II, which helps stimulate thirst, but also stimulates the release of the hormone aldosterone from the adrenal glands. Aldosterone increases the reabsorption of sodium in the distal tubules of the nephrons in the kidneys, and water follows this reabsorbed sodium back into the blood. Circulating angiotensin II can also stimulate the hypothalamus to release ADH.', 'efbcf8d8-d02e-418b-955b-cb911a8c5050': 'If adequate fluids are not consumed, dehydration results and a person’s body contains too little water to function correctly. A person who repeatedly vomits or who has diarrhea may become dehydrated, and infants, because their body mass is so low, can become dangerously dehydrated very quickly. Endurance athletes such as distance runners often become dehydrated during long races. Dehydration can be a medical emergency, and a dehydrated person may lose consciousness, become comatose, or die, if his or her body is not rehydrated quickly.'}"
+Figure 26.2.2,Anatomy_And_Physio/images/Figure 26.2.2.jpg,"Figure 26.2.2 – Antidiuretic Hormone (ADH): ADH is produced in the hypothalamus and released by the posterior pituitary gland. It causes the kidneys to retain water, constricts arterioles in the peripheral circulation, and affects some social behaviors in mammals.","Antidiuretic hormone (ADH), also known as vasopressin, controls the amount of water reabsorbed from the collecting ducts and tubules in the kidney. This hormone is produced in the hypothalamus and is delivered to the posterior pituitary for storage and release (Figure 26.2.2). When the osmoreceptors in the hypothalamus detect an increase in the concentration of blood plasma, the hypothalamus signals the release of ADH from the posterior pituitary into the blood.","{'5d4caa65-f79c-4a0a-8fcf-a14d2a6711a1': 'Antidiuretic hormone (ADH), also known as vasopressin, controls the amount of water reabsorbed from the collecting ducts and tubules in the kidney. This hormone is produced in the hypothalamus and is delivered to the posterior pituitary for storage and release (Figure 26.2.2). When the osmoreceptors in the hypothalamus detect an increase in the concentration of blood plasma, the hypothalamus signals the release of ADH from the posterior pituitary into the blood.', 'c3a554a9-6dd0-4b6a-a77b-0bb8ca98fbeb': 'ADH has two major effects. It constricts the arterioles in the peripheral circulation, which reduces the flow of blood to the extremities and thereby increases the blood supply to the core of the body. ADH also causes the epithelial cells that line the renal collecting tubules to move water channel proteins, called aquaporins, from the interior of the cells to the apical surface, where these proteins are inserted into the cell membrane (Figure 26.2.3). The result is an increase in the water permeability of these cells and, thus, a large increase in water passage from the urine through the walls of the collecting tubules, leading to more reabsorption of water into the bloodstream. When the blood plasma becomes less concentrated and the level of ADH decreases, aquaporins are removed from collecting tubule cell membranes, and the passage of water out of urine and into the blood decreases.', 'add7750d-5bbd-4147-8d07-810e94d61321': 'A diuretic is a compound that increases urine output and therefore decreases water conservation by the body. Diuretics are used to treat hypertension, congestive heart failure, and fluid retention associated with menstruation. Alcohol acts as a diuretic by inhibiting the release of ADH. Additionally, caffeine, when consumed in high concentrations, acts as a diuretic.', '76fad33e-a95b-4f1c-9606-274f802b1dde': 'The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, an electrolyte is referred to as a mineral dissociated from a salt that carries an electrical charge (an ion). For instance, sodium ions (Na+) and chloride ions (Cl–) are often referred to as electrolytes.', '3a96951f-46bf-441b-83a2-5801f164841b': 'In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration to regions of lower concentration, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function.'}"
+Figure 26.2.3,Anatomy_And_Physio/images/Figure 26.2.3.jpg,"Figure 26.2.3 – Aquaporins: The binding of ADH to receptors on the cells of the collecting tubule results in aquaporins being inserted into the plasma membrane, shown in the lower cell. This dramatically increases the flow of water out of the tubule and into the bloodstream.","ADH has two major effects. It constricts the arterioles in the peripheral circulation, which reduces the flow of blood to the extremities and thereby increases the blood supply to the core of the body. ADH also causes the epithelial cells that line the renal collecting tubules to move water channel proteins, called aquaporins, from the interior of the cells to the apical surface, where these proteins are inserted into the cell membrane (Figure 26.2.3). The result is an increase in the water permeability of these cells and, thus, a large increase in water passage from the urine through the walls of the collecting tubules, leading to more reabsorption of water into the bloodstream. When the blood plasma becomes less concentrated and the level of ADH decreases, aquaporins are removed from collecting tubule cell membranes, and the passage of water out of urine and into the blood decreases.","{'5d4caa65-f79c-4a0a-8fcf-a14d2a6711a1': 'Antidiuretic hormone (ADH), also known as vasopressin, controls the amount of water reabsorbed from the collecting ducts and tubules in the kidney. This hormone is produced in the hypothalamus and is delivered to the posterior pituitary for storage and release (Figure 26.2.2). When the osmoreceptors in the hypothalamus detect an increase in the concentration of blood plasma, the hypothalamus signals the release of ADH from the posterior pituitary into the blood.', 'c3a554a9-6dd0-4b6a-a77b-0bb8ca98fbeb': 'ADH has two major effects. It constricts the arterioles in the peripheral circulation, which reduces the flow of blood to the extremities and thereby increases the blood supply to the core of the body. ADH also causes the epithelial cells that line the renal collecting tubules to move water channel proteins, called aquaporins, from the interior of the cells to the apical surface, where these proteins are inserted into the cell membrane (Figure 26.2.3). The result is an increase in the water permeability of these cells and, thus, a large increase in water passage from the urine through the walls of the collecting tubules, leading to more reabsorption of water into the bloodstream. When the blood plasma becomes less concentrated and the level of ADH decreases, aquaporins are removed from collecting tubule cell membranes, and the passage of water out of urine and into the blood decreases.', 'add7750d-5bbd-4147-8d07-810e94d61321': 'A diuretic is a compound that increases urine output and therefore decreases water conservation by the body. Diuretics are used to treat hypertension, congestive heart failure, and fluid retention associated with menstruation. Alcohol acts as a diuretic by inhibiting the release of ADH. Additionally, caffeine, when consumed in high concentrations, acts as a diuretic.', '76fad33e-a95b-4f1c-9606-274f802b1dde': 'The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, an electrolyte is referred to as a mineral dissociated from a salt that carries an electrical charge (an ion). For instance, sodium ions (Na+) and chloride ions (Cl–) are often referred to as electrolytes.', '3a96951f-46bf-441b-83a2-5801f164841b': 'In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration to regions of lower concentration, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function.'}"
+Figure 26.1.1,Anatomy_And_Physio/images/Figure 26.1.1.jpg,"Figure 26.1.1 – Water Content of the Body’s Organs and Tissues: Water content varies in different body organs and tissues, from as little as 8 percent in the teeth to as much as 85 percent in the brain.","Human beings are mostly water, ranging from about 75 percent of body mass in infants to about 50–60 percent in adult men and women, to as low as 45 percent in old age. The percent of body water changes with development, because the proportions of the body given over to each organ and to muscles, fat, bone, and other tissues change from infancy to adulthood (Figure 26.1.1). Your brain and kidneys have the highest proportions of water, which composes 80–85 percent of their masses. In contrast, teeth have the lowest proportion of water, at 8–10 percent.","{'c80686d8-21b8-49b3-9c2e-bedd54b6c955': 'Human beings are mostly water, ranging from about 75 percent of body mass in infants to about 50–60 percent in adult men and women, to as low as 45 percent in old age. The percent of body water changes with development, because the proportions of the body given over to each organ and to muscles, fat, bone, and other tissues change from infancy to adulthood (Figure 26.1.1). Your brain and kidneys have the highest proportions of water, which composes 80–85 percent of their masses. In contrast, teeth have the lowest proportion of water, at 8–10 percent.'}"
+Figure 26.1.2,Anatomy_And_Physio/images/Figure 26.1.2.jpg,Figure 26.1.2 – Fluid Compartments in the Human Body: The intracellular fluid (ICF) is the fluid within cells. The interstitial fluid (IF) is part of the extracellular fluid (ECF) between the cells. Blood plasma is the second part of the ECF. Materials travel between cells and the plasma in capillaries through the IF.,"Body fluids can be discussed in terms of their specific fluid compartment, a location that is largely separate from another compartment by some form of a physical barrier. The intracellular fluid (ICF) compartment is the system that includes all fluid enclosed in cells by their plasma membranes. Extracellular fluid (ECF) surrounds all cells in the body. Extracellular fluid has two primary constituents: the fluid component of the blood (called plasma) and the interstitial fluid (IF) that surrounds all cells not in the blood (Figure 26.1.2).","{'52b0d7ba-fe3c-40bb-8e5a-262497d1dae7': 'Body fluids can be discussed in terms of their specific fluid compartment, a location that is largely separate from another compartment by some form of a physical barrier. The intracellular fluid (ICF) compartment is the system that includes all fluid enclosed in cells by their plasma membranes. Extracellular fluid (ECF) surrounds all cells in the body. Extracellular fluid has two primary constituents: the fluid component of the blood (called plasma) and the interstitial fluid (IF) that surrounds all cells not in the blood (Figure 26.1.2).'}"
+Figure 26.1.4,Anatomy_And_Physio/images/Figure 26.1.4.jpg,"Figure 26.1.4 – The Concentrations of Different Elements in Key Bodily Fluids: The graph shows the composition of the ICF, IF, and plasma. The compositions of plasma and IF are similar to one another but are quite different from the composition of the ICF.","The compositions of the two components of the ECF—plasma and IF—are more similar to each other than either is to the ICF (Figure 26.1.4). Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein. The IF has high concentrations of sodium, chloride, and bicarbonate, but a relatively lower concentration of protein. In contrast, the ICF has elevated amounts of potassium, phosphate, magnesium, and protein. Overall, the ICF contains high concentrations of potassium and phosphate (HPO42−HPO42−), whereas both plasma and the ECF contain high concentrations of sodium and chloride.","{'c258196a-0dd3-4a83-99a3-c4453a0514be': 'The compositions of the two components of the ECF—plasma and IF—are more similar to each other than either is to the ICF (Figure 26.1.4). Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein. The IF has high concentrations of sodium, chloride, and bicarbonate, but a relatively lower concentration of protein. In contrast, the ICF has elevated amounts of potassium, phosphate, magnesium, and protein. Overall, the ICF contains high concentrations of potassium and phosphate (HPO42−HPO42−), whereas both plasma and the ECF contain high concentrations of sodium and chloride.', 'a2448dab-0473-4aec-aa6e-684b5921afa6': 'Most body fluids are neutral in charge. Thus, cations, or positively charged ions, and anions, or negatively charged ions, are balanced in fluids. As seen in the previous graph, sodium (Na+) ions and chloride (Cl–) ions are concentrated in the ECF of the body, whereas potassium (K+) ions are concentrated inside cells. Although sodium and potassium can “leak” through “pores” into and out of cells, respectively, the high levels of potassium and low levels of sodium in the ICF are maintained by sodium-potassium pumps in the cell membranes. These pumps use the energy supplied by ATP to pump sodium out of the cell and potassium into the cell (Figure 26.1.5).'}"
+Figure 26.1.5,Anatomy_And_Physio/images/Figure 26.1.5.jpg,Figure 26.1.5 – The Sodium-Potassium Pump: The sodium-potassium pump is powered by ATP to transfer sodium out of the cytoplasm and into the ECF. The pump also transfers potassium out of the ECF and into the cytoplasm. (credit: modification of work by Mariana Ruiz Villarreal),"Most body fluids are neutral in charge. Thus, cations, or positively charged ions, and anions, or negatively charged ions, are balanced in fluids. As seen in the previous graph, sodium (Na+) ions and chloride (Cl–) ions are concentrated in the ECF of the body, whereas potassium (K+) ions are concentrated inside cells. Although sodium and potassium can “leak” through “pores” into and out of cells, respectively, the high levels of potassium and low levels of sodium in the ICF are maintained by sodium-potassium pumps in the cell membranes. These pumps use the energy supplied by ATP to pump sodium out of the cell and potassium into the cell (Figure 26.1.5).","{'c258196a-0dd3-4a83-99a3-c4453a0514be': 'The compositions of the two components of the ECF—plasma and IF—are more similar to each other than either is to the ICF (Figure 26.1.4). Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein. The IF has high concentrations of sodium, chloride, and bicarbonate, but a relatively lower concentration of protein. In contrast, the ICF has elevated amounts of potassium, phosphate, magnesium, and protein. Overall, the ICF contains high concentrations of potassium and phosphate (HPO42−HPO42−), whereas both plasma and the ECF contain high concentrations of sodium and chloride.', 'a2448dab-0473-4aec-aa6e-684b5921afa6': 'Most body fluids are neutral in charge. Thus, cations, or positively charged ions, and anions, or negatively charged ions, are balanced in fluids. As seen in the previous graph, sodium (Na+) ions and chloride (Cl–) ions are concentrated in the ECF of the body, whereas potassium (K+) ions are concentrated inside cells. Although sodium and potassium can “leak” through “pores” into and out of cells, respectively, the high levels of potassium and low levels of sodium in the ICF are maintained by sodium-potassium pumps in the cell membranes. These pumps use the energy supplied by ATP to pump sodium out of the cell and potassium into the cell (Figure 26.1.5).'}"
+Figure 26.1.6,Anatomy_And_Physio/images/Figure 26.1.6.jpg,Figure 26.1.6 – Capillary Exchange: Net filtration occurs near the arterial end of the capillary since capillary hydrostatic pressure (CHP) is greater than blood colloidal osmotic pressure (BCOP). There is no net movement of fluid near the midpoint of the capillary since CHP = BCOP. Net reabsorption occurs near the venous end of the capillary since BCOP is greater than CHP.,"Hydrostatic pressure, the force exerted by a fluid against a wall, causes movement of fluid between compartments. The hydrostatic pressure of blood is the pressure exerted by blood against the walls of the blood vessels by the pumping action of the heart. In capillaries, hydrostatic pressure (also known as capillary blood pressure) is higher than the opposing “colloid osmotic pressure” in blood—a “constant” pressure primarily produced by circulating albumin—at the arteriolar end of the capillary (Figure 26.1.6). This pressure forces plasma and nutrients out of the capillaries and into surrounding tissues. Fluid and the cellular wastes in the tissues enter the capillaries at the venule end, where the hydrostatic pressure is less than the osmotic pressure in the vessel. Filtration pressure squeezes fluid from the plasma in the blood to the IF surrounding the tissue cells. The surplus fluid in the interstitial space that is not returned directly back to the capillaries is drained from tissues by the lymphatic system, and then re-enters the vascular system at the subclavian veins.","{'9614dfc8-7b1e-4a8b-a0eb-665b3951711f': 'Hydrostatic pressure, the force exerted by a fluid against a wall, causes movement of fluid between compartments. The hydrostatic pressure of blood is the pressure exerted by blood against the walls of the blood vessels by the pumping action of the heart. In capillaries, hydrostatic pressure (also known as capillary blood pressure) is higher than the opposing “colloid osmotic pressure” in blood—a “constant” pressure primarily produced by circulating albumin—at the arteriolar end of the capillary (Figure 26.1.6). This pressure forces plasma and nutrients out of the capillaries and into surrounding tissues. Fluid and the cellular wastes in the tissues enter the capillaries at the venule end, where the hydrostatic pressure is less than the osmotic pressure in the vessel. Filtration pressure squeezes fluid from the plasma in the blood to the IF surrounding the tissue cells. The surplus fluid in the interstitial space that is not returned directly back to the capillaries is drained from tissues by the lymphatic system, and then re-enters the vascular system at the subclavian veins.', 'e55773c2-4d8d-4a2d-aa12-9abf358fd841': 'Hydrostatic pressure is especially important in governing the movement of water in the nephrons of the kidneys to ensure proper filtering of the blood to form urine. As hydrostatic pressure in the kidneys increases, the amount of water leaving the capillaries also increases, and more urine filtrate is formed. If hydrostatic pressure in the kidneys drops too low, as can happen in dehydration, the functions of the kidneys will be impaired, and less nitrogenous wastes will be removed from the bloodstream. Extreme dehydration can result in kidney failure.', '29069c64-40e0-499a-845a-109d1eddb380': 'Fluid also moves between compartments along an osmotic gradient. Recall that an osmotic gradient is produced by the difference in concentration of all solutes on either side of a semi-permeable membrane. The magnitude of the osmotic gradient is proportional to the difference in the concentration of solutes on one side of the cell membrane to that on the other side. Water will move by osmosis from the side where its concentration is high (and the concentration of solute is low) to the side of the membrane where its concentration is low (and the concentration of solute is high). In the body, water moves by osmosis from plasma to the IF (and the reverse) and from the IF to the ICF (and the reverse). In the body, water moves constantly into and out of fluid compartments as conditions change in different parts of the body.', 'a4e30243-cf2f-45dc-846d-dd4f5a55f813': 'For example, if you are sweating, you will lose water through your skin. Sweating depletes your tissues of water and increases the solute concentration in those tissues. As this happens, water diffuses from your blood into sweat glands and surrounding skin tissues that have become dehydrated because of the osmotic gradient. Additionally, as water leaves the blood, it is replaced by the water in other tissues throughout your body that are not dehydrated. If this continues, dehydration spreads throughout the body. When a dehydrated person drinks water and rehydrates, the water is redistributed by the same gradient, but in the opposite direction, replenishing water in all of the tissues.'}"
+Figure 26.1.7,Anatomy_And_Physio/images/Figure 26.1.7.jpg,Figure 26.1.7 – Facilitated Diffusion: Glucose molecules use facilitated diffusion to move down a concentration gradient through the carrier protein channels in the membrane. (credit: modification of work by Mariana Ruiz Villarreal),"Passive transport of a molecule or ion depends on its ability to pass through the membrane, as well as the existence of a concentration gradient that allows the molecules to diffuse from an area of higher concentration to an area of lower concentration. Some molecules, like gases, lipids, and water itself (which also utilizes water channels in the membrane called aquaporins), slip fairly easily through the cell membrane; others, including polar molecules like glucose, amino acids, and ions do not. Some of these molecules enter and leave cells using facilitated transport, whereby the molecules move down a concentration gradient through specific protein channels in the membrane. This process does not require energy. For example, glucose is transferred into cells by glucose transporters that use facilitated transport (Figure 26.1.7).","{'139a179a-f213-49e4-b6e1-3d8dd0398e43': 'The movement of some solutes between compartments is active, which consumes energy and is an active transport process, whereas the movement of other solutes is passive, which does not require energy. Active transport allows cells to move a specific substance against its concentration gradient through a membrane protein, requiring energy in the form of ATP. For example, the sodium-potassium pump employs active transport to pump sodium out of cells and potassium into cells, with both substances moving against their concentration gradients.', 'c3a22990-644c-4e7d-9d7c-60d65710c0d4': 'Passive transport of a molecule or ion depends on its ability to pass through the membrane, as well as the existence of a concentration gradient that allows the molecules to diffuse from an area of higher concentration to an area of lower concentration. Some molecules, like gases, lipids, and water itself (which also utilizes water channels in the membrane called aquaporins), slip fairly easily through the cell membrane; others, including polar molecules like glucose, amino acids, and ions do not. Some of these molecules enter and leave cells using facilitated transport, whereby the molecules move down a concentration gradient through specific protein channels in the membrane. This process does not require energy. For example, glucose is transferred into cells by glucose transporters that use facilitated transport (Figure 26.1.7).', '340c3162-153f-469c-816b-1b05eec97ce3': 'Homeostasis, or the maintenance of constant conditions in the body, is a fundamental property of all living things. In the human body, the substances that participate in chemical reactions must remain within narrows ranges of concentration. Too much or too little of a single substance can disrupt your bodily functions. Because metabolism relies on reactions that are all interconnected, any disruption might affect multiple organs or even organ systems. Water is the most ubiquitous substance in the chemical reactions of life. The interactions of various aqueous solutions—solutions in which water is the solvent—are continuously monitored and adjusted by a large suite of interconnected feedback systems in your body. Understanding the ways in which the body maintains these critical balances is key to understanding good health.', '402d43b1-a21c-495a-be65-2fdd5d5818f7': 'All systems of the body are interrelated. A change in one system may affect all other systems in the body, with mild to devastating effects. A failure of urinary continence can be embarrassing and inconvenient, but is not life threatening. The loss of other urinary functions may prove fatal. A failure to synthesize vitamin D is one such example.'}"
+Figure 25.4.2,Anatomy_And_Physio/images/Figure 25.4.2.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.,"The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin–angiotensin–aldosterone system (see Chapter 25 Figure 25.4.2). The liver synthesizes and secretes the inactive precursor angiotensinogen. When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II (Figure 25.9.1). The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. angiotensin II also stimulates the adrenal cortex to release the steroid hormone aldosterone, which results in renal reabsorption of Na+ and its associated osmotic recovery of water. The reabsorption of Na+ helps to raise and maintain blood pressure over a longer term.","{'e99cae02-7857-43ea-83b5-7d735b71a615': 'Due to osmosis, water follows where Na+ leads. In other words, “water follows salt.” Much of the water the kidneys recover from the filtrate follows the reabsorption of Na+. ADH stimulation of aquaporin channels allows for regulation of water recovery in the collecting ducts. Normally, all of the glucose is recovered, but loss of glucose control (diabetes mellitus) may result in an osmotic diuresis severe enough to produce severe dehydration and death. A loss of renal function means a loss of effective vascular volume control, leading to hypotension (low blood pressure) or hypertension (high blood pressure), which can lead to stroke, heart attack, and aneurysm formation.', '788fb609-c304-4be9-b817-71a9d666ed9f': 'The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin–angiotensin–aldosterone system (see Chapter 25 Figure 25.4.2). The liver synthesizes and secretes the inactive precursor angiotensinogen. When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II (Figure 25.9.1). The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. angiotensin II also stimulates the adrenal cortex to release the steroid hormone aldosterone, which results in renal reabsorption of Na+ and its associated osmotic recovery of water. The reabsorption of Na+ helps to raise and maintain blood pressure over a longer term.', '79e0ed86-7a44-4f7a-9dc3-22e7b0458a9c': 'Sodium has a very strong osmotic effect and attracts water. It plays a larger role in the osmolarity of the plasma than any other circulating component of the blood. If there is too much Na+ present, either due to poor control or excess dietary consumption, a series of metabolic problems ensue. There is an increase in total volume of water, which leads to hypertension (high blood pressure). Over a long period, this increases the risk of serious complications such as heart attacks, strokes, and aneurysms. It can also contribute to system-wide edema (swelling).', '034162d8-3379-4067-99bd-02650fd2733c': 'Mechanisms for regulating Na+ concentration include the renin–angiotensin–aldosterone system and ADH (see Chapter 25 Figure Figure 25.4.2). Aldosterone stimulates the uptake of Na+ on the apical cell membrane of cells in the DCT and collecting ducts, whereas ADH helps to regulate Na+ concentration indirectly by regulating the reabsorption of water.'}"
+Figure 25.8.1,Anatomy_And_Physio/images/Figure 25.8.1.jpg,Figure 25.8.1 Urine Color can change due to degree of hydration.,"The two kidneys filter your entire blood volume many times each day to remove wastes as urine. Characteristics of urine can be variable (Table 25.1) depending on water intake and losses, nutrient intake, and other factors described in this chapter, though cells, proteins and blood are not normally found in the urine. Some of the characteristics such as color and odor are rough descriptors of your state of hydration. For example, if you exercise or work outside, and sweat a great deal, your urine will turn darker and produce a slight odor. Alternatively, a well hydrated person will have light or clear colored urine with little odor (Figure 25.8.1).","{'0c7d998c-3916-4d88-afed-53909b57c003': 'Urine is the end product once the filtrate has been fully manipulated by the nephrons. Until the filtrate passes through the renal papilla into the minor calyx, it can\xa0be affected by nephron processes. This is how kidneys produce anywhere from .4 L of urine/day to as much as 20L urine/day, all while balancing plasma composition and excreting potential toxins in the urine.', 'f00abf42-a84c-44eb-8947-864597089642': 'The two kidneys filter your entire blood volume many times each day to remove wastes as urine. Characteristics of urine can be variable (Table 25.1)\xa0depending on water intake and losses, nutrient intake, and other factors described in this chapter, though cells, proteins and blood are not normally found in the urine. Some of the characteristics such as color and odor are rough descriptors of your state of hydration. For example, if you exercise or work outside, and sweat a great deal, your urine will turn darker and produce a slight odor. Alternatively, a well hydrated person will have light or clear colored urine with little odor (Figure 25.8.1).'}"
+Figure 25.4.2,Anatomy_And_Physio/images/Figure 25.4.2.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.,"The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin–angiotensin–aldosterone system (see Chapter 25 Figure 25.4.2). The liver synthesizes and secretes the inactive precursor angiotensinogen. When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II (Figure 25.9.1). The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. angiotensin II also stimulates the adrenal cortex to release the steroid hormone aldosterone, which results in renal reabsorption of Na+ and its associated osmotic recovery of water. The reabsorption of Na+ helps to raise and maintain blood pressure over a longer term.","{'e99cae02-7857-43ea-83b5-7d735b71a615': 'Due to osmosis, water follows where Na+ leads. In other words, “water follows salt.” Much of the water the kidneys recover from the filtrate follows the reabsorption of Na+. ADH stimulation of aquaporin channels allows for regulation of water recovery in the collecting ducts. Normally, all of the glucose is recovered, but loss of glucose control (diabetes mellitus) may result in an osmotic diuresis severe enough to produce severe dehydration and death. A loss of renal function means a loss of effective vascular volume control, leading to hypotension (low blood pressure) or hypertension (high blood pressure), which can lead to stroke, heart attack, and aneurysm formation.', '788fb609-c304-4be9-b817-71a9d666ed9f': 'The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin–angiotensin–aldosterone system (see Chapter 25 Figure 25.4.2). The liver synthesizes and secretes the inactive precursor angiotensinogen. When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II (Figure 25.9.1). The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. angiotensin II also stimulates the adrenal cortex to release the steroid hormone aldosterone, which results in renal reabsorption of Na+ and its associated osmotic recovery of water. The reabsorption of Na+ helps to raise and maintain blood pressure over a longer term.', '79e0ed86-7a44-4f7a-9dc3-22e7b0458a9c': 'Sodium has a very strong osmotic effect and attracts water. It plays a larger role in the osmolarity of the plasma than any other circulating component of the blood. If there is too much Na+ present, either due to poor control or excess dietary consumption, a series of metabolic problems ensue. There is an increase in total volume of water, which leads to hypertension (high blood pressure). Over a long period, this increases the risk of serious complications such as heart attacks, strokes, and aneurysms. It can also contribute to system-wide edema (swelling).', '034162d8-3379-4067-99bd-02650fd2733c': 'Mechanisms for regulating Na+ concentration include the renin–angiotensin–aldosterone system and ADH (see Chapter 25 Figure Figure 25.4.2). Aldosterone stimulates the uptake of Na+ on the apical cell membrane of cells in the DCT and collecting ducts, whereas ADH helps to regulate Na+ concentration indirectly by regulating the reabsorption of water.'}"
+Figure 25.7.1,Anatomy_And_Physio/images/Figure 25.7.1.jpg,Figure 25.7.1 Nitrogen Wastes.,"Nitrogen wastes are produced by the breakdown of proteins during normal metabolism. Proteins are broken down into amino acids, which in turn are deaminated by having their nitrogen groups removed. Deamination converts the amino (NH2) groups into ammonia (NH3), ammonium ion (NH4+), urea, or uric acid (Figure 25.7.1). Ammonia is extremely toxic, so most of it is very rapidly converted into urea in the liver. Human urinary wastes typically contain primarily urea with small amounts of ammonium and very little uric acid.","{'7af4b12b-37e3-4ab1-aca4-4476d5b6cfca': 'Nitrogen wastes are produced by the breakdown of proteins during normal metabolism. Proteins are broken down into amino acids, which in turn are deaminated by having their nitrogen groups removed. Deamination converts the amino (NH2) groups into ammonia (NH3), ammonium ion (NH4+), urea, or uric acid (Figure 25.7.1). Ammonia is extremely toxic, so most of it is very rapidly converted into urea in the liver. Human urinary wastes typically contain primarily urea with small amounts of ammonium and very little uric acid.'}"
+Figure 25.6.1,Anatomy_And_Physio/images/Figure 25.6.1.jpg,Figure 25.6.1 Countercurrent Multiplier System.,"The structure of the loop of Henle and associated peritubular capillary create a countercurrent multiplier system (Figure 25.6.1). The countercurrent term comes from the fact that the descending and ascending loops are next to each other and their fluid flows in opposite directions (countercurrent). The multiplier term is due to the action of solute pumps that increase (multiply) the concentrations of urea and Na+ deep in the medulla, as described next.","{'5ea3779e-eed6-4a90-a1d5-a762adfc1b04': 'Water-soluble drugs may be excreted in the urine and are influenced by one or all of the following processes: glomerular filtration, tubular secretion, or tubular reabsorption. Drugs that are structurally small can be filtered by the glomerulus with the filtrate. Large drug molecules such as heparin or those that are bound to plasma proteins cannot be filtered and are not readily eliminated. Some drugs can be eliminated by carrier proteins that enable secretion of the drug into the tubule lumen. There are specific carriers that eliminate basic (such as dopamine or histamine) or acidic drugs (such as penicillin or indomethacin). As is the case with other substances, drugs may be both filtered and reabsorbed passively along a concentration gradient.', '5474272e-1046-4fb8-81b1-4bfb31ff7862': 'The structure of the loop of Henle and associated peritubular capillary\xa0create a countercurrent multiplier system (Figure 25.6.1). The countercurrent term comes from the fact that the descending and ascending loops are next to each other and their fluid flows in opposite directions (countercurrent). The multiplier term is due to the action of solute pumps that increase (multiply) the concentrations of urea and Na+ deep in the medulla, as described next.', '18c74f0c-19f9-4ec2-b923-1e5063140221': 'The presence of aquaporin channels in the descending loop allows prodigious quantities of water to leave the loop and enter the hyperosmolar interstitium of the pyramid, where it is returned to the circulation by the vasa recta. As the loop turns to become the ascending loop, there is an absence of aquaporin channels, so water cannot leave the loop. However, in the basal membrane of cells of the thick ascending loop, ATPase pumps actively remove Na+ from the cell into the interstitial space. A Na+/K+/2Cl– symporter in the apical membrane passively allows these ions to enter the cell cytoplasm from the lumen of the loop down a concentration gradient created by the pump. This mechanism works to dilute the fluid of the ascending loop ultimately to approximately 50–100 mOsmol/L.', 'f82bc4fe-ba50-4778-8dd9-ee267396027f': 'At the same time that water is freely diffusing out of the descending loop through aquaporin channels into the interstitial spaces of the medulla, urea freely diffuses into the lumen of the descending loop as it descends deeper into the medulla, much of it to be reabsorbed from the filtrate\xa0when it reaches the collecting duct. In addition, collecting ducts have urea pumps that actively pump urea into the interstitial spaces. This results in the recovery of Na+ to the circulation via the vasa recta and creates a high osmolar environment in the depths of the medulla. Thus, the movement of Na+ and urea into the interstitial spaces by these mechanisms creates the hyperosmotic environment in the depths of the medulla. The net result of this countercurrent multiplier system is to recover both water and Na+ in the circulation.', '5c973816-6b1e-4f41-8665-72299e5417ef': 'At the transition from the DCT to the collecting duct, about 20 percent of the original water is still present and about 10 percent of the sodium. If no other mechanism for water reabsorption existed, about 20–25 liters of urine would be produced. Now consider what is happening in the adjacent capillaries, the vasa recta. They are recovering both solutes and water at a rate that preserves the countercurrent multiplier system. In general, blood flows slowly in capillaries to allow time for exchange of nutrients and wastes. In the vasa recta particularly, this rate of flow is important for two additional reasons. The flow must be slow to allow blood cells to lose and regain water without either crenating or bursting. Second, a rapid flow would remove too much Na+ and urea, destroying the osmolar gradient that is necessary for the recovery of solutes and water. Thus, by flowing slowly to preserve the countercurrent mechanism, as the vasa recta descend, Na+ and urea are freely able to enter the capillary, while water freely leaves; as they ascend, Na+ and urea are secreted into the surrounding medulla, while water reenters and is removed.'}"
+Figure 25.5.1,Anatomy_And_Physio/images/Figure 25.5.1.jpg,Figure 25.5.1 Locations of Secretion and Reabsorption in the Nephron.,"With up to 180 liters per day passing through the nephrons of the kidney, it is quite obvious that most of that fluid and its contents must be reabsorbed. Recall that substances that need to be removd from the body but were not yet filtered, can be secreted. This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5.1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes. While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT. About 10 percent (about 18 L) reaches the collecting ducts. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them, in cases of dehydration, or almost none of the water, in cases of over-hydration.","{'2432fb10-8781-4f42-a4c6-1c77afe51533': 'The major hormones influencing total body water are ADH, aldosterone, and ANH. Circumstances that lead to fluid depletion in the body include blood loss and dehydration. Homeostasis requires that volume and osmolarity be preserved. Blood volume is important in maintaining sufficient blood pressure, and there are nonrenal mechanisms involved in its preservation, including vasoconstriction, which can act within seconds of a drop in pressure. Thirst mechanisms are also activated to promote the consumption of water lost through respiration, evaporation, or urination. Hormonal mechanisms are activated to recover volume while maintaining a normal osmotic environment. These mechanisms act principally on the kidney.', '1a7bcd02-09d3-4f84-be6d-e2a31ad33e26': 'With up to 180 liters per day passing through the nephrons of the kidney, it is quite obvious that most of that fluid and its contents must be reabsorbed. Recall that substances that need to be removd from the body but were not yet filtered, can be secreted. This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5.1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes. While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT. About 10 percent (about 18 L) reaches the collecting ducts. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them, in cases of dehydration, or almost none of the water, in cases of over-hydration.', '610adc61-f5b4-49b5-b918-93c994a25eb3': 'Having reviewed the anatomy and microanatomy of the urinary system, now is the time to focus on the physiology. Recall that the glomerulus produce a simple filtrate of the blood and the remainder of the nephron works to modify the filtrate into urine. You will discover that different parts of the nephron utilize three specific processes to produce urine: filtration, reabsorption, and secretion. You will learn how each of these processes works and where they occur along the nephron and collecting ducts. The physiologic goal is to modify the composition of the plasma and, in doing so, produce the waste product urine.', '0e9dafa2-edd5-4690-8747-5eaabe461aaf': 'Glomerular filtration occurs as blood passes into the glomerulus producing a plasma-like filtrate (minus proteins) that gets captured by the Bowman’s (glomerular) capsule and funneled into the renal tubule. This filtrate produced then becomes highly modified along its route through the nephron by the following processes, finally producing urine at the end of the collecting duct.', '88198aff-edd3-4544-9455-a2de3d3d35ca': 'As the filtrate travels along the length of the nephron, the cells lining the tubule selectively, and often actively, take substances from the filtrate and move them out of the tubule into the blood. Recall that the glomerulus is simply a filter and anything suspended in the plasma that can fit through the holes in the filtration membrane can end up in the filtrate. This includes very physiologically important molecules such as water, sodium, chloride, and bicarbonate (along with many others) as well as molecules that the digestive system used a lot of energy to absorb, such as glucose and amino acids. These molecules would be lost in the urine if not reclaimed by the tubule cells. These cells are so efficient that they can reclaim all of the glucose and amino acids and up to 99% of the water and important ions lost due to glomerular filtration. The filtrate that is not reasbsorbed becomes urine at the base of the collecting duct.', '066b23c9-a978-4fbf-b10b-493ea6dd7838': 'Nephrons are the “functional units” of the kidney; they cleanse the blood of toxins and balance the constituents of the circulation to homeostatic set points through the processes of filtration, reabsorption, and secretion. The nephrons also function to control blood pressure (via production of renin), red blood cell production (via the hormone erythropoetin), and calcium absorption (via conversion of calcidiol into calcitriol, the active form of vitamin D).', '14552618-fe9e-43db-9389-3e93f577e75c': 'This section is about how the immune system goes wrong. When it goes haywire, and becomes too weak or too strong, it leads to a state of disease. The factors that maintain immunological homeostasis are complex and incompletely understood.', '498f8f2a-b050-4166-abb5-9d065a244fdd': 'The immune system is the complex collection of cells and organs that destroys or neutralizes pathogens that would otherwise cause disease or death. The lymphatic system, for most people, is associated with the immune system to such a degree that the two systems are virtually indistinguishable. The lymphatic system is the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood. The swelling of lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels are but two examples of the many connections between these critical organ systems.', '535b8abb-5a6e-4c96-a28d-2f4f781a63c4': 'Describe structural and functional differences of skeletal, cardiac, and smooth muscle tissue', '1b4d95d8-5492-46db-aad8-a65c586e4233': 'Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.', '069a73e3-7426-4a39-9941-c2f6e90737f2': 'A unique property common to all three types of muscle is\xa0contractility,\xa0which is the ability of the cells to shorten and generate force. \xa0While muscle tissue can shorten with contractions, it also displays\xa0extensibility\xa0or the ability to stretch and extend beyond the resting length of the cells. \xa0After being stretched, the elasticity\xa0of muscle allows it to recoil back to its original length.', '74637967-9cc6-445c-b01c-1083803def1b': 'The muscles all begin the mechanical process of contracting (shortening) when a protein called actin is pulled by a protein called myosin, and differences in the microscopic organization of these contractile proteins exist among the three muscle types.\xa0 In both skeletal and cardiac muscle, the actin and myosin proteins are arranged very regularly in the cytoplasm of individual muscle cells, which creates an alternating light and dark striped pattern called striations. The striations are visible with a light microscope under high magnification (see Figure 10.1.1). \xa0Smooth muscle (named for it’s lack of striations), does not produce this striped pattern because the contractile proteins are not arranged in such regular fashion.', '4eaded9d-9d7d-4c33-b204-2507c8b91b08': 'Skeletal muscle\xa0cells (also called muscle fibers)\xa0are unique in that they are multinucleated with the nuclei located on the periphery of the cell under the cell plasma membrane (also called sarcolemma in muscle).\xa0 During early development, embryonic myoblasts, each with its own nucleus, fuse with hundreds of other myoblasts to form long multinucleated skeletal muscle fibers.\xa0Cardiac muscle\xa0cells each generally have one nucleus centrally located in the cell, but the cells are physically and electrically connected to each other so that the contraction signals spread through cells and the entire heart contracts as one unit. \xa0Smooth muscle cells contain a single nucleus and can exist in electrically linked units contracting together as a single-unit or as multi-unit smooth muscle where cells are not electrically linked.', '83607dca-c2a9-41f7-bd6e-f99a9c2c0954': 'The best-known feature of skeletal muscle is its ability to contract and cause movement. Skeletal muscles act not only to produce movement but also to stop movement, such as resisting gravity to maintain posture. Small, constant adjustments of the skeletal muscles are needed to hold a body upright or balanced in any position. Muscles also prevent excess movement of the bones and joints, maintaining skeletal stability and preventing skeletal structure damage or deformation.\xa0\xa0Skeletal muscles are located throughout the body at the openings of internal tracts to control the movement of various substances. These muscles allow functions, such as swallowing, urination, and defecation, to be under voluntary control. Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external barrier or shield to external trauma and by supporting the weight of the organs.', 'b8d405e5-666f-400c-b736-9f516acb3e36': 'Skeletal muscles contribute to the maintenance of homeostasis in the body by generating heat. Muscle contraction requires energy, and when ATP is broken down, heat is produced. This heat is very noticeable during exercise, when sustained muscle movement causes body temperature to rise, and in cases of extreme cold, when shivering produces random skeletal muscle contractions to generate heat.', '981a9036-67c6-4a72-a4c0-44e6778734ed': 'Cardiac muscle is only found in the heart and functions to generate force and build pressure gradients to drive blood flow throughout the body. Smooth muscle in the walls of arteries is a critical component that regulates blood pressure and blood flow through the circulatory system. \xa0Smooth muscle in the skin, visceral organs, and internal passageways is also essential for moving materials through the body. Neither cardiac nor smooth muscle connect to bone and therefore they cannot produce the gross movements we associate with skeletal muscle.', 'd86919ae-8f74-4ed3-98ed-fdfe9173e989': 'When most people think of muscles, they think of the muscles that are visible just under the skin, particularly of the limbs. These are skeletal muscles, so-named because most of them move the skeleton. But there are two other types of muscle in the body, with distinctly different jobs. Cardiac muscle, found in the heart, is concerned with pumping blood through the circulatory system. Smooth muscle is concerned with various involuntary movements, such as having one’s hair stand on end when cold or frightened, or moving food through the digestive system. This chapter will examine the structure and function of these three types of muscles.'}"
+Figure 25.5.2,Anatomy_And_Physio/images/Figure 25.5.2.jpg,Figure 25.5.2 Substances Reabsorbed and Secreted by the PCT.,"The renal corpuscle filters the blood to create a filtrate that still contains many important molecules that the body needs to reclaim. The PCT reclaims more of these than any other portion of the nephron. The cells of the PCT have two surfaces: apical faces the lumen of the tubule and is in contact with the filtrate. The basal surface of the PCT cell faces the interstitial space near the peritubular capillary. Sodium is actively pumped by the PCT cells into the interstitial space and diffuses down its concentration gradient into the peritubular capillary. As it does so, water follows passively by osmosis. This is called obligatory water reabsorption, because water is “obliged” to follow the Na+ (Figure 25.5.2). Filtered amino acids and glucose move with sodium using specific membrane transport proteins (symports), accounting for 100% of reabsorption of these molecules in healthy individuals. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. The numbers and particular types of pumps and channels vary between the apical and basilar surfaces (Table 25.7) as well as the directionality of movement. Some molecules do not require cellular transport proteins but instead move between adjacent cell membranes (paracellular) across the tubule and back into the blood.","{'e2bce7f3-70d4-438f-819c-b5609e6c559a': 'The renal corpuscle filters the blood to create a filtrate that still contains many important molecules that the body needs to reclaim. The\xa0PCT reclaims more of these than any other portion of the nephron. The cells of the PCT have two surfaces: apical faces the lumen of the tubule and is in contact with the filtrate. The basal surface of the PCT cell faces the interstitial space near the peritubular capillary. Sodium is actively pumped by the PCT cells into the interstitial space and diffuses down its concentration gradient into the peritubular capillary. As it does so, water follows passively by osmosis. This is called obligatory water reabsorption, because water is “obliged” to follow the Na+ (Figure 25.5.2).\xa0Filtered amino acids and glucose move with sodium using specific membrane transport proteins (symports), accounting for 100% of reabsorption of these molecules in healthy individuals. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. The numbers and particular types of pumps and channels vary between the apical and basilar surfaces (Table 25.7) as well as the directionality of movement. Some molecules do not require cellular transport proteins but instead move between adjacent cell membranes (paracellular) across the tubule and back into the blood.', '5c0d74cb-3a7f-4b6b-8028-5f99f1d1bb7b': 'About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm) like that seen with diabetes mellitus. Fifty percent of Cl– and variable quantities of HCO3–, Ca++, Mg++, and HPO42−\xa0are also recovered in the PCT.\xa0The significant recovery of solutes from the PCT lumen to the interstitial space creates an osmotic gradient that promotes water recovery.', '30b8c5ec-8a34-4eac-bddf-9ab727547c7e': 'About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm). In men, the maximum amount of glucose that can be recovered is about 375 mg/min, whereas in women, it is about 300 mg/min. This recovery rate translates to an arterial concentration of about 200 mg/dL. Though an exceptionally high sugar intake might cause sugar to appear briefly in the urine, the appearance of glycosuria usually points to type I or II diabetes mellitus. The transport of glucose from the lumen of the PCT to the interstitial space is similar to the way it is absorbed by the small intestine. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. Fifty percent of Cl– and variable quantities of Ca++, Mg++, and HPO42−\xa0are also recovered in the PCT.', '6278ea47-9527-4a70-8196-b083c1e9a4cd': 'Recovery of bicarbonate (HCO3–) is vital to the maintenance of acid–base balance, since it is a very powerful and fast-acting buffer. An important enzyme is used to catalyze this mechanism: carbonic anhydrase (CA). This same enzyme and reaction is used in red blood cells in the transportation of CO2, in the stomach to produce hydrochloric acid, and in the pancreas to produce HCO3– to buffer acidic chyme from the stomach. In the kidney, most of the CA is located within the cell, but a small amount is bound to the brush border of the membrane on the apical surface of the cell. In the lumen of the PCT, HCO3– combines with hydrogen ions to form carbonic acid (H2CO3). This is enzymatically catalyzed into CO2 and water, which diffuse across the apical membrane into the cell. Water can move osmotically across the lipid bilayer membrane due to the presence of aquaporin water channels. Inside the cell, the reverse reaction occurs to produce bicarbonate ions (HCO3–). These bicarbonate ions are cotransported with Na+ across the basal membrane to the interstitial space around the PCT (Figure 25.5.3). At the same time this is occurring, a Na+/H+ antiporter excretes H+ into the lumen, while it recovers Na+. Note how the hydrogen ion is recycled so that bicarbonate can be recovered. Also, note that a Na+ gradient is created by the Na+/K+ pump.'}"
+Figure 25.5.3,Anatomy_And_Physio/images/Figure 25.5.3.jpg,Figure 25.5.3 Reabsorption of Bicarbonate from the PCT.,"Recovery of bicarbonate (HCO3–) is vital to the maintenance of acid–base balance, since it is a very powerful and fast-acting buffer. An important enzyme is used to catalyze this mechanism: carbonic anhydrase (CA). This same enzyme and reaction is used in red blood cells in the transportation of CO2, in the stomach to produce hydrochloric acid, and in the pancreas to produce HCO3– to buffer acidic chyme from the stomach. In the kidney, most of the CA is located within the cell, but a small amount is bound to the brush border of the membrane on the apical surface of the cell. In the lumen of the PCT, HCO3– combines with hydrogen ions to form carbonic acid (H2CO3). This is enzymatically catalyzed into CO2 and water, which diffuse across the apical membrane into the cell. Water can move osmotically across the lipid bilayer membrane due to the presence of aquaporin water channels. Inside the cell, the reverse reaction occurs to produce bicarbonate ions (HCO3–). These bicarbonate ions are cotransported with Na+ across the basal membrane to the interstitial space around the PCT (Figure 25.5.3). At the same time this is occurring, a Na+/H+ antiporter excretes H+ into the lumen, while it recovers Na+. Note how the hydrogen ion is recycled so that bicarbonate can be recovered. Also, note that a Na+ gradient is created by the Na+/K+ pump.","{'e2bce7f3-70d4-438f-819c-b5609e6c559a': 'The renal corpuscle filters the blood to create a filtrate that still contains many important molecules that the body needs to reclaim. The\xa0PCT reclaims more of these than any other portion of the nephron. The cells of the PCT have two surfaces: apical faces the lumen of the tubule and is in contact with the filtrate. The basal surface of the PCT cell faces the interstitial space near the peritubular capillary. Sodium is actively pumped by the PCT cells into the interstitial space and diffuses down its concentration gradient into the peritubular capillary. As it does so, water follows passively by osmosis. This is called obligatory water reabsorption, because water is “obliged” to follow the Na+ (Figure 25.5.2).\xa0Filtered amino acids and glucose move with sodium using specific membrane transport proteins (symports), accounting for 100% of reabsorption of these molecules in healthy individuals. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. The numbers and particular types of pumps and channels vary between the apical and basilar surfaces (Table 25.7) as well as the directionality of movement. Some molecules do not require cellular transport proteins but instead move between adjacent cell membranes (paracellular) across the tubule and back into the blood.', '5c0d74cb-3a7f-4b6b-8028-5f99f1d1bb7b': 'About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm) like that seen with diabetes mellitus. Fifty percent of Cl– and variable quantities of HCO3–, Ca++, Mg++, and HPO42−\xa0are also recovered in the PCT.\xa0The significant recovery of solutes from the PCT lumen to the interstitial space creates an osmotic gradient that promotes water recovery.', '30b8c5ec-8a34-4eac-bddf-9ab727547c7e': 'About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm). In men, the maximum amount of glucose that can be recovered is about 375 mg/min, whereas in women, it is about 300 mg/min. This recovery rate translates to an arterial concentration of about 200 mg/dL. Though an exceptionally high sugar intake might cause sugar to appear briefly in the urine, the appearance of glycosuria usually points to type I or II diabetes mellitus. The transport of glucose from the lumen of the PCT to the interstitial space is similar to the way it is absorbed by the small intestine. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. Fifty percent of Cl– and variable quantities of Ca++, Mg++, and HPO42−\xa0are also recovered in the PCT.', '6278ea47-9527-4a70-8196-b083c1e9a4cd': 'Recovery of bicarbonate (HCO3–) is vital to the maintenance of acid–base balance, since it is a very powerful and fast-acting buffer. An important enzyme is used to catalyze this mechanism: carbonic anhydrase (CA). This same enzyme and reaction is used in red blood cells in the transportation of CO2, in the stomach to produce hydrochloric acid, and in the pancreas to produce HCO3– to buffer acidic chyme from the stomach. In the kidney, most of the CA is located within the cell, but a small amount is bound to the brush border of the membrane on the apical surface of the cell. In the lumen of the PCT, HCO3– combines with hydrogen ions to form carbonic acid (H2CO3). This is enzymatically catalyzed into CO2 and water, which diffuse across the apical membrane into the cell. Water can move osmotically across the lipid bilayer membrane due to the presence of aquaporin water channels. Inside the cell, the reverse reaction occurs to produce bicarbonate ions (HCO3–). These bicarbonate ions are cotransported with Na+ across the basal membrane to the interstitial space around the PCT (Figure 25.5.3). At the same time this is occurring, a Na+/H+ antiporter excretes H+ into the lumen, while it recovers Na+. Note how the hydrogen ion is recycled so that bicarbonate can be recovered. Also, note that a Na+ gradient is created by the Na+/K+ pump.'}"
+Figure 25.4.1,Anatomy_And_Physio/images/Figure 25.4.1.jpg,Figure 25.4.1 – Net Filtration Pressure: The NFP is the sum of osmotic and hydrostatic pressures.,Or: NFP = 55 – [15 + 30] = 10 mm Hg (Figure 25.4.1).,"{'9358d784-9708-4c62-9738-c5cc1b022311': 'Filtrate is produced by the glomerulus when the hydrostatic pressure produced by the heart pushes water and solutes through the filtration membrane. Glomerular filtration is a passive process as cellular energy is not used at the filtration membrane to produce filtrate. Recall that the filtration membrane lies between the blood in the glomerulus and the filtrate in the Bowman’s (glomerular) capsule and this filtration membrane is highly fenestrated allowing the passage of small molecules such as water, sodium, glucose, etc.', '8f5d4eeb-1f53-4ced-a405-7d431288950e': 'The volume of filtrate formed by both kidneys per minute is termed glomerular filtration rate (GFR). Approximately 20% of your cardiac output is filtered by your kidneys per minute under resting conditions. The work of the kidneys produces about 125 mL/min filtrate in men (range of 90 to 140 mL/min) and 105 mL/min filtrate in women (range of 80 to 125 mL/min). This amount equates to a volume of about 180 L/day in men and 150 L/day in women. However, 99% of this filtrate is returned to the circulation through reabsorption resulting in only about 1–2 liters of urine per day.', '5faa8ef0-15d8-4922-8d8c-6ccaa6b71124': 'GFR is influenced by multiple factors, like those seen at tissue capillary beds (see chapter 19). Recall that filtration occurs as pressure forces fluid and solutes through a semipermeable barrier with the solute movement constrained by particle size. Hydrostatic pressure is the pressure produced by a fluid against a surface. The blood inside the glomerulus creates\xa0glomerular hydrostatic pressure which forces fluid out of the glomerulus into the glomerular capsule. The fluid in the glomerular capsule creates pressure pushing fluid out of the glomerular capsule back into the glomerulus, opposing the glomerular hydrostatic pressure. This is the capsular hydrostatic pressure. These fluids exert pressures in opposing directions. Net fluid movement will be in the direction of the lower pressure. However, the concentration of the solutes in the fluids affects net movement of fluid as well.', 'fa84698d-2ff2-4866-a16c-57c15bf38df2': 'Water moves across a membrane from areas of high water concentration (low dissolved solute concentration) to areas of low water concentration (high dissolved solute concentration) through the process of osmosis. The concentration of plasma solutes in the glomerulus is greater than the concentration of the filtrate in the glomerular capsule since the filtration membrane limits the size of particles crossing the membrane. Most proteins cannot pass into the filtrate resulting in water’s movement out of the capsule towards the glomerulus. This pressure acting to draw water into the glomerulus is called blood\xa0colloid osmotic pressure. The absence of proteins in the glomerular space (the lumen within the glomerular capsule) results in a capsular osmotic pressure near zero.', 'adcdc713-1db0-4220-9d47-24b9394b0eed': 'Glomerular filtration occurs when glomerular (blood) hydrostatic pressure exceeds the hydrostatic pressure of the glomerular capsule and the blood colloid osmotic pressure.\xa0The sum of all of the influences, both osmotic and hydrostatic, results in a net filtration pressure (NFP).\xa0Glomerular hydrostatic pressure is typically about 55 mmHg pushing fluid into the glomerular capsule. This outward pressure is countered by a typical capsular hydrostatic pressure of about 15 mmHg and a blood colloid osmotic pressure of 30 mmHg. To calculate the value of NFP:', 'fa2ad3f6-bbfb-4f18-84f4-7f5b0718fd04': 'NFP = Glomerular blood hydrostatic pressure (GBHP) – [capsular hydrostatic pressure (CHP) + blood colloid osmotic pressure (BCOP)] = 10 mm Hg', '02d25208-ecaa-400d-ba68-f51787617c09': 'That is: NFP = GBHP – [CHP + BCOP] = 10 mm Hg', '96a0d48f-81e4-445f-9c67-9978d5f445b8': 'Or: NFP = 55 – [15 + 30] = 10 mm Hg (Figure 25.4.1).', '664e6c0b-b26c-472a-8115-77f7b4b71761': 'A proper concentration of solutes in the blood is important in maintaining osmotic pressure both in the glomerulus and systemically. There are disorders in which too much protein passes through the filtration slits into the kidney filtrate. This excess protein in the filtrate leads to a deficiency of circulating plasma proteins. Together, blood colloid osmotic pressure decreases, resulting in an increase in urine volume potentially causing dehydration.', '3d338015-c49a-4511-9b25-1f6c1c8b3c3f': 'As you can see, there is a low net pressure across the filtration membrane. Intuitively, you should realize that minor changes in osmolarity of the blood or changes in capillary blood pressure result in major changes in the amount of filtrate formed at any given point in time. The kidney is able to cope with a wide range of blood pressures. In large part, this is due to the autoregulatory nature of smooth muscle. When you stretch it, it contracts. Thus, when blood pressure goes up, smooth muscle in the afferent arterioles contracts to limit any increase in blood flow and filtration rate. When blood pressure drops, the same capillaries relax to maintain blood flow and filtration rate. The net result is a relatively steady flow of blood into the glomerulus and a relatively steady filtration rate in spite of significant systemic blood pressure changes. Mean arterial blood pressure is calculated by adding 1/3 of the difference between the systolic and diastolic pressures to the diastolic pressure. Therefore, if the blood pressure is 110/80, the difference between systolic and diastolic pressure is 30. One third of this is 10, and when you add this to the diastolic pressure of 80, you arrive at a calculated mean arterial pressure of 90 mm Hg. Therefore, if you use mean arterial pressure for the GBHP in the formula for calculating NFP, you can determine that as long as mean arterial pressure is above approximately 60 mm Hg, the pressure will be adequate to maintain glomerular filtration. Blood pressures below this level will impair renal function and cause systemic disorders that are severe enough to threaten survival. This condition is called shock.', '9c81a925-e997-4f02-a9ab-6489ec14d2b4': 'It is vital that the flow of blood through the kidney be at a suitable rate to allow for filtration and yet not too fast to overwhelm the reabsorbing potential of the nephron tubule. This rate determines how much solute is retained or discarded, how much water is retained or discarded, and ultimately, the osmolarity of blood and the blood pressure of the body.'}"
+Figure 25.1.1,Anatomy_And_Physio/images/Figure 25.1.1.jpg,Figure 25.1.1 – Kidneys: The kidneys are slightly protected by the ribs and are surrounded by fat for protection. On the superior aspect of each kidney is an adrenal gland.,"The paired kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs. The left kidney is located at about the T12 to L3 vertebrae, whereas the right is lower due to slight displacement by the liver. Upper portions of the kidneys are somewhat protected by the eleventh and twelfth ribs (Figure 25.1.1). Each kidney weighs about 125–175 g in males and 115–155 g in females. They are about 11–14 cm in length, 6 cm wide, and 4 cm thick, and are directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them. This capsule is covered by a shock-absorbing layer of adipose tissue called the renal fat pad, which in turn is encompassed by a tough renal fascia. The fascia and, to a lesser extent, the overlying peritoneum serve to firmly anchor the kidneys to the posterior abdominal wall in a retroperitoneal position.","{'002892cc-d47e-48ff-91d8-233e0f086deb': 'The paired kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs.\xa0The left kidney is located at about the T12 to L3 vertebrae, whereas the right is lower due to slight displacement by the liver. Upper portions of the kidneys are somewhat protected by the eleventh and twelfth ribs (Figure 25.1.1). Each kidney weighs about 125–175 g in males and 115–155 g in females. They are about 11–14 cm in length, 6 cm wide, and 4 cm thick, and are directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them. This capsule is covered by a shock-absorbing layer of adipose tissue called the renal fat pad, which in turn is encompassed by a tough renal fascia. The fascia and, to a lesser extent, the overlying peritoneum serve to firmly anchor the kidneys to the posterior abdominal wall in a retroperitoneal position.', 'a92150a2-8243-4a97-aebf-3c8a50c2899c': 'A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal\xa0medulla (Figure 25.1.2). In the medulla, 5-8\xa0renal pyramids are separated by connective tissue\xa0renal columns.\xa0Each pyramid creates urine and terminates into a renal papilla. Each\xa0renal papilla drains into a collecting pool called a minor calyx; several minor calyces connect to form a major calyx; all major calyces connect to the single renal pelvis\xa0which connects to the ureter.', 'e1bbd5b1-445c-4a0e-926e-cf75a0a6694b': 'The urinary system has many roles including cleansing the blood and ridding the body of wastes. However, there are additional, equally important functions played by the system\xa0including regulation of pH, blood pressure, concentration of red blood cells, and production of vitamin D.\xa0If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on the body. The urinary system, controlled by the nervous system, also stores urine until a convenient time for disposal and then provides the anatomical structures to transport this waste liquid to the outside of the body.', 'b5cf5ce6-c49a-4fb4-88f2-20929ad2e020': 'The urinary system consists of paired kidneys which produce filter blood to produce urine. Urine moves through the ureters to the urinary bladder where it is stored until it is released. When released, urine travels through the urethra to the outside world.', '12ce598b-f51a-4cb0-a903-6a08d31bd434': 'The carbohydrates, lipids, and proteins in the foods you eat are used for energy to power molecular, cellular, and organ system activities. Importantly, the energy is stored primarily as fats. The quantity and quality of food that is ingested, digested, and absorbed affects the amount of fat that is stored as excess calories. Diet—both what you eat and how much you eat—has a dramatic impact on your health. Eating too much or too little food can lead to serious medical issues, including cardiovascular disease, cancer, anorexia, and diabetes, among others. Combine an unhealthy diet with unhealthy environmental conditions, such as smoking, and the potential medical complications increase significantly.'}"
+Figure 25.1.2,Anatomy_And_Physio/images/Figure 25.1.2.jpg,Figure 25.1.2 Left Kidney.,"A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal medulla (Figure 25.1.2). In the medulla, 5-8 renal pyramids are separated by connective tissue renal columns. Each pyramid creates urine and terminates into a renal papilla. Each renal papilla drains into a collecting pool called a minor calyx; several minor calyces connect to form a major calyx; all major calyces connect to the single renal pelvis which connects to the ureter.","{'002892cc-d47e-48ff-91d8-233e0f086deb': 'The paired kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs.\xa0The left kidney is located at about the T12 to L3 vertebrae, whereas the right is lower due to slight displacement by the liver. Upper portions of the kidneys are somewhat protected by the eleventh and twelfth ribs (Figure 25.1.1). Each kidney weighs about 125–175 g in males and 115–155 g in females. They are about 11–14 cm in length, 6 cm wide, and 4 cm thick, and are directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them. This capsule is covered by a shock-absorbing layer of adipose tissue called the renal fat pad, which in turn is encompassed by a tough renal fascia. The fascia and, to a lesser extent, the overlying peritoneum serve to firmly anchor the kidneys to the posterior abdominal wall in a retroperitoneal position.', 'a92150a2-8243-4a97-aebf-3c8a50c2899c': 'A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal\xa0medulla (Figure 25.1.2). In the medulla, 5-8\xa0renal pyramids are separated by connective tissue\xa0renal columns.\xa0Each pyramid creates urine and terminates into a renal papilla. Each\xa0renal papilla drains into a collecting pool called a minor calyx; several minor calyces connect to form a major calyx; all major calyces connect to the single renal pelvis\xa0which connects to the ureter.', 'e1bbd5b1-445c-4a0e-926e-cf75a0a6694b': 'The urinary system has many roles including cleansing the blood and ridding the body of wastes. However, there are additional, equally important functions played by the system\xa0including regulation of pH, blood pressure, concentration of red blood cells, and production of vitamin D.\xa0If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on the body. The urinary system, controlled by the nervous system, also stores urine until a convenient time for disposal and then provides the anatomical structures to transport this waste liquid to the outside of the body.', 'b5cf5ce6-c49a-4fb4-88f2-20929ad2e020': 'The urinary system consists of paired kidneys which produce filter blood to produce urine. Urine moves through the ureters to the urinary bladder where it is stored until it is released. When released, urine travels through the urethra to the outside world.', '12ce598b-f51a-4cb0-a903-6a08d31bd434': 'The carbohydrates, lipids, and proteins in the foods you eat are used for energy to power molecular, cellular, and organ system activities. Importantly, the energy is stored primarily as fats. The quantity and quality of food that is ingested, digested, and absorbed affects the amount of fat that is stored as excess calories. Diet—both what you eat and how much you eat—has a dramatic impact on your health. Eating too much or too little food can lead to serious medical issues, including cardiovascular disease, cancer, anorexia, and diabetes, among others. Combine an unhealthy diet with unhealthy environmental conditions, such as smoking, and the potential medical complications increase significantly.'}"
+Figure 24.7.1,Anatomy_And_Physio/images/Figure 24.7.1.jpg,Figure 24.7.1 – MyPlate: The U.S. Department of Agriculture developed food guidelines called MyPlate to help demonstrate how to maintain a healthy lifestyle.,"To help provide guidelines regarding the types and quantities of food that should be eaten every day, the USDA has updated their food guidelines from MyPyramid to MyPlate. They have put the recommended elements of a healthy meal into the context of a place setting of food. MyPlate categorizes food into the standard six food groups: fruits, vegetables, grains, protein foods, dairy, and oils. The accompanying website gives clear recommendations regarding quantity and type of each food that you should consume each day, as well as identifying which foods belong in each category. The accompanying graphic (Figure 24.7.1) gives a clear visual with general recommendations for a healthy and balanced meal. The guidelines recommend to “Make half your plate fruits and vegetables.” The other half is grains and protein, with a slightly higher quantity of grains than protein. Dairy products are represented by a drink, but the quantity can be applied to other dairy products as well.","{'647943a6-06c1-4863-bfc8-23e1fd17c750': 'The amount of energy that is needed or ingested per day is measured in calories. The nutritional Calorie (C) is the amount of heat it takes to raise 1 kg (1000 g) of water by 1 °C. This is different from the calorie (c) used in the physical sciences, which is the amount of heat it takes to raise 1 g of water by 1 °C. When we refer to “calorie,” we are referring to the nutritional Calorie.', 'ca504579-9ae3-44ea-bba5-09042c59aa95': 'On average, a person needs 1500 to 2000 calories per day to sustain (or carry out) daily activities. The total number of calories needed by one person is dependent on their body mass, age, height, gender, activity level, and the amount of exercise per day. If exercise is regular part of one’s day, more calories are required. As a rule, people underestimate the number of calories ingested and overestimate the amount they burn through exercise. This can lead to ingestion of too many calories per day. The accumulation of an extra 3500 calories adds one pound of weight. If an excess of 200 calories per day is ingested, one extra pound of body weight will be gained every 18 days. At that rate, an extra 20 pounds can be gained over the course of a year. Of course, this increase in calories could be offset by increased exercise. Running or jogging one mile burns almost 100 calories.', '9bb36344-3d40-43e9-90fe-18f8aa49ac01': 'The type of food ingested also affects the body’s metabolic rate. Processing of carbohydrates requires less energy than processing of proteins. In fact, the breakdown of carbohydrates requires the least amount of energy, whereas the processing of proteins demands the most energy. In general, the amount of calories ingested and the amount of calories burned determines the overall weight. To lose weight, the number of calories burned per day must exceed the number ingested. Calories are in almost everything you ingest, so when considering calorie intake, beverages must also be considered.', '5c2091a1-e8ca-4012-a00d-a054e8fdd3c0': 'To help provide guidelines regarding the types and quantities of food that should be eaten every day, the USDA has updated their food guidelines from MyPyramid to MyPlate. They have put the recommended elements of a healthy meal into the context of a place setting of food. MyPlate categorizes food into the standard six food groups: fruits, vegetables, grains, protein foods, dairy, and oils. The accompanying website gives clear recommendations regarding quantity and type of each food that you should consume each day, as well as identifying which foods belong in each category. The accompanying graphic (Figure 24.7.1) gives a clear visual with general recommendations for a healthy and balanced meal. The guidelines recommend to “Make half your plate fruits and vegetables.” The other half is grains and protein, with a slightly higher quantity of grains than protein. Dairy products are represented by a drink, but the quantity can be applied to other dairy products as well.', '8e8f5550-dce5-4993-ae47-0bd5e6fb88a1': 'ChooseMyPlate.gov provides extensive online resources for planning a healthy diet and lifestyle, including offering weight management tips and recommendations for physical activity. It also includes the SuperTracker, a web-based application to help you analyze your own diet and physical activity.'}"
+Figure 24.6.1,Anatomy_And_Physio/images/Figure 24.6.1.jpg,Figure 24.6.1 – Hypothalamus Controls Thermoregulation: The hypothalamus controls thermoregulation.,"The hypothalamus in the brain is the master switch that works as a thermostat to regulate the body’s core temperature (Figure 24.6.1). If the temperature is too high, the hypothalamus can initiate several processes to lower it. These include increasing the circulation of the blood to the surface of the body to allow for the dissipation of heat through the skin and initiation of sweating to allow evaporation of water on the skin to cool its surface. Conversely, if the temperature falls below the set core temperature, the hypothalamus can initiate shivering to generate heat. The body uses more energy and generates more heat. In addition, thyroid hormone will stimulate more energy use and heat production by cells throughout the body. An environment is said to be thermoneutral when the body does not expend or release energy to maintain its core temperature. For a naked human, this is an ambient air temperature of around 84 °F. If the temperature is higher, for example, when wearing clothes, the body compensates with cooling mechanisms. The body loses heat through the mechanisms of heat exchange.","{'9d529932-30f3-49bc-9e15-58f85916316e': 'Minerals in food are inorganic compounds that work with other nutrients to ensure the body functions properly. Minerals cannot be made in the body; they come from the diet. The amount of minerals in the body is small—only 4 percent of the total body mass—and most of that consists of the minerals that the body requires in moderate quantities: potassium, sodium, calcium, phosphorus, magnesium, and chloride.', 'ed14b65e-e0a6-48a1-9fd5-d3d18dcd8fe3': 'The most common minerals in the body are calcium and phosphorous, both of which are stored in the skeleton and necessary for the hardening of bones. Most minerals are ionized, and their ionic forms are used in physiological processes throughout the body. Sodium and chloride ions are electrolytes in the blood and extracellular tissues, and iron ions are critical to the formation of hemoglobin. Many minerals are used as cofactors and coenzymes in metabolic processes. There are additional trace minerals that are still important to the body’s functions, but their required quantities are much lower.', '62b7e3ac-3d25-43bf-bcdf-47f42f334b23': 'Like vitamins, minerals can be consumed in toxic quantities (although it is rare). A healthy diet includes most of the minerals your body requires, so supplements and processed foods can add potentially toxic levels of minerals. Table 24.5 and Table 24.6 provide a summary of minerals and their function in the body.', '954e27da-fec9-49a4-88db-77822e27d7e8': 'The body tightly regulates the body temperature through a process called thermoregulation, in which the body can maintain its temperature within certain boundaries, even when the surrounding temperature is very different. The core temperature of the body remains steady at around 36.5–37.5 °C (or 97.7–99.5 °F). In the process of ATP production by cells throughout the body, approximately 60 percent of the energy produced is in the form of heat used to maintain body temperature. Thermoregulation is an example of negative feedback.', '22bf97a3-dd19-47b3-944f-930a0fbd6405': 'The hypothalamus in the brain is the master switch that works as a thermostat to regulate the body’s core temperature (Figure 24.6.1). If the temperature is too high, the hypothalamus can initiate several processes to lower it. These include increasing the circulation of the blood to the surface of the body to allow for the dissipation of heat through the skin and initiation of sweating to allow evaporation of water on the skin to cool its surface. Conversely, if the temperature falls below the set core temperature, the hypothalamus can initiate shivering to generate heat. The body uses more energy and generates more heat. In addition, thyroid hormone will stimulate more energy use and heat production by cells throughout the body. An environment is said to be thermoneutral when the body does not expend or release energy to maintain its core temperature. For a naked human, this is an ambient air temperature of around 84 °F. If the temperature is higher, for example, when wearing clothes, the body compensates with cooling mechanisms. The body loses heat through the mechanisms of heat exchange.'}"
+Figure 24.5.1,Anatomy_And_Physio/images/Figure 24.5.1.jpg,"Figure 24.5.1 – Absorptive State: During the absorptive state, the body digests food and absorbs the nutrients into cells.",Figure 24.5.1 summarizes the metabolic processes occurring in the body during the absorptive state.,"{'94d1f0ee-4190-45dc-8c34-2e1f4be4206b': 'The absorptive state, or the fed state, occurs after a meal when your body is digesting the food and absorbing the nutrients (anabolism exceeds catabolism). Digestion begins the moment you put food into your mouth, as the food is broken down into its constituent parts to be absorbed through the intestine. The digestion of carbohydrates begins in the mouth, whereas the digestion of proteins and fats begins in the stomach and small intestine. The constituent parts of these carbohydrates, fats, and proteins are transported across the intestinal wall and enter the bloodstream (sugars and amino acids) or the lymphatic system (fats). From the intestines, these systems transport them to the liver, adipose tissue, or muscle cells that will process and use, or store, the energy.', '64bb5a93-1f73-4b86-91bb-73f8a6fead39': 'Depending on the amounts and types of nutrients ingested, the absorptive state can linger for up to 4 hours. The ingestion of food and the rise of glucose concentrations in the bloodstream stimulate pancreatic beta cells to release insulin into the bloodstream, where it initiates the absorption of blood glucose by liver hepatocytes, and by adipose and muscle cells. Once inside these cells, glucose is immediately converted into glucose-6-phosphate. By doing this, a concentration gradient is established where glucose levels are higher in the blood than in the cells. This allows for glucose to continue moving from the blood to the cells where it is needed. Insulin also stimulates the storage of glucose as glycogen in the liver and muscle cells where it can be used for later energy needs of the body. Insulin also promotes the synthesis of protein in muscle. As you will see, muscle protein can be catabolized and used as fuel in times of starvation.', 'be0fe9f2-85ec-4e4e-ad6c-8744f401c488': 'If energy is exerted shortly after eating, the dietary fats and sugars that were just ingested will be processed and used immediately for energy. If not, the excess glucose is stored as glycogen in the liver and muscle cells, or as fat in adipose tissue; excess dietary fat is also stored as triglycerides in adipose tissues.', '6a01f26c-aabd-4d29-955d-62d0dbf6b576': 'Figure 24.5.1 summarizes the metabolic processes occurring in the body during the absorptive state.'}"
+Figure 24.5.2,Anatomy_And_Physio/images/Figure 24.5.2.jpg,"Figure 24.5.2 – Postabsorptive State: During the postabsorptive state, the body must rely on stored glycogen for energy, breaking down glycogen in the cells and releasing it to cell (muscle) or the body (liver).","After ingestion of food, fats and proteins are processed as described previously; however, the glucose processing changes a bit. The peripheral tissues preferentially absorb glucose. The liver, which normally absorbs and processes glucose, will not do so after a prolonged fast. The gluconeogenesis that has been ongoing in the liver will continue after fasting to replace the glycogen stores that were depleted in the liver. After these stores have been replenished, excess glucose that is absorbed by the liver will be converted into triglycerides and fatty acids for long-term storage. Figure 24.5.2 summarizes the metabolic processes occurring in the body during the postabsorptive state.","{'062d9e61-f1dc-4fd4-8378-5af645f70006': 'The postabsorptive state, or the fasting state, occurs when the food has been digested, absorbed, and stored. You commonly fast overnight, but skipping meals during the day puts your body in the postabsorptive state as well. During this state, the body must rely initially on stored glycogen. Glucose levels in the blood begin to drop as it is absorbed and used by the cells. In response to the decrease in glucose, insulin levels also drop. Glycogen and triglyceride storage slows. However, due to the demands of the tissues and organs, blood glucose levels must be maintained in the normal range of 80–120 mg/dL. In response to a drop in blood glucose concentration, the hormone glucagon is released from the alpha cells of the pancreas. Glucagon acts upon the liver cells, where it inhibits the synthesis of glycogen and stimulates the breakdown of stored glycogen back into glucose. This glucose is released from the liver to be used by the peripheral tissues and the brain. As a result, blood glucose levels begin to rise. Gluconeogenesis will also begin in the liver to replace the glucose that has been used by the peripheral tissues.', '79322182-c101-48c5-ad99-8666d655b1c6': 'After ingestion of food, fats and proteins are processed as described previously; however, the glucose processing changes a bit. The peripheral tissues preferentially absorb glucose. The liver, which normally absorbs and processes glucose, will not do so after a prolonged fast. The gluconeogenesis that has been ongoing in the liver will continue after fasting to replace the glycogen stores that were depleted in the liver. After these stores have been replenished, excess glucose that is absorbed by the liver will be converted into triglycerides and fatty acids for long-term storage. Figure 24.5.2 summarizes the metabolic processes occurring in the body during the postabsorptive state.'}"
+Figure 24.1.1,Anatomy_And_Physio/images/Figure 24.1.1.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions.","When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.","{'46979334-fe5d-4d41-9837-40fd6b8173f8': 'When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.', '907c469c-aa0c-4f01-a867-a0f97fa86629': 'After several days of starvation, ketone bodies become the major source of fuel for the heart and other organs. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. This prevents the continued breakdown of proteins that serve as carbon sources for gluconeogenesis. Once these stores are fully depleted, proteins from muscles are released and broken down for glucose synthesis. Overall survival is dependent on the amount of fat and protein stored in the body.', '48726f29-6477-423e-830b-d49780e7b9ef': 'Much of the body is made of protein, and these proteins take on a myriad of forms. They represent cell signaling receptors, signaling molecules, structural members, enzymes, intracellular trafficking components, extracellular matrix scaffolds, ion pumps, ion channels, oxygen and CO2 transporters (hemoglobin). That is not even the complete list! There is protein in bones (collagen), muscles, and tendons; the hemoglobin that transports oxygen; and enzymes that catalyze all biochemical reactions. Protein is also used for growth and repair. Amid all these necessary functions, proteins also hold the potential to serve as a metabolic fuel source. Proteins are not stored for later use, so excess proteins must be converted into glucose or triglycerides, and used to supply energy or build energy reserves. Although the body can synthesize proteins from amino acids, food is an important source of those amino acids, especially because humans cannot synthesize all of the 20 amino acids used to build proteins.', '0fc23cb1-d75a-4329-966b-5dedd44ee9e3': 'The digestion of proteins begins in the stomach. When protein-rich foods enter the stomach, they are greeted by a mixture of the enzyme pepsin and hydrochloric acid (HCl; 0.5 percent). The latter produces an environmental pH of 1.5–3.5 that denatures proteins within food. Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. When the food-gastric juice mixture (chyme) enters the small intestine, the pancreas releases sodium bicarbonate to neutralize the HCl. This helps to protect the lining of the intestine. The small intestine also releases digestive hormones, including secretin and CCK, which stimulate digestive processes to break down the proteins further. Secretin also stimulates the pancreas to release sodium bicarbonate. The pancreas releases most of the digestive enzymes, including the proteases trypsin, chymotrypsin, carboxypeptidase, and elastase, which aid protein digestion. Together, all of these enzymes break complex proteins into smaller individual amino acids (Figure 24.4.1), which are then transported across the intestinal mucosa to be used to create new proteins, or to be converted into fats or acetyl CoA and used in the Krebs cycle.', '9cb34cb2-9701-4310-add8-01e3265350b8': 'In order to avoid breaking down the proteins that make up the pancreas and small intestine, pancreatic enzymes are released as inactive proenzymes that are only activated in the small intestine. In the pancreas, vesicles store trypsin, chymotrypsin, and carboxypeptidase as trypsinogen, chymotrypsinogen, and procarboxypeptidase. Once released into the small intestine, an enzyme found in the wall of the small intestine, called enterokinase, binds to trypsinogen and converts it into its active form, trypsin. Trypsin then binds to chymotrypsinogen and procarboxypeptidase to convert it into the active chymotrypsin and carboxypeptidase. Trypsin, chymotrypsin, and carboxypeptidase break down large proteins into smaller peptides, a process called proteolysis. These smaller peptides are catabolized into their constituent amino acids by the brush border enzymes, aminopeptidase and dipeptidase.\xa0The free amino acids are then transported across the apical surface of the intestinal mucosa in a process that is mediated by secondary active transport using sodium-amino acid transporters. These transporters bind sodium and then bind the amino acid to transport it across the membrane. At the basal surface of the mucosal cells, the sodium and amino acid are released. The sodium can be reused in the transporter, whereas the amino acids are transferred into the bloodstream to be transported to the liver and cells throughout the body for protein synthesis.', '7a8e720a-8b68-48db-bbf1-1e87cd0581e2': 'Freely available amino acids are used to create proteins. If amino acids exist in excess, the body has no capacity or mechanism for their storage; thus, they are converted into glucose or ketones, or they are decomposed. Amino acid decomposition results in hydrocarbons and nitrogenous waste. However, high concentrations of nitrogen are toxic as they produce ammonium ions. The urea cycle processes nitrogen and facilitates its excretion from the body.', '1b0ae55b-89fe-475e-94c6-7f8396ca1699': 'Catabolic reactions break down large organic molecules into smaller molecules, releasing the energy contained in the chemical bonds. These energy releases (conversions) are not 100 percent efficient. The amount of energy released is less than the total amount contained in the molecule. Approximately 40 percent of energy yielded from catabolic reactions is directly transferred to the high-energy molecule adenosine triphosphate (ATP). ATP, the energy currency of cells, can be used immediately to power molecular machines that support cell, tissue, and organ function. This includes building new tissue and repairing damaged tissue. ATP can also be stored to fulfill future energy demands. The remaining 60 percent of the energy released from catabolic reactions is given off as heat, which tissues and body fluids absorb.', 'd71df0fd-28e1-438f-a26a-f2bc7103bb0d': 'Structurally, ATP molecules consist of an adenine, a ribose, and three phosphate groups (Figure 24.1.1). The chemical bond between the second and third phosphate groups, termed a high-energy bond, represents the greatest source of energy in a cell. It is the first bond that catabolic enzymes break when cells require energy to do work. The products of this reaction are a molecule of adenosine diphosphate (ADP) and a lone phosphate group (Pi). ATP, ADP, and Pi are constantly being cycled through reactions that build ATP and store energy, and reactions that break down ATP and release energy.', '65d8da7c-500a-4380-bc4c-603f1877bce2': 'The energy from ATP drives all bodily functions, such as contracting muscles, maintaining the electrical potential of nerve cells, and absorbing food in the gastrointestinal tract. The metabolic reactions that produce ATP come from various sources (Figure 24.1.2).', 'd3a7a739-0cc6-4f09-bd7f-3c13ac821758': 'Of the four major macromolecular groups (carbohydrates, lipids, proteins, and nucleic acids) that are processed by digestion, carbohydrates are considered the most common source of energy to fuel the body. They take the form of either complex carbohydrates, polysaccharides like starch and glycogen, or simple sugars (monosaccharides) like glucose and fructose. Sugar catabolism breaks polysaccharides down into their individual monosaccharides. Among the monosaccharides, glucose is the most common fuel for ATP production in cells, and as such, there are a number of endocrine control mechanisms to regulate glucose concentration in the bloodstream. Excess glucose is either stored as an energy reserve in the liver and skeletal muscles as the complex polymer glycogen, or it is converted into fat (triglyceride) in adipose cells (adipocytes).', '5849f685-335f-41d5-ad90-ed18b01d1612': 'Among the lipids (fats), triglycerides are most often used for energy via a metabolic process called β-oxidation. About one-half of excess fat is stored in adipocytes that accumulate in the subcutaneous tissue under the skin, whereas the rest is stored in adipocytes in other tissues and organs.', '5852e9a6-25cc-4c50-9697-41df37f4c123': 'Proteins, which are polymers, can be broken down into their monomers, individual amino acids. Amino acids can be used as building blocks of new proteins or broken down further for the production of ATP. When one is chronically starving, this use of amino acids for energy production can lead to a wasting away of the body, as more and more proteins are broken down.', '2f9273c5-0e7a-4071-b038-925e92d9ab0e': 'Nucleic acids are present in most of the foods you eat. During digestion, nucleic acids including DNA and various RNAs are broken down into their constituent nucleotides. These nucleotides are readily absorbed and transported throughout the body to be used by individual cells during nucleic acid metabolism.'}"
+Figure 24.4.1,Anatomy_And_Physio/images/Figure 24.4.1.jpg,"Figure 24.4.1 – Digestive Enzymes and Hormones: Enzymes in the stomach and small intestine break down proteins into amino acids. HCl in the stomach aids in proteolysis by denaturing proteins, and hormones secreted by intestinal cells direct the digestive processes.","The digestion of proteins begins in the stomach. When protein-rich foods enter the stomach, they are greeted by a mixture of the enzyme pepsin and hydrochloric acid (HCl; 0.5 percent). The latter produces an environmental pH of 1.5–3.5 that denatures proteins within food. Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. When the food-gastric juice mixture (chyme) enters the small intestine, the pancreas releases sodium bicarbonate to neutralize the HCl. This helps to protect the lining of the intestine. The small intestine also releases digestive hormones, including secretin and CCK, which stimulate digestive processes to break down the proteins further. Secretin also stimulates the pancreas to release sodium bicarbonate. The pancreas releases most of the digestive enzymes, including the proteases trypsin, chymotrypsin, carboxypeptidase, and elastase, which aid protein digestion. Together, all of these enzymes break complex proteins into smaller individual amino acids (Figure 24.4.1), which are then transported across the intestinal mucosa to be used to create new proteins, or to be converted into fats or acetyl CoA and used in the Krebs cycle.","{'46979334-fe5d-4d41-9837-40fd6b8173f8': 'When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.', '907c469c-aa0c-4f01-a867-a0f97fa86629': 'After several days of starvation, ketone bodies become the major source of fuel for the heart and other organs. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. This prevents the continued breakdown of proteins that serve as carbon sources for gluconeogenesis. Once these stores are fully depleted, proteins from muscles are released and broken down for glucose synthesis. Overall survival is dependent on the amount of fat and protein stored in the body.', '48726f29-6477-423e-830b-d49780e7b9ef': 'Much of the body is made of protein, and these proteins take on a myriad of forms. They represent cell signaling receptors, signaling molecules, structural members, enzymes, intracellular trafficking components, extracellular matrix scaffolds, ion pumps, ion channels, oxygen and CO2 transporters (hemoglobin). That is not even the complete list! There is protein in bones (collagen), muscles, and tendons; the hemoglobin that transports oxygen; and enzymes that catalyze all biochemical reactions. Protein is also used for growth and repair. Amid all these necessary functions, proteins also hold the potential to serve as a metabolic fuel source. Proteins are not stored for later use, so excess proteins must be converted into glucose or triglycerides, and used to supply energy or build energy reserves. Although the body can synthesize proteins from amino acids, food is an important source of those amino acids, especially because humans cannot synthesize all of the 20 amino acids used to build proteins.', '0fc23cb1-d75a-4329-966b-5dedd44ee9e3': 'The digestion of proteins begins in the stomach. When protein-rich foods enter the stomach, they are greeted by a mixture of the enzyme pepsin and hydrochloric acid (HCl; 0.5 percent). The latter produces an environmental pH of 1.5–3.5 that denatures proteins within food. Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. When the food-gastric juice mixture (chyme) enters the small intestine, the pancreas releases sodium bicarbonate to neutralize the HCl. This helps to protect the lining of the intestine. The small intestine also releases digestive hormones, including secretin and CCK, which stimulate digestive processes to break down the proteins further. Secretin also stimulates the pancreas to release sodium bicarbonate. The pancreas releases most of the digestive enzymes, including the proteases trypsin, chymotrypsin, carboxypeptidase, and elastase, which aid protein digestion. Together, all of these enzymes break complex proteins into smaller individual amino acids (Figure 24.4.1), which are then transported across the intestinal mucosa to be used to create new proteins, or to be converted into fats or acetyl CoA and used in the Krebs cycle.', '9cb34cb2-9701-4310-add8-01e3265350b8': 'In order to avoid breaking down the proteins that make up the pancreas and small intestine, pancreatic enzymes are released as inactive proenzymes that are only activated in the small intestine. In the pancreas, vesicles store trypsin, chymotrypsin, and carboxypeptidase as trypsinogen, chymotrypsinogen, and procarboxypeptidase. Once released into the small intestine, an enzyme found in the wall of the small intestine, called enterokinase, binds to trypsinogen and converts it into its active form, trypsin. Trypsin then binds to chymotrypsinogen and procarboxypeptidase to convert it into the active chymotrypsin and carboxypeptidase. Trypsin, chymotrypsin, and carboxypeptidase break down large proteins into smaller peptides, a process called proteolysis. These smaller peptides are catabolized into their constituent amino acids by the brush border enzymes, aminopeptidase and dipeptidase.\xa0The free amino acids are then transported across the apical surface of the intestinal mucosa in a process that is mediated by secondary active transport using sodium-amino acid transporters. These transporters bind sodium and then bind the amino acid to transport it across the membrane. At the basal surface of the mucosal cells, the sodium and amino acid are released. The sodium can be reused in the transporter, whereas the amino acids are transferred into the bloodstream to be transported to the liver and cells throughout the body for protein synthesis.', '7a8e720a-8b68-48db-bbf1-1e87cd0581e2': 'Freely available amino acids are used to create proteins. If amino acids exist in excess, the body has no capacity or mechanism for their storage; thus, they are converted into glucose or ketones, or they are decomposed. Amino acid decomposition results in hydrocarbons and nitrogenous waste. However, high concentrations of nitrogen are toxic as they produce ammonium ions. The urea cycle processes nitrogen and facilitates its excretion from the body.'}"
+Figure 24.4.2,Anatomy_And_Physio/images/Figure 24.4.2.jpg,"Figure 24.4.2 – Urea Cycle: Nitrogen is transaminated, creating ammonia and intermediates of the Krebs cycle. Ammonia is processed in the urea cycle to produce urea that is eliminated through the kidneys.","In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).","{'0412ecb6-ba81-4c74-a548-9a7c1b38e114': 'The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.', 'd97a7269-f28f-4082-b370-16285284110d': 'In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).', 'e20e84d7-bbea-4d2e-9db6-1f6e32fe5240': 'Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.', '01ad7802-248d-48a3-a381-509fb7d64007': 'Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.', 'b920dc76-e609-484f-88bb-60df13f1243f': 'Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.', '26f87c4e-8cb9-465d-b9dd-c63fa285d74b': 'Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.'}"
+Figure 24.4.3,Anatomy_And_Physio/images/Figure 24.4.3.jpg,Figure 24.4.3 – Energy from Amino Acids: Amino acids can be broken down into precursors for glycolysis or the Krebs cycle. Amino acids (in bold) can enter the cycle through more than one pathway.,"Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.","{'0412ecb6-ba81-4c74-a548-9a7c1b38e114': 'The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.', 'd97a7269-f28f-4082-b370-16285284110d': 'In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).', 'e20e84d7-bbea-4d2e-9db6-1f6e32fe5240': 'Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.', '01ad7802-248d-48a3-a381-509fb7d64007': 'Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.', 'b920dc76-e609-484f-88bb-60df13f1243f': 'Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.', '26f87c4e-8cb9-465d-b9dd-c63fa285d74b': 'Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.'}"
+Figure 24.3.1,Anatomy_And_Physio/images/Figure 24.3.1.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).,"Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.","{'0412ecb6-ba81-4c74-a548-9a7c1b38e114': 'The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.', 'd97a7269-f28f-4082-b370-16285284110d': 'In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).', 'e20e84d7-bbea-4d2e-9db6-1f6e32fe5240': 'Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.', '01ad7802-248d-48a3-a381-509fb7d64007': 'Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.', 'b920dc76-e609-484f-88bb-60df13f1243f': 'Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.', '26f87c4e-8cb9-465d-b9dd-c63fa285d74b': 'Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.'}"
+Figure 24.3.1,Anatomy_And_Physio/images/Figure 24.3.1.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).,"Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.","{'0412ecb6-ba81-4c74-a548-9a7c1b38e114': 'The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.', 'd97a7269-f28f-4082-b370-16285284110d': 'In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).', 'e20e84d7-bbea-4d2e-9db6-1f6e32fe5240': 'Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.', '01ad7802-248d-48a3-a381-509fb7d64007': 'Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.', 'b920dc76-e609-484f-88bb-60df13f1243f': 'Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.', '26f87c4e-8cb9-465d-b9dd-c63fa285d74b': 'Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.'}"
+Figure 24.3.2,Anatomy_And_Physio/images/Figure 24.3.2.jpg,"Figure 24.3.2 – Chylomicrons: Chylomicrons contain triglycerides, cholesterol molecules, and other apolipoproteins (protein molecules). They function to carry these water-insoluble molecules from the intestine, through the lymphatic system, and into the bloodstream, which carries the lipids to adipose tissue for storage.","Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.","{'0412ecb6-ba81-4c74-a548-9a7c1b38e114': 'The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.', 'd97a7269-f28f-4082-b370-16285284110d': 'In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).', 'e20e84d7-bbea-4d2e-9db6-1f6e32fe5240': 'Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.', '01ad7802-248d-48a3-a381-509fb7d64007': 'Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.', 'b920dc76-e609-484f-88bb-60df13f1243f': 'Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.', '26f87c4e-8cb9-465d-b9dd-c63fa285d74b': 'Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.'}"
+Figure 24.3.3,Anatomy_And_Physio/images/Figure 24.3.3.jpg,"Figure 24.3.3 – Breakdown of Fatty Acids: During fatty acid oxidation, triglycerides can be broken down into acetyl CoA molecules and used for energy when glucose levels are low.","The breakdown of fatty acids, called fatty acid oxidation or beta (β)-oxidation, begins in the cytoplasm, where fatty acids are converted into fatty acyl CoA molecules. This fatty acyl CoA combines with carnitine to create a fatty acyl carnitine molecule, which helps to transport the fatty acid across the mitochondrial membrane. Once inside the mitochondrial matrix, the fatty acyl carnitine molecule is converted back into fatty acyl CoA and then into acetyl CoA (Figure 24.3.3). The newly formed acetyl CoA enters the Krebs cycle and is used to produce ATP in the same way as acetyl CoA derived from pyruvate.","{'386fb610-4721-43c8-bdad-b689630a2cf9': 'To obtain energy from fat, triglycerides must first be broken down by hydrolysis into their two principal components, fatty acids and glycerol. This process, called lipolysis, takes place in the cytoplasm. The resulting fatty acids are oxidized by β-oxidation into acetyl CoA, which is used by the Krebs cycle. The glycerol that is released from triglycerides after lipolysis directly enters the glycolysis pathway as DHAP. Because one triglyceride molecule yields three fatty acid molecules with as much as 16 or more carbons in each one, fat molecules yield more energy than carbohydrates and are an important source of energy for the human body. Triglycerides yield more than twice the energy per unit mass when compared to carbohydrates and proteins. Therefore, when glucose levels are low, triglycerides can be converted into acetyl CoA molecules and used to generate ATP through aerobic respiration.', '20f4138c-ebaf-4436-8a8f-64f9da67147c': 'The breakdown of fatty acids, called fatty acid oxidation or beta (β)-oxidation, begins in the cytoplasm, where fatty acids are converted into fatty acyl CoA molecules. This fatty acyl CoA combines with carnitine to create a fatty acyl carnitine molecule, which helps to transport the fatty acid across the mitochondrial membrane. Once inside the mitochondrial matrix, the fatty acyl carnitine molecule is converted back into fatty acyl CoA and then into acetyl CoA (Figure 24.3.3). The newly formed acetyl CoA enters the Krebs cycle and is used to produce ATP in the same way as acetyl CoA derived from pyruvate.'}"
+Figure 24.3.4,Anatomy_And_Physio/images/Figure 24.3.4.jpg,"Figure 24.3.4 – Ketogenesis: Excess acetyl CoA is diverted from the Krebs cycle to the ketogenesis pathway. This reaction occurs in the mitochondria of liver cells. The result is the production of β-hydroxybutyrate, the primary ketone body found in the blood.","In this ketone synthesis reaction, excess acetyl CoA is converted into hydroxymethylglutaryl CoA (HMG CoA). HMG CoA is a precursor of cholesterol and is an intermediate that is subsequently converted into β-hydroxybutyrate, the primary ketone body in the blood (Figure 24.3.4).","{'6d4940c3-d491-4302-ae2d-a98cbc2749fe': 'If excessive acetyl CoA is created from the oxidation of fatty acids and the Krebs cycle is overloaded and cannot handle it, the acetyl CoA is diverted to create ketone bodies. These ketone bodies can serve as a fuel source if glucose levels are too low in the body. Ketones serve as fuel in times of prolonged starvation or when patients suffer from uncontrolled diabetes and cannot utilize most of the circulating glucose. In both cases, fat stores are liberated to generate energy through the Krebs cycle and will generate ketone bodies when too much acetyl CoA accumulates.', '3837e37d-bbfa-4b8e-b8b6-95af7d47f4e0': 'In this ketone synthesis reaction, excess acetyl CoA is converted into hydroxymethylglutaryl CoA (HMG CoA). HMG CoA is a precursor of cholesterol and is an intermediate that is subsequently converted into β-hydroxybutyrate, the primary ketone body in the blood (Figure 24.3.4).'}"
+Figure 24.3.5,Anatomy_And_Physio/images/Figure 24.3.5.jpg,"Figure 24.3.5 – Ketone Oxidation: When glucose is limited, ketone bodies can be oxidized to produce acetyl CoA to be used in the Krebs cycle to generate energy.","Ketones oxidize to produce energy for the brain. beta (β)-hydroxybutyrate is oxidized to acetoacetate and NADH is released. An HS-CoA molecule is added to acetoacetate, forming acetoacetyl CoA. The carbon within the acetoacetyl CoA that is not bonded to the CoA then detaches, splitting the molecule in two. This carbon then attaches to another free HS-CoA, resulting in two acetyl CoA molecules. These two acetyl CoA molecules are then processed through the Krebs cycle to generate energy (Figure 24.3.5).","{'159e8d45-9b9c-4084-8164-b9f88ccadd1c': 'Organs that have classically been thought to be dependent solely on glucose, such as the brain, can actually use ketones as an alternative energy source. This keeps the brain functioning when glucose is limited. When ketones are produced faster than they can be used, they can be broken down into CO2 and acetone. The acetone is removed by exhalation. One symptom of ketogenesis is that the patient’s breath smells sweet like alcohol. This effect provides one way of telling if a diabetic is properly controlling the disease. The carbon dioxide produced can acidify the blood, leading to diabetic ketoacidosis, a dangerous condition in diabetics.', 'd2071756-ed36-4df1-b2fe-5463b2ea55fd': 'Ketones oxidize to produce energy for the brain. beta (β)-hydroxybutyrate is oxidized to acetoacetate and NADH is released. An HS-CoA molecule is added to acetoacetate, forming acetoacetyl CoA. The carbon within the acetoacetyl CoA that is not bonded to the CoA then detaches, splitting the molecule in two. This carbon then attaches to another free HS-CoA, resulting in two acetyl CoA molecules. These two acetyl CoA molecules are then processed through the Krebs cycle to generate energy (Figure 24.3.5).'}"
+Figure 24.3.6,Anatomy_And_Physio/images/Figure 24.3.6.jpg,Figure 24.3.6 – Lipid Metabolism: Lipids may follow one of several pathways during metabolism. Glycerol and fatty acids follow different pathways.,"Although lipogenesis occurs in the cytoplasm, the necessary acetyl CoA is created in the mitochondria and cannot be transported across the mitochondrial membrane. To solve this problem, pyruvate is converted into both oxaloacetate and acetyl CoA. Two different enzymes are required for these conversions. Oxaloacetate forms via the action of pyruvate carboxylase, whereas the action of pyruvate dehydrogenase creates acetyl CoA. Oxaloacetate and acetyl CoA combine to form citrate, which can cross the mitochondrial membrane and enter the cytoplasm. In the cytoplasm, citrate is converted back into oxaloacetate and acetyl CoA. Oxaloacetate is converted into malate and then into pyruvate. Pyruvate crosses back across the mitochondrial membrane to wait for the next cycle of lipogenesis. The acetyl CoA is converted into malonyl CoA that is used to synthesize fatty acids. Figure 24.3.6 summarizes the pathways of lipid metabolism.","{'24c5e97c-72e8-4218-a07d-d2dc1efaa725': 'When glucose levels are plentiful, the excess acetyl CoA generated by glycolysis can be converted into fatty acids, triglycerides, cholesterol, steroids, and bile salts. This process, called lipogenesis, creates lipids (fat) from the acetyl CoA and takes place in the cytoplasm of adipocytes (fat cells) and hepatocytes (liver cells). When you eat more glucose or carbohydrates than your body needs, your system uses acetyl CoA to turn the excess into fat. Although there are several metabolic sources of acetyl CoA, it is most commonly derived from glycolysis. Acetyl CoA availability is significant, because it initiates lipogenesis. Lipogenesis begins with acetyl CoA and advances by the subsequent addition of two carbon atoms from another acetyl CoA; this process is repeated until fatty acids are the appropriate length. Because this is a bond-creating anabolic process, ATP is consumed. However, the creation of triglycerides and lipids is an efficient way of storing the energy available in carbohydrates. Triglycerides and lipids, both high-energy molecules, are stored in adipose tissue until they are needed.', '8a199751-3180-45d0-a5b7-b2647f721571': 'Although lipogenesis occurs in the cytoplasm, the necessary acetyl CoA is created in the mitochondria and cannot be transported across the mitochondrial membrane. To solve this problem, pyruvate is converted into both oxaloacetate and acetyl CoA. Two different enzymes are required for these conversions. Oxaloacetate forms via the action of pyruvate carboxylase, whereas the action of pyruvate dehydrogenase creates acetyl CoA. Oxaloacetate and acetyl CoA combine to form citrate, which can cross the mitochondrial membrane and enter the cytoplasm. In the cytoplasm, citrate is converted back into oxaloacetate and acetyl CoA. Oxaloacetate is converted into malate and then into pyruvate. Pyruvate crosses back across the mitochondrial membrane to wait for the next cycle of lipogenesis. The acetyl CoA is converted into malonyl CoA that is used to synthesize fatty acids. Figure 24.3.6 summarizes the pathways of lipid metabolism.', '6aa0f074-8169-4164-a441-67f2520ce809': 'Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen atoms. The family of carbohydrates includes both simple and complex sugars. Glucose and fructose are examples of simple sugars, and starch, glycogen, and cellulose are all examples of complex sugars. The complex sugars are also called polysaccharides and are made of multiple monosaccharide molecules. Polysaccharides serve as energy storage (e.g., starch and glycogen) and as structural components (e.g., chitin in insects and cellulose in plants).', '1b4d6f86-9f98-4bc9-90ed-db5b6006ac38': 'During digestion, carbohydrates are broken down into simple, soluble sugars that can be transported across the intestinal wall into the circulatory system to be transported throughout the body. Carbohydrate digestion begins in the mouth with the action of salivary amylase on starches, continues in the duodenum with the action of pancreatic amylase, and ends with monosaccharides being absorbed across the epithelium of the small intestine. Once the absorbed monosaccharides are transported to the tissues, the process of cellular respiration begins (Figure 24.2.1). The goal of cellular respiration is to produce ATP for use by the body to power physiological processes. To start the process, a glucose molecule will get modified to two pyruvate molecules in the metabolic pathway called glycolysis. When oxygen is available, the pyruvate molecules will then be converted to acetyl CoA which enters the mitochondria and enters the citric acid cycle. Both glycolysis and the citric acid cycle produce a small amount of ATP (2 ATP per pathway), but the majority of the ATP produced by aerobic metabolism is achieved when the products of glyolysis and the citric acid, NADH and FADH2, carry their electrons to the electron transport chain. The electron transport chain transfers electrons through electron carriers, ultimately to oxygen in a process called oxidative phosphorylaton. This final process of cellular respiration harnesses the energy delivered by NADH and FADH2 to drive ATP synthase to produce 34 ATP per glucose. This first section will focus first on glycolysis, a process where the monosaccharide glucose is oxidized, releasing the energy stored in its bonds to produce ATP.'}"
+Figure 24.2.1,Anatomy_And_Physio/images/Figure 24.2.1.jpg,"Figure 24.2.1 – Cellular Respiration: Cellular respiration oxidizes glucose molecules through glycolysis, the Krebs cycle, and oxidative phosphorylation to produce ATP.","During digestion, carbohydrates are broken down into simple, soluble sugars that can be transported across the intestinal wall into the circulatory system to be transported throughout the body. Carbohydrate digestion begins in the mouth with the action of salivary amylase on starches, continues in the duodenum with the action of pancreatic amylase, and ends with monosaccharides being absorbed across the epithelium of the small intestine. Once the absorbed monosaccharides are transported to the tissues, the process of cellular respiration begins (Figure 24.2.1). The goal of cellular respiration is to produce ATP for use by the body to power physiological processes. To start the process, a glucose molecule will get modified to two pyruvate molecules in the metabolic pathway called glycolysis. When oxygen is available, the pyruvate molecules will then be converted to acetyl CoA which enters the mitochondria and enters the citric acid cycle. Both glycolysis and the citric acid cycle produce a small amount of ATP (2 ATP per pathway), but the majority of the ATP produced by aerobic metabolism is achieved when the products of glyolysis and the citric acid, NADH and FADH2, carry their electrons to the electron transport chain. The electron transport chain transfers electrons through electron carriers, ultimately to oxygen in a process called oxidative phosphorylaton. This final process of cellular respiration harnesses the energy delivered by NADH and FADH2 to drive ATP synthase to produce 34 ATP per glucose. This first section will focus first on glycolysis, a process where the monosaccharide glucose is oxidized, releasing the energy stored in its bonds to produce ATP.","{'24c5e97c-72e8-4218-a07d-d2dc1efaa725': 'When glucose levels are plentiful, the excess acetyl CoA generated by glycolysis can be converted into fatty acids, triglycerides, cholesterol, steroids, and bile salts. This process, called lipogenesis, creates lipids (fat) from the acetyl CoA and takes place in the cytoplasm of adipocytes (fat cells) and hepatocytes (liver cells). When you eat more glucose or carbohydrates than your body needs, your system uses acetyl CoA to turn the excess into fat. Although there are several metabolic sources of acetyl CoA, it is most commonly derived from glycolysis. Acetyl CoA availability is significant, because it initiates lipogenesis. Lipogenesis begins with acetyl CoA and advances by the subsequent addition of two carbon atoms from another acetyl CoA; this process is repeated until fatty acids are the appropriate length. Because this is a bond-creating anabolic process, ATP is consumed. However, the creation of triglycerides and lipids is an efficient way of storing the energy available in carbohydrates. Triglycerides and lipids, both high-energy molecules, are stored in adipose tissue until they are needed.', '8a199751-3180-45d0-a5b7-b2647f721571': 'Although lipogenesis occurs in the cytoplasm, the necessary acetyl CoA is created in the mitochondria and cannot be transported across the mitochondrial membrane. To solve this problem, pyruvate is converted into both oxaloacetate and acetyl CoA. Two different enzymes are required for these conversions. Oxaloacetate forms via the action of pyruvate carboxylase, whereas the action of pyruvate dehydrogenase creates acetyl CoA. Oxaloacetate and acetyl CoA combine to form citrate, which can cross the mitochondrial membrane and enter the cytoplasm. In the cytoplasm, citrate is converted back into oxaloacetate and acetyl CoA. Oxaloacetate is converted into malate and then into pyruvate. Pyruvate crosses back across the mitochondrial membrane to wait for the next cycle of lipogenesis. The acetyl CoA is converted into malonyl CoA that is used to synthesize fatty acids. Figure 24.3.6 summarizes the pathways of lipid metabolism.', '6aa0f074-8169-4164-a441-67f2520ce809': 'Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen atoms. The family of carbohydrates includes both simple and complex sugars. Glucose and fructose are examples of simple sugars, and starch, glycogen, and cellulose are all examples of complex sugars. The complex sugars are also called polysaccharides and are made of multiple monosaccharide molecules. Polysaccharides serve as energy storage (e.g., starch and glycogen) and as structural components (e.g., chitin in insects and cellulose in plants).', '1b4d6f86-9f98-4bc9-90ed-db5b6006ac38': 'During digestion, carbohydrates are broken down into simple, soluble sugars that can be transported across the intestinal wall into the circulatory system to be transported throughout the body. Carbohydrate digestion begins in the mouth with the action of salivary amylase on starches, continues in the duodenum with the action of pancreatic amylase, and ends with monosaccharides being absorbed across the epithelium of the small intestine. Once the absorbed monosaccharides are transported to the tissues, the process of cellular respiration begins (Figure 24.2.1). The goal of cellular respiration is to produce ATP for use by the body to power physiological processes. To start the process, a glucose molecule will get modified to two pyruvate molecules in the metabolic pathway called glycolysis. When oxygen is available, the pyruvate molecules will then be converted to acetyl CoA which enters the mitochondria and enters the citric acid cycle. Both glycolysis and the citric acid cycle produce a small amount of ATP (2 ATP per pathway), but the majority of the ATP produced by aerobic metabolism is achieved when the products of glyolysis and the citric acid, NADH and FADH2, carry their electrons to the electron transport chain. The electron transport chain transfers electrons through electron carriers, ultimately to oxygen in a process called oxidative phosphorylaton. This final process of cellular respiration harnesses the energy delivered by NADH and FADH2 to drive ATP synthase to produce 34 ATP per glucose. This first section will focus first on glycolysis, a process where the monosaccharide glucose is oxidized, releasing the energy stored in its bonds to produce ATP.'}"
+Figure 24.2.2,Anatomy_And_Physio/images/Figure 24.2.2.jpg,"Figure 24.2.2 – Glycolysis Overview: During the energy-consuming phase of glycolysis, two ATPs are consumed, transferring two phosphates to the glucose molecule. The glucose molecule then splits into two three-carbon compounds, each containing a phosphate. During the second phase, an additional phosphate is added to each of the three-carbon compounds. The energy for this endergonic reaction is provided by the removal (oxidation) of two electrons from each three-carbon compound. During the energy-releasing phase, the phosphates are removed from both three-carbon compounds and used to produce four ATP molecules.","Glucose is the body’s most readily available source of energy. After digestive processes break polysaccharides down into monosaccharides, including glucose, the monosaccharides are transported across the wall of the small intestine and into the circulatory system, which transports them to the liver. In the liver, hepatocytes either pass the glucose on through the circulatory system or store excess glucose as glycogen. Cells in the body take up the circulating glucose in response to insulin and, through a series of reactions called glycolysis, transfer some of the energy in glucose to ADP to form ATP (Figure 24.2.2). The last step in glycolysis produces the product pyruvate.","{'bc08bdd7-b014-49c8-90c9-20025c93c7f3': 'Glucose is the body’s most readily available source of energy. After digestive processes break polysaccharides down into monosaccharides, including glucose, the monosaccharides are transported across the wall of the small intestine and into the circulatory system, which transports them to the liver. In the liver, hepatocytes either pass the glucose on through the circulatory system or store excess glucose as glycogen. Cells in the body take up the circulating glucose in response to insulin and, through a series of reactions called glycolysis, transfer some of the energy in glucose to ADP to form ATP (Figure 24.2.2). The last step in glycolysis produces the product pyruvate.', 'a22e42d6-c450-47bf-a8bd-042ee25bb924': 'Glycolysis begins with the phosphorylation of glucose by hexokinase to form glucose-6-phosphate. This step uses one ATP, which is the donor of the phosphate group. Under the action of phosphofructokinase, glucose-6-phosphate is converted into fructose-6-phosphate. At this point, a second ATP donates its phosphate group, forming fructose-1,6-bisphosphate. This six-carbon sugar is split to form two phosphorylated three-carbon molecules, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate, which are both converted into glyceraldehyde-3-phosphate. The glyceraldehyde-3-phosphate is further phosphorylated with groups donated by dihydrogen phosphate present in the cell to form the three-carbon molecule 1,3-bisphosphoglycerate. The energy of this reaction comes from the oxidation of (removal of electrons from) glyceraldehyde-3-phosphate. In a series of reactions leading to pyruvate, the two phosphate groups are then transferred to two ADPs to form two ATPs. Thus, glycolysis uses two ATPs but generates four ATPs, yielding a net gain of two ATPs and two molecules of pyruvate. In the presence of oxygen, pyruvate continues on to the Krebs cycle (also called the citric acid cycle or tricarboxylic acid cycle (TCA), where additional energy is extracted and passed on.', '04d405b1-c78e-4bf0-bc66-a5f1e486b068': 'Glycolysis can be divided into two phases: energy consuming (also called chemical priming) and energy yielding. The first phase is the energy-consuming phase, so it requires two ATP molecules to start the reaction for each molecule of glucose. However, the end of the reaction produces four ATPs, resulting in a net gain of two ATP energy molecules.'}"
+Figure 24.2.4,Anatomy_And_Physio/images/Figure 24.2.4.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules.","The pyruvate molecules generated during glycolysis are transported across the mitochondrial membrane into the inner mitochondrial matrix, where they are metabolized by enzymes in a pathway called the Krebs cycle (Figure 24.2.4). The Krebs cycle is also commonly called the citric acid cycle or the tricarboxylic acid (TCA) cycle. During the Krebs cycle, high-energy molecules, including ATP, NADH, and FADH2, are created. NADH and FADH2 then pass electrons through the electron transport chain in the mitochondria to generate more ATP molecules.","{'b25ad104-5b60-41bb-a4ef-a7383ef8e1ae': 'The pyruvate molecules generated during glycolysis are transported across the mitochondrial membrane into the inner mitochondrial matrix, where they are metabolized by enzymes in a pathway called the Krebs cycle (Figure 24.2.4). The Krebs cycle is also commonly called the citric acid cycle or the tricarboxylic acid (TCA) cycle. During the Krebs cycle, high-energy molecules, including ATP, NADH, and FADH2, are created. NADH and FADH2 then pass electrons through the electron transport chain in the mitochondria to generate more ATP molecules.', '747822ad-89f4-43c0-b6df-1ac631c84a65': 'The three-carbon pyruvate molecule generated during glycolysis moves from the cytoplasm into the mitochondrial matrix, where it is converted by the enzyme pyruvate dehydrogenase into a two-carbon acetyl coenzyme A (acetyl CoA) molecule. This reaction is an oxidative decarboxylation reaction. It converts the three-carbon pyruvate into a two-carbon acetyl CoA molecule, releasing carbon dioxide and transferring two electrons that combine with NAD+ to form NADH. Acetyl CoA enters the Krebs cycle by combining with a four-carbon molecule, oxaloacetate, to form the six-carbon molecule citrate, or citric acid, at the same time releasing the coenzyme A molecule.', '2673bafb-84ac-415e-98db-e3e08594f7e8': 'The six-carbon citrate molecule is systematically converted to a five-carbon molecule and then a four-carbon molecule, ending with oxaloacetate, the beginning of the cycle. Along the way, each citrate molecule will produce one ATP, one FADH2, and three NADH. The FADH2 and NADH will enter the oxidative phosphorylation system located in the inner mitochondrial membrane. In addition, the Krebs cycle supplies the starting materials to process and break down proteins and fats.', '3f7582ea-f269-4c12-800a-dbb7b2f63f66': 'To start the Krebs cycle, citrate synthase combines acetyl CoA and oxaloacetate to form a six-carbon citrate molecule; CoA is subsequently released and can combine with another pyruvate molecule to begin the cycle again. The aconitase enzyme converts citrate into isocitrate. In two successive steps of oxidative decarboxylation, two molecules of CO2 and two NADH molecules are produced when isocitrate dehydrogenase converts isocitrate into the five-carbon α-ketoglutarate, which is then catalyzed and converted into the four-carbon succinyl CoA by α-ketoglutarate dehydrogenase. The enzyme succinyl CoA dehydrogenase then converts succinyl CoA into succinate and forms the high-energy molecule GTP, which transfers its energy to ADP to produce ATP. Succinate dehydrogenase then converts succinate into fumarate, forming a molecule of FADH2. Fumarase then converts fumarate into malate, which malate dehydrogenase then converts back into oxaloacetate while reducing NAD+ to NADH. Oxaloacetate is then ready to combine with the next acetyl CoA to start the Krebs cycle again (see Figure 24.2.4). For each turn of the cycle, three NADH, one ATP (through GTP), and one FADH2 are created. Each carbon of pyruvate is converted into CO2, which is released as a byproduct of oxidative (aerobic) respiration.'}"
+Figure 24.2.4,Anatomy_And_Physio/images/Figure 24.2.4.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules.","The pyruvate molecules generated during glycolysis are transported across the mitochondrial membrane into the inner mitochondrial matrix, where they are metabolized by enzymes in a pathway called the Krebs cycle (Figure 24.2.4). The Krebs cycle is also commonly called the citric acid cycle or the tricarboxylic acid (TCA) cycle. During the Krebs cycle, high-energy molecules, including ATP, NADH, and FADH2, are created. NADH and FADH2 then pass electrons through the electron transport chain in the mitochondria to generate more ATP molecules.","{'b25ad104-5b60-41bb-a4ef-a7383ef8e1ae': 'The pyruvate molecules generated during glycolysis are transported across the mitochondrial membrane into the inner mitochondrial matrix, where they are metabolized by enzymes in a pathway called the Krebs cycle (Figure 24.2.4). The Krebs cycle is also commonly called the citric acid cycle or the tricarboxylic acid (TCA) cycle. During the Krebs cycle, high-energy molecules, including ATP, NADH, and FADH2, are created. NADH and FADH2 then pass electrons through the electron transport chain in the mitochondria to generate more ATP molecules.', '747822ad-89f4-43c0-b6df-1ac631c84a65': 'The three-carbon pyruvate molecule generated during glycolysis moves from the cytoplasm into the mitochondrial matrix, where it is converted by the enzyme pyruvate dehydrogenase into a two-carbon acetyl coenzyme A (acetyl CoA) molecule. This reaction is an oxidative decarboxylation reaction. It converts the three-carbon pyruvate into a two-carbon acetyl CoA molecule, releasing carbon dioxide and transferring two electrons that combine with NAD+ to form NADH. Acetyl CoA enters the Krebs cycle by combining with a four-carbon molecule, oxaloacetate, to form the six-carbon molecule citrate, or citric acid, at the same time releasing the coenzyme A molecule.', '2673bafb-84ac-415e-98db-e3e08594f7e8': 'The six-carbon citrate molecule is systematically converted to a five-carbon molecule and then a four-carbon molecule, ending with oxaloacetate, the beginning of the cycle. Along the way, each citrate molecule will produce one ATP, one FADH2, and three NADH. The FADH2 and NADH will enter the oxidative phosphorylation system located in the inner mitochondrial membrane. In addition, the Krebs cycle supplies the starting materials to process and break down proteins and fats.', '3f7582ea-f269-4c12-800a-dbb7b2f63f66': 'To start the Krebs cycle, citrate synthase combines acetyl CoA and oxaloacetate to form a six-carbon citrate molecule; CoA is subsequently released and can combine with another pyruvate molecule to begin the cycle again. The aconitase enzyme converts citrate into isocitrate. In two successive steps of oxidative decarboxylation, two molecules of CO2 and two NADH molecules are produced when isocitrate dehydrogenase converts isocitrate into the five-carbon α-ketoglutarate, which is then catalyzed and converted into the four-carbon succinyl CoA by α-ketoglutarate dehydrogenase. The enzyme succinyl CoA dehydrogenase then converts succinyl CoA into succinate and forms the high-energy molecule GTP, which transfers its energy to ADP to produce ATP. Succinate dehydrogenase then converts succinate into fumarate, forming a molecule of FADH2. Fumarase then converts fumarate into malate, which malate dehydrogenase then converts back into oxaloacetate while reducing NAD+ to NADH. Oxaloacetate is then ready to combine with the next acetyl CoA to start the Krebs cycle again (see Figure 24.2.4). For each turn of the cycle, three NADH, one ATP (through GTP), and one FADH2 are created. Each carbon of pyruvate is converted into CO2, which is released as a byproduct of oxidative (aerobic) respiration.'}"
+Figure 24.2.5,Anatomy_And_Physio/images/Figure 24.2.5.jpg,Figure 24.2.5 – Electron Transport Chain: The electron transport chain is a series of electron carriers and ion pumps that are used to pump H+ ions out of the inner mitochondrial matrix.,"The electron transport chain (ETC) uses the NADH and FADH2 produced by the Krebs cycle to generate ATP. Electrons from NADH and FADH2 are transferred through protein complexes embedded in the inner mitochondrial membrane by a series of enzymatic reactions. The electron transport chain consists of a series of four enzyme complexes (Complex I – Complex IV) and two coenzymes (ubiquinone and Cytochrome c), which act as electron carriers and proton pumps used to transfer H+ ions into the space between the inner and outer mitochondrial membranes (Figure 24.2.5). The ETC couples the transfer of electrons between a donor (like NADH) and an electron acceptor (like O2) with the transfer of protons (H+ ions) across the inner mitochondrial membrane, enabling the process of oxidative phosphorylation. In the presence of oxygen, energy is passed, stepwise, through the electron carriers to collect gradually the energy needed to attach a phosphate to ADP and produce ATP. The role of molecular oxygen, O2, is as the terminal electron acceptor for the ETC. This means that once the electrons have passed through the entire ETC, they must be passed to another, separate molecule. These electrons, O2, and H+ ions from the matrix combine to form new water molecules. This is the basis for your need to breathe in oxygen. Without oxygen, electron flow through the ETC ceases.","{'c74ffc00-7aec-42ae-ab88-c562a2437d5d': 'The electron transport chain (ETC) uses the NADH and FADH2 produced by the Krebs cycle to generate ATP. Electrons from NADH and FADH2 are transferred through protein complexes embedded in the inner mitochondrial membrane by a series of enzymatic reactions. The electron transport chain consists of a series of four enzyme complexes (Complex I – Complex IV) and two coenzymes (ubiquinone and Cytochrome c), which act as electron carriers and proton pumps used to transfer H+ ions into the space between the inner and outer mitochondrial membranes (Figure 24.2.5). The ETC couples the transfer of electrons between a donor (like NADH) and an electron acceptor (like O2) with the transfer of protons (H+ ions) across the inner mitochondrial membrane, enabling the process of oxidative phosphorylation. In the presence of oxygen, energy is passed, stepwise, through the electron carriers to collect gradually the energy needed to attach a phosphate to ADP and produce ATP. The role of molecular oxygen, O2, is as the terminal electron acceptor for the ETC. This means that once the electrons have passed through the entire ETC, they must be passed to another, separate molecule. These electrons, O2, and H+ ions from the matrix combine to form new water molecules. This is the basis for your need to breathe in oxygen. Without oxygen, electron flow through the ETC ceases.', 'debe9ce5-6f9f-492b-a7d1-c81a2fcf8dee': 'The electrons released from NADH and FADH2 are passed along the chain by each of the carriers, which are reduced when they receive the electron and oxidized when passing it on to the next carrier. Each of these reactions releases a small amount of energy, which is used to pump H+ ions across the inner membrane. The accumulation of these protons in the space between the membranes creates a proton gradient with respect to the mitochondrial matrix.', '94f9b4ef-ae7d-4cfd-8ac2-112ccb5f342a': 'Also embedded in the inner mitochondrial membrane is an amazing protein pore complex called ATP synthase. Effectively, it is a turbine that is powered by the flow of H+ ions across the inner membrane down a gradient and into the mitochondrial matrix. As the H+ ions traverse the complex, the shaft of the complex rotates. This rotation enables other portions of ATP synthase to encourage ADP and Pi to create ATP. In accounting for the total number of ATP produced per glucose molecule through aerobic respiration, it is important to remember the following points:', 'c2a14cf6-30a6-4d80-9aa5-98ca28ebf97e': 'Therefore, for every glucose molecule that enters aerobic respiration, a net total of 36 ATPs are produced (Figure 24.2.6).'}"
+Figure 24.2.6,Anatomy_And_Physio/images/Figure 24.2.6.jpg,"Figure 24.2.6 – Carbohydrate Metabolism: Carbohydrate metabolism involves glycolysis, the Krebs cycle, and the electron transport chain.","Therefore, for every glucose molecule that enters aerobic respiration, a net total of 36 ATPs are produced (Figure 24.2.6).","{'c74ffc00-7aec-42ae-ab88-c562a2437d5d': 'The electron transport chain (ETC) uses the NADH and FADH2 produced by the Krebs cycle to generate ATP. Electrons from NADH and FADH2 are transferred through protein complexes embedded in the inner mitochondrial membrane by a series of enzymatic reactions. The electron transport chain consists of a series of four enzyme complexes (Complex I – Complex IV) and two coenzymes (ubiquinone and Cytochrome c), which act as electron carriers and proton pumps used to transfer H+ ions into the space between the inner and outer mitochondrial membranes (Figure 24.2.5). The ETC couples the transfer of electrons between a donor (like NADH) and an electron acceptor (like O2) with the transfer of protons (H+ ions) across the inner mitochondrial membrane, enabling the process of oxidative phosphorylation. In the presence of oxygen, energy is passed, stepwise, through the electron carriers to collect gradually the energy needed to attach a phosphate to ADP and produce ATP. The role of molecular oxygen, O2, is as the terminal electron acceptor for the ETC. This means that once the electrons have passed through the entire ETC, they must be passed to another, separate molecule. These electrons, O2, and H+ ions from the matrix combine to form new water molecules. This is the basis for your need to breathe in oxygen. Without oxygen, electron flow through the ETC ceases.', 'debe9ce5-6f9f-492b-a7d1-c81a2fcf8dee': 'The electrons released from NADH and FADH2 are passed along the chain by each of the carriers, which are reduced when they receive the electron and oxidized when passing it on to the next carrier. Each of these reactions releases a small amount of energy, which is used to pump H+ ions across the inner membrane. The accumulation of these protons in the space between the membranes creates a proton gradient with respect to the mitochondrial matrix.', '94f9b4ef-ae7d-4cfd-8ac2-112ccb5f342a': 'Also embedded in the inner mitochondrial membrane is an amazing protein pore complex called ATP synthase. Effectively, it is a turbine that is powered by the flow of H+ ions across the inner membrane down a gradient and into the mitochondrial matrix. As the H+ ions traverse the complex, the shaft of the complex rotates. This rotation enables other portions of ATP synthase to encourage ADP and Pi to create ATP. In accounting for the total number of ATP produced per glucose molecule through aerobic respiration, it is important to remember the following points:', 'c2a14cf6-30a6-4d80-9aa5-98ca28ebf97e': 'Therefore, for every glucose molecule that enters aerobic respiration, a net total of 36 ATPs are produced (Figure 24.2.6).'}"
+Figure 24.1.1,Anatomy_And_Physio/images/Figure 24.1.1.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions.","When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.","{'46979334-fe5d-4d41-9837-40fd6b8173f8': 'When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.', '907c469c-aa0c-4f01-a867-a0f97fa86629': 'After several days of starvation, ketone bodies become the major source of fuel for the heart and other organs. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. This prevents the continued breakdown of proteins that serve as carbon sources for gluconeogenesis. Once these stores are fully depleted, proteins from muscles are released and broken down for glucose synthesis. Overall survival is dependent on the amount of fat and protein stored in the body.', '48726f29-6477-423e-830b-d49780e7b9ef': 'Much of the body is made of protein, and these proteins take on a myriad of forms. They represent cell signaling receptors, signaling molecules, structural members, enzymes, intracellular trafficking components, extracellular matrix scaffolds, ion pumps, ion channels, oxygen and CO2 transporters (hemoglobin). That is not even the complete list! There is protein in bones (collagen), muscles, and tendons; the hemoglobin that transports oxygen; and enzymes that catalyze all biochemical reactions. Protein is also used for growth and repair. Amid all these necessary functions, proteins also hold the potential to serve as a metabolic fuel source. Proteins are not stored for later use, so excess proteins must be converted into glucose or triglycerides, and used to supply energy or build energy reserves. Although the body can synthesize proteins from amino acids, food is an important source of those amino acids, especially because humans cannot synthesize all of the 20 amino acids used to build proteins.', '0fc23cb1-d75a-4329-966b-5dedd44ee9e3': 'The digestion of proteins begins in the stomach. When protein-rich foods enter the stomach, they are greeted by a mixture of the enzyme pepsin and hydrochloric acid (HCl; 0.5 percent). The latter produces an environmental pH of 1.5–3.5 that denatures proteins within food. Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. When the food-gastric juice mixture (chyme) enters the small intestine, the pancreas releases sodium bicarbonate to neutralize the HCl. This helps to protect the lining of the intestine. The small intestine also releases digestive hormones, including secretin and CCK, which stimulate digestive processes to break down the proteins further. Secretin also stimulates the pancreas to release sodium bicarbonate. The pancreas releases most of the digestive enzymes, including the proteases trypsin, chymotrypsin, carboxypeptidase, and elastase, which aid protein digestion. Together, all of these enzymes break complex proteins into smaller individual amino acids (Figure 24.4.1), which are then transported across the intestinal mucosa to be used to create new proteins, or to be converted into fats or acetyl CoA and used in the Krebs cycle.', '9cb34cb2-9701-4310-add8-01e3265350b8': 'In order to avoid breaking down the proteins that make up the pancreas and small intestine, pancreatic enzymes are released as inactive proenzymes that are only activated in the small intestine. In the pancreas, vesicles store trypsin, chymotrypsin, and carboxypeptidase as trypsinogen, chymotrypsinogen, and procarboxypeptidase. Once released into the small intestine, an enzyme found in the wall of the small intestine, called enterokinase, binds to trypsinogen and converts it into its active form, trypsin. Trypsin then binds to chymotrypsinogen and procarboxypeptidase to convert it into the active chymotrypsin and carboxypeptidase. Trypsin, chymotrypsin, and carboxypeptidase break down large proteins into smaller peptides, a process called proteolysis. These smaller peptides are catabolized into their constituent amino acids by the brush border enzymes, aminopeptidase and dipeptidase.\xa0The free amino acids are then transported across the apical surface of the intestinal mucosa in a process that is mediated by secondary active transport using sodium-amino acid transporters. These transporters bind sodium and then bind the amino acid to transport it across the membrane. At the basal surface of the mucosal cells, the sodium and amino acid are released. The sodium can be reused in the transporter, whereas the amino acids are transferred into the bloodstream to be transported to the liver and cells throughout the body for protein synthesis.', '7a8e720a-8b68-48db-bbf1-1e87cd0581e2': 'Freely available amino acids are used to create proteins. If amino acids exist in excess, the body has no capacity or mechanism for their storage; thus, they are converted into glucose or ketones, or they are decomposed. Amino acid decomposition results in hydrocarbons and nitrogenous waste. However, high concentrations of nitrogen are toxic as they produce ammonium ions. The urea cycle processes nitrogen and facilitates its excretion from the body.', '1b0ae55b-89fe-475e-94c6-7f8396ca1699': 'Catabolic reactions break down large organic molecules into smaller molecules, releasing the energy contained in the chemical bonds. These energy releases (conversions) are not 100 percent efficient. The amount of energy released is less than the total amount contained in the molecule. Approximately 40 percent of energy yielded from catabolic reactions is directly transferred to the high-energy molecule adenosine triphosphate (ATP). ATP, the energy currency of cells, can be used immediately to power molecular machines that support cell, tissue, and organ function. This includes building new tissue and repairing damaged tissue. ATP can also be stored to fulfill future energy demands. The remaining 60 percent of the energy released from catabolic reactions is given off as heat, which tissues and body fluids absorb.', 'd71df0fd-28e1-438f-a26a-f2bc7103bb0d': 'Structurally, ATP molecules consist of an adenine, a ribose, and three phosphate groups (Figure 24.1.1). The chemical bond between the second and third phosphate groups, termed a high-energy bond, represents the greatest source of energy in a cell. It is the first bond that catabolic enzymes break when cells require energy to do work. The products of this reaction are a molecule of adenosine diphosphate (ADP) and a lone phosphate group (Pi). ATP, ADP, and Pi are constantly being cycled through reactions that build ATP and store energy, and reactions that break down ATP and release energy.', '65d8da7c-500a-4380-bc4c-603f1877bce2': 'The energy from ATP drives all bodily functions, such as contracting muscles, maintaining the electrical potential of nerve cells, and absorbing food in the gastrointestinal tract. The metabolic reactions that produce ATP come from various sources (Figure 24.1.2).', 'd3a7a739-0cc6-4f09-bd7f-3c13ac821758': 'Of the four major macromolecular groups (carbohydrates, lipids, proteins, and nucleic acids) that are processed by digestion, carbohydrates are considered the most common source of energy to fuel the body. They take the form of either complex carbohydrates, polysaccharides like starch and glycogen, or simple sugars (monosaccharides) like glucose and fructose. Sugar catabolism breaks polysaccharides down into their individual monosaccharides. Among the monosaccharides, glucose is the most common fuel for ATP production in cells, and as such, there are a number of endocrine control mechanisms to regulate glucose concentration in the bloodstream. Excess glucose is either stored as an energy reserve in the liver and skeletal muscles as the complex polymer glycogen, or it is converted into fat (triglyceride) in adipose cells (adipocytes).', '5849f685-335f-41d5-ad90-ed18b01d1612': 'Among the lipids (fats), triglycerides are most often used for energy via a metabolic process called β-oxidation. About one-half of excess fat is stored in adipocytes that accumulate in the subcutaneous tissue under the skin, whereas the rest is stored in adipocytes in other tissues and organs.', '5852e9a6-25cc-4c50-9697-41df37f4c123': 'Proteins, which are polymers, can be broken down into their monomers, individual amino acids. Amino acids can be used as building blocks of new proteins or broken down further for the production of ATP. When one is chronically starving, this use of amino acids for energy production can lead to a wasting away of the body, as more and more proteins are broken down.', '2f9273c5-0e7a-4071-b038-925e92d9ab0e': 'Nucleic acids are present in most of the foods you eat. During digestion, nucleic acids including DNA and various RNAs are broken down into their constituent nucleotides. These nucleotides are readily absorbed and transported throughout the body to be used by individual cells during nucleic acid metabolism.'}"
+Figure 24.1.2,Anatomy_And_Physio/images/Figure 24.1.2.jpg,"Figure 24.1.2 – Sources of ATP: During catabolic reactions, proteins are broken down into amino acids, lipids are broken down into fatty acids, and polysaccharides are broken down into monosaccharides. These building blocks are then used for the synthesis of molecules in anabolic reactions.","The energy from ATP drives all bodily functions, such as contracting muscles, maintaining the electrical potential of nerve cells, and absorbing food in the gastrointestinal tract. The metabolic reactions that produce ATP come from various sources (Figure 24.1.2).","{'1b0ae55b-89fe-475e-94c6-7f8396ca1699': 'Catabolic reactions break down large organic molecules into smaller molecules, releasing the energy contained in the chemical bonds. These energy releases (conversions) are not 100 percent efficient. The amount of energy released is less than the total amount contained in the molecule. Approximately 40 percent of energy yielded from catabolic reactions is directly transferred to the high-energy molecule adenosine triphosphate (ATP). ATP, the energy currency of cells, can be used immediately to power molecular machines that support cell, tissue, and organ function. This includes building new tissue and repairing damaged tissue. ATP can also be stored to fulfill future energy demands. The remaining 60 percent of the energy released from catabolic reactions is given off as heat, which tissues and body fluids absorb.', 'd71df0fd-28e1-438f-a26a-f2bc7103bb0d': 'Structurally, ATP molecules consist of an adenine, a ribose, and three phosphate groups (Figure 24.1.1). The chemical bond between the second and third phosphate groups, termed a high-energy bond, represents the greatest source of energy in a cell. It is the first bond that catabolic enzymes break when cells require energy to do work. The products of this reaction are a molecule of adenosine diphosphate (ADP) and a lone phosphate group (Pi). ATP, ADP, and Pi are constantly being cycled through reactions that build ATP and store energy, and reactions that break down ATP and release energy.', '65d8da7c-500a-4380-bc4c-603f1877bce2': 'The energy from ATP drives all bodily functions, such as contracting muscles, maintaining the electrical potential of nerve cells, and absorbing food in the gastrointestinal tract. The metabolic reactions that produce ATP come from various sources (Figure 24.1.2).', 'd3a7a739-0cc6-4f09-bd7f-3c13ac821758': 'Of the four major macromolecular groups (carbohydrates, lipids, proteins, and nucleic acids) that are processed by digestion, carbohydrates are considered the most common source of energy to fuel the body. They take the form of either complex carbohydrates, polysaccharides like starch and glycogen, or simple sugars (monosaccharides) like glucose and fructose. Sugar catabolism breaks polysaccharides down into their individual monosaccharides. Among the monosaccharides, glucose is the most common fuel for ATP production in cells, and as such, there are a number of endocrine control mechanisms to regulate glucose concentration in the bloodstream. Excess glucose is either stored as an energy reserve in the liver and skeletal muscles as the complex polymer glycogen, or it is converted into fat (triglyceride) in adipose cells (adipocytes).', '5849f685-335f-41d5-ad90-ed18b01d1612': 'Among the lipids (fats), triglycerides are most often used for energy via a metabolic process called β-oxidation. About one-half of excess fat is stored in adipocytes that accumulate in the subcutaneous tissue under the skin, whereas the rest is stored in adipocytes in other tissues and organs.', '5852e9a6-25cc-4c50-9697-41df37f4c123': 'Proteins, which are polymers, can be broken down into their monomers, individual amino acids. Amino acids can be used as building blocks of new proteins or broken down further for the production of ATP. When one is chronically starving, this use of amino acids for energy production can lead to a wasting away of the body, as more and more proteins are broken down.', '2f9273c5-0e7a-4071-b038-925e92d9ab0e': 'Nucleic acids are present in most of the foods you eat. During digestion, nucleic acids including DNA and various RNAs are broken down into their constituent nucleotides. These nucleotides are readily absorbed and transported throughout the body to be used by individual cells during nucleic acid metabolism.'}"
+Figure 23.7.1,Anatomy_And_Physio/images/Figure 23.7.1.jpg,Figure 23.7.1 – Digestion and Absorption: Digestion begins in the mouth and continues as food travels through the small intestine. Most absorption occurs in the small intestine.,"As you have learned, the process of mechanical digestion is relatively simple. It involves the physical breakdown of food but does not alter its chemical makeup. Chemical digestion, on the other hand, is a complex process that reduces food into its chemical building blocks, which are then absorbed to nourish the cells of the body (Figure 23.7.1). In this section, you will look more closely at the processes of chemical digestion and absorption.","{'31d904c2-c8d4-40f8-bd7f-79f201fc9c98': 'The chemical reactions underlying metabolism involve the transfer of electrons from one compound to another by processes catalyzed by enzymes. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a hydrogen atom, in the form of a hydrogen ion (H+) and an electron, breaking the molecule into smaller parts. The loss of an electron, or oxidation, releases a small amount of energy; both the electron and the energy are then passed to another molecule in the process of reduction, or the gaining of an electron. These two reactions always happen together in an oxidation-reduction reaction (also called a redox reaction)—when an electron is passed between molecules, the donor is oxidized and the recipient is reduced. Oxidation-reduction reactions often happen in a series, so that a molecule that is reduced is subsequently oxidized, passing on not only the electron it just received but also the energy it received. As the series of reactions progresses, energy accumulates that is used to combine Pi and ADP to form ATP, the high-energy molecule that the body uses for fuel.', '73c8f638-b2d9-4e03-a7e1-edb6894915f3': 'Oxidation-reduction reactions are catalyzed by enzymes that trigger the removal of hydrogen atoms. Coenzymes work with enzymes and accept hydrogen atoms. The two most common coenzymes of oxidation-reduction reactions are nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). Their respective reduced coenzymes are NADH and FADH2, which are energy-containing molecules used to transfer energy during the creation of ATP.', 'cffb5033-7853-4566-a487-1545455c6043': 'Eating is essential to life. Many of us look to eating as not only a necessity, but also a pleasure. You may have been told since childhood to start the day with a good breakfast to give you the energy to get through most of the day. You most likely have heard about the importance of a balanced diet, with plenty of fruits and vegetables. But what does this all mean to your body and the physiological processes it carries out each day? You need to absorb a range of nutrients so that your cells have the building blocks for metabolic processes that release the energy for the cells to carry out their daily jobs, to manufacture new proteins, cells, and body parts, and to recycle materials in the cell.', '76ffb395-b78d-4614-aeeb-0716b9e47079': 'This chapter will take you through some of the chemical reactions essential to life, the sum of which is referred to as metabolism. The focus of these discussions will be anabolic (building up) reactions and catabolic (breaking down) reactions. You will examine the various chemical reactions that are important to sustain life, including why you must have oxygen, how mitochondria transfer energy, and the importance of certain “metabolic” hormones and vitamins.', '9d2a0c22-c38a-493e-a508-459c6a49ffcd': 'Metabolism varies, depending on age, gender, activity level, fuel consumption, and lean body mass. Your own metabolic rate fluctuates throughout life. By modifying your diet and exercise regimen, you can increase both lean body mass and metabolic rate. Factors affecting metabolism also play important roles in controlling muscle mass. Aging is known to decrease the metabolic rate by as much as 5 percent per year. Additionally, because men tend have more lean muscle mass then women, their basal metabolic rate (metabolic rate at rest) is higher; therefore, men tend to burn more calories than women do. Lastly, an individual’s inherent metabolic rate is a function of the proteins and enzymes derived from their genetic background. Thus, your genes play a big role in your metabolism. Nonetheless, each person’s body engages in the same overall metabolic processes.', '8bcdca8e-fede-4532-831b-3807650d7c5b': 'As you have learned, the process of mechanical digestion is relatively simple. It involves the physical breakdown of food but does not alter its chemical makeup. Chemical digestion, on the other hand, is a complex process that reduces food into its chemical building blocks, which are then absorbed to nourish the cells of the body (Figure 23.7.1). In this section, you will look more closely at the processes of chemical digestion and absorption.'}"
+Figure 23.7.2,Anatomy_And_Physio/images/Figure 23.7.2.jpg,Figure 23.7.2 – Carbohydrate Digestion Flow Chart: Carbohydrates are broken down into their monomers in a series of steps.,"In the small intestine, pancreatic amylase does the ‘heavy lifting’ for starch and carbohydrate digestion (Figure 23.7.2). After amylases break down starch into smaller fragments, the brush border enzyme α-dextrinase starts working on α-dextrin, breaking off one glucose unit at a time. Three brush border enzymes hydrolyze sucrose, lactose, and maltose into monosaccharides. Sucrase splits sucrose into one molecule of fructose and one molecule of glucose; maltase breaks down maltose and maltotriose into two and three glucose molecules, respectively; and lactase breaks down lactose into one molecule of glucose and one molecule of galactose. Insufficient lactase can lead to lactose intolerance.","{'8469032a-167f-4235-8208-c0d800a5fd50': 'The average American diet is about 50 percent carbohydrates, which may be classified according to the number of monomers they contain of simple sugars (monosaccharides and disaccharides) and/or complex sugars (polysaccharides). Glucose, galactose, and fructose are the three monosaccharides that are commonly consumed and are readily absorbed. Your digestive system is also able to break down the disaccharide sucrose (regular table sugar: glucose + fructose), lactose (milk sugar: glucose + galactose), and maltose (grain sugar: glucose + glucose), and the polysaccharides glycogen and starch (chains of monosaccharides). Your bodies do not produce enzymes that can break down most fibrous polysaccharides, such as cellulose. While indigestible polysaccharides do not provide any nutritional value, they do provide dietary fiber, which helps propel food through the alimentary canal.', 'fc5dbdcd-5909-4b50-bcb4-d3cb81ba6c56': 'The chemical digestion of starches begins in the mouth and has been reviewed above.', 'eea843c6-37b6-4293-a28b-aa4a658a1878': 'In the small intestine, pancreatic amylase does the ‘heavy lifting’ for starch and carbohydrate digestion (Figure 23.7.2). After amylases break down starch into smaller fragments, the brush border enzyme α-dextrinase starts working on α-dextrin, breaking off one glucose unit at a time. Three brush border enzymes hydrolyze sucrose, lactose, and maltose into monosaccharides. Sucrase splits sucrose into one molecule of fructose and one molecule of glucose; maltase breaks down maltose and maltotriose into two and three glucose molecules, respectively; and lactase breaks down lactose into one molecule of glucose and one molecule of galactose. Insufficient lactase can lead to lactose intolerance.'}"
+Figure 23.7.3,Anatomy_And_Physio/images/Figure 23.7.3.jpg,Figure 23.7.3 – Digestion of Protein: The digestion of protein begins in the stomach and is completed in the small intestine.,"The digestion of protein starts in the stomach, where HCl denatures the proteins and then pepsin begins to break them down into smaller polypeptides, which then travel to the small intestine (Figure 23.7.3). Chemical digestion in the small intestine is continued by pancreatic enzymes, including trypsin, chymotrypsin and carboxypeptidase, each of which act on specific bonds in amino acid sequences. At the same time, the cells of the brush border secrete enzymes such as aminopeptidase and dipeptidase, which further break down peptide chains. This results in molecules small enough to enter the bloodstream (Figure 23.7.4).","{'2b217221-bdc2-41a6-a111-f60ca0f2725a': 'Proteins are polymers composed of amino acids linked by peptide bonds to form long chains. Digestion reduces them to their constituent amino acids. You usually consume about 15 to 20 percent of your total calorie intake as protein.', 'e82f9977-e36b-4b98-b982-e860dacce8ef': 'The digestion of protein starts in the stomach, where HCl denatures the proteins and then pepsin begins to break them down into smaller polypeptides, which then travel to the small intestine (Figure 23.7.3). Chemical digestion in the small intestine is continued by pancreatic enzymes, including trypsin, chymotrypsin and carboxypeptidase, each of which act on specific bonds in amino acid sequences. At the same time, the cells of the brush border secrete enzymes such as aminopeptidase and dipeptidase, which further break down peptide chains. This results in molecules small enough to enter the bloodstream (Figure 23.7.4).'}"
+Figure 23.7.5,Anatomy_And_Physio/images/Figure 23.7.5.jpg,"Figure 23.7.5 – Digestive Secretions and Absorption of Water: Absorption is a complex process, in which nutrients from digested food are harvested.","The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi. The absorptive capacity of the alimentary canal is almost endless. Each day, the alimentary canal processes up to 10 liters of food, liquids, and GI secretions, yet less than one liter enters the large intestine. Almost all ingested food, 80 percent of electrolytes, and 90 percent of water are absorbed in the small intestine. Although the entire small intestine is involved in the absorption of water and lipids, most absorption of carbohydrates and proteins occurs in the jejunum. Notably, bile salts and vitamin B12 are absorbed in the terminal ileum. By the time chyme passes from the ileum into the large intestine, it is essentially indigestible food residue (mainly plant fibers like cellulose), some water, and millions of bacteria (Figure 23.7.5).","{'ecf2aa5d-15b6-492e-b62d-c1e3dad7df3e': 'The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi. The absorptive capacity of the alimentary canal is almost endless. Each day, the alimentary canal processes up to 10 liters of food, liquids, and GI secretions, yet less than one liter enters the large intestine. Almost all ingested food, 80 percent of electrolytes, and 90 percent of water are absorbed in the small intestine. Although the entire small intestine is involved in the absorption of water and lipids, most absorption of carbohydrates and proteins occurs in the jejunum. Notably, bile salts and vitamin B12 are absorbed in the terminal ileum. By the time chyme passes from the ileum into the large intestine, it is essentially indigestible food residue (mainly plant fibers like cellulose), some water, and millions of bacteria (Figure 23.7.5).', '50d5fb56-081d-4439-990a-9422cc08edcb': 'Absorption can occur through five mechanisms: (1) active transport, (2) passive diffusion, (3) facilitated diffusion, (4) co-transport (or secondary active transport), and (5) endocytosis. As you will recall from Chapter 3, active transport refers to the movement of a substance across a cell membrane going from an area of lower concentration to an area of higher concentration (up the concentration gradient). In this type of transport, proteins within the cell membrane act as “pumps,” using cellular energy (ATP) to move the substance. Passive diffusion refers to the movement of substances from an area of higher concentration to an area of lower concentration, while facilitated diffusion refers to the movement of substances from an area of higher to an area of lower concentration using a carrier protein in the cell membrane. Co-transport uses the movement of one molecule through the membrane from higher to lower concentration to power the movement of another from lower to higher. Finally, endocytosis is a transportation process in which the cell membrane engulfs material. It requires energy, generally in the form of ATP.', 'a8b5c722-ec8b-49b7-a888-123d095e9354': 'Because the cell’s plasma membrane is made up of hydrophobic phospholipids, water-soluble nutrients must use transport molecules embedded in the membrane to enter cells. Moreover, substances cannot pass between the epithelial cells of the intestinal mucosa because these cells are bound together by tight junctions. Thus, substances can only enter blood capillaries by passing through the apical surfaces of epithelial cells and into the interstitial fluid. Water-soluble nutrients enter the capillary blood in the villi and travel to the liver via the hepatic portal vein.', '7c4c3030-df7e-42de-a6c5-dc8040e3064c': 'In contrast to the water-soluble nutrients, lipid-soluble nutrients can diffuse through the plasma membrane. Once inside the cell, they are packaged for transport via the base of the cell and then enter the lacteals of the villi to be transported by lymphatic vessels to the systemic circulation via the thoracic duct. The absorption of most nutrients through the mucosa of the intestinal villi requires active transport fueled by ATP. The routes of absorption for each food category are summarized in Table 23.10.'}"
+Figure 23.7.6,Anatomy_And_Physio/images/Figure 23.7.6.jpg,"Figure 23.7.6 – Lipid Absorption: Unlike amino acids and simple sugars, lipids are transformed as they are absorbed through epithelial cells.","The free fatty acids and monoacylglycerides that enter the epithelial cells are reincorporated into triglycerides. The triglycerides are mixed with phospholipids and cholesterol, and surrounded with a protein coat. This new complex, called a chylomicron, is a water-soluble lipoprotein. After being processed by the Golgi apparatus, chylomicrons are released from the cell (Figure 23.7.6). Too big to pass through the basement membranes of blood capillaries, chylomicrons instead enter the large pores of lacteals. The lacteals come together to form the lymphatic vessels. The chylomicrons are transported in the lymphatic vessels and empty through the thoracic duct into the subclavian vein of the circulatory system. Once in the bloodstream, the enzyme lipoprotein lipase breaks down the triglycerides of the chylomicrons into free fatty acids and glycerol. These breakdown products then pass through capillary walls to be used for energy by cells or stored in adipose tissue as fat. Liver cells combine the remaining chylomicron remnants with proteins, forming lipoproteins that transport cholesterol in the blood.","{'0c6d08c5-3230-42a2-80ea-326c1765c6a1': 'About 95 percent of lipids are absorbed in the small intestine. Bile salts not only speed up lipid digestion, they are also essential to the absorption of the end products of lipid digestion. Short-chain fatty acids are relatively water soluble and can enter the absorptive cells (enterocytes) directly. Despite being hydrophobic, the small size of short-chain fatty acids enables them to be absorbed by enterocytes via simple diffusion, and then take the same path as monosaccharides and amino acids into the blood capillary of a villus.', '64bebc18-ae7f-4a31-a376-a274f3425d5a': 'The large and hydrophobic long-chain fatty acids and monoacylglycerides are not so easily suspended in the watery intestinal chyme. However, bile salts and lecithin resolve this issue by enclosing them in a micelle, which is a tiny sphere with polar (hydrophilic) ends facing the watery environment and hydrophobic tails turned to the interior, creating a receptive environment for the long-chain fatty acids. The core also includes cholesterol and fat-soluble vitamins. Without micelles, lipids would sit on the surface of chyme and never come in contact with the absorptive surfaces of the epithelial cells. Micelles can easily squeeze between microvilli and get very near the luminal cell surface. At this point, lipid substances exit the micelle and are absorbed via simple diffusion.', '1fb2dda4-d6de-403b-8ad4-2b1dcbe84b44': 'The free fatty acids and monoacylglycerides that enter the epithelial cells are reincorporated into triglycerides. The triglycerides are mixed with phospholipids and cholesterol, and surrounded with a protein coat. This new complex, called a chylomicron, is a water-soluble lipoprotein. After being processed by the Golgi apparatus, chylomicrons are released from the cell (Figure 23.7.6). Too big to pass through the basement membranes of blood capillaries, chylomicrons instead enter the large pores of lacteals. The lacteals come together to form the lymphatic vessels. The chylomicrons are transported in the lymphatic vessels and empty through the thoracic duct into the subclavian vein of the circulatory system. Once in the bloodstream, the enzyme lipoprotein lipase breaks down the triglycerides of the chylomicrons into free fatty acids and glycerol. These breakdown products then pass through capillary walls to be used for energy by cells or stored in adipose tissue as fat. Liver cells combine the remaining chylomicron remnants with proteins, forming lipoproteins that transport cholesterol in the blood.'}"
+Figure 23.5.1,Anatomy_And_Physio/images/Figure 23.5.1.jpg,"Figure 23.5.1 – Accessory Organs: The liver, pancreas, and gallbladder are considered accessory digestive organs, but their roles in the digestive system are vital.","Chemical digestion in the small intestine relies on the activities of three accessory digestive organs: the liver, pancreas, and gallbladder (Figure 23.5.1). The digestive role of the liver is to produce bile and export it to the duodenum. The gallbladder primarily stores, concentrates, and releases bile. The pancreas produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum.","{'1226475b-ed13-4bbc-aaf9-4dffbb027f67': 'The large intestine is the terminal part of the alimentary canal. The primary function of this organ is to finish absorption of nutrients and water, synthesize certain vitamins, as well as to form, store, and eliminate feces from the body.', 'bd8ea296-82a2-4b00-b9e0-cc353620747d': 'Chemical digestion in the small intestine relies on the activities of three accessory digestive organs: the liver, pancreas, and gallbladder (Figure 23.5.1). The digestive role of the liver is to produce bile and export it to the duodenum. The gallbladder primarily stores, concentrates, and releases bile. The pancreas produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum.'}"
+Figure 23.5.2,Anatomy_And_Physio/images/Figure 23.5.2.jpg,Figure 23.5.2 – Microscopic Anatomy of the Liver: The liver is organized into repeating structures called lobules made up of hepatocytes. The liver receives oxygenated blood from the hepatic artery and nutrient-rich deoxygenated blood from the hepatic portal vein and drain the bile formed by the hepatocytes into the bile duct.,"The porta hepatis (“gate to the liver”) is where the hepatic artery and hepatic portal vein enter the liver. These two vessels, along with the common hepatic duct, run behind the lateral border of the lesser omentum on the way to their destinations. As shown in Figure 23.5.2, the hepatic artery delivers oxygenated blood from the heart to the liver. The hepatic portal vein delivers partially deoxygenated blood containing nutrients absorbed from the small intestine and actually supplies more oxygen to the liver than do the much smaller hepatic arteries. In addition to nutrients, drugs and toxins are also absorbed. After processing the bloodborne nutrients and toxins, the liver releases nutrients needed by other cells back into the blood, which drains into the central vein and then through the hepatic vein to the inferior vena cava. With this hepatic portal circulation, all blood from the alimentary canal passes through the liver. This largely explains why the liver is the most common site for the metastasis of cancers that originate in the alimentary canal.","{'0710b319-a783-44bb-a0e4-2a47df70b9bd': 'The liver is the largest gland in the body, weighing about three pounds in an adult. It is also one of the most important organs. In addition to being an accessory digestive organ, it plays a number of roles in metabolism and regulation. The liver lies inferior to the diaphragm in the right upper quadrant of the abdominal cavity and receives protection from the surrounding ribs.', '650d3de9-7974-4780-849a-5f65c2738586': 'The liver is divided into two primary lobes: a large right lobe and a much smaller left lobe. In the right lobe, some anatomists also identify an inferior quadrate lobe and a posterior caudate lobe, which are defined by internal features. The liver is connected to the abdominal wall and diaphragm by five peritoneal folds referred to as ligaments. These are the falciform ligament, the coronary ligament, two lateral ligaments, and the ligamentum teres hepatis. The falciform ligament and ligamentum teres hepatis are actually remnants of the umbilical vein, and separate the right and left lobes anteriorly. The lesser omentum tethers the liver to the lesser curvature of the stomach.', '4e160623-2f0e-42f8-abcc-656c0134652a': 'The porta hepatis (“gate to the liver”) is where the hepatic artery and hepatic portal vein enter the liver. These two vessels, along with the common hepatic duct, run behind the lateral border of the lesser omentum on the way to their destinations. As shown in Figure 23.5.2, the hepatic artery delivers oxygenated blood from the heart to the liver. The hepatic portal vein delivers partially deoxygenated blood containing nutrients absorbed from the small intestine and actually supplies more oxygen to the liver than do the much smaller hepatic arteries. In addition to nutrients, drugs and toxins are also absorbed. After processing the bloodborne nutrients and toxins, the liver releases nutrients needed by other cells back into the blood, which drains into the central vein and then through the hepatic vein to the inferior vena cava. With this hepatic portal circulation, all blood from the alimentary canal passes through the liver. This largely explains why the liver is the most common site for the metastasis of cancers that originate in the alimentary canal.'}"
+Figure 23.5.3,Anatomy_And_Physio/images/Figure 23.5.3.jpg,"Figure 23.5.3 – Exocrine and Endocrine Pancreas: The pancreas has a head, a body, and a tail. It delivers pancreatic juice to the duodenum through the pancreatic duct.","The soft, oblong, glandular pancreas lies transversely in the retroperitoneum behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen. It is a curious mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions (Figure 23.5.3).","{'ebeefd9e-0d3f-4976-82db-3e2e4870711d': 'The soft, oblong, glandular pancreas lies transversely in the retroperitoneum behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen. It is a curious mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions (Figure 23.5.3).', 'd3cc7eca-d65c-42ed-a211-a2aa72e7d3d5': 'The exocrine part of the pancreas arises as little grape-like cell clusters, each called an acinus (plural = acini), located at the terminal ends of pancreatic ducts. These acinar cells secrete enzyme-rich pancreatic juice into tiny merging ducts that form two dominant ducts. The larger duct fuses with the common bile duct (carrying bile from the liver and gallbladder) just before entering the duodenum via a common opening (the hepatopancreatic ampulla). The smooth muscle sphincter of the hepatopancreatic ampulla controls the release of pancreatic juice and bile into the small intestine. The second and smaller pancreatic duct, the accessory duct (duct of Santorini), runs from the pancreas directly into the duodenum, approximately 1 inch above the hepatopancreatic ampulla. When present, it is a persistent remnant of pancreatic development.', '05703c0b-c686-484d-b96d-0a9cfce3a2ab': 'Scattered through the sea of exocrine acini are small islands of endocrine cells, the islets of Langerhans. These vital cells produce the hormones pancreatic polypeptide, insulin, glucagon, and somatostatin.'}"
+Figure 23.5.4,Anatomy_And_Physio/images/Figure 23.5.4.jpg,"Figure 23.5.4 – Gallbladder: The gallbladder stores and concentrates bile, and releases it into the two-way cystic duct when it is needed by the small intestine.","The simple columnar epithelium of the gallbladder mucosa is organized in rugae, similar to those of the stomach. There is no submucosa in the gallbladder wall. The wall’s middle, muscular coat is made of smooth muscle fibers. When these fibers contract, the gallbladder’s contents are ejected through the cystic duct and into the bile duct (Figure 23.5.4). Visceral peritoneum reflected from the liver capsule holds the gallbladder against the liver and forms the outer coat of the gallbladder. The gallbladder’s mucosa absorbs water and ions from bile, concentrating it by up to 10-fold.","{'9fd704ae-913b-4b28-80b2-5a73c5a0c626': 'The gallbladder is 8–10 cm (~3–4 in) long and is nested in a shallow area on the posterior aspect of the right lobe of the liver. It is divided into three regions. The fundus is the widest portion and tapers medially into the body, which in turn narrows to become the neck. The neck angles slightly superiorly as it approaches the hepatic duct. The cystic duct is 1–2 cm (less than 1 in) long and turns inferiorly as it bridges the neck and hepatic duct.', 'f933d02f-9b2b-428f-94e8-0dea40bf6f47': 'The simple columnar epithelium of the gallbladder mucosa is organized in rugae, similar to those of the stomach. There is no submucosa in the gallbladder wall. The wall’s middle, muscular coat is made of smooth muscle fibers. When these fibers contract, the gallbladder’s contents are ejected through the cystic duct and into the bile duct (Figure 23.5.4). Visceral peritoneum reflected from the liver capsule holds the gallbladder against the liver and forms the outer coat of the gallbladder. The gallbladder’s mucosa absorbs water and ions from bile, concentrating it by up to 10-fold.', '714c8c1d-0c11-40c6-bc60-afdbd954c88a': 'This gall bladder stores, concentrates, and, when stimulated, propels the bile into the duodenum via the common bile duct. When fatty chyme enters the duodenum, CCK is released which causes the smooth muscle of the gall bladder to contract. Also, stimulation of the gall bladder by the vagus nerve and stimulate muscle contraction. Both CCK and vagal stimulation cause the gall bladder to release the stored bile into the duodenum to emulsify the lipids present in the chyme.', '425fff51-c92a-4f06-9ff3-8bbc07c3149d': 'Although a minimal amount of digestion occurs in the mouth, chemical digestion really gets underway in the stomach, primarily as the initial site of protein digestion. An expansion of the alimentary canal that lies immediately inferior to the esophagus, the stomach links the esophagus to the first part of the small intestine (the duodenum) and is relatively fixed in place at its esophageal and duodenal ends. In between, however, it can be a highly active structure, contracting and continually changing position and size. These contractions provide mechanical assistance to digestion. The empty stomach is only about the size of your fist, but can stretch to hold as much as 4 liters of food and fluid, or more than 75 times its empty volume, and then return to its resting size when empty. Although you might think that the size of a person’s stomach is related to how much food that individual consumes, body weight does not correlate with stomach size. Rather, when you eat greater quantities of food—such as at holiday dinner—you stretch the stomach more than when you eat less.', '0429fe01-5976-46fa-9629-61859e6d0893': 'Popular culture tends to refer to the stomach as the location where all digestion takes place. Of course, this is not true. An important function of the stomach is to serve as a temporary holding chamber. You can ingest a meal far more quickly than it can be digested and absorbed by the small intestine. Thus, the stomach holds food and parses only small amounts into the small intestine at a time. Foods are not processed in the order they are eaten; rather, they are mixed together with digestive juices in the stomach until they are converted into chyme, which is released into the small intestine.', 'ce80e02a-9ad2-4c0b-9103-d8b19b8e8071': 'As you will see in the sections that follow, the stomach plays several important roles in chemical digestion, including the continued digestion of carbohydrates until salivary amylase is inactivated by stomach acid, and the initial digestion of proteins and triglycerides. Little if any absorption occurs in the stomach, with the exception of lipid soluble substances such as alcohol and aspirin.'}"
+Figure 23.4.1,Anatomy_And_Physio/images/Figure 23.4.1.jpg,"Figure 23.4.1 – Stomach: The stomach has four major regions: the cardia, fundus, body, and pylorus. The addition of an inner oblique smooth muscle layer gives the muscularis the ability to vigorously churn and mix food.","There are four main regions in the stomach: the cardia, fundus, body, and pylorus (Figure 23.4.1). The cardia (or cardiac region) is the point where the esophagus connects to the stomach and through which food passes into the stomach. Located inferior to the diaphragm, above and to the left of the cardia, is the dome-shaped fundus. Below the fundus is the body, the main part of the stomach. The funnel-shaped pylorus connects the stomach to the duodenum. The wider end of the funnel, the pyloric antrum, connects to the body of the stomach. The narrower end is called the pyloric canal, which connects to the duodenum. The smooth muscle pyloric sphincter is located at this latter point of connection and controls stomach emptying. In the absence of food, the stomach deflates inward, and its mucosa and submucosa fall into large folds called  rugae.","{'68bd869a-b396-4c36-b21e-986f1eb39540': 'There are four main regions in the stomach: the cardia, fundus, body, and pylorus (Figure 23.4.1). The cardia (or cardiac region) is the point where the esophagus connects to the stomach and through which food passes into the stomach. Located inferior to the diaphragm, above and to the left of the cardia, is the dome-shaped fundus. Below the fundus is the body, the main part of the stomach. The funnel-shaped pylorus connects the stomach to the duodenum. The wider end of the funnel, the pyloric antrum, connects to the body of the stomach. The narrower end is called the pyloric canal, which connects to the duodenum. The smooth muscle pyloric sphincter is located at this latter point of connection and controls stomach emptying. In the absence of food, the stomach deflates inward, and its mucosa and submucosa fall into large folds called\xa0 rugae.', 'b8c5a5dd-de3a-4e48-8556-a84c156e5ce9': 'The convex lateral surface of the stomach is called the greater curvature; the concave medial border is the lesser curvature. The stomach is held in place by the lesser omentum, which extends from the liver to the lesser curvature, and the greater omentum, which runs from the greater curvature to the posterior abdominal wall.'}"
+Figure 23.4.2,Anatomy_And_Physio/images/Figure 23.4.2.jpg,"Figure 23.4.2 – Histology of the Stomach: The stomach wall is adapted for the functions of the stomach. In the epithelium, gastric pits lead to gastric glands that secrete gastric juice. The gastric glands (one gland is shown enlarged on the right) contain different types of cells that secrete a variety of enzymes, including hydrochloride acid, which activates the protein-digesting enzyme pepsin.","The wall of the stomach is made of the same four layers as most of the rest of the alimentary canal, but with adaptations to the mucosa and muscularis for the unique functions of this organ. In addition to the typical circular and longitudinal smooth muscle layers, the muscularis has an inner oblique smooth muscle layer (Figure 23.4.2). As a result, in addition to moving food through the canal, the stomach can vigorously churn food, mechanically breaking it down into smaller particles.","{'a4e36078-7841-41b3-acea-c348412050b0': 'The wall of the stomach is made of the same four layers as most of the rest of the alimentary canal, but with adaptations to the mucosa and muscularis for the unique functions of this organ. In addition to the typical circular and longitudinal smooth muscle layers, the muscularis has an inner oblique smooth muscle layer (Figure 23.4.2). As a result, in addition to moving food through the canal, the stomach can vigorously churn food, mechanically breaking it down into smaller particles.', '74964477-aa22-4d7f-8ebf-6238c4e9afc0': 'The stomach mucosa’s epithelial lining consists only of surface mucus cells, which secrete a protective coat of alkaline mucus. A vast number of gastric pits dot the surface of the epithelium, giving it the appearance of a well-used pincushion, and mark the entry to each gastric gland, which secretes a complex digestive fluid referred to as gastric juice.', '89e0d179-2b93-4d7a-a45e-7e3bef9a606c': 'Although the walls of the gastric pits are made up primarily of mucus cells, the gastric glands are made up of different types of cells. The glands of the cardia and pylorus are composed primarily of mucus-secreting cells. Cells that make up the pyloric antrum secrete mucus and a number of hormones, including the majority of the stimulatory hormone, gastrin. The much larger glands of the fundus and body of the stomach, the site of most chemical digestion, produce most of the gastric secretions. These glands are made up of a variety of secretory cells. These include parietal cells, chief cells, mucous neck cells, and enteroendocrine cells.', '5fa42fba-d76e-4dcf-82f4-38bd69b14e0b': 'Parietal cells—Located primarily in the middle region of the gastric glands are parietal cells, which are among the most highly differentiated of the body’s epithelial cells. These relatively large cells produce both hydrochloric acid (HCl) and intrinsic factor. HCl is responsible for the high acidity (pH 1.5 to 3.5) of the stomach contents and is needed to activate the protein-digesting enzyme, pepsin. The acidity also kills much of the bacteria you ingest with food and helps to denature proteins, making them more available for enzymatic digestion. Intrinsic factor is a glycoprotein necessary for the absorption of vitamin B12 in the small intestine.', '636df4f7-d4db-445a-b2dd-dda177342fab': 'Chief cells—Located primarily in the basal regions of gastric glands are chief cells, which secrete pepsinogen, the inactive proenzyme form of pepsin. HCl is necessary for the conversion of pepsinogen to pepsin.', '34d92fe8-8ff9-4a67-863c-2504661ad6b9': 'Mucous neck cells—Gastric glands in the upper part of the stomach contain mucous neck cells that secrete alkaline mucus that is similary to the mucus secreted by the cells of the surface epithelium.', 'd1887fa2-9ef9-4068-b6c6-7ef1c3de3bed': 'Enteroendocrine cells—Finally, enteroendocrine cells found in the gastric glands secrete various hormones into the interstitial fluid of the lamina propria. These include gastrin, which is released mainly by enteroendocrine G cells.', 'd5ba8c10-dc6e-4818-8beb-cf3375fcf5d7': 'Table 23.6 describes the digestive functions of important hormones secreted by the stomach.'}"
+Figure 23.4.3,Anatomy_And_Physio/images/Figure 23.4.3.jpg,"Figure 23.4.3 – The Three Phases of Gastric Secretion: Gastric secretion occurs in three phases: cephalic, gastric, and intestinal. During each phase, the secretion of gastric juice can be stimulated or inhibited. EDITOR’S NOTE: Each place where figure says “Stimulates stomach secretory activity,” describe what that activity is and how much it is activated. In the section on the cephalic phase it could say something like: secretion of HCl and pepsin. In the section on the gastric phase it could say something like: increased secretion of HCl and pepsin and increased gastric motility. Etc.","The secretion of gastric juice is controlled by both nerves and hormones. Stimuli in the brain, stomach, and small intestine activate or inhibit gastric juice production. This is why the three phases of gastric secretion are called the cephalic, gastric, and intestinal phases (Figure 23.4.3). However, once gastric secretion begins, all three phases can occur simultaneously.","{'a4e565af-937b-4ec5-9604-c95465946543': 'The secretion of gastric juice is controlled by both nerves and hormones. Stimuli in the brain, stomach, and small intestine activate or inhibit gastric juice production. This is why the three phases of gastric secretion are called the cephalic, gastric, and intestinal phases (Figure 23.4.3). However, once gastric secretion begins, all three phases can occur simultaneously.', 'ba4045cc-6ed1-4d23-85cd-d5ea1a2f0b80': 'The cephalic phase (reflex phase) of gastric secretion, which is relatively brief, takes place before food enters the stomach. The smell, taste, sight, or thought of food triggers this phase. For example, when you bring a piece of sushi to your lips, impulses from receptors in your taste buds or the nose are relayed to your brain, which returns signals that increase gastric secretion to prepare your stomach for digestion. This enhanced secretion is a conditioned reflex, meaning it occurs only if you like or want a particular food. Depression and loss of appetite can suppress the cephalic reflex.', '9a6dd7ab-8eaa-4f3c-9d3b-4a02997e633d': 'The gastric phase of secretion lasts 3 to 4 hours, and is set in motion by local neural and hormonal mechanisms triggered by the entry of food into the stomach. For example, when your sushi reaches the stomach, it creates distention that activates the stretch receptors. This stimulates parasympathetic neurons to release acetylcholine, which then provokes increased secretion of gastric juice. Partially digested proteins, caffeine, and rising pH stimulate the release of gastrin from enteroendocrine G cells, which in turn induces parietal cells to increase their production of HCl, which is needed to create an acidic environment for the conversion of pepsinogen to pepsin, and protein digestion. Additionally, the release of gastrin activates vigorous smooth muscle contractions. However, it should be noted that the stomach does have a natural means of avoiding excessive acid secretion and potential heartburn. Whenever pH levels drop too low, cells in the stomach react by suspending HCl secretion and increasing mucous secretions.', '13e381ca-9fb3-4717-986a-068f69dd3187': 'The intestinal phase of gastric secretion has both excitatory and inhibitory elements. The duodenum has a major role in regulating the stomach and its emptying. When partially digested food fills the duodenum, intestinal mucosal cells release a hormone called intestinal (enteric) gastrin, which further excites gastric juice secretion. This stimulatory activity is brief, however, because when the intestine distends with chyme, the enterogastric reflex inhibits secretion.\xa0One of the effects of this reflex is to close the pyloric sphincter, which blocks additional chyme from entering the duodenum. In addition to the enterogastric reflex, several hormones such as cholecystokinin (CCK) and secretin are released by the enteroendocrine cells of the duodenum when fatty, acidic, or carbohydrate rich chyme enters the duodenum. CCK and secretin enter the blood and travel to the stomach inhibiting the production of HCl and pepsin as well as inhibiting gastric motility allowing time for the duodenum to break down the chyme.'}"
+Figure 23.3.1,Anatomy_And_Physio/images/Figure 23.3.1.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth.","The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or buccal cavity). The structures of the mouth are illustrated in Figure 23.3.1.","{'cf3e0ed7-aaa0-4d0b-93ed-1dca144426d4': 'The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or buccal cavity). The structures of the mouth are illustrated in Figure 23.3.1.', '55dade2e-ce68-4a4e-93b3-d1f6a5e25d9b': 'At the entrance to the mouth are the lips, or labia (singular = labium). Their outer covering is skin, which transitions to a mucous membrane in the mouth proper. Lips are very vascular with only a thin layer of keratinized epithelium and therefore they look red due to the red blood cell color showing through the thin, transparent epithelium. They have a huge representation on the cerebral cortex, which probably explains the human fascination with kissing! The lips cover the orbicularis oris muscle, which regulates what comes in and goes out of the mouth. The labial frenulum is a midline fold of mucous membrane that attaches the inner surface of each lip to the gum. The cheeks make up the oral cavity’s sidewalls. While their outer covering is skin, their inner covering is mucous membrane. This membrane is made up of non-keratinized, stratified squamous epithelium. Between the skin and mucous membranes are connective tissue and buccinator muscles. The next time you eat some food, notice how the buccinator muscles in your cheeks and the orbicularis oris muscle in your lips contract, helping you keep the food from falling out of your mouth. Additionally, notice how these muscles work when you are speaking.', 'a5eb0072-b458-424e-857d-cf36b0b3a208': 'The pocket-like part of the mouth that is framed on the inside by the gums and teeth, and on the outside by the cheeks and lips is called the oral vestibule. Moving farther into the mouth, the opening between the oral cavity and throat (oropharynx) is called the fauces (like the kitchen “faucet”). The main open area of the mouth, or oral cavity proper, runs from the gums and teeth to the fauces.', '2e665ef4-d0f0-4363-abcd-2ccefa0dbb02': 'When you are chewing, you do not find it difficult to breathe simultaneously. The next time you have food in your mouth, notice how the arched shape of the roof of your mouth allows you to handle both digestion and respiration at the same time. This arch is called the palate. The anterior region of the palate serves as a wall (or septum) between the oral and nasal cavities as well as a rigid shelf against which the tongue can push food. It is created by the maxillary and palatine bones of the skull and, given its bony structure, is known as the hard palate. If you run your tongue along the roof of your mouth, you’ll notice that the hard palate ends in the posterior oral cavity, and the tissue becomes fleshier. This part of the palate, known as the soft palate, is composed mainly of skeletal muscle. You can therefore manipulate, subconsciously, the soft palate—for instance, to yawn, swallow, or sing (see Figure 23.3.1).', 'a389905c-f734-45ba-a7da-7e1114b2f475': 'A fleshy bead of tissue called the uvula drops down from the center of the posterior edge of the soft palate. Although some have suggested that the uvula is a vestigial organ, it serves an important purpose. When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity. Unfortunately, it can also contribute to the sound produced by snoring. Two muscular folds extend downward from the soft palate, on either side of the uvula. Toward the front, the palatoglossal arch lies next to the base of the tongue; behind it, the palatopharyngeal arch forms the superior and lateral margins of the fauces. Between these two arches are the palatine tonsils, clusters of lymphoid tissue that protect the pharynx. The lingual tonsils are located at the base of the tongue.'}"
+Figure 23.3.1,Anatomy_And_Physio/images/Figure 23.3.1.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth.","The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or buccal cavity). The structures of the mouth are illustrated in Figure 23.3.1.","{'cf3e0ed7-aaa0-4d0b-93ed-1dca144426d4': 'The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or buccal cavity). The structures of the mouth are illustrated in Figure 23.3.1.', '55dade2e-ce68-4a4e-93b3-d1f6a5e25d9b': 'At the entrance to the mouth are the lips, or labia (singular = labium). Their outer covering is skin, which transitions to a mucous membrane in the mouth proper. Lips are very vascular with only a thin layer of keratinized epithelium and therefore they look red due to the red blood cell color showing through the thin, transparent epithelium. They have a huge representation on the cerebral cortex, which probably explains the human fascination with kissing! The lips cover the orbicularis oris muscle, which regulates what comes in and goes out of the mouth. The labial frenulum is a midline fold of mucous membrane that attaches the inner surface of each lip to the gum. The cheeks make up the oral cavity’s sidewalls. While their outer covering is skin, their inner covering is mucous membrane. This membrane is made up of non-keratinized, stratified squamous epithelium. Between the skin and mucous membranes are connective tissue and buccinator muscles. The next time you eat some food, notice how the buccinator muscles in your cheeks and the orbicularis oris muscle in your lips contract, helping you keep the food from falling out of your mouth. Additionally, notice how these muscles work when you are speaking.', 'a5eb0072-b458-424e-857d-cf36b0b3a208': 'The pocket-like part of the mouth that is framed on the inside by the gums and teeth, and on the outside by the cheeks and lips is called the oral vestibule. Moving farther into the mouth, the opening between the oral cavity and throat (oropharynx) is called the fauces (like the kitchen “faucet”). The main open area of the mouth, or oral cavity proper, runs from the gums and teeth to the fauces.', '2e665ef4-d0f0-4363-abcd-2ccefa0dbb02': 'When you are chewing, you do not find it difficult to breathe simultaneously. The next time you have food in your mouth, notice how the arched shape of the roof of your mouth allows you to handle both digestion and respiration at the same time. This arch is called the palate. The anterior region of the palate serves as a wall (or septum) between the oral and nasal cavities as well as a rigid shelf against which the tongue can push food. It is created by the maxillary and palatine bones of the skull and, given its bony structure, is known as the hard palate. If you run your tongue along the roof of your mouth, you’ll notice that the hard palate ends in the posterior oral cavity, and the tissue becomes fleshier. This part of the palate, known as the soft palate, is composed mainly of skeletal muscle. You can therefore manipulate, subconsciously, the soft palate—for instance, to yawn, swallow, or sing (see Figure 23.3.1).', 'a389905c-f734-45ba-a7da-7e1114b2f475': 'A fleshy bead of tissue called the uvula drops down from the center of the posterior edge of the soft palate. Although some have suggested that the uvula is a vestigial organ, it serves an important purpose. When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity. Unfortunately, it can also contribute to the sound produced by snoring. Two muscular folds extend downward from the soft palate, on either side of the uvula. Toward the front, the palatoglossal arch lies next to the base of the tongue; behind it, the palatopharyngeal arch forms the superior and lateral margins of the fauces. Between these two arches are the palatine tonsils, clusters of lymphoid tissue that protect the pharynx. The lingual tonsils are located at the base of the tongue.'}"
+Figure 23.3.2,Anatomy_And_Physio/images/Figure 23.3.2.jpg,Figure 23.3.2 – Tongue: This superior view of the tongue shows the locations and types of lingual papillae.,"The top and sides of the tongue are studded with papillae, extensions of lamina propria of the mucosa, which are covered in stratified squamous epithelium (Figure 23.3.2). Fungiform papillae, which are mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear of the tongue and smaller on the tip and sides. Circumvallate papillae are much fewer in number, only 8 to 12, and lie in a row along the posterior portion of the tongue anterior to the lingual tonsil. In contrast, filiform papillae are long and thin. Fungiform and circumvallate papillae contain taste buds, and filiform papillae have touch receptors that help the tongue move food around in the mouth. The filiform papillae create an abrasive surface that performs mechanically, much like a cat’s rough tongue that is used for grooming. Lingual glands in the lamina propria of the tongue secrete mucus and a watery serous fluid that contains the enzyme lingual lipase, which plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach. A fold of mucous membrane on the underside of the tongue, the lingual frenulum, tethers the tongue to the floor of the mouth. People with the congenital anomaly ankyloglossia, also known by the non-medical term “tongue tie,” have a lingual frenulum that is too short or otherwise malformed. Severe ankyloglossia can impair speech and must be corrected with surgery.","{'e97300ff-4a5e-40c6-872c-1b3121559e37': 'Perhaps you have heard it said that the tongue is the strongest muscle in the body. Those who stake this claim cite its strength proportionate to its size. Although it is difficult to quantify the relative strength of different muscles, it remains indisputable that the tongue is a workhorse, facilitating ingestion, mechanical digestion, chemical digestion (lingual lipase), sensation (of taste, texture, and temperature of food), swallowing, and vocalization.', '145b4c00-1e05-45bb-b79f-adb937738727': 'The tongue is attached to the mandible, the styloid processes of the temporal bones, and the hyoid bone. The hyoid is unique in that it only distantly/indirectly articulates with other bones. The tongue is positioned over the floor of the oral cavity. A medial septum extends the entire length of the tongue, dividing it into symmetrical halves.', '002aa59b-67e7-46e7-ab0b-ea3452632b57': 'Beneath its mucous membrane covering, each half of the tongue is composed of the same number and type of intrinsic and extrinsic skeletal muscles. The intrinsic muscles (those within the tongue) are the longitudinalis inferior, longitudinalis superior, transversus linguae, and verticalis linguae muscles. These allow you to change the size and shape of your tongue, as well as to stick it out, if you wish. Having such a flexible tongue facilitates both swallowing and speech.', 'ec8199b1-fe42-47dd-860f-7650f89fb749': 'As you learned in your study of the muscular system, the extrinsic muscles of the tongue are the mylohyoid, hyoglossus, styloglossus, and genioglossus muscles. These muscles originate outside the tongue and insert into connective tissues within the tongue. The mylohyoid is responsible for raising the tongue, the hyoglossus pulls it down and back, the styloglossus pulls it up and back, and the genioglossus pulls it forward. Working in concert, these muscles perform three important digestive functions in the mouth: (1) position food for optimal chewing, (2) gather food into a bolus (rounded mass), and (3) position food so it can be swallowed.', '8703c972-8143-4f96-b9ae-4d3611d1fa01': 'The top and sides of the tongue are studded with papillae, extensions of lamina propria of the mucosa, which are covered in stratified squamous epithelium (Figure 23.3.2). Fungiform papillae, which are mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear of the tongue and smaller on the tip and sides. Circumvallate papillae are much fewer in number, only 8 to 12, and lie in a row along the posterior portion of the tongue anterior to the lingual tonsil. In contrast, filiform papillae are long and thin. Fungiform and circumvallate papillae contain taste buds, and filiform papillae have touch receptors that help the tongue move food around in the mouth. The filiform papillae create an abrasive surface that performs mechanically, much like a cat’s rough tongue that is used for grooming. Lingual glands in the lamina propria of the tongue secrete mucus and a watery serous fluid that contains the enzyme lingual lipase, which plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach. A fold of mucous membrane on the underside of the tongue, the lingual frenulum, tethers the tongue to the floor of the mouth. People with the congenital anomaly ankyloglossia, also known by the non-medical term “tongue tie,” have a lingual frenulum that is too short or otherwise malformed. Severe ankyloglossia can impair speech and must be corrected with surgery.'}"
+Figure 23.3.6,Anatomy_And_Physio/images/Figure 23.3.6.jpg,Figure 23.3.6 – Pharynx: The pharynx runs from the nostrils to the esophagus and the larynx.,"A short tube of skeletal muscle lined with a mucous membrane, the pharynx runs from the posterior oral and nasal cavities to the opening of the esophagus and larynx. It has three subdivisions. The most superior, the nasopharynx, is involved only in breathing and speech. The other two subdivisions, the oropharynx and the laryngopharynx, are used for both breathing and digestion. The oropharynx begins inferior to the nasopharynx and is continuous below with the laryngopharynx (Figure 23.3.6). The inferior border of the laryngopharynx connects to the esophagus, whereas the anterior portion connects to the larynx, allowing air to flow into the bronchial tree.","{'675f530d-0ee3-4d10-9d2d-7ea6ccad0b4e': 'The pharynx (throat) is involved in both digestion and respiration. It receives food and air from the mouth, and air from the nasal cavities. When food enters the pharynx, involuntary muscle contractions close off the air passageways.', '1f8a07a6-b298-4e71-b2a2-f5a22d928f5d': 'A short tube of skeletal muscle lined with a mucous membrane, the pharynx runs from the posterior oral and nasal cavities to the opening of the esophagus and larynx. It has three subdivisions. The most superior, the nasopharynx, is involved only in breathing and speech. The other two subdivisions, the oropharynx and the laryngopharynx, are used for both breathing and digestion. The oropharynx begins inferior to the nasopharynx and is continuous below with the laryngopharynx (Figure 23.3.6). The inferior border of the laryngopharynx connects to the esophagus, whereas the anterior portion connects to the larynx, allowing air to flow into the bronchial tree.', '833d84b8-fdd3-4a27-a401-5c201005f237': 'Histologically, the wall of the oropharynx is similar to that of the oral cavity. The mucosa includes a stratified squamous epithelium that is endowed with mucus-producing glands. During swallowing, the elevator skeletal muscles of the pharynx contract, raising and expanding the pharynx to receive the bolus of food. Once received, these muscles relax and the constrictor muscles of the pharynx contract, forcing the bolus into the esophagus and initiating peristalsis.', '717b58ee-2b1d-4591-b6d4-f0fe1475cdd5': 'Usually during swallowing, the soft palate and uvula rise reflexively to close off the entrance to the nasopharynx. At the same time, the larynx is pulled superiorly and the cartilaginous epiglottis, its most superior structure, folds inferiorly, covering the glottis (the opening to the larynx); this process effectively blocks access to the trachea and bronchi. When the food “goes down the wrong way,” it goes into the trachea. When food enters the trachea, the reaction is to cough, which usually forces the food up and out of the trachea, and back into the pharynx.'}"
+Figure 23.3.7,Anatomy_And_Physio/images/Figure 23.3.7.jpg,Figure 23.3.7 – Esophagus: The upper esophageal sphincter controls the movement of food from the pharynx to the esophagus. The lower esophageal sphincter controls the movement of food from the esophagus to the stomach.,"The esophagus is a muscular tube that connects the pharynx to the stomach. It is approximately 25.4 cm (10 in) in length, located posterior to the trachea, and remains in a collapsed form when not engaged in swallowing. As you can see in Figure 23.3.7, the esophagus runs a mainly straight route through the mediastinum of the thorax. To enter the abdomen, the esophagus penetrates the diaphragm through an opening called the esophageal hiatus.","{'8ed2bf48-da3a-4889-97e8-04adcd297886': 'The esophagus is a muscular tube that connects the pharynx to the stomach. It is approximately 25.4 cm (10 in) in length, located posterior to the trachea, and remains in a collapsed form when not engaged in swallowing. As you can see in Figure 23.3.7, the esophagus runs a mainly straight route through the mediastinum of the thorax. To enter the abdomen, the esophagus penetrates the diaphragm through an opening called the esophageal hiatus.'}"
+Figure 23.3.8,Anatomy_And_Physio/images/Figure 23.3.8.jpg,Figure 23.3.8 – Deglutition: Deglutition includes the voluntary phase and two involuntary phases: the pharyngeal phase and the esophageal phase.,"Deglutition is another word for swallowing—the movement of food from the mouth to the stomach. The entire process takes about 4 to 8 seconds for solid or semisolid food, and about 1 second for very soft food and liquids. Although this sounds quick and effortless, deglutition is, in fact, a complex process that involves both the skeletal muscle of the tongue and the muscles of the pharynx and esophagus. It is aided by the presence of mucus and saliva. There are three stages in deglutition: the voluntary phase, the pharyngeal phase, and the esophageal phase (Figure 23.3.8). The autonomic nervous system controls the latter two phases.","{'1d328887-f4dc-4233-9dcb-f059f274aeda': 'Deglutition is another word for swallowing—the movement of food from the mouth to the stomach. The entire process takes about 4 to 8 seconds for solid or semisolid food, and about 1 second for very soft food and liquids. Although this sounds quick and effortless, deglutition is, in fact, a complex process that involves both the skeletal muscle of the tongue and the muscles of the pharynx and esophagus. It is aided by the presence of mucus and saliva. There are three stages in deglutition: the voluntary phase, the pharyngeal phase, and the esophageal phase (Figure 23.3.8). The autonomic nervous system controls the latter two phases.', 'f89a2600-5384-4a20-891c-23684b085cdc': 'Parotid gland saliva is watery with little mucus but a lot of amylase, which allows it to mix freely with food during mastication and begin the digestion of carbohydrates. In contrast, sublingual gland saliva has a lot of mucus with the least amount of amylase of all the salivary glands. The high mucus content serves to lubricate the food for swallowing.', 'f1ec99f6-2051-4260-b1e6-8c5a6240ad0a': 'The incisors. Since these teeth are used for tearing off pieces of food during ingestion, the player will need to ingest foods that have already been cut into bite-sized pieces until the broken teeth are replaced.', 'e035dfdd-54ea-4518-b170-6812a5e1ec28': 'If the lower esophageal sphincter does not close completely, the stomach’s acidic contents can back up into the esophagus, a phenomenon known as GERD.', 'd8446994-fd83-4754-af13-4b9f4151f49f': 'Peristalsis moves the bolus down the esophagus and toward the stomach. Esophageal glands secrete mucus that lubricates the bolus and reduces friction. When the bolus nears the stomach, the lower esophageal sphincter relaxes, allowing the bolus to pass into the stomach.', 'b2f90e57-1d84-4d2d-9e5e-4f35971ce7c1': 'The digestive system uses mechanical and chemical activities to break food down into absorbable substances during its journey through the digestive system. Table 23.3 provides an overview of the basic functions of the digestive organs.'}"
+Figure 23.2.1,Anatomy_And_Physio/images/Figure 23.2.1.jpg,Figure 23.2.1 – Peristalsis: Peristalsis moves food through the digestive tract with alternating waves of muscle contraction and relaxation.,"Food leaves the mouth when the tongue and pharyngeal muscles propel it into the esophagus. This act of swallowing, the last voluntary act until defecation, is an example of propulsion, which refers to the movement of food through the digestive tract. It includes both the voluntary process of swallowing and the involuntary process of peristalsis. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along (Figure 23.2.1). These waves also play a role in mixing food with digestive juices. Peristalsis is so powerful that foods and liquids you swallow enter your stomach even if you are standing on your head.","{'40059ada-dc1b-4397-913d-05cb46665af2': 'The processes of digestion include six activities: ingestion, propulsion, mechanical or physical digestion, chemical digestion, absorption, and defecation.', 'de5586e4-4690-456c-b95d-3103b7d198bf': 'The first of these processes, ingestion, refers to the entry of food into the alimentary canal through the mouth. There, the food is chewed and mixed with saliva, which contains enzymes that begin breaking down the carbohydrates in the food plus some lipid digestion via lingual lipase. Chewing increases the surface area of the food and allows an appropriately sized bolus to be produced.', 'c99c61f3-6927-4afe-8476-f9b291b60971': 'Food leaves the mouth when the tongue and pharyngeal muscles propel it into the esophagus. This act of swallowing, the last voluntary act until defecation, is an example of propulsion, which refers to the movement of food through the digestive tract. It includes both the voluntary process of swallowing and the involuntary process of peristalsis. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along (Figure 23.2.1). These waves also play a role in mixing food with digestive juices. Peristalsis is so powerful that foods and liquids you swallow enter your stomach even if you are standing on your head.', 'ba0f1158-5dc9-49ba-953f-230cb9011b26': 'Digestion includes both mechanical and chemical processes. Mechanical digestion is a purely physical process that does not change the chemical nature of the food. Instead, it makes the food smaller to increase both surface area and mobility. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with saliva. Although there may be a tendency to think that mechanical digestion is limited to the first steps of the digestive process, it occurs after the food leaves the mouth, as well. The mechanical churning of food in the stomach serves to further break it apart and expose more of its surface area to digestive juices, creating an acidic “soup” called chyme. Segmentation, which occurs mainly in the small intestine, consists of localized contractions of circular muscle of the muscularis layer of the alimentary canal. These contractions isolate small sections of the intestine, moving their contents back and forth while continuously subdividing, breaking up, and mixing the contents. By moving food back and forth in the intestinal lumen, segmentation mixes food with digestive juices and facilitates absorption.', 'db810bab-139a-4e0b-9253-42fcbf696b4f': 'In chemical digestion, starting in the mouth, digestive secretions break down complex food molecules into their chemical building blocks (for example, proteins into separate amino acids). These secretions vary in composition, but typically contain water, various enzymes, acids, and salts. The process is completed in the small intestine.', '26cd0057-ef6a-47df-aab0-9b07d5a95d18': 'Food that has been broken down is of no value to the body unless it enters the bloodstream and its nutrients are put to work. This occurs through the process of absorption, which takes place primarily within the small intestine. There, most nutrients are absorbed from the lumen of the alimentary canal into the bloodstream through the epithelial cells that make up the mucosa. Lipids are absorbed into lacteals and are transported via the lymphatic vessels to the bloodstream (the subclavian veins near the heart). The details of these processes will be discussed later.', '914dc44b-571c-4612-804b-9212ab8ac1d8': 'In defecation, the final step in digestion, undigested materials are removed from the body as feces.', '46b5fe96-7dd8-4d56-8fa5-dc45365edc56': 'In some cases, a single organ is in charge of a digestive process. For example, ingestion occurs only in the mouth and defecation only in the anus. However, most digestive processes involve the interaction of several organs and occur gradually as food moves through the alimentary canal (Figure 23.2.2).', '03ff3e7e-99f7-43f1-8800-aba411106de4': 'Some chemical digestion occurs in the mouth. Some absorption can occur in the mouth and stomach, for example, alcohol and aspirin.'}"
+Figure 23.2.2,Anatomy_And_Physio/images/Figure 23.2.2.jpg,"Figure 23.2.2 – Digestive Processes: The digestive processes are ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation.","In some cases, a single organ is in charge of a digestive process. For example, ingestion occurs only in the mouth and defecation only in the anus. However, most digestive processes involve the interaction of several organs and occur gradually as food moves through the alimentary canal (Figure 23.2.2).","{'40059ada-dc1b-4397-913d-05cb46665af2': 'The processes of digestion include six activities: ingestion, propulsion, mechanical or physical digestion, chemical digestion, absorption, and defecation.', 'de5586e4-4690-456c-b95d-3103b7d198bf': 'The first of these processes, ingestion, refers to the entry of food into the alimentary canal through the mouth. There, the food is chewed and mixed with saliva, which contains enzymes that begin breaking down the carbohydrates in the food plus some lipid digestion via lingual lipase. Chewing increases the surface area of the food and allows an appropriately sized bolus to be produced.', 'c99c61f3-6927-4afe-8476-f9b291b60971': 'Food leaves the mouth when the tongue and pharyngeal muscles propel it into the esophagus. This act of swallowing, the last voluntary act until defecation, is an example of propulsion, which refers to the movement of food through the digestive tract. It includes both the voluntary process of swallowing and the involuntary process of peristalsis. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along (Figure 23.2.1). These waves also play a role in mixing food with digestive juices. Peristalsis is so powerful that foods and liquids you swallow enter your stomach even if you are standing on your head.', 'ba0f1158-5dc9-49ba-953f-230cb9011b26': 'Digestion includes both mechanical and chemical processes. Mechanical digestion is a purely physical process that does not change the chemical nature of the food. Instead, it makes the food smaller to increase both surface area and mobility. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with saliva. Although there may be a tendency to think that mechanical digestion is limited to the first steps of the digestive process, it occurs after the food leaves the mouth, as well. The mechanical churning of food in the stomach serves to further break it apart and expose more of its surface area to digestive juices, creating an acidic “soup” called chyme. Segmentation, which occurs mainly in the small intestine, consists of localized contractions of circular muscle of the muscularis layer of the alimentary canal. These contractions isolate small sections of the intestine, moving their contents back and forth while continuously subdividing, breaking up, and mixing the contents. By moving food back and forth in the intestinal lumen, segmentation mixes food with digestive juices and facilitates absorption.', 'db810bab-139a-4e0b-9253-42fcbf696b4f': 'In chemical digestion, starting in the mouth, digestive secretions break down complex food molecules into their chemical building blocks (for example, proteins into separate amino acids). These secretions vary in composition, but typically contain water, various enzymes, acids, and salts. The process is completed in the small intestine.', '26cd0057-ef6a-47df-aab0-9b07d5a95d18': 'Food that has been broken down is of no value to the body unless it enters the bloodstream and its nutrients are put to work. This occurs through the process of absorption, which takes place primarily within the small intestine. There, most nutrients are absorbed from the lumen of the alimentary canal into the bloodstream through the epithelial cells that make up the mucosa. Lipids are absorbed into lacteals and are transported via the lymphatic vessels to the bloodstream (the subclavian veins near the heart). The details of these processes will be discussed later.', '914dc44b-571c-4612-804b-9212ab8ac1d8': 'In defecation, the final step in digestion, undigested materials are removed from the body as feces.', '46b5fe96-7dd8-4d56-8fa5-dc45365edc56': 'In some cases, a single organ is in charge of a digestive process. For example, ingestion occurs only in the mouth and defecation only in the anus. However, most digestive processes involve the interaction of several organs and occur gradually as food moves through the alimentary canal (Figure 23.2.2).', '03ff3e7e-99f7-43f1-8800-aba411106de4': 'Some chemical digestion occurs in the mouth. Some absorption can occur in the mouth and stomach, for example, alcohol and aspirin.'}"
+Figure 23.1.1,Anatomy_And_Physio/images/Figure 23.1.1.jpg,Figure 23.1.1 – Components of the Digestive System: All digestive organs play integral roles in the life-sustaining process of digestion.,"The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process (Figure 23.1.1).","{'5db7d62e-7ba0-47bd-bcc8-dfab38e4bd88': 'Neural and endocrine regulatory mechanisms work to maintain the optimal conditions in the lumen needed for digestion and absorption. These regulatory mechanisms, which stimulate digestive activity through mechanical and chemical activity, are controlled both extrinsically and intrinsically.', 'b38cc90c-46eb-472e-9efe-c8b376dace71': 'The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process (Figure 23.1.1).', 'fed48418-0c90-40e5-9fc9-3aaffa197bca': 'As is the case with all body systems, the digestive system does not work in isolation; it functions cooperatively with the other systems of the body. Consider for example, the interrelationship between the digestive and cardiovascular systems. Arteries supply the digestive organs with oxygen and processed nutrients, and veins drain the digestive tract. These intestinal veins, constituting the hepatic portal system, are unique in that they do not return blood directly to the heart. Rather, this blood is diverted to the liver where its nutrients are off-loaded for processing before blood completes its circuit back to the heart. At the same time, the digestive system provides nutrients to the heart muscle and vascular tissue to support their functioning. The interrelationship of the digestive and endocrine systems is also critical. Hormones secreted by several endocrine glands, as well as endocrine cells of the pancreas, the stomach, and the small intestine, contribute to the control of digestion and nutrient metabolism. In turn, the digestive system provides the nutrients to fuel endocrine function. Table 23.1 gives a quick glimpse at how these other systems contribute to the functioning of the digestive system.'}"
+Figure 23.1.2,Anatomy_And_Physio/images/Figure 23.1.2.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa.","Throughout its length, the alimentary tract is composed of the same four tissue layers; the details of their structural arrangements vary to fit their specific functions. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2).","{'e51eb039-bc24-4ec8-b43d-7a508a9925c3': 'Throughout its length, the alimentary tract is composed of the same four tissue layers; the details of their structural arrangements vary to fit their specific functions. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2).', '419c8372-8eaf-4649-b1f4-a9be7fbea21d': 'The mucosa is referred to as a mucous membrane, because mucus production is a characteristic feature of gut epithelium. The membrane consists of epithelium, which is in direct contact with ingested food, and the lamina propria, a layer of connective tissue analogous to the dermis. In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosa (not to be confused with the muscularis layer, described below).', '615e75f5-5dc2-4371-9a8d-37474183fc5e': 'Epithelium—In the mouth, pharynx, esophagus, and anal canal, the epithelium is primarily a non-keratinized, stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. Interspersed among its epithelial cells are goblet cells, which secrete mucus and fluid into the lumen, and enteroendocrine cells, which secrete hormones into the interstitial spaces between cells. Epithelial cells have a very brief lifespan, averaging from only a couple of days (in the mouth) to about a week (in the gut). This process of rapid renewal helps preserve the health of the alimentary canal, despite the wear and tear resulting from continued contact with foodstuffs.', '7a0511f7-f95a-4377-8747-4c782a568c85': 'Lamina propria—In addition to loose connective tissue, the lamina propria contains numerous blood and lymphatic vessels that transport nutrients absorbed through the alimentary canal to other parts of the body. The lamina propria also serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT). These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyer’s patches. When you consider that the alimentary canal is exposed to foodborne bacteria and other foreign matter, it is not hard to appreciate why the immune system has evolved a means of defending against the pathogens encountered within it.', 'b720673d-c68a-4ae4-bf26-bc5a19030843': 'Muscularis mucosa—This thin layer of smooth muscle is in a constant state of tension, pulling the mucosa of the stomach and small intestine into undulating folds. These folds dramatically increase the surface area available for digestion and absorption.', '6f1cd849-13b5-40a3-a9af-42f843531729': 'As its name implies, the submucosa lies immediately beneath the mucosa. A broad layer of dense connective tissue, it connects the overlying mucosa to the underlying muscularis. It includes blood and lymphatic vessels (which transport absorbed nutrients), and a scattering of submucosal glands that release digestive secretions. Additionally, it serves as a conduit for a dense branching network of nerves, the submucosal plexus, which functions as described below.', 'f8269a06-9fb4-433e-84f2-a0e208eebda5': 'The third layer of the alimentary canal is the muscalaris (also called the muscularis externa). The muscularis in the small intestine is made up of a double layer of smooth muscle: an inner circular layer and an outer longitudinal layer. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal. In the most proximal and distal regions of the alimentary canal, including the mouth, pharynx, anterior part of the esophagus, and external anal sphincter, the muscularis is made up of skeletal muscle, which gives you voluntary control over swallowing and defecation. The basic two-layer structure found in the small intestine is modified in the organs proximal and distal to it. The stomach is equipped for its churning function by the addition of a third layer, the oblique muscle. While the colon has two layers like the small intestine, its longitudinal layer is segregated into three narrow parallel bands, the tenia coli, which make it look like a series of pouches rather than a simple tube.', 'd9023a82-6b63-4461-8dae-d85dcaf2b5a3': 'The serosa is the portion of the alimentary canal superficial to the muscularis. Present only in the region of the alimentary canal within the abdominal cavity, it consists of a layer of visceral peritoneum overlying a layer of loose connective tissue. Instead of serosa, the mouth, pharynx, and esophagus have a dense sheath of collagen fibers called the adventitia. These tissues serve to hold the alimentary canal in place near the ventral surface of the vertebral column.', 'b43c85fa-90a5-451b-a2a5-fc56d8dc8bee': 'As soon as food enters the mouth, it is detected by receptors that send impulses along the sensory neurons of cranial nerves. Without these nerves, not only would your food be without taste, but you would also be unable to feel either the food or the structures of your mouth, and you would be unable to avoid biting yourself as you chew, an action enabled by the motor branches of cranial nerves.', '9212f6b9-ee8e-4f91-8a6d-c427c8452631': 'Intrinsic innervation of much of the alimentary canal is provided by the enteric nervous system, which runs from the esophagus to the anus, and contains approximately 100 million motor, sensory, and interneurons (unique to this system compared to all other parts of the peripheral nervous system). These enteric neurons are grouped into two plexuses. The myenteric plexus (plexus of Auerbach) lies in the muscularis layer of the alimentary canal and is responsible for motility, especially the rhythm and force of the contractions of the muscularis. The submucosal plexus (plexus of Meissner) lies in the submucosal layer and is responsible for regulating digestive secretions and reacting to the presence of food (see Figure 23.1.2).', 'beaae40a-878b-4028-a3a0-48b3c95e933c': 'Extrinsic innervations of the alimentary canal are provided by the autonomic nervous system, which includes both sympathetic and parasympathetic nerves. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. In contrast, parasympathetic activation (the rest-and-digest response) increases GI secretion and motility by stimulating neurons of the enteric nervous system.'}"
+Figure 23.1.2,Anatomy_And_Physio/images/Figure 23.1.2.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa.","Throughout its length, the alimentary tract is composed of the same four tissue layers; the details of their structural arrangements vary to fit their specific functions. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2).","{'e51eb039-bc24-4ec8-b43d-7a508a9925c3': 'Throughout its length, the alimentary tract is composed of the same four tissue layers; the details of their structural arrangements vary to fit their specific functions. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2).', '419c8372-8eaf-4649-b1f4-a9be7fbea21d': 'The mucosa is referred to as a mucous membrane, because mucus production is a characteristic feature of gut epithelium. The membrane consists of epithelium, which is in direct contact with ingested food, and the lamina propria, a layer of connective tissue analogous to the dermis. In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosa (not to be confused with the muscularis layer, described below).', '615e75f5-5dc2-4371-9a8d-37474183fc5e': 'Epithelium—In the mouth, pharynx, esophagus, and anal canal, the epithelium is primarily a non-keratinized, stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. Interspersed among its epithelial cells are goblet cells, which secrete mucus and fluid into the lumen, and enteroendocrine cells, which secrete hormones into the interstitial spaces between cells. Epithelial cells have a very brief lifespan, averaging from only a couple of days (in the mouth) to about a week (in the gut). This process of rapid renewal helps preserve the health of the alimentary canal, despite the wear and tear resulting from continued contact with foodstuffs.', '7a0511f7-f95a-4377-8747-4c782a568c85': 'Lamina propria—In addition to loose connective tissue, the lamina propria contains numerous blood and lymphatic vessels that transport nutrients absorbed through the alimentary canal to other parts of the body. The lamina propria also serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT). These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyer’s patches. When you consider that the alimentary canal is exposed to foodborne bacteria and other foreign matter, it is not hard to appreciate why the immune system has evolved a means of defending against the pathogens encountered within it.', 'b720673d-c68a-4ae4-bf26-bc5a19030843': 'Muscularis mucosa—This thin layer of smooth muscle is in a constant state of tension, pulling the mucosa of the stomach and small intestine into undulating folds. These folds dramatically increase the surface area available for digestion and absorption.', '6f1cd849-13b5-40a3-a9af-42f843531729': 'As its name implies, the submucosa lies immediately beneath the mucosa. A broad layer of dense connective tissue, it connects the overlying mucosa to the underlying muscularis. It includes blood and lymphatic vessels (which transport absorbed nutrients), and a scattering of submucosal glands that release digestive secretions. Additionally, it serves as a conduit for a dense branching network of nerves, the submucosal plexus, which functions as described below.', 'f8269a06-9fb4-433e-84f2-a0e208eebda5': 'The third layer of the alimentary canal is the muscalaris (also called the muscularis externa). The muscularis in the small intestine is made up of a double layer of smooth muscle: an inner circular layer and an outer longitudinal layer. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal. In the most proximal and distal regions of the alimentary canal, including the mouth, pharynx, anterior part of the esophagus, and external anal sphincter, the muscularis is made up of skeletal muscle, which gives you voluntary control over swallowing and defecation. The basic two-layer structure found in the small intestine is modified in the organs proximal and distal to it. The stomach is equipped for its churning function by the addition of a third layer, the oblique muscle. While the colon has two layers like the small intestine, its longitudinal layer is segregated into three narrow parallel bands, the tenia coli, which make it look like a series of pouches rather than a simple tube.', 'd9023a82-6b63-4461-8dae-d85dcaf2b5a3': 'The serosa is the portion of the alimentary canal superficial to the muscularis. Present only in the region of the alimentary canal within the abdominal cavity, it consists of a layer of visceral peritoneum overlying a layer of loose connective tissue. Instead of serosa, the mouth, pharynx, and esophagus have a dense sheath of collagen fibers called the adventitia. These tissues serve to hold the alimentary canal in place near the ventral surface of the vertebral column.', 'b43c85fa-90a5-451b-a2a5-fc56d8dc8bee': 'As soon as food enters the mouth, it is detected by receptors that send impulses along the sensory neurons of cranial nerves. Without these nerves, not only would your food be without taste, but you would also be unable to feel either the food or the structures of your mouth, and you would be unable to avoid biting yourself as you chew, an action enabled by the motor branches of cranial nerves.', '9212f6b9-ee8e-4f91-8a6d-c427c8452631': 'Intrinsic innervation of much of the alimentary canal is provided by the enteric nervous system, which runs from the esophagus to the anus, and contains approximately 100 million motor, sensory, and interneurons (unique to this system compared to all other parts of the peripheral nervous system). These enteric neurons are grouped into two plexuses. The myenteric plexus (plexus of Auerbach) lies in the muscularis layer of the alimentary canal and is responsible for motility, especially the rhythm and force of the contractions of the muscularis. The submucosal plexus (plexus of Meissner) lies in the submucosal layer and is responsible for regulating digestive secretions and reacting to the presence of food (see Figure 23.1.2).', 'beaae40a-878b-4028-a3a0-48b3c95e933c': 'Extrinsic innervations of the alimentary canal are provided by the autonomic nervous system, which includes both sympathetic and parasympathetic nerves. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. In contrast, parasympathetic activation (the rest-and-digest response) increases GI secretion and motility by stimulating neurons of the enteric nervous system.'}"
+Figure 23.1.3,Anatomy_And_Physio/images/Figure 23.1.3.jpg,"Figure 23.1.3 – The Peritoneum: A cross-section of the abdomen shows the relationship between abdominal organs and the peritoneum (darker lines). EDITOR’S NOTE: Please add an anterior and sagittal image showing the mesentery, mesocolon, greater omentum, and lesser omentum.","The digestive organs within the abdominal cavity are held in place by the peritoneum, a broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue. It is composed of two different regions: the parietal peritoneum, which lines the abdominal wall, and the visceral peritoneum, which envelopes the abdominal organs (Figure 23.1.3). The peritoneal cavity is the space bounded by the visceral and parietal peritoneal surfaces. A few milliliters of watery fluid act as a lubricant to minimize friction between the serosal surfaces of the peritoneum.","{'cef33a08-3c23-4acf-a670-968cb492c0a8': 'The digestive organs within the abdominal cavity are held in place by the peritoneum, a broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue. It is composed of two different regions: the parietal peritoneum, which lines the abdominal wall, and the visceral peritoneum, which envelopes the abdominal organs (Figure 23.1.3). The peritoneal cavity is the space bounded by the visceral and parietal peritoneal surfaces. A few milliliters of watery fluid act as a lubricant to minimize friction between the serosal surfaces of the peritoneum.', 'aa4fa40b-8a1d-47c8-94c8-392844e21e03': 'The visceral peritoneum includes multiple large folds that envelope various abdominal organs, holding them to the dorsal surface of the body wall. Within these folds are blood vessels, lymphatic vessels, and nerves that innervate the organs with which they are in contact, supplying their adjacent organs. The five major peritoneal folds are described in Table 23.2. An important one of these folds is the mesentery which attaches the small intestine to the body wall allowing for blood vessels, nerves, and lymphatic vessels to have a secure structure to travel through on their way to and from the small intestine. The mesocolon is the portion of the mesentery serving the colon and is considered part of the larger mesentery organ. Note that during fetal development, certain digestive structures, including the first portion of the small intestine (called the duodenum), the pancreas, and portions of the large intestine (the ascending and descending colon, and the rectum) remain completely or partially posterior to the peritoneum. Thus, the location of these organs is described as retroperitoneal.', '534c606f-c19b-4879-a89f-594821705f7e': 'The digestive system is continually at work, yet people seldom appreciate the complex tasks it performs in a choreographed biologic symphony. Consider what happens when you eat an apple. Of course, you enjoy the apple’s taste as you chew it, but in the hours that follow, unless something goes amiss and you get a stomachache, you don’t notice that your digestive system is working. You may be taking a walk or studying or sleeping, having forgotten all about the apple, but your stomach and intestines are busy digesting it and absorbing its vitamins and other nutrients. By the time any waste material is excreted, the body has appropriated all it can use from the apple. In short, whether you pay attention or not, the organs of the digestive system perform their specific functions, allowing you to use the food you eat to keep you going. This chapter examines the structure and functions of these organs, and explores the mechanics and chemistry of the digestive processes.', 'db8ff036-5884-4279-ae75-5d992647c603': 'Development of the respiratory system begins early in the fetus. It is a complex process that includes many structures, most of which arise from the endoderm. Towards the end of development, the fetus can be observed making breathing movements. Until birth, however, the mother provides all of the oxygen to the fetus as well as removes all of the fetal carbon dioxide via the placenta.'}"
+Figure 22.5.1,Anatomy_And_Physio/images/Figure 22.5.1.jpg,"Figure 22.5.1 – Erythrocyte and Hemoglobin: Hemoglobin consists of four subunits, each of which contains one molecule of iron.","Even though oxygen is transported via the blood, you may recall that oxygen is not very soluble in liquids. A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Erythrocytes contain a metalloprotein, hemoglobin, which serves to bind oxygen molecules to the erythrocyte (Figure 22.5.1). Heme is the portion of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing Heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product, oxyhemoglobin (Hb–O2), which is formed when oxygen binds to hemoglobin. Oxyhemoglobin is a bright red-colored molecule that contributes to the bright red color of oxygenated blood.","{'a640bc7d-a55b-4d00-8f6f-29ec9b0cca37': 'Even though oxygen is transported via the blood, you may recall that oxygen is not very soluble in liquids. A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Erythrocytes contain a metalloprotein, hemoglobin, which serves to bind oxygen molecules to the erythrocyte (Figure 22.5.1). Heme is the portion of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing Heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product, oxyhemoglobin (Hb–O2), which is formed when oxygen binds to hemoglobin. Oxyhemoglobin is a bright red-colored molecule that contributes to the bright red color of oxygenated blood.', '69b21a62-3d24-454c-8451-2e23b095092e': 'In this formula, Hb represents reduced hemoglobin, that is, hemoglobin that does not have oxygen bound to it. There are multiple factors involved in how readily heme binds to and dissociates from oxygen, which will be discussed in the subsequent sections.'}"
+Figure 22.5.4,Anatomy_And_Physio/images/Figure 22.5.4.jpg,"Figure 22.5.4 – Carbon Dioxide Transport: Carbon dioxide is transported by three different methods: (a) in erythrocytes; (b) after forming carbonic acid (H2CO3 ), which is dissolved in plasma; (c) and in plasma.","Carbon dioxide is transported by three major mechanisms. The first mechanism of carbon dioxide transport is by blood plasma, as some carbon dioxide molecules dissolve in the blood. The second mechanism is transport in the form of bicarbonate (HCO3–), which also dissolves in plasma. The third mechanism of carbon dioxide transport is similar to the transport of oxygen by erythrocytes (Figure 22.5.4).","{'66bce94f-8c0a-4634-9c16-aad8fcd453c8': 'Carbon dioxide is transported by three major mechanisms. The first mechanism of carbon dioxide transport is by blood plasma, as some carbon dioxide molecules dissolve in the blood. The second mechanism is transport in the form of bicarbonate (HCO3–), which also dissolves in plasma. The third mechanism of carbon dioxide transport is similar to the transport of oxygen by erythrocytes (Figure 22.5.4).', '0c44030f-5e03-48bb-a052-73155c9dd9d5': 'The purpose of the respiratory system is to perform gas exchange. Pulmonary ventilation provides air to the alveoli for this gas exchange process. At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.'}"
+Figure 22.3.3,Anatomy_And_Physio/images/Figure 22.3.3.jpg,"Figure 22.3.3 – Inspiration and Expiration: Inspiration and expiration occur due to the expansion and contraction of the thoracic cavity, respectively.","Pulmonary ventilation comprises two major steps: inspiration and expiration. Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs (Figure 22.3.3). A respiratory cycle is one sequence of inspiration and expiration. In general, two muscle groups are used during normal inspiration: the diaphragm and the external intercostal muscles. Additional muscles can be used if a bigger breath is required. When the diaphragm contracts, it moves inferiorly toward the abdominal cavity, creating a larger thoracic cavity and more space for the lungs. Contraction of the external intercostal muscles moves the ribs upward and outward, causing the rib cage to expand, which increases the volume of the thoracic cavity. Due to the adhesive force of the pleural fluid, the expansion of the thoracic cavity forces the lungs to stretch and expand as well. This increase in volume leads to a decrease in intra-alveolar pressure, creating a pressure lower than atmospheric pressure. As a result, a pressure gradient is created that drives air into the lungs.","{'fc2b2bc3-c3fa-4621-9b51-46132ef6d8c7': 'The difference in pressures drives pulmonary ventilation because air flows down a pressure gradient, that is, air flows from an area of higher pressure to an area of lower pressure. Air flows into the lungs largely due to a difference in pressure; atmospheric pressure is greater than intra-alveolar pressure, and intra-alveolar pressure is greater than intrapleural pressure. Air flows out of the lungs during expiration based on the same principle; pressure within the lungs becomes greater than the atmospheric pressure.', '93566d34-1c6d-4e26-9da5-454210281ed3': 'Pulmonary ventilation comprises two major steps: inspiration and expiration. Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs (Figure 22.3.3). A respiratory cycle is one sequence of inspiration and expiration. In general, two muscle groups are used during normal inspiration: the diaphragm and the external intercostal muscles. Additional muscles can be used if a bigger breath is required. When the diaphragm contracts, it moves inferiorly toward the abdominal cavity, creating a larger thoracic cavity and more space for the lungs. Contraction of the external intercostal muscles moves the ribs upward and outward, causing the rib cage to expand, which increases the volume of the thoracic cavity. Due to the adhesive force of the pleural fluid, the expansion of the thoracic cavity forces the lungs to stretch and expand as well. This increase in volume leads to a decrease in intra-alveolar pressure, creating a pressure lower than atmospheric pressure. As a result, a pressure gradient is created that drives air into the lungs.', 'e50c3793-f51f-4611-afdf-1397a9712946': 'The process of normal expiration is passive, meaning that energy is not required to push air out of the lungs. Instead, the elasticity of the lung tissue causes the lung to recoil, as the diaphragm and intercostal muscles relax following inspiration. In turn, the thoracic cavity and lungs decrease in volume, causing an increase in interpulmonary pressure. The interpulmonary pressure rises above atmospheric pressure, creating a pressure gradient that causes air to leave the lungs.', 'efcb7e14-2457-4a80-a988-f65446e74487': 'There are different types, or modes, of breathing that require a slightly different process to allow inspiration and expiration. Quiet breathing, also known as eupnea, is a mode of breathing that occurs at rest and does not require the cognitive thought of the individual. During quiet breathing, the diaphragm and external intercostals must contract.', '8f13c1a1-c535-4ed1-b922-421616c75267': 'A deep breath, called diaphragmatic breathing, requires the diaphragm to contract. As the diaphragm relaxes, air passively leaves the lungs. A shallow breath, called costal breathing, requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs.', '02806de7-fafc-4f47-ae2e-850f599de454': 'In contrast, forced breathing, also known as hyperpnea, is a mode of breathing that can occur during exercise or actions that require the active manipulation of breathing, such as singing. During forced breathing, inspiration and expiration both occur due to muscle contractions. In addition to the contraction of the diaphragm and intercostal muscles, other accessory muscles must also contract. During forced inspiration, muscles of the neck, including the scalenes, contract and lift the thoracic wall, increasing lung volume. During forced expiration, accessory muscles of the abdomen, including the obliques, contract, forcing abdominal organs upward against the diaphragm. This helps to push the diaphragm further into the thorax, pushing more air out. In addition, accessory muscles (primarily the internal intercostals) help to compress the rib cage, which also reduces the volume of the thoracic cavity.'}"
+Figure 22.3.4,Anatomy_And_Physio/images/Figure 22.3.4.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.,"Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22.3.4). Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men. Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration. This is the extra volume that can be brought into the lungs during a forced inspiration. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible. The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22.3.5).","{'c555c2d7-9885-4226-a304-1dcd756209b0': 'Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22.3.4). Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men. Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration. This is the extra volume that can be brought into the lungs during a forced inspiration. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible. The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22.3.5).', '4418d1f4-b796-4700-9681-80ad3497f01a': 'Respiratory capacity is the combination of two or more selected volumes, which further describes the amount of air in the lungs during a given time. For example, total lung capacity (TLC) is the sum of all of the lung volumes (TV, ERV, IRV, and RV), which represents the total amount of air a person can hold in the lungs after a forceful inhalation. TLC is about 6000 mL air for men, and about 4200 mL for women. Vital capacity (VC) is the amount of air a person can move into or out of his or her lungs, and is the sum of all of the volumes except residual volume (TV, ERV, and IRV), which is between 4000 and 5000 milliliters. Inspiratory capacity (IC) is the maximum amount of air that can be inhaled past a normal tidal expiration, is the sum of the tidal volume and inspiratory reserve volume. On the other hand, the functional residual capacity (FRC) is the amount of air that remains in the lung after a normal tidal expiration; it is the sum of expiratory reserve volume and residual volume (see Figure 22.3.4).', '32c77cd5-629f-40cc-ad20-d5debee0add3': 'In addition to the air that creates respiratory volumes, the respiratory system also contains anatomical dead space, which is air that is present in the airway that never reaches the alveoli and therefore never participates in gas exchange. Alveolar dead space involves air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow. Total dead space is the anatomical dead space and alveolar dead space together, and represents all of the air in the respiratory system that is not being used in the gas exchange process.'}"
+Figure 22.3.4,Anatomy_And_Physio/images/Figure 22.3.4.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.,"Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22.3.4). Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men. Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration. This is the extra volume that can be brought into the lungs during a forced inspiration. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible. The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22.3.5).","{'c555c2d7-9885-4226-a304-1dcd756209b0': 'Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22.3.4). Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men. Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration. This is the extra volume that can be brought into the lungs during a forced inspiration. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible. The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22.3.5).', '4418d1f4-b796-4700-9681-80ad3497f01a': 'Respiratory capacity is the combination of two or more selected volumes, which further describes the amount of air in the lungs during a given time. For example, total lung capacity (TLC) is the sum of all of the lung volumes (TV, ERV, IRV, and RV), which represents the total amount of air a person can hold in the lungs after a forceful inhalation. TLC is about 6000 mL air for men, and about 4200 mL for women. Vital capacity (VC) is the amount of air a person can move into or out of his or her lungs, and is the sum of all of the volumes except residual volume (TV, ERV, and IRV), which is between 4000 and 5000 milliliters. Inspiratory capacity (IC) is the maximum amount of air that can be inhaled past a normal tidal expiration, is the sum of the tidal volume and inspiratory reserve volume. On the other hand, the functional residual capacity (FRC) is the amount of air that remains in the lung after a normal tidal expiration; it is the sum of expiratory reserve volume and residual volume (see Figure 22.3.4).', '32c77cd5-629f-40cc-ad20-d5debee0add3': 'In addition to the air that creates respiratory volumes, the respiratory system also contains anatomical dead space, which is air that is present in the airway that never reaches the alveoli and therefore never participates in gas exchange. Alveolar dead space involves air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow. Total dead space is the anatomical dead space and alveolar dead space together, and represents all of the air in the respiratory system that is not being used in the gas exchange process.'}"
+Figure 22.2.1,Anatomy_And_Physio/images/Figure 22.2.1.jpg,Figure 22.2.1 Gross Anatomy of the Lungs.,"The lungs are pyramid-shaped, paired organs that are connected to the trachea by the right and left bronchi; on the inferior surface, the lungs are bordered by the diaphragm. The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity. The lungs are enclosed by the pleurae, which are attached to the mediastinum. The right lung is shorter and wider than the left lung, and the left lung occupies a smaller volume than the right. The cardiac notch is an indentation on the surface of the left lung, and it allows space for the heart (Figure 22.2.1). The apex of the lung is the superior region, whereas the base is the opposite region near the diaphragm. The costal surface of the lung borders the ribs. The mediastinal surface faces the midline.","{'61c2f229-1c42-4a12-95fb-29d9eabb5ba5': 'The lungs are pyramid-shaped, paired organs that are connected to the trachea by the right and left bronchi; on the inferior surface, the lungs are bordered by the diaphragm. The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity. The lungs are enclosed by the pleurae, which are attached to the mediastinum. The right lung is shorter and wider than the left lung, and the left lung occupies a smaller volume than the right. The cardiac notch is an indentation on the surface of the left lung, and it allows space for the heart (Figure 22.2.1). The apex of the lung is the superior region, whereas the base is the opposite region near the diaphragm. The costal surface of the lung borders the ribs. The mediastinal surface faces the midline.', 'd6cb9dc5-0026-4faa-b538-d0d85f87a6de': 'Each lung is composed of smaller units called lobes. Fissures separate these lobes from each other. The right lung consists of three lobes: the superior, middle, and inferior lobes. The left lung consists of two lobes: the superior and inferior lobes. A bronchopulmonary segment is a division of a lobe, and each lobe houses multiple bronchopulmonary segments. Each segment receives air from its own tertiary bronchus and is supplied with blood by its own artery. Some diseases of the lungs typically affect one or more bronchopulmonary segments, and in some cases, the diseased segments can be surgically removed with little influence on neighboring segments. A pulmonary lobule is a subdivision formed as the bronchi branch into bronchioles. Each lobule receives its own large bronchiole that has multiple branches. An interlobular septum is a wall, composed of connective tissue, which separates lobules from one another.'}"
+Figure 22.2.2,Anatomy_And_Physio/images/Figure 22.2.2.jpg,Figure 22.2.2 Parietal and Visceral Pleurae of the Lungs.,"Each lung is enclosed within a cavity that is surrounded by the pleura. The pleura (plural = pleurae) is a serous membrane that surrounds the lung. The right and left pleurae, which enclose the right and left lungs, respectively, are separated by the mediastinum. The pleurae consist of two layers. The visceral pleura is the layer that is superficial to the lungs, and extends into and lines the lung fissures (Figure 22.2.2). In contrast, the parietal pleura is the outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The visceral and parietal pleurae connect to each other at the hilum. The pleural cavity is the space between the visceral and parietal layers.","{'7e8691f6-86cc-4b5b-aaef-cc87ecee4e0f': 'Each lung is enclosed within a cavity that is surrounded by the pleura. The pleura (plural = pleurae) is a serous membrane that surrounds the lung. The right and left pleurae, which enclose the right and left lungs, respectively, are separated by the mediastinum. The pleurae consist of two layers. The visceral pleura is the layer that is superficial to the lungs, and extends into and lines the lung fissures (Figure 22.2.2). In contrast, the parietal pleura is the outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The visceral and parietal pleurae connect to each other at the hilum. The pleural cavity is the space between the visceral and parietal layers.', 'cf415e07-eee1-4022-b124-f24bb13f2b0d': 'The pleurae perform two major functions: They produce pleural fluid and create cavities that separate the major organs. Pleural fluid is secreted by mesothelial cells from both pleural layers and acts to lubricate their surfaces. This lubrication reduces friction between the two layers to prevent trauma during breathing, and creates surface tension that helps maintain the position of the lungs against the thoracic wall. This adhesive characteristic of the pleural fluid causes the lungs to enlarge when the thoracic wall expands during ventilation, allowing the lungs to fill with air. The pleurae also create a division between major organs that prevents interference due to the movement of the organs, while preventing the spread of infection.', '92650709-902a-4da9-842e-bba61bd8500f': 'The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to maintain acid-base balance. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing (Figure 22.1.1).', '3c5b3ebb-327e-4558-bc22-2784b05a67f5': 'Functionally, the respiratory system can be divided into a conducting zone and a respiratory zone. The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. The gas exchange occurs in the respiratory zone.'}"
+Figure 22.1.1,Anatomy_And_Physio/images/Figure 22.1.1.jpg,Figure 22.1.1 – Major Respiratory Structures: The major respiratory structures span the nasal cavity to the diaphragm.,"The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to maintain acid-base balance. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing (Figure 22.1.1).","{'7e8691f6-86cc-4b5b-aaef-cc87ecee4e0f': 'Each lung is enclosed within a cavity that is surrounded by the pleura. The pleura (plural = pleurae) is a serous membrane that surrounds the lung. The right and left pleurae, which enclose the right and left lungs, respectively, are separated by the mediastinum. The pleurae consist of two layers. The visceral pleura is the layer that is superficial to the lungs, and extends into and lines the lung fissures (Figure 22.2.2). In contrast, the parietal pleura is the outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The visceral and parietal pleurae connect to each other at the hilum. The pleural cavity is the space between the visceral and parietal layers.', 'cf415e07-eee1-4022-b124-f24bb13f2b0d': 'The pleurae perform two major functions: They produce pleural fluid and create cavities that separate the major organs. Pleural fluid is secreted by mesothelial cells from both pleural layers and acts to lubricate their surfaces. This lubrication reduces friction between the two layers to prevent trauma during breathing, and creates surface tension that helps maintain the position of the lungs against the thoracic wall. This adhesive characteristic of the pleural fluid causes the lungs to enlarge when the thoracic wall expands during ventilation, allowing the lungs to fill with air. The pleurae also create a division between major organs that prevents interference due to the movement of the organs, while preventing the spread of infection.', '92650709-902a-4da9-842e-bba61bd8500f': 'The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to maintain acid-base balance. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing (Figure 22.1.1).', '3c5b3ebb-327e-4558-bc22-2784b05a67f5': 'Functionally, the respiratory system can be divided into a conducting zone and a respiratory zone. The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. The gas exchange occurs in the respiratory zone.'}"
+Figure 22.1.9,Anatomy_And_Physio/images/Figure 22.1.9.jpg,"Figure 22.1.9 – Respiratory Zone: Bronchioles lead to alveolar sacs in the respiratory zone, where gas exchange occurs.","In contrast to the conducting zone, the respiratory zone includes structures that are directly involved in gas exchange. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole (Figure 22.1.9), which then leads to an alveolar duct, opening into a cluster of alveoli.","{'9096842f-f5e9-45ab-9170-185b498566f5': 'In contrast to the conducting zone, the respiratory zone includes structures that are directly involved in gas exchange. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole (Figure 22.1.9), which then leads to an alveolar duct, opening into a cluster of alveoli.', '43ab76bd-12db-456c-b5b5-696f39abb9f4': 'Hold your breath. Really! See how long you can hold your breath as you continue reading…How long can you do it? Chances are you are feeling uncomfortable already. A typical human cannot survive without breathing for more than 3 minutes, and even if you wanted to hold your breath longer, your autonomic nervous system would take control. This is because every cell in the body needs to run the oxidative stages of cellular respiration, the process by which energy is produced in the form of adenosine triphosphate (ATP). For oxidative phosphorylation to occur, oxygen is used as a reactant and carbon dioxide is released as a waste product. You may be surprised to learn that although oxygen is a critical need for cells, it is actually the accumulation of carbon dioxide that primarily drives your need to breathe. Carbon dioxide is exhaled and oxygen is inhaled through the respiratory system, which includes muscles to move air into and out of the lungs, passageways through which air moves, and microscopic gas exchange surfaces covered by capillaries. The circulatory system transports gases from the lungs to tissues throughout the body and vice versa. A variety of diseases can affect the respiratory system, such as asthma, emphysema, chronic obstruction pulmonary disorder (COPD), and lung cancer. All of these conditions affect the gas exchange process and result in labored breathing and other difficulties.', '05e5b04f-206a-4614-b5b0-f17b14f77ac2': 'The immune responses to transplanted organs and to cancer cells are both important medical issues. With the use of tissue typing and anti-rejection drugs, transplantation of organs and the control of the anti-transplant immune response have made huge strides in the past 50 years. Today, these procedures are commonplace. Tissue typing is the determination of MHC molecules in the tissue to be transplanted to better match the donor to the recipient. The immune response to cancer, on the other hand, has been more difficult to understand and control. Although it is clear that the immune system can recognize some cancers and control them, others seem to be resistant to immune mechanisms.'}"
+Figure 21.7.1,Anatomy_And_Physio/images/Figure 21.7.1.jpg,"Figure 21.7.1 – Erythroblastosis Fetalis: Erythroblastosis fetalis (hemolytic disease of the newborn) is the result of an immune response in an Rh-negative mother who has multiple children with an Rh-positive father. During the first birth, fetal blood enters the mother’s circulatory system, and anti-Rh antibodies are made. During the gestation of the second child, these antibodies cross the placenta and attack the blood of the fetus. The treatment for this disease is to give the mother anti-Rh antibodies (RhoGAM) during the first pregnancy to destroy Rh-positive fetal red blood cells from entering her system and causing the anti-Rh antibody response in the first place.","An interesting consequence of Rh factor expression is seen in erythroblastosis fetalis, a hemolytic disease of the newborn (Figure 21.7.1). This disease occurs when mothers negative for Rh antigen have multiple Rh-positive children. During the birth of a first Rh-positive child, the mother makes a primary anti-Rh antibody response to the fetal blood cells that enter the maternal bloodstream. If the mother has a second Rh-positive child, IgG antibodies against Rh-positive blood mounted during this secondary response cross the placenta and attack the fetal blood, causing anemia. This is a consequence of the fact that the fetus is not genetically identical to the mother, and thus the mother is capable of mounting an immune response against it. This disease is treated with antibodies specific for Rh factor. These are given to the mother during the subsequent births, destroying any fetal blood that might enter her system and preventing the immune response.","{'521e348f-e4e0-40f1-88f4-9f38b4724d4e': 'Red blood cells can be typed based on their surface antigens. ABO blood type, in which individuals are type A, B, AB, or O according to their genetics, is one example. A separate antigen system seen on red blood cells is the Rh antigen. When someone is “A positive” for example, the positive refers to the presence of the Rh antigen, whereas someone who is “A negative” would lack this molecule.', '1af60fc7-ab69-4e51-acf7-ac86c3568f2a': 'An interesting consequence of Rh factor expression is seen in erythroblastosis fetalis, a hemolytic disease of the newborn (Figure 21.7.1). This disease occurs when mothers negative for Rh antigen have multiple Rh-positive children. During the birth of a first Rh-positive child, the mother makes a primary anti-Rh antibody response to the fetal blood cells that enter the maternal bloodstream. If the mother has a second Rh-positive child, IgG antibodies against Rh-positive blood mounted during this secondary response cross the placenta and attack the fetal blood, causing anemia. This is a consequence of the fact that the fetus is not genetically identical to the mother, and thus the mother is capable of mounting an immune response against it. This disease is treated with antibodies specific for Rh factor. These are given to the mother during the subsequent births, destroying any fetal blood that might enter her system and preventing the immune response.'}"
+Figure 21.7.2,Anatomy_And_Physio/images/Figure 21.7.2.jpg,Figure 21.7.2 Karposi’s Sarcoma Lesions. (credit: National Cancer Institute),"It is clear that with some cancers, for example Kaposi’s sarcoma, a healthy immune system does a good job at controlling them (Figure 21.7.2). This disease, which is caused by the human herpesvirus, is almost never observed in individuals with strong immune systems, such as the young and immunocompetent. Other examples of cancers caused by viruses include liver cancer caused by the hepatitis B virus and cervical cancer caused by the human papilloma virus. As these last two viruses have vaccines available for them, getting vaccinated can help prevent these two types of cancer by stimulating the immune response.","{'397a0647-10e8-4931-a9ff-2175c7c07934': 'It is clear that with some cancers, for example Kaposi’s sarcoma, a healthy immune system does a good job at controlling them (Figure 21.7.2). This disease, which is caused by the human herpesvirus, is almost never observed in individuals with strong immune systems, such as the young and immunocompetent. Other examples of cancers caused by viruses include liver cancer caused by the hepatitis B virus and cervical cancer caused by the human papilloma virus. As these last two viruses have vaccines available for them, getting vaccinated can help prevent these two types of cancer by stimulating the immune response.', '8a1a5576-8909-4ad9-a2c3-a2670b4e57a4': 'On the other hand, as cancer cells are often able to divide and mutate rapidly, they may escape the immune response, just as certain pathogens such as HIV do. There are three stages in the immune response to many cancers: elimination, equilibrium, and escape. Elimination occurs when the immune response first develops toward tumor-specific antigens specific to the cancer and actively kills most cancer cells, followed by a period of controlled equilibrium during which the remaining cancer cells are held in check. Unfortunately, many cancers mutate, so they no longer express any specific antigens for the immune system to respond to, and a subpopulation of cancer cells escapes the immune response, continuing the disease process.', 'a1e862cc-96fc-4bd4-8976-ab354cb1e101': 'This fact has led to extensive research in trying to develop ways to enhance the early immune response to completely eliminate the early cancer and thus prevent a later escape. One method that has shown some success is the use of cancer vaccines, which differ from viral and bacterial vaccines in that they are directed against the cells of one’s own body. Treated cancer cells are injected into cancer patients to enhance their anti-cancer immune response and thereby prolong survival. The immune system has the capability to detect these cancer cells and proliferate faster than the cancer cells do, overwhelming the cancer in a similar way as they do for viruses. Cancer vaccines have been developed for malignant melanoma, a highly fatal skin cancer, and renal (kidney) cell carcinoma. These vaccines are still in the development stages, but some positive and encouraging results have been obtained clinically.', 'ef6af9a6-8ab8-4d8b-9384-56cf63fe9439': 'It is tempting to focus on the complexity of the immune system and the problems it causes as a negative. The upside to immunity, however, is so much greater: The benefit of staying alive far outweighs the negatives caused when the system does sometimes go awry. Working on “autopilot,” the immune system helps to maintain your health and kill pathogens. The only time you really miss the immune response is when it is not being effective and illness results, or, as in the extreme case of HIV disease, the immune system is gone completely.', '0708744f-e05c-4d70-ac2d-b5751cd97c50': 'At one time, it was assumed that all types of stress reduced all aspects of the immune response, but the last few decades of research have painted a different picture. First, most short-term stress does not impair the immune system in healthy individuals enough to lead to a greater incidence of diseases. However, older individuals and those with suppressed immune responses due to disease or immunosuppressive drugs may respond even to short-term stressors by getting sicker more often. It has been found that short-term stress diverts the body’s resources towards enhancing innate immune responses, which have the ability to act fast and would seem to help the body prepare better for possible infections associated with the trauma that may result from a fight-or-flight exchange. The diverting of resources away from the adaptive immune response, however, causes its own share of problems in fighting disease.', 'f405fcb4-15fb-4199-b004-7501deed66da': 'Chronic stress, unlike short-term stress, may inhibit immune responses even in otherwise healthy adults. The suppression of both innate and adaptive immune responses is clearly associated with increases in some diseases, as seen when individuals lose a spouse or have other long-term stresses, such as taking care of a spouse with a fatal disease or dementia. The new science of psychoneuroimmunology, while still in its relative infancy, has great potential to make exciting advances in our understanding of how the nervous, endocrine, and immune systems have evolved together and communicate with each other.'}"
+Figure 21.6.1,Anatomy_And_Physio/images/Figure 21.6.1.jpg,"Figure 21.6.1 – Immune Hypersensitivity: Components of the immune system cause four types of hypersensitivity. Notice that types I–III are B cell mediated, whereas type IV hypersensitivity is exclusively a T cell phenomenon.","The word “hypersensitivity” simply means sensitive beyond normal levels of activation. Allergies and inflammatory responses to nonpathogenic environmental substances have been observed since the dawn of history. Hypersensitivity is a medical term describing symptoms that are now known to be caused by unrelated mechanisms of immunity. Still, it is useful for this discussion to use the four types of hypersensitivities as a guide to understand these mechanisms (Figure 21.6.1).","{'3fb7cb07-dc85-4fcc-b821-aac90ef43b26': 'The word “hypersensitivity” simply means sensitive beyond normal levels of activation. Allergies and inflammatory responses to nonpathogenic environmental substances have been observed since the dawn of history. Hypersensitivity is a medical term describing symptoms that are now known to be caused by unrelated mechanisms of immunity. Still, it is useful for this discussion to use the four types of hypersensitivities as a guide to understand these mechanisms (Figure 21.6.1).'}"
+Figure 21.6.2,Anatomy_And_Physio/images/Figure 21.6.2.jpg,Figure 21.6.2 – Autoimmune Disorders: Rheumatoid Arthritis and Lupus. (a) Extensive damage to the right hand of a rheumatoid arthritis sufferer is shown in the x-ray. (b) The diagram shows a variety of possible symptoms of systemic lupus erythematosus.,"The worst cases of the immune system over-reacting are autoimmune diseases. Somehow, tolerance breaks down and the immune systems in individuals with these diseases begin to attack their own bodies, causing significant damage. The trigger for these diseases is, more often than not, unknown, and the treatments are usually based on resolving the symptoms using immunosuppressive and anti-inflammatory drugs such as steroids. These diseases can be localized and crippling, as in rheumatoid arthritis, or diffuse in the body with multiple symptoms that differ in different individuals, as is the case with systemic lupus erythematosus (Figure 21.6.2).","{'fe715004-25db-470c-a211-cf0a5dd6e63b': 'The worst cases of the immune system over-reacting are autoimmune diseases. Somehow, tolerance breaks down and the immune systems in individuals with these diseases begin to attack their own bodies, causing significant damage. The trigger for these diseases is, more often than not, unknown, and the treatments are usually based on resolving the symptoms using immunosuppressive and anti-inflammatory drugs such as steroids. These diseases can be localized and crippling, as in rheumatoid arthritis, or diffuse in the body with multiple symptoms that differ in different individuals, as is the case with systemic lupus erythematosus (Figure 21.6.2).', 'd0cafc68-ab9f-4dd7-bdbf-e2e7d809ac0b': 'Environmental triggers seem to play large roles in autoimmune responses. One explanation for the breakdown of tolerance is that, after certain bacterial infections, an immune response to a component of the bacterium cross-reacts with a self-antigen. This mechanism is seen in rheumatic fever, a result of infection with Streptococcus bacteria, which causes strep throat. The antibodies to this pathogen’s M protein cross-react with an antigenic component of heart myosin, a major contractile protein of the heart that is critical to its normal function. The antibody binds to these molecules and activates complement proteins, causing damage to the heart, especially to the heart valves. On the other hand, some theories propose that having multiple common infectious diseases actually prevents autoimmune responses. The fact that autoimmune diseases are rare in countries that have a high incidence of infectious diseases supports this idea, another example of the hygiene hypothesis discussed earlier in this chapter.', '4f866bd9-bb0d-4472-a5e2-0837d0209a60': 'There are genetic factors in autoimmune diseases as well. Some diseases are associated with the MHC genes that an individual expresses. The reason for this association is likely because if one’s MHC molecules are not able to present a certain self-antigen, then that particular autoimmune disease cannot occur. Overall, there are more than 80 different autoimmune diseases, which are a significant health problem in the elderly. Table 21.7 lists several of the most common autoimmune diseases, the antigens that are targeted, and the segment of the adaptive immune response that causes the damage.'}"
+Figure 21.4.5,Anatomy_And_Physio/images/Figure 21.4.5.jpg,"Figure 21.4.5 – T and B Cell Binding: To elicit a response to a T cell-dependent antigen, the B and T cells must come close together. To become fully activated, the B cell must receive two signals from the native antigen and the T cell’s cytokines.","A T cell-dependent antigen, on the other hand, usually is not repeated to the same degree on the pathogen and thus does not crosslink surface antibody with the same efficiency. To elicit a response to such antigens, the B and T cells must come close together (Figure 21.4.5). The B cell must receive two signals to become activated. Its surface immunoglobulin must recognize native antigen. Some of this antigen is internalized, processed, and presented to the Th2 cells on a class II MHC molecule. The T cell then binds using its antigen receptor and is activated to secrete cytokines that diffuse to the B cell, finally activating it completely. Thus, the B cell receives signals from both its surface antibody and the T cell via its cytokines, and acts as a professional antigen-presenting cell in the process.","{'b79678a3-f7b4-434a-ab53-20dcc2ff668a': 'As discussed previously, Th2 cells secrete cytokines that drive the production of antibodies in a B cell, responding to complex antigens such as those made by proteins. On the other hand, some antigens are T cell independent. A T cell-independent antigen usually is in the form of repeated carbohydrate moieties found on the cell walls of bacteria. Each antibody on the B cell surface has two binding sites, and the repeated nature of T cell-independent antigen leads to crosslinking of the surface antibodies on the B cell. The crosslinking is enough to activate it in the absence of T cell cytokines.', '6d05cfe6-98ee-46f1-823d-9475b2eba651': 'A T cell-dependent antigen, on the other hand, usually is not repeated to the same degree on the pathogen and thus does not crosslink surface antibody with the same efficiency. To elicit a response to such antigens, the B and T cells must come close together (Figure 21.4.5). The B cell must receive two signals to become activated. Its surface immunoglobulin must recognize native antigen. Some of this antigen is internalized, processed, and presented to the Th2 cells on a class II MHC molecule. The T cell then binds using its antigen receptor and is activated to secrete cytokines that diffuse to the B cell, finally activating it completely. Thus, the B cell receives signals from both its surface antibody and the T cell via its cytokines, and acts as a professional antigen-presenting cell in the process.', '6a39eb4c-60e2-4f74-9b58-e41b3f10a725': 'Innate immune responses (and early induced responses) are in many cases ineffective at completely controlling pathogen growth. However, they slow pathogen growth and allow time for the adaptive immune response to strengthen and either control or eliminate the pathogen. The innate immune system also sends signals to the cells of the adaptive immune system, guiding them in how to attack the pathogen. Thus, these are the two important arms of the immune response.'}"
+Figure 21.3.1,Anatomy_And_Physio/images/Figure 21.3.1.jpg,"Figure 21.3.1 – Alpha-beta T Cell Receptor: Notice the constant and variable regions of each chain, anchored by the transmembrane region.",T lymphocytes recognize antigens based on a two-chain protein receptor. The most common and important of these are the alpha-beta T cell receptors (Figure 21.3.1).,"{'657b0e2c-3139-421b-9d55-6b908f715c9f': 'The primary cells that control the adaptive immune response are the lymphocytes, the T and B cells. T cells are particularly important, as they not only control a multitude of immune responses directly, but also control B cell immune responses in many cases as well. Thus, many of the decisions about how to attack a pathogen are made at the T cell level, and knowledge of their functional types is crucial to understanding the functioning and regulation of adaptive immune responses as a whole.', 'b9c47509-f15d-48fa-bc82-3dfab3fad601': 'T lymphocytes recognize antigens based on a two-chain protein receptor. The most common and important of these are the alpha-beta T cell receptors (Figure 21.3.1).', '5edcf582-4349-4d1c-aa41-fe5e4c0ce297': 'There are two chains in the T cell receptor, and each chain consists of two domains. The variable region domain is furthest away from the T cell membrane and is so named because its amino acid sequence varies between receptors. In contrast, the constant region domain has less variation. The differences in the amino acid sequences of the variable domains are the molecular basis of the diversity of antigens the receptor can recognize. Thus, the antigen-binding site of the receptor consists of the terminal ends of both receptor chains, and the amino acid sequences of those two areas combine to determine its antigenic specificity. Each T cell produces only one type of receptor and thus is specific for a single particular antigen.'}"
+Figure 21.3.2,Anatomy_And_Physio/images/Figure 21.3.2.jpg,"Figure 21.3.2 – Antigenic Determinants: A typical protein antigen has multiple antigenic determinants, shown by the ability of T cells with three different specificities to bind to different parts of the same antigen.","Antigens on pathogens are usually large and complex, and consist of many antigenic determinants. An antigenic determinant (epitope) is one of the small regions within an antigen to which a receptor can bind, and antigenic determinants are limited by the size of the receptor itself. They usually consist of six or fewer amino acid residues in a protein, or one or two sugar moieties in a carbohydrate antigen. Antigenic determinants on a carbohydrate antigen are usually less diverse than on a protein antigen. Carbohydrate antigens are found on bacterial cell walls and on red blood cells (the ABO blood group antigens). Protein antigens are complex because of the variety of three-dimensional shapes that proteins can assume, and are especially important for the immune responses to viruses and worm parasites. It is the interaction of the shape of the antigen and the complementary shape of the amino acids of the antigen-binding site that accounts for the chemical basis of specificity (Figure 21.3.2).","{'e5c3bf77-723c-4754-8ebb-baaeb8d84d1e': 'Antigens on pathogens are usually large and complex, and consist of many antigenic determinants. An antigenic determinant (epitope) is one of the small regions within an antigen to which a receptor can bind, and antigenic determinants are limited by the size of the receptor itself. They usually consist of six or fewer amino acid residues in a protein, or one or two sugar moieties in a carbohydrate antigen. Antigenic determinants on a carbohydrate antigen are usually less diverse than on a protein antigen. Carbohydrate antigens are found on bacterial cell walls and on red blood cells (the ABO blood group antigens). Protein antigens are complex because of the variety of three-dimensional shapes that proteins can assume, and are especially important for the immune responses to viruses and worm parasites. It is the interaction of the shape of the antigen and the complementary shape of the amino acids of the antigen-binding site that accounts for the chemical basis of specificity (Figure 21.3.2).'}"
+Figure 21.3.4,Anatomy_And_Physio/images/Figure 21.3.4.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.,"The process of eliminating T cells that might attack the cells of one’s own body is referred to as T cell tolerance. While thymocytes are in the cortex of the thymus, they are referred to as “double negatives,” meaning that they do not bear the CD4 or CD8 molecules that you can use to follow their pathways of differentiation (Figure 21.3.4). In the cortex of the thymus, they are exposed to cortical epithelial cells. In a process known as positive selection, double-negative thymocytes bind to the MHC molecules they observe on the thymic epithelia, and the MHC molecules of “self” are selected. This mechanism kills many thymocytes during T cell differentiation. In fact, only two percent of the thymocytes that enter the thymus leave it as mature, functional T cells.","{'45b7a359-cd5f-43a6-bad8-c639e5c39041': 'The process of eliminating T cells that might attack the cells of one’s own body is referred to as T cell tolerance. While thymocytes are in the cortex of the thymus, they are referred to as “double negatives,” meaning that they do not bear the CD4 or CD8 molecules that you can use to follow their pathways of differentiation (Figure 21.3.4). In the cortex of the thymus, they are exposed to cortical epithelial cells. In a process known as positive selection, double-negative thymocytes bind to the MHC molecules they observe on the thymic epithelia, and the MHC molecules of “self” are selected. This mechanism kills many thymocytes during T cell differentiation. In fact, only two percent of the thymocytes that enter the thymus leave it as mature, functional T cells.', '50a4fb71-65e2-42e9-b79e-a4037222e7b0': 'Later, the cells become double positives that express both CD4 and CD8 markers and move from the cortex to the junction between the cortex and medulla. It is here that negative selection takes place. In negative selection, self-antigens are brought into the thymus from other parts of the body by professional antigen-presenting cells. The T cells that bind to these self-antigens are selected for negatively and are killed by apoptosis. In summary, the only T cells left are those that can bind to MHC molecules of the body with foreign antigens presented on their binding clefts, preventing an attack on one’s own body tissues, at least under normal circumstances. Tolerance can be broken, however, by the development of an autoimmune response, to be discussed later in this chapter.', 'afe8a533-6f65-4333-9d26-c4297fd27142': 'The cells that leave the thymus become single positives, expressing either CD4 or CD8, but not both (see Figure 21.3.4). The CD4+ T cells will bind to class II MHC and the CD8+ cells will bind to class I MHC. The discussion that follows explains the functions of these molecules and how they can be used to differentiate between the different T cell functional types.'}"
+Figure 21.3.4,Anatomy_And_Physio/images/Figure 21.3.4.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.,"The process of eliminating T cells that might attack the cells of one’s own body is referred to as T cell tolerance. While thymocytes are in the cortex of the thymus, they are referred to as “double negatives,” meaning that they do not bear the CD4 or CD8 molecules that you can use to follow their pathways of differentiation (Figure 21.3.4). In the cortex of the thymus, they are exposed to cortical epithelial cells. In a process known as positive selection, double-negative thymocytes bind to the MHC molecules they observe on the thymic epithelia, and the MHC molecules of “self” are selected. This mechanism kills many thymocytes during T cell differentiation. In fact, only two percent of the thymocytes that enter the thymus leave it as mature, functional T cells.","{'45b7a359-cd5f-43a6-bad8-c639e5c39041': 'The process of eliminating T cells that might attack the cells of one’s own body is referred to as T cell tolerance. While thymocytes are in the cortex of the thymus, they are referred to as “double negatives,” meaning that they do not bear the CD4 or CD8 molecules that you can use to follow their pathways of differentiation (Figure 21.3.4). In the cortex of the thymus, they are exposed to cortical epithelial cells. In a process known as positive selection, double-negative thymocytes bind to the MHC molecules they observe on the thymic epithelia, and the MHC molecules of “self” are selected. This mechanism kills many thymocytes during T cell differentiation. In fact, only two percent of the thymocytes that enter the thymus leave it as mature, functional T cells.', '50a4fb71-65e2-42e9-b79e-a4037222e7b0': 'Later, the cells become double positives that express both CD4 and CD8 markers and move from the cortex to the junction between the cortex and medulla. It is here that negative selection takes place. In negative selection, self-antigens are brought into the thymus from other parts of the body by professional antigen-presenting cells. The T cells that bind to these self-antigens are selected for negatively and are killed by apoptosis. In summary, the only T cells left are those that can bind to MHC molecules of the body with foreign antigens presented on their binding clefts, preventing an attack on one’s own body tissues, at least under normal circumstances. Tolerance can be broken, however, by the development of an autoimmune response, to be discussed later in this chapter.', 'afe8a533-6f65-4333-9d26-c4297fd27142': 'The cells that leave the thymus become single positives, expressing either CD4 or CD8, but not both (see Figure 21.3.4). The CD4+ T cells will bind to class II MHC and the CD8+ cells will bind to class I MHC. The discussion that follows explains the functions of these molecules and how they can be used to differentiate between the different T cell functional types.'}"
+Figure 21.3.5,Anatomy_And_Physio/images/Figure 21.3.5.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded.","Mature T cells become activated by recognizing processed foreign antigen in association with a self-MHC molecule and begin dividing rapidly by mitosis. This proliferation of T cells is called clonal expansion and is necessary to make the immune response strong enough to effectively control a pathogen. How does the body select only those T cells that are needed against a specific pathogen? Again, the specificity of a T cell is based on the amino acid sequence and the three-dimensional shape of the antigen-binding site formed by the variable regions of the two chains of the T cell receptor (Figure 21.3.5). Clonal selection is the process of antigen binding only to those T cells that have receptors specific to that antigen. Each T cell that is activated has a specific receptor “hard-wired” into its DNA, and all of its progeny will have identical DNA and T cell receptors, forming clones of the original T cell.","{'408030f4-c427-4a1d-83a7-35c5a0b0dd11': 'Mature T cells become activated by recognizing processed foreign antigen in association with a self-MHC molecule and begin dividing rapidly by mitosis. This proliferation of T cells is called clonal expansion and is necessary to make the immune response strong enough to effectively control a pathogen. How does the body select only those T cells that are needed against a specific pathogen? Again, the specificity of a T cell is based on the amino acid sequence and the three-dimensional shape of the antigen-binding site formed by the variable regions of the two chains of the T cell receptor (Figure 21.3.5). Clonal selection is the process of antigen binding only to those T cells that have receptors specific to that antigen. Each T cell that is activated has a specific receptor “hard-wired” into its DNA, and all of its progeny will have identical DNA and T cell receptors, forming clones of the original T cell.', 'db783d22-3e77-4242-b8d7-1cbca32dff62': 'The clonal selection theory was proposed by Frank Burnet in the 1950s. However, the term clonal selection is not a complete description of the theory, as clonal expansion goes hand in glove with the selection process. The main tenet of the theory is that a typical individual has a multitude (1011) of different types of T cell clones based on their receptors. In this use, a clone is a group of lymphocytes that share the same antigen receptor. Each clone is necessarily present in the body in low numbers. Otherwise, the body would not have room for lymphocytes with so many specificities.', '9d5bb4aa-e2b7-4454-aadc-5a9a96abfe86': 'Only those clones of lymphocytes whose receptors are activated by the antigen are stimulated to proliferate. Keep in mind that most antigens have multiple antigenic determinants, so a T cell response to a typical antigen involves a polyclonal response. A polyclonal response is the stimulation of multiple T cell clones. Once activated, the selected clones increase in number and make many copies of each cell type, each clone with its unique receptor. By the time this process is complete, the body will have large numbers of specific lymphocytes available to fight the infection (see Figure 21.3.5).'}"
+Figure 21.3.5,Anatomy_And_Physio/images/Figure 21.3.5.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded.","Mature T cells become activated by recognizing processed foreign antigen in association with a self-MHC molecule and begin dividing rapidly by mitosis. This proliferation of T cells is called clonal expansion and is necessary to make the immune response strong enough to effectively control a pathogen. How does the body select only those T cells that are needed against a specific pathogen? Again, the specificity of a T cell is based on the amino acid sequence and the three-dimensional shape of the antigen-binding site formed by the variable regions of the two chains of the T cell receptor (Figure 21.3.5). Clonal selection is the process of antigen binding only to those T cells that have receptors specific to that antigen. Each T cell that is activated has a specific receptor “hard-wired” into its DNA, and all of its progeny will have identical DNA and T cell receptors, forming clones of the original T cell.","{'408030f4-c427-4a1d-83a7-35c5a0b0dd11': 'Mature T cells become activated by recognizing processed foreign antigen in association with a self-MHC molecule and begin dividing rapidly by mitosis. This proliferation of T cells is called clonal expansion and is necessary to make the immune response strong enough to effectively control a pathogen. How does the body select only those T cells that are needed against a specific pathogen? Again, the specificity of a T cell is based on the amino acid sequence and the three-dimensional shape of the antigen-binding site formed by the variable regions of the two chains of the T cell receptor (Figure 21.3.5). Clonal selection is the process of antigen binding only to those T cells that have receptors specific to that antigen. Each T cell that is activated has a specific receptor “hard-wired” into its DNA, and all of its progeny will have identical DNA and T cell receptors, forming clones of the original T cell.', 'db783d22-3e77-4242-b8d7-1cbca32dff62': 'The clonal selection theory was proposed by Frank Burnet in the 1950s. However, the term clonal selection is not a complete description of the theory, as clonal expansion goes hand in glove with the selection process. The main tenet of the theory is that a typical individual has a multitude (1011) of different types of T cell clones based on their receptors. In this use, a clone is a group of lymphocytes that share the same antigen receptor. Each clone is necessarily present in the body in low numbers. Otherwise, the body would not have room for lymphocytes with so many specificities.', '9d5bb4aa-e2b7-4454-aadc-5a9a96abfe86': 'Only those clones of lymphocytes whose receptors are activated by the antigen are stimulated to proliferate. Keep in mind that most antigens have multiple antigenic determinants, so a T cell response to a typical antigen involves a polyclonal response. A polyclonal response is the stimulation of multiple T cell clones. Once activated, the selected clones increase in number and make many copies of each cell type, each clone with its unique receptor. By the time this process is complete, the body will have large numbers of specific lymphocytes available to fight the infection (see Figure 21.3.5).'}"
+Figure 21.3.6,Anatomy_And_Physio/images/Figure 21.3.6.jpg,"Figure 21.3.6 – Pathogen Presentation: (a) CD4 is associated with helper and regulatory T cells. An extracellular pathogen is processed and presented in the binding cleft of a class II MHC molecule, and this interaction is strengthened by the CD4 molecule. (b) CD8 is associated with cytotoxic T cells. An intracellular pathogen is presented by a class I MHC molecule, and CD8 interacts with it.","In the discussion of T cell development, you saw that mature T cells express either the CD4 marker or the CD8 marker, but not both. These markers are cell adhesion molecules that keep the T cell in close contact with the antigen-presenting cell by directly binding to the MHC molecule (to a different part of the molecule than does the antigen). Thus, T cells and antigen-presenting cells are held together in two ways: by CD4 or CD8 attaching to MHC and by the T cell receptor binding to antigen (Figure 21.3.6).","{'4b6dbf0b-001e-4155-8d97-3a7d1e34ae05': 'In the discussion of T cell development, you saw that mature T cells express either the CD4 marker or the CD8 marker, but not both. These markers are cell adhesion molecules that keep the T cell in close contact with the antigen-presenting cell by directly binding to the MHC molecule (to a different part of the molecule than does the antigen). Thus, T cells and antigen-presenting cells are held together in two ways: by CD4 or CD8 attaching to MHC and by the T cell receptor binding to antigen (Figure 21.3.6).', 'fd6ef7d6-d470-4a76-8f02-441d801e1d81': 'Although the correlation is not 100 percent, CD4-bearing T cells are associated with helper functions and CD8-bearing T cells are associated with cytotoxicity. These functional distinctions based on CD4 and CD8 markers are useful in defining the function of each type.', '3567e14b-5da8-44e4-a13a-d38e1e9e7123': 'The immune system can be divided into two overlapping mechanisms to destroy pathogens: the innate immune response, which is relatively rapid but nonspecific and thus not always effective, and the adaptive immune response, which is slower in its development during an initial infection with a pathogen, but is highly specific and effective at attacking a wide variety of pathogens (Figure 21.2.1).', '2452b440-2a72-4feb-ba3c-9715ec613c45': 'Any discussion of the innate immune response usually begins with the physical barriers that prevent pathogens from entering the body, destroy them after they enter, or flush them out before they can establish themselves in the hospitable environment of the body’s soft tissues. Barrier defenses are part of the body’s most basic defense mechanisms. The barrier defenses are not a response to infections, but they are continuously working to protect against a broad range of pathogens.', 'bce31ede-2cf9-4049-8501-7374d273e8e3': 'The different modes of barrier defenses are associated with the external surfaces of the body, where pathogens may try to enter (Table 21.2). The primary barrier to the entrance of microorganisms into the body is the skin. Not only is the skin covered with a layer of dead, keratinized epithelium that is too dry for bacteria in which to grow, but as these cells are continuously sloughed off from the skin, they carry bacteria and other pathogens with them. Additionally, sweat and other skin secretions may lower pH, contain toxic lipids, and physically wash microbes away.', 'a30c6e31-7bcd-496b-a74d-b693e6b6dd1e': 'Another barrier is the saliva in the mouth, which is rich in lysozyme—an enzyme that destroys bacteria by digesting their cell walls. The acidic environment of the stomach, which is fatal to many pathogens, is also a barrier. Additionally, the mucus layer of the gastrointestinal tract, respiratory tract, reproductive tract, eyes, ears, and nose traps both microbes and debris, and facilitates their removal. In the case of the upper respiratory tract, ciliated epithelial cells move potentially contaminated mucus upwards to the mouth, where it is then swallowed into the digestive tract, ending up in the harsh acidic environment of the stomach. Considering how often you breathe compared to how often you eat or perform other activities that expose you to pathogens, it is not surprising that multiple barrier mechanisms have evolved to work in concert to protect this vital area.'}"
+Figure 21.2.1,Anatomy_And_Physio/images/Figure 21.2.1.jpg,Figure 21.2.1 – Cooperation between Innate and Adaptive Immune Responses: The innate immune system enhances adaptive immune responses so they can be more effective,"The immune system can be divided into two overlapping mechanisms to destroy pathogens: the innate immune response, which is relatively rapid but nonspecific and thus not always effective, and the adaptive immune response, which is slower in its development during an initial infection with a pathogen, but is highly specific and effective at attacking a wide variety of pathogens (Figure 21.2.1).","{'4b6dbf0b-001e-4155-8d97-3a7d1e34ae05': 'In the discussion of T cell development, you saw that mature T cells express either the CD4 marker or the CD8 marker, but not both. These markers are cell adhesion molecules that keep the T cell in close contact with the antigen-presenting cell by directly binding to the MHC molecule (to a different part of the molecule than does the antigen). Thus, T cells and antigen-presenting cells are held together in two ways: by CD4 or CD8 attaching to MHC and by the T cell receptor binding to antigen (Figure 21.3.6).', 'fd6ef7d6-d470-4a76-8f02-441d801e1d81': 'Although the correlation is not 100 percent, CD4-bearing T cells are associated with helper functions and CD8-bearing T cells are associated with cytotoxicity. These functional distinctions based on CD4 and CD8 markers are useful in defining the function of each type.', '3567e14b-5da8-44e4-a13a-d38e1e9e7123': 'The immune system can be divided into two overlapping mechanisms to destroy pathogens: the innate immune response, which is relatively rapid but nonspecific and thus not always effective, and the adaptive immune response, which is slower in its development during an initial infection with a pathogen, but is highly specific and effective at attacking a wide variety of pathogens (Figure 21.2.1).', '2452b440-2a72-4feb-ba3c-9715ec613c45': 'Any discussion of the innate immune response usually begins with the physical barriers that prevent pathogens from entering the body, destroy them after they enter, or flush them out before they can establish themselves in the hospitable environment of the body’s soft tissues. Barrier defenses are part of the body’s most basic defense mechanisms. The barrier defenses are not a response to infections, but they are continuously working to protect against a broad range of pathogens.', 'bce31ede-2cf9-4049-8501-7374d273e8e3': 'The different modes of barrier defenses are associated with the external surfaces of the body, where pathogens may try to enter (Table 21.2). The primary barrier to the entrance of microorganisms into the body is the skin. Not only is the skin covered with a layer of dead, keratinized epithelium that is too dry for bacteria in which to grow, but as these cells are continuously sloughed off from the skin, they carry bacteria and other pathogens with them. Additionally, sweat and other skin secretions may lower pH, contain toxic lipids, and physically wash microbes away.', 'a30c6e31-7bcd-496b-a74d-b693e6b6dd1e': 'Another barrier is the saliva in the mouth, which is rich in lysozyme—an enzyme that destroys bacteria by digesting their cell walls. The acidic environment of the stomach, which is fatal to many pathogens, is also a barrier. Additionally, the mucus layer of the gastrointestinal tract, respiratory tract, reproductive tract, eyes, ears, and nose traps both microbes and debris, and facilitates their removal. In the case of the upper respiratory tract, ciliated epithelial cells move potentially contaminated mucus upwards to the mouth, where it is then swallowed into the digestive tract, ending up in the harsh acidic environment of the stomach. Considering how often you breathe compared to how often you eat or perform other activities that expose you to pathogens, it is not surprising that multiple barrier mechanisms have evolved to work in concert to protect this vital area.'}"
+Figure 21.2.3,Anatomy_And_Physio/images/Figure 21.2.3.jpg,Figure 21.2.3 Inflammatory Response.,"The hallmark of the innate immune response is inflammation. Inflammation is something everyone has experienced. Stub a toe, cut a finger, or do any activity that causes tissue damage and inflammation will result, with its four characteristics: heat, redness, pain, and swelling (“loss of function” is sometimes mentioned as a fifth characteristic). It is important to note that inflammation does not have to be initiated by an infection, but can also be caused by tissue injuries. The release of damaged cellular contents into the site of injury is enough to stimulate the response, even in the absence of breaks in physical barriers that would allow pathogens to enter (by hitting your thumb with a hammer, for example). The inflammatory reaction brings in phagocytic cells to the damaged area to clear cellular debris and to set the stage for wound repair (Figure 21.2.3).","{'3349a431-ac4d-4c48-8477-fb335ba81721': 'The hallmark of the innate immune response is inflammation. Inflammation is something everyone has experienced. Stub a toe, cut a finger, or do any activity that causes tissue damage and inflammation will result, with its four characteristics: heat, redness, pain, and swelling (“loss of function” is sometimes mentioned as a fifth characteristic). It is important to note that inflammation does not have to be initiated by an infection, but can also be caused by tissue injuries. The release of damaged cellular contents into the site of injury is enough to stimulate the response, even in the absence of breaks in physical barriers that would allow pathogens to enter (by hitting your thumb with a hammer, for example). The inflammatory reaction brings in phagocytic cells to the damaged area to clear cellular debris and to set the stage for wound repair (Figure 21.2.3).', 'b51546ad-c4a8-4fcb-9523-b5462b183ce0': 'This reaction also brings in the cells of the innate immune system, allowing them to get rid of the sources of a possible infection. Inflammation is part of a very basic form of immune response. The process not only brings fluid and cells into the site to destroy the pathogen and remove it and debris from the site, but also helps to isolate the site, limiting the spread of the pathogen. Acute inflammation is a short-term inflammatory response to an insult to the body. If the cause of the inflammation is not resolved, however, it can lead to chronic inflammation, which is associated with major tissue destruction and fibrosis. Chronic inflammation is ongoing inflammation. It can be caused by foreign bodies, persistent pathogens, and autoimmune diseases such as rheumatoid arthritis.'}"
+Figure 21.1.1,Anatomy_And_Physio/images/Figure 21.1.1.jpg,Figure 21.1.1 – Anatomy of the Lymphatic System: Lymphatic vessels in the arms and legs convey lymph to the larger lymphatic vessels in the torso.,"The lymphatic vessels begin as open-ended capillaries, which feed into larger and larger lymphatic vessels, and eventually empty into the bloodstream by a series of ducts. Along the way, the lymph travels through the lymph nodes, which are commonly found near the groin, armpits, neck, chest, and abdomen. Humans have about 500–600 lymph nodes throughout the body (Figure 21.1.1).","{'3b29af0e-ebb7-4bed-99c8-cfe1082503a5': 'The lymphatic vessels begin as open-ended capillaries, which feed into larger and larger lymphatic vessels, and eventually empty into the bloodstream by a series of ducts. Along the way, the lymph travels through the lymph nodes, which are commonly found near the groin, armpits, neck, chest, and abdomen. Humans have about 500–600 lymph nodes throughout the body (Figure 21.1.1).', 'bea393eb-1903-48e5-86c8-bd7a8636a1b6': 'A major distinction between the lymphatic and cardiovascular systems in humans is that lymph is not actively pumped by the heart, but is forced through the vessels by the movements of the body, the contraction of skeletal muscles during body movements, and breathing. One-way valves (semi-lunar valves) in lymphatic vessels keep the lymph moving toward the heart. Lymph flows from the lymphatic capillaries, through lymphatic vessels, and then is dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck.'}"
+Figure 21.1.4,Anatomy_And_Physio/images/Figure 21.1.4.jpg,Figure 21.1.4 – Hematopoietic System of the Bone Marrow: All the cells of the immune response as well as of the blood arise by differentiation from hematopoietic stem cells. Platelets are cell fragments involved in the clotting of blood.,"The cells of the blood, including all those involved in the immune response, arise in the bone marrow via various differentiation pathways from hematopoietic stem cells (Figure 21.1.4). In contrast with embryonic stem cells, hematopoietic stem cells are present throughout adulthood and allow for the continuous differentiation of blood cells to replace those lost to age or function. These cells can be divided into three classes based on function:","{'1cfaf7fe-8e7f-4ca3-b180-18dfabbb532d': 'The immune system is a collection of barriers, cells, and soluble proteins that interact and communicate with each other in extraordinarily complex ways. The modern model of immune function is organized into three phases based on the timing of their effects. The three temporal phases consist of the following:', 'd25ed840-6c78-4058-b7bd-806c49e6bd9a': 'The cells of the blood, including all those involved in the immune response, arise in the bone marrow via various differentiation pathways from hematopoietic stem cells (Figure 21.1.4). In contrast with embryonic stem cells, hematopoietic stem cells are present throughout adulthood and allow for the continuous differentiation of blood cells to replace those lost to age or function. These cells can be divided into three classes based on function:', 'fd7924fe-b638-401b-9036-4d776facdc8b': 'Lymphocytes: B Cells, T Cells, Plasma Cells, and Natural Killer Cells', '9709cb71-5d6d-4dd8-9fdb-cc09231361f6': 'As stated above, lymphocytes are the primary cells of adaptive immune responses (Table 21.1). The two basic types of lymphocytes, B cells and T cells, are identical morphologically with a large central nucleus surrounded by a thin layer of cytoplasm. They are distinguished from each other by their surface protein markers as well as by the molecules they secrete. While B cells mature in red bone marrow and T cells mature in the thymus, they both initially develop from bone marrow. T cells migrate from bone marrow to the thymus gland where they further mature. B cells and T cells are found in many parts of the body, circulating in the bloodstream and lymph, and residing in secondary lymphoid organs, including the spleen and lymph nodes, which will be described later in this section. The human body contains approximately 1012 lymphocytes.'}"
+Figure 20.6.1,Anatomy_And_Physio/images/Figure 20.6.1.jpg,"Figure 20.6.1 – Fetal Shunts: The foramen ovale in the interatrial septum allows blood to flow from the right atrium to the left atrium. The ductus arteriosus is a temporary vessel, connecting the aorta to the pulmonary trunk. The ductus venosus links the umbilical vein to the inferior vena cava largely through the liver.","There are three major shunts—alternate paths for blood flow—found in the circulatory system of the fetus. Two of these shunts divert blood from the pulmonary to the systemic circuit, whereas the third connects the umbilical vein to the inferior vena cava. The first two shunts are critical during fetal life, when the lungs are compressed, filled with amniotic fluid, and nonfunctional, and gas exchange is provided by the placenta. These shunts close shortly after birth, however, when the newborn begins to breathe. The third shunt persists a bit longer but becomes nonfunctional once the umbilical cord is severed. The three shunts are as follows (Figure 20.6.1):","{'d4dc1d30-4a0d-42be-9176-4381d0a9524b': 'Lymphocytes develop and mature in the primary lymphoid organs, but they mount immune responses from the secondary lymphoid organs. A naïve lymphocyte is one that has left the primary organ and entered a secondary lymphoid organ. Naïve lymphocytes are fully functional immunologically, but have yet to encounter an antigen to respond to. In addition to circulating in the blood and lymph, lymphocytes concentrate in secondary lymphoid organs, which include the lymph nodes, spleen, and lymphoid nodules. All of these tissues have many features in common, including the following:', 'd4d4b87a-1cd9-45d2-b756-5bf6447ed43d': 'In June 1981, the Centers for Disease Control and Prevention (CDC), in Atlanta, Georgia, published a report of an unusual cluster of five patients in Los Angeles, California. All five were diagnosed with a rare pneumonia caused by a fungus called Pneumocystis jirovecii (formerly known as Pneumocystis carinii).', 'bdc1a13c-dfd5-408e-bc44-d92e5511a686': 'Why was this unusual? Although commonly found in the lungs of healthy individuals, this fungus is an opportunistic pathogen that causes disease in individuals with suppressed or underdeveloped immune systems. The very young, whose immune systems have yet to mature, and the elderly, whose immune systems have declined with age, are particularly susceptible. The five patients from LA, though, were between 29 and 36 years of age and should have been in the prime of their lives, immunologically speaking. What could be going on?', 'fbe437dd-37e7-45f2-b651-c7ce1dd2da49': 'A few days later, a cluster of eight cases was reported in New York City, also involving young patients, this time exhibiting a rare form of skin cancer known as Kaposi’s sarcoma. This cancer of the cells that line the blood and lymphatic vessels was previously observed as a relatively innocuous disease of the elderly. The disease that doctors saw in 1981 was frighteningly more severe, with multiple, fast-growing lesions that spread to all parts of the body, including the trunk and face. Could the immune systems of these young patients have been compromised in some way? Indeed, when they were tested, they exhibited extremely low numbers of a specific type of white blood cell in their bloodstreams, indicating that they had somehow lost a major part of the immune system.', 'b653175f-b632-42d8-a71f-a8617d0a8206': 'Acquired immune deficiency syndrome, or AIDS, turned out to be a new disease caused by the previously unknown human immunodeficiency virus (HIV). Although nearly 100 percent fatal in those with active HIV infections in the early years, the development of anti-HIV drugs has transformed HIV infection into a chronic, manageable disease and not the certain death sentence it once was. One positive outcome resulting from the emergence of HIV disease was that the public’s attention became focused as never before on the importance of having a functional and healthy immune system.', 'a7f8c62f-18e2-4be4-b9c6-7d7e7e0b05f6': 'In a developing embryo,the heart has developed enough by day 21 post-fertilization to begin beating. Circulation patterns are clearly established by the fourth week of embryonic life. It is critical to the survival of the developing human that the circulatory system forms early to supply the growing tissue with nutrients and gases, and to remove waste products. Blood cells and vessel production in structures outside the embryo proper called the yolk sac, chorion, and connecting stalk begin about 15 to 16 days following fertilization. Development of these circulatory elements within the embryo itself begins approximately 2 days later. You will learn more about the formation and function of these early structures when you study the chapter on development. During those first few weeks, blood vessels begin to form from the embryonic mesoderm. The precursor cells are known as hemangioblasts. These in turn differentiate into angioblasts, which give rise to the blood vessels and pluripotent stem cells, which differentiate into the formed elements of blood. (Seek additional content for more detail on fetal development and circulation.) Together, these cells form masses known as blood islands scattered throughout the embryonic disc. Spaces appear on the blood islands that develop into vessel lumens. The endothelial lining of the vessels arise from the angioblasts within these islands. Surrounding mesenchymal cells give rise to the smooth muscle and connective tissue layers of the vessels. While the vessels are developing, the pluripotent stem cells begin to form the blood.', '77c844ef-63c4-4434-b8f7-4956ae5de163': 'Vascular tubes also develop on the blood islands, and they eventually connect to one another as well as to the developing, tubular heart. Thus, the developmental pattern, rather than beginning from the formation of one central vessel and spreading outward, occurs in many regions simultaneously with vessels later joining together. This angiogenesis—the creation of new blood vessels from existing ones—continues as needed throughout life as we grow and develop.', '427a3fc0-7dc8-4a31-92c8-24439b4a0ea2': 'Blood vessel development often follows the same pattern as nerve development and travels to the same target tissues and organs. This occurs because the many factors directing growth of nerves also stimulate blood vessels to follow a similar pattern. Whether a given vessel develops into an artery or a vein is dependent upon local concentrations of signaling proteins.', 'a811788b-c20c-424d-8119-60a14856d92e': 'As the embryo grows within the mother’s uterus, its requirements for nutrients and gas exchange also grow. The placenta—a circulatory organ unique to pregnancy—develops jointly from the embryo and uterine wall structures to fill this need. Emerging from the placenta is the umbilical vein, which carries oxygen-rich blood from the mother to the fetal inferior vena cava via the ductus venosus to the heart that pumps it into fetal circulation. Two umbilical arteries carry oxygen-depleted fetal blood, including wastes and carbon dioxide, to the placenta. Remnants of the umbilical arteries remain in the adult. (Seek additional content for more information on the role of the placenta in fetal circulation.)', 'a8c61662-70ce-4090-8a45-d8d45002e9f2': 'There are three major shunts—alternate paths for blood flow—found in the circulatory system of the fetus. Two of these shunts divert blood from the pulmonary to the systemic circuit, whereas the third connects the umbilical vein to the inferior vena cava. The first two shunts are critical during fetal life, when the lungs are compressed, filled with amniotic fluid, and nonfunctional, and gas exchange is provided by the placenta. These shunts close shortly after birth, however, when the newborn begins to breathe. The third shunt persists a bit longer but becomes nonfunctional once the umbilical cord is severed. The three shunts are as follows (Figure 20.6.1):', 'e1b9b10a-8065-4e77-bbf6-bd29edac1695': 'The foramen ovale is an opening in the interatrial septum that allows blood to flow from the right atrium to the left atrium. A valve associated with this opening prevents backflow of blood during the fetal period. As the newborn begins to breathe and blood pressure in the atria increases, this shunt closes. The fossa ovalis remains in the interatrial septum after birth, marking the location of the former foramen ovale.', 'ff464996-97f4-4f0d-9163-f5b32e1c887b': 'The ductus arteriosus is a short, muscular vessel that connects the pulmonary trunk to the aorta. Most of the blood pumped from the right ventricle into the pulmonary trunk is thereby diverted into the aorta. Only enough blood reaches the fetal lungs to maintain the developing lung tissue. When the newborn takes the first breath, pressure within the lungs drops dramatically, and both the lungs and the pulmonary vessels expand. As the amount of oxygen increases, the smooth muscles in the wall of the ductus arteriosus constrict, sealing off the passage. Eventually, the muscular and endothelial components of the ductus arteriosus degenerate, leaving only the connective tissue component of the ligamentum arteriosum.', '0bee3300-fc24-41c7-8d00-00c5bb95d695': 'The ductus venosus is a temporary blood vessel that branches from the umbilical vein, allowing much of the freshly oxygenated blood from the placenta—the organ of gas exchange between the mother and fetus—to bypass the fetal liver and go directly to the fetal heart. The ductus venosus closes slowly during the first weeks of infancy and degenerates to become the ligamentum venosum.', '9e8443eb-1715-4181-a62c-3ffb2d056281': 'Virtually every cell, tissue, organ, and system in the body is impacted by the circulatory system. This includes the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. Figure 20.5.1 summarizes these relationships.', '0f806f4e-b87f-4a08-99cc-a79294270ad3': 'As you learn about the vessels of the systemic and pulmonary circuits, notice that many arteries and veins share the same names, parallel one another throughout the body, and are very similar on the right and left sides of the body. These pairs of vessels will be traced through only one side of the body. Where differences occur in branching patterns or when vessels are singular, this will be indicated. For example, you will find a pair of femoral arteries and a pair of femoral veins, with one vessel on each side of the body. In contrast, some vessels closer to the midline of the body, such as the aorta, are unique. Moreover, some superficial veins, such as the great saphenous vein in the femoral region, have no arterial counterpart. Another phenomenon that can make the study of vessels challenging is that names of vessels can change with location. Like a street that changes name as it passes through an intersection, an artery or vein can change names as it passes an anatomical landmark. For example, the left subclavian artery becomes the axillary artery as it passes through the body wall and into the axillary region, and then becomes the brachial artery as it flows from the axillary region into the upper arm (or brachium). You will also find examples of anastomoses where two blood vessels that previously branched reconnect. Anastomoses are especially common in veins, where they help maintain blood flow even when one vessel is blocked or narrowed, although there are some important ones in the arteries supplying the brain.', '732adedb-3fc1-49eb-9402-5ae01e7a1720': 'As you read about circular pathways, notice that there is an occasional, very large artery referred to as a trunk, a term indicating that the vessel gives rise to several smaller arteries. For example, the celiac trunk gives rise to the left gastric, common hepatic, and splenic arteries.', 'b6b98e94-c865-45ba-b3be-afcd039c5131': 'As you study this section, imagine you are on a “Voyage of Discovery” similar to Lewis and Clark’s expedition in 1804–1806, which followed rivers and streams through unfamiliar territory, seeking a water route from the Atlantic to the Pacific Ocean. You might envision being inside a miniature boat, exploring the various branches of the circulatory system. This simple approach has proven effective for many students in mastering these major circulatory patterns. Another approach that works well for many students is to create simple line drawings similar to the ones provided, labeling each of the major vessels. It is beyond the scope of this text to name every vessel in the body. However, we will attempt to discuss the major pathways for blood and acquaint you with the major named arteries and veins in the body. Also, please keep in mind that individual variations in circulation patterns are not uncommon.'}"
+Figure 20.5.1,Anatomy_And_Physio/images/Figure 20.5.1.jpg,Figure 20.5.1 Interaction of the Circulatory System with Other Body Systems,"Virtually every cell, tissue, organ, and system in the body is impacted by the circulatory system. This includes the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. Figure 20.5.1 summarizes these relationships.","{'d4dc1d30-4a0d-42be-9176-4381d0a9524b': 'Lymphocytes develop and mature in the primary lymphoid organs, but they mount immune responses from the secondary lymphoid organs. A naïve lymphocyte is one that has left the primary organ and entered a secondary lymphoid organ. Naïve lymphocytes are fully functional immunologically, but have yet to encounter an antigen to respond to. In addition to circulating in the blood and lymph, lymphocytes concentrate in secondary lymphoid organs, which include the lymph nodes, spleen, and lymphoid nodules. All of these tissues have many features in common, including the following:', 'd4d4b87a-1cd9-45d2-b756-5bf6447ed43d': 'In June 1981, the Centers for Disease Control and Prevention (CDC), in Atlanta, Georgia, published a report of an unusual cluster of five patients in Los Angeles, California. All five were diagnosed with a rare pneumonia caused by a fungus called Pneumocystis jirovecii (formerly known as Pneumocystis carinii).', 'bdc1a13c-dfd5-408e-bc44-d92e5511a686': 'Why was this unusual? Although commonly found in the lungs of healthy individuals, this fungus is an opportunistic pathogen that causes disease in individuals with suppressed or underdeveloped immune systems. The very young, whose immune systems have yet to mature, and the elderly, whose immune systems have declined with age, are particularly susceptible. The five patients from LA, though, were between 29 and 36 years of age and should have been in the prime of their lives, immunologically speaking. What could be going on?', 'fbe437dd-37e7-45f2-b651-c7ce1dd2da49': 'A few days later, a cluster of eight cases was reported in New York City, also involving young patients, this time exhibiting a rare form of skin cancer known as Kaposi’s sarcoma. This cancer of the cells that line the blood and lymphatic vessels was previously observed as a relatively innocuous disease of the elderly. The disease that doctors saw in 1981 was frighteningly more severe, with multiple, fast-growing lesions that spread to all parts of the body, including the trunk and face. Could the immune systems of these young patients have been compromised in some way? Indeed, when they were tested, they exhibited extremely low numbers of a specific type of white blood cell in their bloodstreams, indicating that they had somehow lost a major part of the immune system.', 'b653175f-b632-42d8-a71f-a8617d0a8206': 'Acquired immune deficiency syndrome, or AIDS, turned out to be a new disease caused by the previously unknown human immunodeficiency virus (HIV). Although nearly 100 percent fatal in those with active HIV infections in the early years, the development of anti-HIV drugs has transformed HIV infection into a chronic, manageable disease and not the certain death sentence it once was. One positive outcome resulting from the emergence of HIV disease was that the public’s attention became focused as never before on the importance of having a functional and healthy immune system.', 'a7f8c62f-18e2-4be4-b9c6-7d7e7e0b05f6': 'In a developing embryo,the heart has developed enough by day 21 post-fertilization to begin beating. Circulation patterns are clearly established by the fourth week of embryonic life. It is critical to the survival of the developing human that the circulatory system forms early to supply the growing tissue with nutrients and gases, and to remove waste products. Blood cells and vessel production in structures outside the embryo proper called the yolk sac, chorion, and connecting stalk begin about 15 to 16 days following fertilization. Development of these circulatory elements within the embryo itself begins approximately 2 days later. You will learn more about the formation and function of these early structures when you study the chapter on development. During those first few weeks, blood vessels begin to form from the embryonic mesoderm. The precursor cells are known as hemangioblasts. These in turn differentiate into angioblasts, which give rise to the blood vessels and pluripotent stem cells, which differentiate into the formed elements of blood. (Seek additional content for more detail on fetal development and circulation.) Together, these cells form masses known as blood islands scattered throughout the embryonic disc. Spaces appear on the blood islands that develop into vessel lumens. The endothelial lining of the vessels arise from the angioblasts within these islands. Surrounding mesenchymal cells give rise to the smooth muscle and connective tissue layers of the vessels. While the vessels are developing, the pluripotent stem cells begin to form the blood.', '77c844ef-63c4-4434-b8f7-4956ae5de163': 'Vascular tubes also develop on the blood islands, and they eventually connect to one another as well as to the developing, tubular heart. Thus, the developmental pattern, rather than beginning from the formation of one central vessel and spreading outward, occurs in many regions simultaneously with vessels later joining together. This angiogenesis—the creation of new blood vessels from existing ones—continues as needed throughout life as we grow and develop.', '427a3fc0-7dc8-4a31-92c8-24439b4a0ea2': 'Blood vessel development often follows the same pattern as nerve development and travels to the same target tissues and organs. This occurs because the many factors directing growth of nerves also stimulate blood vessels to follow a similar pattern. Whether a given vessel develops into an artery or a vein is dependent upon local concentrations of signaling proteins.', 'a811788b-c20c-424d-8119-60a14856d92e': 'As the embryo grows within the mother’s uterus, its requirements for nutrients and gas exchange also grow. The placenta—a circulatory organ unique to pregnancy—develops jointly from the embryo and uterine wall structures to fill this need. Emerging from the placenta is the umbilical vein, which carries oxygen-rich blood from the mother to the fetal inferior vena cava via the ductus venosus to the heart that pumps it into fetal circulation. Two umbilical arteries carry oxygen-depleted fetal blood, including wastes and carbon dioxide, to the placenta. Remnants of the umbilical arteries remain in the adult. (Seek additional content for more information on the role of the placenta in fetal circulation.)', 'a8c61662-70ce-4090-8a45-d8d45002e9f2': 'There are three major shunts—alternate paths for blood flow—found in the circulatory system of the fetus. Two of these shunts divert blood from the pulmonary to the systemic circuit, whereas the third connects the umbilical vein to the inferior vena cava. The first two shunts are critical during fetal life, when the lungs are compressed, filled with amniotic fluid, and nonfunctional, and gas exchange is provided by the placenta. These shunts close shortly after birth, however, when the newborn begins to breathe. The third shunt persists a bit longer but becomes nonfunctional once the umbilical cord is severed. The three shunts are as follows (Figure 20.6.1):', 'e1b9b10a-8065-4e77-bbf6-bd29edac1695': 'The foramen ovale is an opening in the interatrial septum that allows blood to flow from the right atrium to the left atrium. A valve associated with this opening prevents backflow of blood during the fetal period. As the newborn begins to breathe and blood pressure in the atria increases, this shunt closes. The fossa ovalis remains in the interatrial septum after birth, marking the location of the former foramen ovale.', 'ff464996-97f4-4f0d-9163-f5b32e1c887b': 'The ductus arteriosus is a short, muscular vessel that connects the pulmonary trunk to the aorta. Most of the blood pumped from the right ventricle into the pulmonary trunk is thereby diverted into the aorta. Only enough blood reaches the fetal lungs to maintain the developing lung tissue. When the newborn takes the first breath, pressure within the lungs drops dramatically, and both the lungs and the pulmonary vessels expand. As the amount of oxygen increases, the smooth muscles in the wall of the ductus arteriosus constrict, sealing off the passage. Eventually, the muscular and endothelial components of the ductus arteriosus degenerate, leaving only the connective tissue component of the ligamentum arteriosum.', '0bee3300-fc24-41c7-8d00-00c5bb95d695': 'The ductus venosus is a temporary blood vessel that branches from the umbilical vein, allowing much of the freshly oxygenated blood from the placenta—the organ of gas exchange between the mother and fetus—to bypass the fetal liver and go directly to the fetal heart. The ductus venosus closes slowly during the first weeks of infancy and degenerates to become the ligamentum venosum.', '9e8443eb-1715-4181-a62c-3ffb2d056281': 'Virtually every cell, tissue, organ, and system in the body is impacted by the circulatory system. This includes the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. Figure 20.5.1 summarizes these relationships.', '0f806f4e-b87f-4a08-99cc-a79294270ad3': 'As you learn about the vessels of the systemic and pulmonary circuits, notice that many arteries and veins share the same names, parallel one another throughout the body, and are very similar on the right and left sides of the body. These pairs of vessels will be traced through only one side of the body. Where differences occur in branching patterns or when vessels are singular, this will be indicated. For example, you will find a pair of femoral arteries and a pair of femoral veins, with one vessel on each side of the body. In contrast, some vessels closer to the midline of the body, such as the aorta, are unique. Moreover, some superficial veins, such as the great saphenous vein in the femoral region, have no arterial counterpart. Another phenomenon that can make the study of vessels challenging is that names of vessels can change with location. Like a street that changes name as it passes through an intersection, an artery or vein can change names as it passes an anatomical landmark. For example, the left subclavian artery becomes the axillary artery as it passes through the body wall and into the axillary region, and then becomes the brachial artery as it flows from the axillary region into the upper arm (or brachium). You will also find examples of anastomoses where two blood vessels that previously branched reconnect. Anastomoses are especially common in veins, where they help maintain blood flow even when one vessel is blocked or narrowed, although there are some important ones in the arteries supplying the brain.', '732adedb-3fc1-49eb-9402-5ae01e7a1720': 'As you read about circular pathways, notice that there is an occasional, very large artery referred to as a trunk, a term indicating that the vessel gives rise to several smaller arteries. For example, the celiac trunk gives rise to the left gastric, common hepatic, and splenic arteries.', 'b6b98e94-c865-45ba-b3be-afcd039c5131': 'As you study this section, imagine you are on a “Voyage of Discovery” similar to Lewis and Clark’s expedition in 1804–1806, which followed rivers and streams through unfamiliar territory, seeking a water route from the Atlantic to the Pacific Ocean. You might envision being inside a miniature boat, exploring the various branches of the circulatory system. This simple approach has proven effective for many students in mastering these major circulatory patterns. Another approach that works well for many students is to create simple line drawings similar to the ones provided, labeling each of the major vessels. It is beyond the scope of this text to name every vessel in the body. However, we will attempt to discuss the major pathways for blood and acquaint you with the major named arteries and veins in the body. Also, please keep in mind that individual variations in circulation patterns are not uncommon.'}"
+Figure 20.5.2,Anatomy_And_Physio/images/Figure 20.5.2.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium.","Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.","{'9534f415-fb1f-40ef-abe3-0b7e88b8c450': 'Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.', 'fadadb34-f49f-4b07-9c44-97cd50672bef': 'The single vessel exiting the right ventricle is the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve, which prevents backflow of blood into the right ventricle during ventricular diastole. As the pulmonary trunk reaches the superior surface of the heart, it curves posteriorly and rapidly bifurcates (divides) into two branches, a left and a right pulmonary artery. To prevent confusion between these vessels, it is important to refer to the vessel exiting the heart as the pulmonary trunk, rather than also calling it a pulmonary artery. The pulmonary arteries in turn branch many times within the lung, forming a series of smaller arteries and arterioles that eventually lead to the pulmonary capillaries. The pulmonary capillaries surround lung structures known as alveoli that are the sites of oxygen and carbon dioxide exchange.', '4f0e12ff-1d08-4bd0-9bf4-226090a59960': 'Once gas exchange is completed, oxygenated blood flows from the pulmonary capillaries into a series of pulmonary venules that eventually lead to a series of larger pulmonary veins. Four pulmonary veins, two on the left and two on the right, return blood to the left atrium. At this point, the pulmonary circuit is complete. Table 20.4 defines the major arteries and veins of the pulmonary circuit discussed in the text.', '71540d30-3c6a-4b2d-b58f-063abf28b254': 'There are three major branches of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian (literally “under the clavicle”) artery. As you would expect based upon proximity to the heart, each of these vessels is classified as an elastic artery.', '74ca4cd9-836b-42e1-b99b-0bed8dcc002e': 'The brachiocephalic artery is located only on the right side of the body; there is no corresponding artery on the left. The brachiocephalic artery branches into the right subclavian artery and the right common carotid artery. The left subclavian and left common carotid arteries arise independently from the aortic arch but otherwise follow a similar pattern and distribution to the corresponding arteries on the right side (see Figure 20.5.2).', '8d6502df-45e6-4e43-89f6-9be49024bcc5': 'Each subclavian artery supplies blood to the arms, chest, shoulders, back, and central nervous system. It then gives rise to three major branches: the internal thoracic artery, the vertebral artery, and the thyrocervical artery. The internal thoracic artery, or mammary artery, supplies blood to the thymus, the pericardium of the heart, and the anterior chest wall. The vertebral artery passes through the vertebral foramen in the cervical vertebrae and then through the foramen magnum into the cranial cavity to supply blood to the brain and spinal cord. The paired vertebral arteries join together to form the large basilar artery at the base of the medulla oblongata. This is an example of an anastomosis. The subclavian artery also gives rise to the thyrocervical artery that provides blood to the thyroid, the cervical region of the neck, and the upper back and shoulder.', 'f32f9637-71bb-4aab-abb0-d6e5ae1d11da': 'The common carotid artery divides into internal and external carotid arteries. The right common carotid artery arises from the brachiocephalic artery and the left common carotid artery arises directly from the aortic arch. The external carotid artery supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx. These branches include the lingual, facial, occipital, maxillary, and superficial temporal arteries. The internal carotid artery initially forms an expansion known as the carotid sinus, containing the carotid baroreceptors and chemoreceptors. Like their counterparts in the aortic sinuses, the information provided by these receptors is critical to maintaining cardiovascular homeostasis (see Figure 20.5.2).', 'b40b9f53-291f-47e3-adc0-2bc14a8c1c72': 'The internal carotid arteries along with the vertebral arteries are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. Recall that blood flow to the brain is remarkably constant, with approximately 20 percent of blood flow directed to this organ at any given time. When blood flow is interrupted, even for just a few seconds, a transient ischemic attack (TIA), or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. In some cases, the damage may be permanent. Loss of blood flow for longer periods, typically between 3 and 4 minutes, will likely produce irreversible brain damage or a stroke, also called a cerebrovascular accident (CVA). The locations of the arteries in the brain not only provide blood flow to the brain tissue but also prevent interruption in the flow of blood. Both the carotid and vertebral arteries branch once they enter the cranial cavity, and some of these branches form a structure known as the arterial circle (or circle of Willis), an anastomosis that is remarkably like a traffic circle that sends off branches (in this case, arterial branches to the brain). As a rule, branches to the anterior portion of the cerebrum are normally fed by the internal carotid arteries; the remainder of the brain receives blood flow from branches associated with the vertebral arteries.', 'fef21dcb-882c-49fa-af65-370bae1aeb11': 'The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.', '616cb18b-7157-47cd-8ff7-2815136bc36e': 'The right and left anterior cerebral arteries join together to form an anastomosis called the anterior communicating artery. The initial segments of the anterior cerebral arteries and the anterior communicating artery form the anterior portion of the arterial circle. The posterior portion of the arterial circle is formed by a left and a right posterior communicating artery that branches from the posterior cerebral artery, which arises from the basilar artery. It provides blood to the posterior portion of the cerebrum and brain stem. The basilar artery is an anastomosis that begins at the junction of the two vertebral arteries and sends branches to the cerebellum and brain stem. It flows into the posterior cerebral arteries. Table 20.6 summarizes the aortic arch branches, including the major branches supplying the brain.'}"
+Figure 20.5.3,Anatomy_And_Physio/images/Figure 20.5.3.jpg,Figure 20.5.3 – Systemic Arteries: The major systemic arteries shown here deliver oxygenated blood throughout the body.,"Blood relatively high in oxygen concentration is returned from the pulmonary circuit to the left atrium via the four pulmonary veins. From the left atrium, blood moves into the left ventricle, which pumps blood into the aorta. The aorta and its branches—the systemic arteries—send blood to virtually every organ of the body (Figure 20.5.3).","{'7a6b1494-a4e7-402b-b61d-0e8592e29d7e': 'Blood relatively high in oxygen concentration is returned from the pulmonary circuit to the left atrium via the four pulmonary veins. From the left atrium, blood moves into the left ventricle, which pumps blood into the aorta. The aorta and its branches—the systemic arteries—send blood to virtually every organ of the body (Figure 20.5.3).'}"
+Figure 20.5.4,Anatomy_And_Physio/images/Figure 20.5.4.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions.","The aorta is the largest artery in the body (Figure 20.5.4). It arises from the left ventricle and eventually descends to the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the superior thoracic and inferior abdominal components. Arteries originating from the aorta ultimately distribute blood to virtually all tissues of the body. At the base of the aorta is the aortic semilunar valve that prevents backflow of blood into the left ventricle while the heart is relaxing. After exiting the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. Following this ascent, it reverses direction, forming a graceful arc to the left, called the aortic arch. The aortic arch descends toward the inferior portions of the body and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues close to the bodies of the vertebrae and passes through an opening in the diaphragm known as the aortic hiatus. Superior to the diaphragm, the aorta is called the thoracic aorta, and inferior to the diaphragm, it is called the abdominal aorta. The abdominal aorta terminates when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 20.5.4 for an illustration of the ascending aorta, the aortic arch, and the initial segment of the descending aorta plus major branches; Table 20.5 summarizes the structures of the aorta.","{'f75f21eb-0d0a-4f11-afcc-b58d75a0bb1e': 'The aorta is the largest artery in the body (Figure 20.5.4). It arises from the left ventricle and eventually descends to the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the superior thoracic and inferior abdominal components. Arteries originating from the aorta ultimately distribute blood to virtually all tissues of the body. At the base of the aorta is the aortic semilunar valve that prevents backflow of blood into the left ventricle while the heart is relaxing. After exiting the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. Following this ascent, it reverses direction, forming a graceful arc to the left, called the aortic arch. The aortic arch descends toward the inferior portions of the body and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues close to the bodies of the vertebrae and passes through an opening in the diaphragm known as the aortic hiatus. Superior to the diaphragm, the aorta is called the thoracic aorta, and inferior to the diaphragm, it is called the abdominal aorta. The abdominal aorta terminates when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 20.5.4 for an illustration of the ascending aorta, the aortic arch, and the initial segment of the descending aorta plus major branches; Table 20.5 summarizes the structures of the aorta.', 'a6f34745-61d0-40e4-a69f-42beb5122847': 'The first vessels that branch from the ascending aorta are the paired coronary arteries (see Figure 20.5.4), which arise from two of the three sinuses in the ascending aorta just superior to the aortic semilunar valve. These sinuses contain the aortic baroreceptors and chemoreceptors critical to maintain cardiac function. The left coronary artery arises from the left posterior aortic sinus. The right coronary artery arises from the anterior aortic sinus. Normally, the right posterior aortic sinus does not give rise to a vessel.', 'e7239930-574e-4dcb-9501-1e95aed19236': 'The coronary arteries encircle the heart, forming a ring-like structure that divides into the next level of branches that supplies blood to the heart tissues. (Seek additional content for more detail on cardiac circulation.)', '50847ff9-c968-42a8-b6b4-76f0b8c8e783': 'You will recall that the heart is a remarkable pump composed largely of cardiac muscle cells that are incredibly active throughout life. Like all other cells, a cardiomyocyte requires a reliable supply of oxygen and nutrients, and a way to remove wastes, so it needs a dedicated, complex, and extensive coronary circulation to supply the thick myocardium. And because of the critical and nearly ceaseless activity of the heart throughout life, this need for a blood supply is even greater than for a typical cell. However, coronary circulation is not continuous; rather, it cycles, reaching a peak when the heart muscle is relaxed and nearly ceasing while it is contracting.', 'e6399f6f-7c6a-4389-b103-87d2ce250bd6': 'In this chapter, you will explore the remarkable pump that propels the blood into the vessels. There is no single better word to describe the function of the heart other than “pump,” since its contraction develops the pressure that ejects blood into the major vessels: the aorta and pulmonary trunk. From these vessels, the blood is distributed to the remainder of the body. Although the connotation of the term “pump” suggests a mechanical device made of steel and plastic, the anatomical structure is a living, sophisticated muscle. As you read this chapter, try to keep these twin concepts in mind: pump and muscle.', '31732258-9f0a-472c-93ad-18616a4e5362': 'Although the term “heart” is an English word, cardiac (heart-related) terminology can be traced back to the Latin term, “kardia.” Cardiology is the study of the heart, and cardiologists are the physicians who deal primarily with the heart.', '8439c407-e31f-46f9-9b58-6abdf3f6f88e': 'Explain the significance of ABO and Rh blood groups in blood transfusions', 'a768244b-07bf-4e6b-be50-07b1febf4db1': 'Blood transfusions in humans were risky procedures until the discovery of the major human blood groups by Karl Landsteiner, an Austrian biologist and physician, in 1900. Until that point, physicians did not understand that death sometimes followed blood transfusions, when the type of donor blood infused into the patient was incompatible with the patient’s own blood. Blood groups are determined by the presence or absence of specific marker molecules on the plasma membranes of erythrocytes. With their discovery, it became possible for the first time to match patient-donor blood types and prevent transfusion reactions and deaths.'}"
+Figure 20.5.4,Anatomy_And_Physio/images/Figure 20.5.4.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions.","The aorta is the largest artery in the body (Figure 20.5.4). It arises from the left ventricle and eventually descends to the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the superior thoracic and inferior abdominal components. Arteries originating from the aorta ultimately distribute blood to virtually all tissues of the body. At the base of the aorta is the aortic semilunar valve that prevents backflow of blood into the left ventricle while the heart is relaxing. After exiting the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. Following this ascent, it reverses direction, forming a graceful arc to the left, called the aortic arch. The aortic arch descends toward the inferior portions of the body and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues close to the bodies of the vertebrae and passes through an opening in the diaphragm known as the aortic hiatus. Superior to the diaphragm, the aorta is called the thoracic aorta, and inferior to the diaphragm, it is called the abdominal aorta. The abdominal aorta terminates when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 20.5.4 for an illustration of the ascending aorta, the aortic arch, and the initial segment of the descending aorta plus major branches; Table 20.5 summarizes the structures of the aorta.","{'f75f21eb-0d0a-4f11-afcc-b58d75a0bb1e': 'The aorta is the largest artery in the body (Figure 20.5.4). It arises from the left ventricle and eventually descends to the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the superior thoracic and inferior abdominal components. Arteries originating from the aorta ultimately distribute blood to virtually all tissues of the body. At the base of the aorta is the aortic semilunar valve that prevents backflow of blood into the left ventricle while the heart is relaxing. After exiting the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. Following this ascent, it reverses direction, forming a graceful arc to the left, called the aortic arch. The aortic arch descends toward the inferior portions of the body and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues close to the bodies of the vertebrae and passes through an opening in the diaphragm known as the aortic hiatus. Superior to the diaphragm, the aorta is called the thoracic aorta, and inferior to the diaphragm, it is called the abdominal aorta. The abdominal aorta terminates when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 20.5.4 for an illustration of the ascending aorta, the aortic arch, and the initial segment of the descending aorta plus major branches; Table 20.5 summarizes the structures of the aorta.', 'a6f34745-61d0-40e4-a69f-42beb5122847': 'The first vessels that branch from the ascending aorta are the paired coronary arteries (see Figure 20.5.4), which arise from two of the three sinuses in the ascending aorta just superior to the aortic semilunar valve. These sinuses contain the aortic baroreceptors and chemoreceptors critical to maintain cardiac function. The left coronary artery arises from the left posterior aortic sinus. The right coronary artery arises from the anterior aortic sinus. Normally, the right posterior aortic sinus does not give rise to a vessel.', 'e7239930-574e-4dcb-9501-1e95aed19236': 'The coronary arteries encircle the heart, forming a ring-like structure that divides into the next level of branches that supplies blood to the heart tissues. (Seek additional content for more detail on cardiac circulation.)', '50847ff9-c968-42a8-b6b4-76f0b8c8e783': 'You will recall that the heart is a remarkable pump composed largely of cardiac muscle cells that are incredibly active throughout life. Like all other cells, a cardiomyocyte requires a reliable supply of oxygen and nutrients, and a way to remove wastes, so it needs a dedicated, complex, and extensive coronary circulation to supply the thick myocardium. And because of the critical and nearly ceaseless activity of the heart throughout life, this need for a blood supply is even greater than for a typical cell. However, coronary circulation is not continuous; rather, it cycles, reaching a peak when the heart muscle is relaxed and nearly ceasing while it is contracting.', 'e6399f6f-7c6a-4389-b103-87d2ce250bd6': 'In this chapter, you will explore the remarkable pump that propels the blood into the vessels. There is no single better word to describe the function of the heart other than “pump,” since its contraction develops the pressure that ejects blood into the major vessels: the aorta and pulmonary trunk. From these vessels, the blood is distributed to the remainder of the body. Although the connotation of the term “pump” suggests a mechanical device made of steel and plastic, the anatomical structure is a living, sophisticated muscle. As you read this chapter, try to keep these twin concepts in mind: pump and muscle.', '31732258-9f0a-472c-93ad-18616a4e5362': 'Although the term “heart” is an English word, cardiac (heart-related) terminology can be traced back to the Latin term, “kardia.” Cardiology is the study of the heart, and cardiologists are the physicians who deal primarily with the heart.', '8439c407-e31f-46f9-9b58-6abdf3f6f88e': 'Explain the significance of ABO and Rh blood groups in blood transfusions', 'a768244b-07bf-4e6b-be50-07b1febf4db1': 'Blood transfusions in humans were risky procedures until the discovery of the major human blood groups by Karl Landsteiner, an Austrian biologist and physician, in 1900. Until that point, physicians did not understand that death sometimes followed blood transfusions, when the type of donor blood infused into the patient was incompatible with the patient’s own blood. Blood groups are determined by the presence or absence of specific marker molecules on the plasma membranes of erythrocytes. With their discovery, it became possible for the first time to match patient-donor blood types and prevent transfusion reactions and deaths.'}"
+Figure 20.5.2,Anatomy_And_Physio/images/Figure 20.5.2.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium.","Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.","{'9534f415-fb1f-40ef-abe3-0b7e88b8c450': 'Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.', 'fadadb34-f49f-4b07-9c44-97cd50672bef': 'The single vessel exiting the right ventricle is the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve, which prevents backflow of blood into the right ventricle during ventricular diastole. As the pulmonary trunk reaches the superior surface of the heart, it curves posteriorly and rapidly bifurcates (divides) into two branches, a left and a right pulmonary artery. To prevent confusion between these vessels, it is important to refer to the vessel exiting the heart as the pulmonary trunk, rather than also calling it a pulmonary artery. The pulmonary arteries in turn branch many times within the lung, forming a series of smaller arteries and arterioles that eventually lead to the pulmonary capillaries. The pulmonary capillaries surround lung structures known as alveoli that are the sites of oxygen and carbon dioxide exchange.', '4f0e12ff-1d08-4bd0-9bf4-226090a59960': 'Once gas exchange is completed, oxygenated blood flows from the pulmonary capillaries into a series of pulmonary venules that eventually lead to a series of larger pulmonary veins. Four pulmonary veins, two on the left and two on the right, return blood to the left atrium. At this point, the pulmonary circuit is complete. Table 20.4 defines the major arteries and veins of the pulmonary circuit discussed in the text.', '71540d30-3c6a-4b2d-b58f-063abf28b254': 'There are three major branches of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian (literally “under the clavicle”) artery. As you would expect based upon proximity to the heart, each of these vessels is classified as an elastic artery.', '74ca4cd9-836b-42e1-b99b-0bed8dcc002e': 'The brachiocephalic artery is located only on the right side of the body; there is no corresponding artery on the left. The brachiocephalic artery branches into the right subclavian artery and the right common carotid artery. The left subclavian and left common carotid arteries arise independently from the aortic arch but otherwise follow a similar pattern and distribution to the corresponding arteries on the right side (see Figure 20.5.2).', '8d6502df-45e6-4e43-89f6-9be49024bcc5': 'Each subclavian artery supplies blood to the arms, chest, shoulders, back, and central nervous system. It then gives rise to three major branches: the internal thoracic artery, the vertebral artery, and the thyrocervical artery. The internal thoracic artery, or mammary artery, supplies blood to the thymus, the pericardium of the heart, and the anterior chest wall. The vertebral artery passes through the vertebral foramen in the cervical vertebrae and then through the foramen magnum into the cranial cavity to supply blood to the brain and spinal cord. The paired vertebral arteries join together to form the large basilar artery at the base of the medulla oblongata. This is an example of an anastomosis. The subclavian artery also gives rise to the thyrocervical artery that provides blood to the thyroid, the cervical region of the neck, and the upper back and shoulder.', 'f32f9637-71bb-4aab-abb0-d6e5ae1d11da': 'The common carotid artery divides into internal and external carotid arteries. The right common carotid artery arises from the brachiocephalic artery and the left common carotid artery arises directly from the aortic arch. The external carotid artery supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx. These branches include the lingual, facial, occipital, maxillary, and superficial temporal arteries. The internal carotid artery initially forms an expansion known as the carotid sinus, containing the carotid baroreceptors and chemoreceptors. Like their counterparts in the aortic sinuses, the information provided by these receptors is critical to maintaining cardiovascular homeostasis (see Figure 20.5.2).', 'b40b9f53-291f-47e3-adc0-2bc14a8c1c72': 'The internal carotid arteries along with the vertebral arteries are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. Recall that blood flow to the brain is remarkably constant, with approximately 20 percent of blood flow directed to this organ at any given time. When blood flow is interrupted, even for just a few seconds, a transient ischemic attack (TIA), or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. In some cases, the damage may be permanent. Loss of blood flow for longer periods, typically between 3 and 4 minutes, will likely produce irreversible brain damage or a stroke, also called a cerebrovascular accident (CVA). The locations of the arteries in the brain not only provide blood flow to the brain tissue but also prevent interruption in the flow of blood. Both the carotid and vertebral arteries branch once they enter the cranial cavity, and some of these branches form a structure known as the arterial circle (or circle of Willis), an anastomosis that is remarkably like a traffic circle that sends off branches (in this case, arterial branches to the brain). As a rule, branches to the anterior portion of the cerebrum are normally fed by the internal carotid arteries; the remainder of the brain receives blood flow from branches associated with the vertebral arteries.', 'fef21dcb-882c-49fa-af65-370bae1aeb11': 'The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.', '616cb18b-7157-47cd-8ff7-2815136bc36e': 'The right and left anterior cerebral arteries join together to form an anastomosis called the anterior communicating artery. The initial segments of the anterior cerebral arteries and the anterior communicating artery form the anterior portion of the arterial circle. The posterior portion of the arterial circle is formed by a left and a right posterior communicating artery that branches from the posterior cerebral artery, which arises from the basilar artery. It provides blood to the posterior portion of the cerebrum and brain stem. The basilar artery is an anastomosis that begins at the junction of the two vertebral arteries and sends branches to the cerebellum and brain stem. It flows into the posterior cerebral arteries. Table 20.6 summarizes the aortic arch branches, including the major branches supplying the brain.'}"
+Figure 20.5.2,Anatomy_And_Physio/images/Figure 20.5.2.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium.","Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.","{'9534f415-fb1f-40ef-abe3-0b7e88b8c450': 'Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.', 'fadadb34-f49f-4b07-9c44-97cd50672bef': 'The single vessel exiting the right ventricle is the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve, which prevents backflow of blood into the right ventricle during ventricular diastole. As the pulmonary trunk reaches the superior surface of the heart, it curves posteriorly and rapidly bifurcates (divides) into two branches, a left and a right pulmonary artery. To prevent confusion between these vessels, it is important to refer to the vessel exiting the heart as the pulmonary trunk, rather than also calling it a pulmonary artery. The pulmonary arteries in turn branch many times within the lung, forming a series of smaller arteries and arterioles that eventually lead to the pulmonary capillaries. The pulmonary capillaries surround lung structures known as alveoli that are the sites of oxygen and carbon dioxide exchange.', '4f0e12ff-1d08-4bd0-9bf4-226090a59960': 'Once gas exchange is completed, oxygenated blood flows from the pulmonary capillaries into a series of pulmonary venules that eventually lead to a series of larger pulmonary veins. Four pulmonary veins, two on the left and two on the right, return blood to the left atrium. At this point, the pulmonary circuit is complete. Table 20.4 defines the major arteries and veins of the pulmonary circuit discussed in the text.', '71540d30-3c6a-4b2d-b58f-063abf28b254': 'There are three major branches of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian (literally “under the clavicle”) artery. As you would expect based upon proximity to the heart, each of these vessels is classified as an elastic artery.', '74ca4cd9-836b-42e1-b99b-0bed8dcc002e': 'The brachiocephalic artery is located only on the right side of the body; there is no corresponding artery on the left. The brachiocephalic artery branches into the right subclavian artery and the right common carotid artery. The left subclavian and left common carotid arteries arise independently from the aortic arch but otherwise follow a similar pattern and distribution to the corresponding arteries on the right side (see Figure 20.5.2).', '8d6502df-45e6-4e43-89f6-9be49024bcc5': 'Each subclavian artery supplies blood to the arms, chest, shoulders, back, and central nervous system. It then gives rise to three major branches: the internal thoracic artery, the vertebral artery, and the thyrocervical artery. The internal thoracic artery, or mammary artery, supplies blood to the thymus, the pericardium of the heart, and the anterior chest wall. The vertebral artery passes through the vertebral foramen in the cervical vertebrae and then through the foramen magnum into the cranial cavity to supply blood to the brain and spinal cord. The paired vertebral arteries join together to form the large basilar artery at the base of the medulla oblongata. This is an example of an anastomosis. The subclavian artery also gives rise to the thyrocervical artery that provides blood to the thyroid, the cervical region of the neck, and the upper back and shoulder.', 'f32f9637-71bb-4aab-abb0-d6e5ae1d11da': 'The common carotid artery divides into internal and external carotid arteries. The right common carotid artery arises from the brachiocephalic artery and the left common carotid artery arises directly from the aortic arch. The external carotid artery supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx. These branches include the lingual, facial, occipital, maxillary, and superficial temporal arteries. The internal carotid artery initially forms an expansion known as the carotid sinus, containing the carotid baroreceptors and chemoreceptors. Like their counterparts in the aortic sinuses, the information provided by these receptors is critical to maintaining cardiovascular homeostasis (see Figure 20.5.2).', 'b40b9f53-291f-47e3-adc0-2bc14a8c1c72': 'The internal carotid arteries along with the vertebral arteries are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. Recall that blood flow to the brain is remarkably constant, with approximately 20 percent of blood flow directed to this organ at any given time. When blood flow is interrupted, even for just a few seconds, a transient ischemic attack (TIA), or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. In some cases, the damage may be permanent. Loss of blood flow for longer periods, typically between 3 and 4 minutes, will likely produce irreversible brain damage or a stroke, also called a cerebrovascular accident (CVA). The locations of the arteries in the brain not only provide blood flow to the brain tissue but also prevent interruption in the flow of blood. Both the carotid and vertebral arteries branch once they enter the cranial cavity, and some of these branches form a structure known as the arterial circle (or circle of Willis), an anastomosis that is remarkably like a traffic circle that sends off branches (in this case, arterial branches to the brain). As a rule, branches to the anterior portion of the cerebrum are normally fed by the internal carotid arteries; the remainder of the brain receives blood flow from branches associated with the vertebral arteries.', 'fef21dcb-882c-49fa-af65-370bae1aeb11': 'The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.', '616cb18b-7157-47cd-8ff7-2815136bc36e': 'The right and left anterior cerebral arteries join together to form an anastomosis called the anterior communicating artery. The initial segments of the anterior cerebral arteries and the anterior communicating artery form the anterior portion of the arterial circle. The posterior portion of the arterial circle is formed by a left and a right posterior communicating artery that branches from the posterior cerebral artery, which arises from the basilar artery. It provides blood to the posterior portion of the cerebrum and brain stem. The basilar artery is an anastomosis that begins at the junction of the two vertebral arteries and sends branches to the cerebellum and brain stem. It flows into the posterior cerebral arteries. Table 20.6 summarizes the aortic arch branches, including the major branches supplying the brain.'}"
+Figure 20.5.5,Anatomy_And_Physio/images/Figure 20.5.5.jpg,"Figure 20.5.5 – Arteries Supplying the Head and Neck: The common carotid artery gives rise to the external and internal carotid arteries. The external carotid artery remains superficial and gives rise to many arteries of the head. The internal carotid artery first forms the carotid sinus and then reaches the brain via the carotid canal and carotid foramen, emerging into the cranium via the foramen lacerum. The vertebral artery branches from the subclavian artery and passes through the transverse foramen in the cervical vertebrae, entering the base of the skull at the vertebral foramen. The subclavian artery continues toward the arm as the axillary artery.","The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.","{'71540d30-3c6a-4b2d-b58f-063abf28b254': 'There are three major branches of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian (literally “under the clavicle”) artery. As you would expect based upon proximity to the heart, each of these vessels is classified as an elastic artery.', '74ca4cd9-836b-42e1-b99b-0bed8dcc002e': 'The brachiocephalic artery is located only on the right side of the body; there is no corresponding artery on the left. The brachiocephalic artery branches into the right subclavian artery and the right common carotid artery. The left subclavian and left common carotid arteries arise independently from the aortic arch but otherwise follow a similar pattern and distribution to the corresponding arteries on the right side (see Figure 20.5.2).', '8d6502df-45e6-4e43-89f6-9be49024bcc5': 'Each subclavian artery supplies blood to the arms, chest, shoulders, back, and central nervous system. It then gives rise to three major branches: the internal thoracic artery, the vertebral artery, and the thyrocervical artery. The internal thoracic artery, or mammary artery, supplies blood to the thymus, the pericardium of the heart, and the anterior chest wall. The vertebral artery passes through the vertebral foramen in the cervical vertebrae and then through the foramen magnum into the cranial cavity to supply blood to the brain and spinal cord. The paired vertebral arteries join together to form the large basilar artery at the base of the medulla oblongata. This is an example of an anastomosis. The subclavian artery also gives rise to the thyrocervical artery that provides blood to the thyroid, the cervical region of the neck, and the upper back and shoulder.', 'f32f9637-71bb-4aab-abb0-d6e5ae1d11da': 'The common carotid artery divides into internal and external carotid arteries. The right common carotid artery arises from the brachiocephalic artery and the left common carotid artery arises directly from the aortic arch. The external carotid artery supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx. These branches include the lingual, facial, occipital, maxillary, and superficial temporal arteries. The internal carotid artery initially forms an expansion known as the carotid sinus, containing the carotid baroreceptors and chemoreceptors. Like their counterparts in the aortic sinuses, the information provided by these receptors is critical to maintaining cardiovascular homeostasis (see Figure 20.5.2).', 'b40b9f53-291f-47e3-adc0-2bc14a8c1c72': 'The internal carotid arteries along with the vertebral arteries are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. Recall that blood flow to the brain is remarkably constant, with approximately 20 percent of blood flow directed to this organ at any given time. When blood flow is interrupted, even for just a few seconds, a transient ischemic attack (TIA), or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. In some cases, the damage may be permanent. Loss of blood flow for longer periods, typically between 3 and 4 minutes, will likely produce irreversible brain damage or a stroke, also called a cerebrovascular accident (CVA). The locations of the arteries in the brain not only provide blood flow to the brain tissue but also prevent interruption in the flow of blood. Both the carotid and vertebral arteries branch once they enter the cranial cavity, and some of these branches form a structure known as the arterial circle (or circle of Willis), an anastomosis that is remarkably like a traffic circle that sends off branches (in this case, arterial branches to the brain). As a rule, branches to the anterior portion of the cerebrum are normally fed by the internal carotid arteries; the remainder of the brain receives blood flow from branches associated with the vertebral arteries.', 'fef21dcb-882c-49fa-af65-370bae1aeb11': 'The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.', '616cb18b-7157-47cd-8ff7-2815136bc36e': 'The right and left anterior cerebral arteries join together to form an anastomosis called the anterior communicating artery. The initial segments of the anterior cerebral arteries and the anterior communicating artery form the anterior portion of the arterial circle. The posterior portion of the arterial circle is formed by a left and a right posterior communicating artery that branches from the posterior cerebral artery, which arises from the basilar artery. It provides blood to the posterior portion of the cerebrum and brain stem. The basilar artery is an anastomosis that begins at the junction of the two vertebral arteries and sends branches to the cerebellum and brain stem. It flows into the posterior cerebral arteries. Table 20.6 summarizes the aortic arch branches, including the major branches supplying the brain.'}"
+Figure 20.5.7,Anatomy_And_Physio/images/Figure 20.5.7.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.,"The thoracic aorta begins at the level of vertebra T5 and continues through to the diaphragm at the level of T12, initially traveling within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are collectively referred to as visceral branches and parietal branches (Figure 20.5.7). Those branches that supply blood primarily to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. Each bronchial artery (typically two on the left and one on the right) supplies systemic blood to the lungs and visceral pleura, in addition to the blood pumped to the lungs for oxygenation via the pulmonary circuit. The bronchial arteries follow the same path as the respiratory branches, beginning with the bronchi and ending with the bronchioles. There is considerable, but not total, intermingling of the systemic and pulmonary blood at anastomoses in the smaller branches of the lungs. This may sound incongruous—that is, the mixing of systemic arterial blood high in oxygen with the pulmonary arterial blood lower in oxygen—but the systemic vessels also deliver nutrients to the lung tissue just as they do elsewhere in the body. The mixed blood drains into typical pulmonary veins, whereas the bronchial artery branches remain separate and drain into bronchial veins described later. Each pericardial artery supplies blood to the pericardium, the esophageal artery provides blood to the esophagus, and the mediastinal artery provides blood to the mediastinum. The remaining thoracic aorta branches are collectively referred to as parietal branches or somatic branches, and include the intercostal and superior phrenic arteries. Each intercostal artery provides blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery provides blood to the superior surface of the diaphragm. Table 20.7 lists the arteries of the thoracic region.","{'f0e8e9c1-adb9-43a6-9541-cb3dbcf71427': 'The thoracic aorta begins at the level of vertebra T5 and continues through to the diaphragm at the level of T12, initially traveling within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are collectively referred to as visceral branches and parietal branches (Figure 20.5.7). Those branches that supply blood primarily to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. Each bronchial artery (typically two on the left and one on the right) supplies systemic blood to the lungs and visceral pleura, in addition to the blood pumped to the lungs for oxygenation via the pulmonary circuit. The bronchial arteries follow the same path as the respiratory branches, beginning with the bronchi and ending with the bronchioles. There is considerable, but not total, intermingling of the systemic and pulmonary blood at anastomoses in the smaller branches of the lungs. This may sound incongruous—that is, the mixing of systemic arterial blood high in oxygen with the pulmonary arterial blood lower in oxygen—but the systemic vessels also deliver nutrients to the lung tissue just as they do elsewhere in the body. The mixed blood drains into typical pulmonary veins, whereas the bronchial artery branches remain separate and drain into bronchial veins described later. Each pericardial artery supplies blood to the pericardium, the esophageal artery provides blood to the esophagus, and the mediastinal artery provides blood to the mediastinum. The remaining thoracic aorta branches are collectively referred to as parietal branches or somatic branches, and include the intercostal and superior phrenic arteries. Each intercostal artery provides blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery provides blood to the superior surface of the diaphragm. Table 20.7 lists the arteries of the thoracic region.', 'c2f0e198-a2ab-47dd-9fe6-48303185de99': 'After crossing through the diaphragm at the aortic hiatus, the thoracic aorta is called the abdominal aorta (see Figure 20.5.7). This vessel remains to the left of the vertebral column and is embedded in adipose tissue behind the peritoneal cavity. It formally ends at approximately the level of vertebra L4, where it bifurcates to form the common iliac arteries. Before this division, the abdominal aorta gives rise to several important branches. A single celiac trunk (artery) emerges and divides into the left gastric artery to supply blood to the stomach and esophagus, the splenic artery to supply blood to the spleen, and the common hepatic artery, which in turn gives rise to the hepatic artery proper to supply blood to the liver, the right gastric artery to supply blood to the stomach, the cystic artery to supply blood to the gall bladder, and several branches, one to supply blood to the duodenum and another to supply blood to the pancreas. Two additional single vessels arise from the abdominal aorta. These are the superior and inferior mesenteric arteries. The superior mesenteric artery arises approximately 2.5 cm after the celiac trunk and branches into several major vessels that supply blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine. The inferior mesenteric artery supplies blood to the distal segment of the large intestine, including the rectum. It arises approximately 5 cm superior to the common iliac arteries.', '50f418cc-fa11-4d05-8a30-4eeb58b5c90b': 'In addition to these single branches, the abdominal aorta gives rise to several significant paired arteries along the way. These include the inferior phrenic arteries, the adrenal arteries, the renal arteries, the gonadal arteries, and the lumbar arteries. Each inferior phrenic artery is a counterpart of a superior phrenic artery and supplies blood to the inferior surface of the diaphragm. The adrenal artery supplies blood to the adrenal (suprarenal) glands and arises near the superior mesenteric artery. Each renal artery branches approximately 2.5 cm inferior to the superior mesenteric arteries and supplies a kidney. The right renal artery is longer than the left since the aorta lies to the left of the vertebral column and the vessel must travel a greater distance to reach its target. Renal arteries branch repeatedly to supply blood to the kidneys. Each gonadal artery supplies blood to the gonads, or reproductive organs, and is also described as either an ovarian artery or a testicular artery (internal spermatic), depending upon the sex of the individual. An ovarian artery supplies blood to an ovary, uterine (Fallopian) tube, and the uterus, and is located within the suspensory ligament of the uterus. It is considerably shorter than a testicular artery, which ultimately travels outside the body cavity to the testes, forming one component of the spermatic cord. The gonadal arteries arise inferior to the renal arteries and are generally retroperitoneal. The ovarian artery continues to the uterus where it forms an anastomosis with the uterine artery that supplies blood to the uterus. Both the uterine arteries and vaginal arteries, which distribute blood to the vagina, are branches of the internal iliac artery. The four paired lumbar arteries are the counterparts of the intercostal arteries and supply blood to the lumbar region, the abdominal wall, and the spinal cord. In some instances, a fifth pair of lumbar arteries emerges from the median sacral artery.', '6a603ab0-c8e1-4ac7-86ff-5c536ebae134': 'The aorta divides at approximately the level of vertebra L4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries provide blood to the pelvic region and ultimately to the lower limbs. They split into external and internal iliac arteries approximately at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also provide blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs. Figure 20.5.8 shows the distribution of the major branches of the aorta into the thoracic and abdominal regions. Figure 20.5.9 shows the distribution of the major branches of the common iliac arteries. Table 20.8 summarizes the major branches of the abdominal aorta.'}"
+Figure 20.5.7,Anatomy_And_Physio/images/Figure 20.5.7.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.,"The thoracic aorta begins at the level of vertebra T5 and continues through to the diaphragm at the level of T12, initially traveling within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are collectively referred to as visceral branches and parietal branches (Figure 20.5.7). Those branches that supply blood primarily to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. Each bronchial artery (typically two on the left and one on the right) supplies systemic blood to the lungs and visceral pleura, in addition to the blood pumped to the lungs for oxygenation via the pulmonary circuit. The bronchial arteries follow the same path as the respiratory branches, beginning with the bronchi and ending with the bronchioles. There is considerable, but not total, intermingling of the systemic and pulmonary blood at anastomoses in the smaller branches of the lungs. This may sound incongruous—that is, the mixing of systemic arterial blood high in oxygen with the pulmonary arterial blood lower in oxygen—but the systemic vessels also deliver nutrients to the lung tissue just as they do elsewhere in the body. The mixed blood drains into typical pulmonary veins, whereas the bronchial artery branches remain separate and drain into bronchial veins described later. Each pericardial artery supplies blood to the pericardium, the esophageal artery provides blood to the esophagus, and the mediastinal artery provides blood to the mediastinum. The remaining thoracic aorta branches are collectively referred to as parietal branches or somatic branches, and include the intercostal and superior phrenic arteries. Each intercostal artery provides blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery provides blood to the superior surface of the diaphragm. Table 20.7 lists the arteries of the thoracic region.","{'f0e8e9c1-adb9-43a6-9541-cb3dbcf71427': 'The thoracic aorta begins at the level of vertebra T5 and continues through to the diaphragm at the level of T12, initially traveling within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are collectively referred to as visceral branches and parietal branches (Figure 20.5.7). Those branches that supply blood primarily to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. Each bronchial artery (typically two on the left and one on the right) supplies systemic blood to the lungs and visceral pleura, in addition to the blood pumped to the lungs for oxygenation via the pulmonary circuit. The bronchial arteries follow the same path as the respiratory branches, beginning with the bronchi and ending with the bronchioles. There is considerable, but not total, intermingling of the systemic and pulmonary blood at anastomoses in the smaller branches of the lungs. This may sound incongruous—that is, the mixing of systemic arterial blood high in oxygen with the pulmonary arterial blood lower in oxygen—but the systemic vessels also deliver nutrients to the lung tissue just as they do elsewhere in the body. The mixed blood drains into typical pulmonary veins, whereas the bronchial artery branches remain separate and drain into bronchial veins described later. Each pericardial artery supplies blood to the pericardium, the esophageal artery provides blood to the esophagus, and the mediastinal artery provides blood to the mediastinum. The remaining thoracic aorta branches are collectively referred to as parietal branches or somatic branches, and include the intercostal and superior phrenic arteries. Each intercostal artery provides blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery provides blood to the superior surface of the diaphragm. Table 20.7 lists the arteries of the thoracic region.', 'c2f0e198-a2ab-47dd-9fe6-48303185de99': 'After crossing through the diaphragm at the aortic hiatus, the thoracic aorta is called the abdominal aorta (see Figure 20.5.7). This vessel remains to the left of the vertebral column and is embedded in adipose tissue behind the peritoneal cavity. It formally ends at approximately the level of vertebra L4, where it bifurcates to form the common iliac arteries. Before this division, the abdominal aorta gives rise to several important branches. A single celiac trunk (artery) emerges and divides into the left gastric artery to supply blood to the stomach and esophagus, the splenic artery to supply blood to the spleen, and the common hepatic artery, which in turn gives rise to the hepatic artery proper to supply blood to the liver, the right gastric artery to supply blood to the stomach, the cystic artery to supply blood to the gall bladder, and several branches, one to supply blood to the duodenum and another to supply blood to the pancreas. Two additional single vessels arise from the abdominal aorta. These are the superior and inferior mesenteric arteries. The superior mesenteric artery arises approximately 2.5 cm after the celiac trunk and branches into several major vessels that supply blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine. The inferior mesenteric artery supplies blood to the distal segment of the large intestine, including the rectum. It arises approximately 5 cm superior to the common iliac arteries.', '50f418cc-fa11-4d05-8a30-4eeb58b5c90b': 'In addition to these single branches, the abdominal aorta gives rise to several significant paired arteries along the way. These include the inferior phrenic arteries, the adrenal arteries, the renal arteries, the gonadal arteries, and the lumbar arteries. Each inferior phrenic artery is a counterpart of a superior phrenic artery and supplies blood to the inferior surface of the diaphragm. The adrenal artery supplies blood to the adrenal (suprarenal) glands and arises near the superior mesenteric artery. Each renal artery branches approximately 2.5 cm inferior to the superior mesenteric arteries and supplies a kidney. The right renal artery is longer than the left since the aorta lies to the left of the vertebral column and the vessel must travel a greater distance to reach its target. Renal arteries branch repeatedly to supply blood to the kidneys. Each gonadal artery supplies blood to the gonads, or reproductive organs, and is also described as either an ovarian artery or a testicular artery (internal spermatic), depending upon the sex of the individual. An ovarian artery supplies blood to an ovary, uterine (Fallopian) tube, and the uterus, and is located within the suspensory ligament of the uterus. It is considerably shorter than a testicular artery, which ultimately travels outside the body cavity to the testes, forming one component of the spermatic cord. The gonadal arteries arise inferior to the renal arteries and are generally retroperitoneal. The ovarian artery continues to the uterus where it forms an anastomosis with the uterine artery that supplies blood to the uterus. Both the uterine arteries and vaginal arteries, which distribute blood to the vagina, are branches of the internal iliac artery. The four paired lumbar arteries are the counterparts of the intercostal arteries and supply blood to the lumbar region, the abdominal wall, and the spinal cord. In some instances, a fifth pair of lumbar arteries emerges from the median sacral artery.', '6a603ab0-c8e1-4ac7-86ff-5c536ebae134': 'The aorta divides at approximately the level of vertebra L4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries provide blood to the pelvic region and ultimately to the lower limbs. They split into external and internal iliac arteries approximately at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also provide blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs. Figure 20.5.8 shows the distribution of the major branches of the aorta into the thoracic and abdominal regions. Figure 20.5.9 shows the distribution of the major branches of the common iliac arteries. Table 20.8 summarizes the major branches of the abdominal aorta.'}"
+Figure 20.5.8,Anatomy_And_Physio/images/Figure 20.5.8.jpg,Figure 20.5.8 – Major Branches of the Aorta: The flow chart summarizes the distribution of the major branches of the aorta into the thoracic and abdominal regions.,"The aorta divides at approximately the level of vertebra L4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries provide blood to the pelvic region and ultimately to the lower limbs. They split into external and internal iliac arteries approximately at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also provide blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs. Figure 20.5.8 shows the distribution of the major branches of the aorta into the thoracic and abdominal regions. Figure 20.5.9 shows the distribution of the major branches of the common iliac arteries. Table 20.8 summarizes the major branches of the abdominal aorta.","{'c2f0e198-a2ab-47dd-9fe6-48303185de99': 'After crossing through the diaphragm at the aortic hiatus, the thoracic aorta is called the abdominal aorta (see Figure 20.5.7). This vessel remains to the left of the vertebral column and is embedded in adipose tissue behind the peritoneal cavity. It formally ends at approximately the level of vertebra L4, where it bifurcates to form the common iliac arteries. Before this division, the abdominal aorta gives rise to several important branches. A single celiac trunk (artery) emerges and divides into the left gastric artery to supply blood to the stomach and esophagus, the splenic artery to supply blood to the spleen, and the common hepatic artery, which in turn gives rise to the hepatic artery proper to supply blood to the liver, the right gastric artery to supply blood to the stomach, the cystic artery to supply blood to the gall bladder, and several branches, one to supply blood to the duodenum and another to supply blood to the pancreas. Two additional single vessels arise from the abdominal aorta. These are the superior and inferior mesenteric arteries. The superior mesenteric artery arises approximately 2.5 cm after the celiac trunk and branches into several major vessels that supply blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine. The inferior mesenteric artery supplies blood to the distal segment of the large intestine, including the rectum. It arises approximately 5 cm superior to the common iliac arteries.', '50f418cc-fa11-4d05-8a30-4eeb58b5c90b': 'In addition to these single branches, the abdominal aorta gives rise to several significant paired arteries along the way. These include the inferior phrenic arteries, the adrenal arteries, the renal arteries, the gonadal arteries, and the lumbar arteries. Each inferior phrenic artery is a counterpart of a superior phrenic artery and supplies blood to the inferior surface of the diaphragm. The adrenal artery supplies blood to the adrenal (suprarenal) glands and arises near the superior mesenteric artery. Each renal artery branches approximately 2.5 cm inferior to the superior mesenteric arteries and supplies a kidney. The right renal artery is longer than the left since the aorta lies to the left of the vertebral column and the vessel must travel a greater distance to reach its target. Renal arteries branch repeatedly to supply blood to the kidneys. Each gonadal artery supplies blood to the gonads, or reproductive organs, and is also described as either an ovarian artery or a testicular artery (internal spermatic), depending upon the sex of the individual. An ovarian artery supplies blood to an ovary, uterine (Fallopian) tube, and the uterus, and is located within the suspensory ligament of the uterus. It is considerably shorter than a testicular artery, which ultimately travels outside the body cavity to the testes, forming one component of the spermatic cord. The gonadal arteries arise inferior to the renal arteries and are generally retroperitoneal. The ovarian artery continues to the uterus where it forms an anastomosis with the uterine artery that supplies blood to the uterus. Both the uterine arteries and vaginal arteries, which distribute blood to the vagina, are branches of the internal iliac artery. The four paired lumbar arteries are the counterparts of the intercostal arteries and supply blood to the lumbar region, the abdominal wall, and the spinal cord. In some instances, a fifth pair of lumbar arteries emerges from the median sacral artery.', '6a603ab0-c8e1-4ac7-86ff-5c536ebae134': 'The aorta divides at approximately the level of vertebra L4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries provide blood to the pelvic region and ultimately to the lower limbs. They split into external and internal iliac arteries approximately at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also provide blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs. Figure 20.5.8 shows the distribution of the major branches of the aorta into the thoracic and abdominal regions. Figure 20.5.9 shows the distribution of the major branches of the common iliac arteries. Table 20.8 summarizes the major branches of the abdominal aorta.'}"
+Figure 20.5.10,Anatomy_And_Physio/images/Figure 20.5.10.jpg,Figure 20.5.10 – Major Arteries Serving the Thorax and Upper Limb: The arteries that supply blood to the arms and hands are extensions of the subclavian arteries.,"As the subclavian artery exits the thorax into the axillary region, it is renamed the axillary artery. Although it does branch and supply blood to the region near the head of the humerus (via the humeral circumflex arteries), the majority of the vessel continues into the upper arm, or brachium, and becomes the brachial artery (Figure 20.5.10). The brachial artery supplies blood to much of the brachial region and divides at the elbow into several smaller branches, including the deep brachial arteries, which provide blood to the posterior surface of the arm, and the ulnar collateral arteries, which supply blood to the region of the elbow. As the brachial artery approaches the coronoid fossa, it bifurcates into the radial and ulnar arteries, which continue into the forearm, or antebrachium. The radial artery and ulnar artery parallel their namesake bones, giving off smaller branches until they reach the wrist, or carpal region. At this level, they fuse to form the superficial and deep palmar arches that supply blood to the hand, as well as the digital arteries that supply blood to the digits. Figure 20.5.11 shows the distribution of systemic arteries from the heart into the upper limb. Table 20.9 summarizes the arteries serving the upper limbs.","{'e04bc1b2-7aca-42c5-ba62-9f152c8e7a61': 'As the subclavian artery exits the thorax into the axillary region, it is renamed the axillary artery. Although it does branch and supply blood to the region near the head of the humerus (via the humeral circumflex arteries), the majority of the vessel continues into the upper arm, or brachium, and becomes the brachial artery (Figure 20.5.10). The brachial artery supplies blood to much of the brachial region and divides at the elbow into several smaller branches, including the deep brachial arteries, which provide blood to the posterior surface of the arm, and the ulnar collateral arteries, which supply blood to the region of the elbow. As the brachial artery approaches the coronoid fossa, it bifurcates into the radial and ulnar arteries, which continue into the forearm, or antebrachium. The radial artery and ulnar artery parallel their namesake bones, giving off smaller branches until they reach the wrist, or carpal region. At this level, they fuse to form the superficial and deep palmar arches that supply blood to the hand, as well as the digital arteries that supply blood to the digits. Figure 20.5.11 shows the distribution of systemic arteries from the heart into the upper limb. Table 20.9 summarizes the arteries serving the upper limbs.'}"
+Figure 20.5.12,Anatomy_And_Physio/images/Figure 20.5.12.jpg,Figure 20.5.12 – Major Arteries Serving the Lower Limb: Major arteries serving the lower limb are shown in anterior and posterior views.,"The external iliac artery exits the body cavity and enters the femoral region of the lower leg (Figure 20.5.12). As it passes through the body wall, it is renamed the femoral artery. It gives off several smaller branches as well as the lateral deep femoral artery that in turn gives rise to a lateral circumflex artery. These arteries supply blood to the deep muscles of the thigh as well as ventral and lateral regions of the integument. The femoral artery also gives rise to the genicular artery, which provides blood to the region of the knee. As the femoral artery passes posterior to the knee near the popliteal fossa, it is called the popliteal artery. The popliteal artery branches into the anterior and posterior tibial arteries.","{'a3471d74-cf23-437c-816e-2534a1be2a3b': 'The external iliac artery exits the body cavity and enters the femoral region of the lower leg (Figure 20.5.12). As it passes through the body wall, it is renamed the femoral artery. It gives off several smaller branches as well as the lateral deep femoral artery that in turn gives rise to a lateral circumflex artery. These arteries supply blood to the deep muscles of the thigh as well as ventral and lateral regions of the integument. The femoral artery also gives rise to the genicular artery, which provides blood to the region of the knee. As the femoral artery passes posterior to the knee near the popliteal fossa, it is called the popliteal artery. The popliteal artery branches into the anterior and posterior tibial arteries.', '2e3cdecf-aba9-4c3f-bbae-0a2ebf2d40d8': 'The anterior tibial artery is located between the tibia and fibula, and supplies blood to the muscles and integument of the anterior tibial region. Upon reaching the tarsal region, it becomes the dorsalis pedis artery, which branches repeatedly and provides blood to the tarsal and dorsal regions of the foot. The posterior tibial artery provides blood to the muscles and integument on the posterior surface of the tibial region. The fibular or peroneal artery branches from the posterior tibial artery. It bifurcates and becomes the medial plantar artery and lateral plantar artery, providing blood to the plantar surfaces. There is an anastomosis with the dorsalis pedis artery, and the medial and lateral plantar arteries form two arches called the dorsal arch (also called the arcuate arch) and the plantar arch, which provide blood to the remainder of the foot and toes. Figure 20.5.13 shows the distribution of the major systemic arteries in the lower limb. Table 20.10 summarizes the major systemic arteries discussed in the text.'}"
+Figure 20.5.13,Anatomy_And_Physio/images/Figure 20.5.13.jpg,Figure 20.5.13 – Systemic Arteries of the Lower Limb: The flow chart summarizes the distribution of the systemic arteries from the external iliac artery into the lower limb.,"The anterior tibial artery is located between the tibia and fibula, and supplies blood to the muscles and integument of the anterior tibial region. Upon reaching the tarsal region, it becomes the dorsalis pedis artery, which branches repeatedly and provides blood to the tarsal and dorsal regions of the foot. The posterior tibial artery provides blood to the muscles and integument on the posterior surface of the tibial region. The fibular or peroneal artery branches from the posterior tibial artery. It bifurcates and becomes the medial plantar artery and lateral plantar artery, providing blood to the plantar surfaces. There is an anastomosis with the dorsalis pedis artery, and the medial and lateral plantar arteries form two arches called the dorsal arch (also called the arcuate arch) and the plantar arch, which provide blood to the remainder of the foot and toes. Figure 20.5.13 shows the distribution of the major systemic arteries in the lower limb. Table 20.10 summarizes the major systemic arteries discussed in the text.","{'a3471d74-cf23-437c-816e-2534a1be2a3b': 'The external iliac artery exits the body cavity and enters the femoral region of the lower leg (Figure 20.5.12). As it passes through the body wall, it is renamed the femoral artery. It gives off several smaller branches as well as the lateral deep femoral artery that in turn gives rise to a lateral circumflex artery. These arteries supply blood to the deep muscles of the thigh as well as ventral and lateral regions of the integument. The femoral artery also gives rise to the genicular artery, which provides blood to the region of the knee. As the femoral artery passes posterior to the knee near the popliteal fossa, it is called the popliteal artery. The popliteal artery branches into the anterior and posterior tibial arteries.', '2e3cdecf-aba9-4c3f-bbae-0a2ebf2d40d8': 'The anterior tibial artery is located between the tibia and fibula, and supplies blood to the muscles and integument of the anterior tibial region. Upon reaching the tarsal region, it becomes the dorsalis pedis artery, which branches repeatedly and provides blood to the tarsal and dorsal regions of the foot. The posterior tibial artery provides blood to the muscles and integument on the posterior surface of the tibial region. The fibular or peroneal artery branches from the posterior tibial artery. It bifurcates and becomes the medial plantar artery and lateral plantar artery, providing blood to the plantar surfaces. There is an anastomosis with the dorsalis pedis artery, and the medial and lateral plantar arteries form two arches called the dorsal arch (also called the arcuate arch) and the plantar arch, which provide blood to the remainder of the foot and toes. Figure 20.5.13 shows the distribution of the major systemic arteries in the lower limb. Table 20.10 summarizes the major systemic arteries discussed in the text.'}"
+Figure 20.5.14,Anatomy_And_Physio/images/Figure 20.5.14.jpg,Figure 20.5.14 – Major Systemic Veins of the Body: The major systemic veins of the body are shown here in an anterior view.,"The “Voyage of Discovery” analogy and stick drawings mentioned earlier remain valid techniques for the study of systemic veins, but veins present a more difficult challenge because there are numerous anastomoses and multiple branches. It is like following a river with many tributaries and channels, several of which interconnect. Tracing blood flow through arteries follows the current in the direction of blood flow, so that we move from the heart through the large arteries and into the smaller arteries to the capillaries. From the capillaries, we move into the smallest veins and follow the direction of blood flow into larger veins and back to the heart. Figure 20.5.14 outlines the path of the major systemic veins.","{'86d62c3e-1bf0-44cd-b4be-206e28c51439': 'Systemic veins return blood to the right atrium. Since the blood has already passed through the systemic capillaries, it will be relatively low in oxygen concentration. In many cases, there will be veins draining organs and regions of the body with the same name as the arteries that supplied these regions and the two often parallel one another. This is often described as a “complementary” pattern. However, there is a great deal more variability in the venous circulation than normally occurs in the arteries. For the sake of brevity and clarity, this text will discuss only the most commonly encountered patterns. However, keep this variation in mind when you move from the classroom to clinical practice.', '2d325877-0ae8-4695-a328-5e433d2ccdbb': 'In both the neck and limb regions, there are often both superficial and deeper levels of veins. The deeper veins generally correspond to the complementary arteries. The superficial veins do not normally have direct arterial counterparts, but in addition to returning blood, they also make contributions to the maintenance of body temperature. When the ambient temperature is warm, more blood is diverted to the superficial veins where heat can be more easily dissipated to the environment. In colder weather, there is more constriction of the superficial veins and blood is diverted deeper where the body can retain more of the heat.', '9a3887eb-290e-4190-9e4e-e1842cd54c66': 'The “Voyage of Discovery” analogy and stick drawings mentioned earlier remain valid techniques for the study of systemic veins, but veins present a more difficult challenge because there are numerous anastomoses and multiple branches. It is like following a river with many tributaries and channels, several of which interconnect. Tracing blood flow through arteries follows the current in the direction of blood flow, so that we move from the heart through the large arteries and into the smaller arteries to the capillaries. From the capillaries, we move into the smallest veins and follow the direction of blood flow into larger veins and back to the heart. Figure 20.5.14 outlines the path of the major systemic veins.', '98cfaca8-b747-4c2e-80f1-e98aab13c761': 'The right atrium receives all of the systemic venous return. Most of the blood flows into either the superior vena cava or inferior vena cava. If you draw an imaginary line at the level of the diaphragm, systemic venous circulation from above that line will generally flow into the superior vena cava; this includes blood from the head, neck, chest, shoulders, and upper limbs. The exception to this is that most venous blood flow from the coronary veins flows directly into the coronary sinus and from there directly into the right atrium. Beneath the diaphragm, systemic venous flow enters the inferior vena cava, that is, blood from the abdominal and pelvic regions and the lower limbs.'}"
+Figure 20.5.15,Anatomy_And_Physio/images/Figure 20.5.15.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava.","The superior vena cava drains most of the body superior to the diaphragm (Figure 20.5.15). On both the left and right sides, the subclavian vein forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein. Each vertebral vein also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein, also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.","{'2b8d552c-9209-45d9-bb04-4da5b0d8a7dc': 'The superior vena cava drains most of the body superior to the diaphragm (Figure 20.5.15). On both the left and right sides, the subclavian vein forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein. Each vertebral vein also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein, also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.', '48706185-8c5e-458e-bbc6-a0a3775c81db': 'The remainder of the blood supply from the thorax drains into the azygos vein. Each intercostal vein drains muscles of the thoracic wall, each esophageal vein delivers blood from the inferior portions of the esophagus, each bronchial vein drains the systemic circulation from the lungs, and several smaller veins drain the mediastinal region. Bronchial veins carry approximately 13 percent of the blood that flows into the bronchial arteries; the remainder intermingles with the pulmonary circulation and returns to the heart via the pulmonary veins. These veins flow into the azygos vein, and with the smaller hemiazygos vein (hemi- = “half”) on the left of the vertebral column, drain blood from the thoracic region. The hemiazygos vein does not drain directly into the superior vena cava but enters the brachiocephalic vein via the superior intercostal vein.', 'bdc8105a-9b90-46d7-b230-588e57d3517b': 'The azygos vein passes through the diaphragm from the thoracic cavity on the right side of the vertebral column and begins in the lumbar region of the thoracic cavity. It flows into the superior vena cava at approximately the level of T2, making a significant contribution to the flow of blood. It combines with the two large left and right brachiocephalic veins to form the superior vena cava.', 'ea060d2b-bf29-4292-bf05-8a94357de234': 'Table 20.11 summarizes the veins of the thoracic region that flow into the superior vena cava.', '35dc9b32-4dbc-4a68-8578-d3558ed6e087': 'Other than the small amount of blood drained by the azygos and hemiazygos veins, most of the blood inferior to the diaphragm drains into the inferior vena cava before it is returned to the heart (see Figure 20.5.15). Lying just beneath the parietal peritoneum in the abdominal cavity, the inferior vena cava parallels the abdominal aorta, where it can receive blood from abdominal veins. The lumbar portions of the abdominal wall and spinal cord are drained by a series of lumbar veins, usually four on each side. The ascending lumbar veins drain into either the azygos vein on the right or the hemiazygos vein on the left, and return to the superior vena cava. The remaining lumbar veins drain directly into the inferior vena cava.', 'e53da91e-ee4e-4815-84d9-dbbeaccb7bd8': 'Blood supply from the kidneys flows into each renal vein, normally the largest veins entering the inferior vena cava. A number of other, smaller veins empty into the left renal vein. Each adrenal vein drains the adrenal or suprarenal glands located immediately superior to the kidneys. The right adrenal vein enters the inferior vena cava directly, whereas the left adrenal vein enters the left renal vein.', '2fed4871-1f8b-44b8-aa95-8ceea7f770b0': 'From the male reproductive organs, each testicular vein flows from the scrotum, forming a portion of the spermatic cord. Each ovarian vein drains an ovary in females. Each of these veins is generically called a gonadal vein. The right gonadal vein empties directly into the inferior vena cava, and the left gonadal vein empties into the left renal vein.', '688999fc-9efe-4dd1-a9c8-69d93c4db91f': 'Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation. Figure 20.5.19 provides a flow chart of the veins flowing into the inferior vena cava. Table 20.15 summarizes the major veins of the abdominal region.'}"
+Figure 20.5.16,Anatomy_And_Physio/images/Figure 20.5.16.jpg,"Figure 20.5.16 – Veins of the Head and Neck: This left lateral view shows the veins of the head and neck, including the intercranial sinuses.","Blood from the brain and the superficial facial vein flow into each internal jugular vein (Figure 20.5.16). Blood from the more superficial portions of the head, scalp, and cranial regions, including the temporal vein and maxillary vein, flow into each external jugular vein. Although the external and internal jugular veins are separate vessels, there are anastomoses between them close to the thoracic region. Blood from the external jugular vein empties into the subclavian vein. Table 20.12 summarizes the major veins of the head and neck.","{'ad88eef5-4cfb-4ef5-be05-4422bc011739': 'Blood from the brain and the superficial facial vein flow into each internal jugular vein (Figure 20.5.16). Blood from the more superficial portions of the head, scalp, and cranial regions, including the temporal vein and maxillary vein, flow into each external jugular vein. Although the external and internal jugular veins are separate vessels, there are anastomoses between them close to the thoracic region. Blood from the external jugular vein empties into the subclavian vein. Table 20.12 summarizes the major veins of the head and neck.'}"
+Figure 20.5.17,Anatomy_And_Physio/images/Figure 20.5.17.jpg,Figure 20.5.17 – Veins of the Upper Limb: This anterior view shows the veins that drain the upper limb.,"The digital veins in the fingers come together in the hand to form the palmar venous arches (Figure 20.5.17). From here, the veins come together to form the radial vein, the ulnar vein, and the median antebrachial vein. The radial vein and the ulnar vein parallel the bones of the forearm and join together at the antebrachium to form the brachial vein, a deep vein that flows into the axillary vein in the brachium.","{'ee669d45-2e21-4189-91ce-5bcee5408ee6': 'The digital veins in the fingers come together in the hand to form the palmar venous arches (Figure 20.5.17). From here, the veins come together to form the radial vein, the ulnar vein, and the median antebrachial vein. The radial vein and the ulnar vein parallel the bones of the forearm and join together at the antebrachium to form the brachial vein, a deep vein that flows into the axillary vein in the brachium.', 'a3d8f78e-63a4-4636-8acd-0f3b5bcef490': 'The median antebrachial vein parallels the ulnar vein, is more medial in location, and joins the basilic vein in the forearm. As the basilic vein reaches the antecubital region, it gives off a branch called the median cubital vein that crosses at an angle to join the cephalic vein. The median cubital vein is the most common site for drawing venous blood in humans. The basilic vein continues through the arm medially and superficially to the axillary vein.', '386e2e76-7839-4145-8d06-18829bcc1396': 'The cephalic vein begins in the antebrachium and drains blood from the superficial surface of the arm into the axillary vein. It is extremely superficial and easily seen along the surface of the biceps brachii muscle in individuals with good muscle tone and in those without excessive subcutaneous adipose tissue in the arms.', '52b81a42-97e3-4e39-ac70-b3f42c87a9dd': 'The subscapular vein drains blood from the subscapular region and joins the cephalic vein to form the axillary vein. As it passes through the body wall and enters the thorax, the axillary vein becomes the subclavian vein.', '42fba2cc-1059-4672-8ef5-8015b84641da': 'Many of the larger veins of the thoracic and abdominal region and upper limb are further represented in the flow chart in Figure 20.5.18. Table 20.14 summarizes the veins of the upper limbs.'}"
+Figure 20.5.18,Anatomy_And_Physio/images/Figure 20.5.18.jpg,Figure 20.5.18 – Veins Flowing into the Superior Vena Cava: The flow chart summarizes the distribution of the veins flowing into the superior vena cava.,Many of the larger veins of the thoracic and abdominal region and upper limb are further represented in the flow chart in Figure 20.5.18. Table 20.14 summarizes the veins of the upper limbs.,"{'ee669d45-2e21-4189-91ce-5bcee5408ee6': 'The digital veins in the fingers come together in the hand to form the palmar venous arches (Figure 20.5.17). From here, the veins come together to form the radial vein, the ulnar vein, and the median antebrachial vein. The radial vein and the ulnar vein parallel the bones of the forearm and join together at the antebrachium to form the brachial vein, a deep vein that flows into the axillary vein in the brachium.', 'a3d8f78e-63a4-4636-8acd-0f3b5bcef490': 'The median antebrachial vein parallels the ulnar vein, is more medial in location, and joins the basilic vein in the forearm. As the basilic vein reaches the antecubital region, it gives off a branch called the median cubital vein that crosses at an angle to join the cephalic vein. The median cubital vein is the most common site for drawing venous blood in humans. The basilic vein continues through the arm medially and superficially to the axillary vein.', '386e2e76-7839-4145-8d06-18829bcc1396': 'The cephalic vein begins in the antebrachium and drains blood from the superficial surface of the arm into the axillary vein. It is extremely superficial and easily seen along the surface of the biceps brachii muscle in individuals with good muscle tone and in those without excessive subcutaneous adipose tissue in the arms.', '52b81a42-97e3-4e39-ac70-b3f42c87a9dd': 'The subscapular vein drains blood from the subscapular region and joins the cephalic vein to form the axillary vein. As it passes through the body wall and enters the thorax, the axillary vein becomes the subclavian vein.', '42fba2cc-1059-4672-8ef5-8015b84641da': 'Many of the larger veins of the thoracic and abdominal region and upper limb are further represented in the flow chart in Figure 20.5.18. Table 20.14 summarizes the veins of the upper limbs.'}"
+Figure 20.5.15,Anatomy_And_Physio/images/Figure 20.5.15.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava.","The superior vena cava drains most of the body superior to the diaphragm (Figure 20.5.15). On both the left and right sides, the subclavian vein forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein. Each vertebral vein also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein, also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.","{'2b8d552c-9209-45d9-bb04-4da5b0d8a7dc': 'The superior vena cava drains most of the body superior to the diaphragm (Figure 20.5.15). On both the left and right sides, the subclavian vein forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein. Each vertebral vein also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein, also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.', '48706185-8c5e-458e-bbc6-a0a3775c81db': 'The remainder of the blood supply from the thorax drains into the azygos vein. Each intercostal vein drains muscles of the thoracic wall, each esophageal vein delivers blood from the inferior portions of the esophagus, each bronchial vein drains the systemic circulation from the lungs, and several smaller veins drain the mediastinal region. Bronchial veins carry approximately 13 percent of the blood that flows into the bronchial arteries; the remainder intermingles with the pulmonary circulation and returns to the heart via the pulmonary veins. These veins flow into the azygos vein, and with the smaller hemiazygos vein (hemi- = “half”) on the left of the vertebral column, drain blood from the thoracic region. The hemiazygos vein does not drain directly into the superior vena cava but enters the brachiocephalic vein via the superior intercostal vein.', 'bdc8105a-9b90-46d7-b230-588e57d3517b': 'The azygos vein passes through the diaphragm from the thoracic cavity on the right side of the vertebral column and begins in the lumbar region of the thoracic cavity. It flows into the superior vena cava at approximately the level of T2, making a significant contribution to the flow of blood. It combines with the two large left and right brachiocephalic veins to form the superior vena cava.', 'ea060d2b-bf29-4292-bf05-8a94357de234': 'Table 20.11 summarizes the veins of the thoracic region that flow into the superior vena cava.', '35dc9b32-4dbc-4a68-8578-d3558ed6e087': 'Other than the small amount of blood drained by the azygos and hemiazygos veins, most of the blood inferior to the diaphragm drains into the inferior vena cava before it is returned to the heart (see Figure 20.5.15). Lying just beneath the parietal peritoneum in the abdominal cavity, the inferior vena cava parallels the abdominal aorta, where it can receive blood from abdominal veins. The lumbar portions of the abdominal wall and spinal cord are drained by a series of lumbar veins, usually four on each side. The ascending lumbar veins drain into either the azygos vein on the right or the hemiazygos vein on the left, and return to the superior vena cava. The remaining lumbar veins drain directly into the inferior vena cava.', 'e53da91e-ee4e-4815-84d9-dbbeaccb7bd8': 'Blood supply from the kidneys flows into each renal vein, normally the largest veins entering the inferior vena cava. A number of other, smaller veins empty into the left renal vein. Each adrenal vein drains the adrenal or suprarenal glands located immediately superior to the kidneys. The right adrenal vein enters the inferior vena cava directly, whereas the left adrenal vein enters the left renal vein.', '2fed4871-1f8b-44b8-aa95-8ceea7f770b0': 'From the male reproductive organs, each testicular vein flows from the scrotum, forming a portion of the spermatic cord. Each ovarian vein drains an ovary in females. Each of these veins is generically called a gonadal vein. The right gonadal vein empties directly into the inferior vena cava, and the left gonadal vein empties into the left renal vein.', '688999fc-9efe-4dd1-a9c8-69d93c4db91f': 'Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation. Figure 20.5.19 provides a flow chart of the veins flowing into the inferior vena cava. Table 20.15 summarizes the major veins of the abdominal region.'}"
+Figure 20.5.19,Anatomy_And_Physio/images/Figure 20.5.19.jpg,Figure 20.5.19 – Venous Flow into Inferior Vena Cava: The flow chart summarizes veins that deliver blood to the inferior vena cava.,"Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation. Figure 20.5.19 provides a flow chart of the veins flowing into the inferior vena cava. Table 20.15 summarizes the major veins of the abdominal region.","{'35dc9b32-4dbc-4a68-8578-d3558ed6e087': 'Other than the small amount of blood drained by the azygos and hemiazygos veins, most of the blood inferior to the diaphragm drains into the inferior vena cava before it is returned to the heart (see Figure 20.5.15). Lying just beneath the parietal peritoneum in the abdominal cavity, the inferior vena cava parallels the abdominal aorta, where it can receive blood from abdominal veins. The lumbar portions of the abdominal wall and spinal cord are drained by a series of lumbar veins, usually four on each side. The ascending lumbar veins drain into either the azygos vein on the right or the hemiazygos vein on the left, and return to the superior vena cava. The remaining lumbar veins drain directly into the inferior vena cava.', 'e53da91e-ee4e-4815-84d9-dbbeaccb7bd8': 'Blood supply from the kidneys flows into each renal vein, normally the largest veins entering the inferior vena cava. A number of other, smaller veins empty into the left renal vein. Each adrenal vein drains the adrenal or suprarenal glands located immediately superior to the kidneys. The right adrenal vein enters the inferior vena cava directly, whereas the left adrenal vein enters the left renal vein.', '2fed4871-1f8b-44b8-aa95-8ceea7f770b0': 'From the male reproductive organs, each testicular vein flows from the scrotum, forming a portion of the spermatic cord. Each ovarian vein drains an ovary in females. Each of these veins is generically called a gonadal vein. The right gonadal vein empties directly into the inferior vena cava, and the left gonadal vein empties into the left renal vein.', '688999fc-9efe-4dd1-a9c8-69d93c4db91f': 'Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation. Figure 20.5.19 provides a flow chart of the veins flowing into the inferior vena cava. Table 20.15 summarizes the major veins of the abdominal region.'}"
+Figure 20.5.20,Anatomy_And_Physio/images/Figure 20.5.20.jpg,Figure 20.5.20 – Major Veins Serving the Lower Limbs: Anterior and posterior views show the major veins that drain the lower limb into the inferior vena cava.,"The superior surface of the foot drains into the digital veins, and the inferior surface drains into the plantar veins, which flow into a complex series of anastomoses in the feet and ankles, including the dorsal venous arch and the plantar venous arch (Figure 20.5.20). From the dorsal venous arch, blood supply drains into the anterior and posterior tibial veins. The anterior tibial vein drains the area near the tibialis anterior muscle and combines with the posterior tibial vein and the fibular vein to form the popliteal vein. The posterior tibial vein drains the posterior surface of the tibia and joins the popliteal vein. The fibular vein drains the muscles and integument in proximity to the fibula and also joins the popliteal vein. The small saphenous vein located on the lateral surface of the leg drains blood from the superficial regions of the lower leg and foot, and flows into to the popliteal vein. As the popliteal vein passes behind the knee in the popliteal region, it becomes the femoral vein. It is palpable in patients without excessive adipose tissue.","{'78b92780-d75a-4089-8054-eaae96134dfc': 'The superior surface of the foot drains into the digital veins, and the inferior surface drains into the plantar veins, which flow into a complex series of anastomoses in the feet and ankles, including the dorsal venous arch and the plantar venous arch (Figure 20.5.20). From the dorsal venous arch, blood supply drains into the anterior and posterior tibial veins. The anterior tibial vein drains the area near the tibialis anterior muscle and combines with the posterior tibial vein and the fibular vein to form the popliteal vein. The posterior tibial vein drains the posterior surface of the tibia and joins the popliteal vein. The fibular vein drains the muscles and integument in proximity to the fibula and also joins the popliteal vein. The small saphenous vein located on the lateral surface of the leg drains blood from the superficial regions of the lower leg and foot, and flows into to the popliteal vein. As the popliteal vein passes behind the knee in the popliteal region, it becomes the femoral vein. It is palpable in patients without excessive adipose tissue.', '502ed3d6-01c1-4507-9163-a378b3f060cd': 'Close to the body wall, the great saphenous vein, the deep femoral vein, and the femoral circumflex vein drain into the femoral vein. The great saphenous vein is a prominent surface vessel located on the medial surface of the leg and thigh that collects blood from the superficial portions of these areas. The deep femoral vein, as the name suggests, drains blood from the deeper portions of the thigh. The femoral circumflex vein forms a loop around the femur just inferior to the trochanters and drains blood from the areas in proximity to the head and neck of the femur.', '74cf82bc-891a-4751-990c-fb7c69619182': 'As the femoral vein penetrates the body wall from the femoral portion of the upper limb, it becomes the external iliac vein, a large vein that drains blood from the leg to the common iliac vein. The pelvic organs and integument drain into the internal iliac vein, which forms from several smaller veins in the region, including the umbilical veins that run on either side of the bladder. The external and internal iliac veins combine near the inferior portion of the sacroiliac joint to form the common iliac vein. In addition to blood supply from the external and internal iliac veins, the middle sacral vein drains the sacral region into the common iliac vein. Similar to the common iliac arteries, the common iliac veins come together at the level of L5 to form the inferior vena cava.', 'c8a385e1-af91-4456-9228-eb8e8f9b3cfa': 'Figure 20.5.21 is a flow chart of veins flowing into the lower limb. Table 20.16 summarizes the major veins of the lower limbs.'}"
+Figure 20.5.21,Anatomy_And_Physio/images/Figure 20.5.21.jpg,Figure 20.5.21 – Major Veins of the Lower Limb: The flow chart summarizes venous flow from the lower limb.,Figure 20.5.21 is a flow chart of veins flowing into the lower limb. Table 20.16 summarizes the major veins of the lower limbs.,"{'78b92780-d75a-4089-8054-eaae96134dfc': 'The superior surface of the foot drains into the digital veins, and the inferior surface drains into the plantar veins, which flow into a complex series of anastomoses in the feet and ankles, including the dorsal venous arch and the plantar venous arch (Figure 20.5.20). From the dorsal venous arch, blood supply drains into the anterior and posterior tibial veins. The anterior tibial vein drains the area near the tibialis anterior muscle and combines with the posterior tibial vein and the fibular vein to form the popliteal vein. The posterior tibial vein drains the posterior surface of the tibia and joins the popliteal vein. The fibular vein drains the muscles and integument in proximity to the fibula and also joins the popliteal vein. The small saphenous vein located on the lateral surface of the leg drains blood from the superficial regions of the lower leg and foot, and flows into to the popliteal vein. As the popliteal vein passes behind the knee in the popliteal region, it becomes the femoral vein. It is palpable in patients without excessive adipose tissue.', '502ed3d6-01c1-4507-9163-a378b3f060cd': 'Close to the body wall, the great saphenous vein, the deep femoral vein, and the femoral circumflex vein drain into the femoral vein. The great saphenous vein is a prominent surface vessel located on the medial surface of the leg and thigh that collects blood from the superficial portions of these areas. The deep femoral vein, as the name suggests, drains blood from the deeper portions of the thigh. The femoral circumflex vein forms a loop around the femur just inferior to the trochanters and drains blood from the areas in proximity to the head and neck of the femur.', '74cf82bc-891a-4751-990c-fb7c69619182': 'As the femoral vein penetrates the body wall from the femoral portion of the upper limb, it becomes the external iliac vein, a large vein that drains blood from the leg to the common iliac vein. The pelvic organs and integument drain into the internal iliac vein, which forms from several smaller veins in the region, including the umbilical veins that run on either side of the bladder. The external and internal iliac veins combine near the inferior portion of the sacroiliac joint to form the common iliac vein. In addition to blood supply from the external and internal iliac veins, the middle sacral vein drains the sacral region into the common iliac vein. Similar to the common iliac arteries, the common iliac veins come together at the level of L5 to form the inferior vena cava.', 'c8a385e1-af91-4456-9228-eb8e8f9b3cfa': 'Figure 20.5.21 is a flow chart of veins flowing into the lower limb. Table 20.16 summarizes the major veins of the lower limbs.'}"
+Figure 20.5.22,Anatomy_And_Physio/images/Figure 20.5.22.jpg,"Figure 20.5.22 – Hepatic Portal System: The liver receives blood from the normal systemic circulation via the hepatic artery. It also receives and processes blood from other organs, delivered via the veins of the hepatic portal system. All blood exits the liver via the hepatic vein, which delivers the blood to the inferior vena cava. (Different colors are used to help distinguish among the different vessels in the system.)","The liver is a complex biochemical processing plant. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile; and disposes of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes (for example, materials produced by the spleen) travel to the liver for processing. They do so via the hepatic portal system (Figure 20.5.22). Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver, the hepatic sinusoids. You saw the only other portal system with the hypothalamic-hypophyseal portal vessel in the endocrine chapter.","{'40cba48e-e75f-4d53-8fcf-203d632c7969': 'The liver is a complex biochemical processing plant. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile; and disposes of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes (for example, materials produced by the spleen) travel to the liver for processing. They do so via the hepatic portal system (Figure 20.5.22). Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver, the hepatic sinusoids. You saw the only other portal system with the hypothalamic-hypophyseal portal vessel in the endocrine chapter.', 'd7d401ec-c4c1-4489-9953-33f11f419d0a': 'The hepatic portal system consists of the hepatic portal vein and the veins that drain into it. The hepatic portal vein itself is relatively short, beginning at the level of L2 with the confluence of the superior mesenteric and splenic veins. It also receives branches from the inferior mesenteric vein, plus the splenic veins and all their tributaries. The superior mesenteric vein receives blood from the small intestine, two-thirds of the large intestine, and the stomach. The inferior mesenteric vein drains the distal third of the large intestine, including the descending colon, the sigmoid colon, and the rectum. The splenic vein is formed from branches from the spleen, pancreas, and portions of the stomach, and the inferior mesenteric vein. After its formation, the hepatic portal vein also receives branches from the gastric veins of the stomach and cystic veins from the gall bladder. The hepatic portal vein delivers materials from these digestive and circulatory organs directly to the liver for processing.', 'dedec192-3bb1-4f7e-bb79-7055d494aaf8': 'Because of the hepatic portal system, the liver receives its blood supply from two different sources: from normal systemic circulation via the hepatic artery and from the hepatic portal vein. The liver processes the blood from the portal system to remove certain wastes and excess nutrients, which are stored for later use. This processed blood, as well as the systemic blood that came from the hepatic artery, exits the liver via the right, left, and middle hepatic veins, and flows into the inferior vena cava. Overall systemic blood composition remains relatively stable, since the liver is able to metabolize the absorbed digestive components.', 'a1363acb-e9a0-4c16-b215-9b2d3ab1a09f': 'In order to maintain homeostasis in the cardiovascular system and provide adequate blood to the tissues, blood flow must be redirected continually to the tissues as they become more active. In a very real sense, the cardiovascular system engages in resource allocation, because there is not enough blood flow to distribute blood equally to all tissues simultaneously. For example, when an individual is exercising, more blood will be directed to skeletal muscles, the heart, and the lungs. Following a meal, more blood is directed to the digestive system. Only the brain receives a more or less constant supply of blood whether you are active, resting, thinking, or engaged in any other activity.', 'a5f4ecea-3873-4733-88af-4cca948e97c8': 'Table 20.3 provides the distribution of systemic blood at rest and during exercise. Although most of the data appears logical, the values for the distribution of blood to the integument may seem surprising. During exercise, the body distributes more blood to the body surface where it can dissipate the excess heat generated by increased activity into the environment.', 'e398dc76-0027-472d-b5ec-79a6863bef15': 'Three homeostatic mechanisms ensure adequate blood flow, blood pressure, distribution, and ultimately perfusion: neural, endocrine, and autoregulatory mechanisms. They are summarized in Figure 20.4.1.'}"
+Figure 20.4.1,Anatomy_And_Physio/images/Figure 20.4.1.jpg,"Figure 20.4.1 – Summary of Factors Maintaining Vascular Homeostasis: Adequate blood flow, blood pressure, distribution, and perfusion involve autoregulatory, neural, and endocrine mechanisms.","Three homeostatic mechanisms ensure adequate blood flow, blood pressure, distribution, and ultimately perfusion: neural, endocrine, and autoregulatory mechanisms. They are summarized in Figure 20.4.1.","{'40cba48e-e75f-4d53-8fcf-203d632c7969': 'The liver is a complex biochemical processing plant. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile; and disposes of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes (for example, materials produced by the spleen) travel to the liver for processing. They do so via the hepatic portal system (Figure 20.5.22). Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver, the hepatic sinusoids. You saw the only other portal system with the hypothalamic-hypophyseal portal vessel in the endocrine chapter.', 'd7d401ec-c4c1-4489-9953-33f11f419d0a': 'The hepatic portal system consists of the hepatic portal vein and the veins that drain into it. The hepatic portal vein itself is relatively short, beginning at the level of L2 with the confluence of the superior mesenteric and splenic veins. It also receives branches from the inferior mesenteric vein, plus the splenic veins and all their tributaries. The superior mesenteric vein receives blood from the small intestine, two-thirds of the large intestine, and the stomach. The inferior mesenteric vein drains the distal third of the large intestine, including the descending colon, the sigmoid colon, and the rectum. The splenic vein is formed from branches from the spleen, pancreas, and portions of the stomach, and the inferior mesenteric vein. After its formation, the hepatic portal vein also receives branches from the gastric veins of the stomach and cystic veins from the gall bladder. The hepatic portal vein delivers materials from these digestive and circulatory organs directly to the liver for processing.', 'dedec192-3bb1-4f7e-bb79-7055d494aaf8': 'Because of the hepatic portal system, the liver receives its blood supply from two different sources: from normal systemic circulation via the hepatic artery and from the hepatic portal vein. The liver processes the blood from the portal system to remove certain wastes and excess nutrients, which are stored for later use. This processed blood, as well as the systemic blood that came from the hepatic artery, exits the liver via the right, left, and middle hepatic veins, and flows into the inferior vena cava. Overall systemic blood composition remains relatively stable, since the liver is able to metabolize the absorbed digestive components.', 'a1363acb-e9a0-4c16-b215-9b2d3ab1a09f': 'In order to maintain homeostasis in the cardiovascular system and provide adequate blood to the tissues, blood flow must be redirected continually to the tissues as they become more active. In a very real sense, the cardiovascular system engages in resource allocation, because there is not enough blood flow to distribute blood equally to all tissues simultaneously. For example, when an individual is exercising, more blood will be directed to skeletal muscles, the heart, and the lungs. Following a meal, more blood is directed to the digestive system. Only the brain receives a more or less constant supply of blood whether you are active, resting, thinking, or engaged in any other activity.', 'a5f4ecea-3873-4733-88af-4cca948e97c8': 'Table 20.3 provides the distribution of systemic blood at rest and during exercise. Although most of the data appears logical, the values for the distribution of blood to the integument may seem surprising. During exercise, the body distributes more blood to the body surface where it can dissipate the excess heat generated by increased activity into the environment.', 'e398dc76-0027-472d-b5ec-79a6863bef15': 'Three homeostatic mechanisms ensure adequate blood flow, blood pressure, distribution, and ultimately perfusion: neural, endocrine, and autoregulatory mechanisms. They are summarized in Figure 20.4.1.'}"
+Figure 20.4.4,Anatomy_And_Physio/images/Figure 20.4.4.jpg,Figure 20.4.4 Summary of Mechanisms Regulating Arteriole Smooth Muscle and Veins.,"Tissue perfusion also increases as the body transitions from a resting state to light exercise and eventually to heavy exercise (see Figure 20.4.4). These changes result in selective vasodilation in the skeletal muscles, heart, lungs, liver, and integument. Simultaneously, vasoconstriction occurs in the vessels leading to the kidneys and most of the digestive and reproductive organs. The flow of blood to the brain remains largely unchanged whether at rest or exercising, since the vessels in the brain largely do not respond to regulatory stimuli, in most cases, because they lack the appropriate receptors.","{'e78e346b-b7cd-4591-8700-5b6599749708': 'The heart is a muscle and, like any muscle, it responds dramatically to exercise. For a healthy young adult, cardiac output (heart rate × stroke volume) increases in the nonathlete from approximately 5.0 liters (5.25 quarts) per minute to a maximum of about 20 liters (21 quarts) per minute. Accompanying this will be an increase in blood pressure from about 120/80 to 185/75. However, well-trained aerobic athletes can increase these values substantially. For these individuals, cardiac output soars from approximately 5.3 liters (5.57 quarts) per minute resting to more than 30 liters (31.5 quarts) per minute during maximal exercise. Along with this increase in cardiac output, blood pressure increases from 120/80 at rest to 200/90 at maximum values.', '526a6c55-23f3-49c9-91d8-ffb6ef725dc1': 'In addition to improved cardiac function, exercise increases the size and mass of the heart. The average weight of the heart for the nonathlete is about 300 g, whereas in an athlete it will increase to 500 g. This increase in size generally makes the heart stronger and more efficient at pumping blood, increasing both stroke volume and cardiac output.', '53ecd47e-5dea-4285-aa6a-3b4b8a7c4a33': 'Tissue perfusion also increases as the body transitions from a resting state to light exercise and eventually to heavy exercise (see Figure 20.4.4). These changes result in selective vasodilation in the skeletal muscles, heart, lungs, liver, and integument. Simultaneously, vasoconstriction occurs in the vessels leading to the kidneys and most of the digestive and reproductive organs. The flow of blood to the brain remains largely unchanged whether at rest or exercising, since the vessels in the brain largely do not respond to regulatory stimuli, in most cases, because they lack the appropriate receptors.', '68dbe977-212f-4ef9-930e-a090f875fdc0': 'As vasodilation occurs in selected vessels, resistance drops and more blood rushes into the organs they supply. This blood eventually returns to the venous system. Venous return is further enhanced by both the skeletal muscle and respiratory pumps. As blood returns to the heart more quickly, preload rises and the Frank-Starling principle tells us that contraction of the cardiac muscle in the atria and ventricles will be more forceful. Eventually, even the best-trained athletes will fatigue and must undergo a period of rest following exercise. Cardiac output and distribution of blood then return to normal.', 'dc80fe33-7e8a-4b1c-8973-bbf77fb6a76e': 'Regular exercise promotes cardiovascular health in a variety of ways. Because an athlete’s heart is larger than a nonathlete’s, stroke volume increases, so the athletic heart can deliver the same amount of blood as the nonathletic heart but with a lower heart rate. This increased efficiency allows the athlete to exercise for longer periods of time before muscles fatigue and places less stress on the heart. Exercise also lowers overall cholesterol levels by removing from the circulation a complex form of cholesterol, triglycerides, and proteins known as low-density lipoproteins (LDLs), which are widely associated with increased risk of cardiovascular disease. Although there is no way to remove deposits of plaque from the walls of arteries other than specialized surgery, exercise does promote the health of vessels by decreasing the rate of plaque formation and reducing blood pressure, so the heart does not have to generate as much force to overcome resistance.', '22c7632f-19e9-4e98-9ec7-a57a2d11aa03': 'Generally as little as 30 minutes of noncontinuous exercise over the course of each day has beneficial effects and has been shown to lower the rate of heart attack by nearly 50 percent. While it is always advisable to follow a healthy diet, stop smoking, and lose weight, studies have clearly shown that fit, overweight people may actually be healthier overall than sedentary slender people. Thus, the benefits of moderate exercise are undeniable.'}"
+Figure 20.2.1,Anatomy_And_Physio/images/Figure 20.2.1.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures.",Arterial blood pressure in the larger vessels varies between systolic and diastolic pressures. Pulse pressure and mean arterial pressure are calculated values based upon the systolic and diastolic pressures (Figure 20.2.1).,"{'e07da81a-8522-4db3-8fb9-a8d75c2e3933': 'Arterial blood pressure in the larger vessels varies between systolic and diastolic pressures. Pulse pressure and mean arterial pressure are calculated values based upon the systolic and diastolic pressures (Figure 20.2.1).', '56188638-73ca-46c1-af42-55701e546ab5': 'Recall that blood moves from higher pressure to lower pressure. It is pumped from the heart into the arteries at high pressure. Since pressure in the veins is normally relatively low, for blood to flow back into the heart, the pressure in the atria during atrial diastole must be even lower. It normally approaches zero, except when the atria contract (see Figure 20.2.1).'}"
+Figure 20.2.2,Anatomy_And_Physio/images/Figure 20.2.2.jpg,"Figure 20.2.2 – Pulse Sites: The pulse is most readily measured at the radial artery, but can be measured at any of the pulse points shown.","Pulse can be palpated manually by lightly pressing the tips of the fingers across an artery that runs close to the body surface. While this procedure is normally performed using the radial artery in the wrist or the common carotid artery in the neck, any superficial artery that can be palpated may be used (Figure 20.2.2). Common sites to find a pulse include temporal and facial arteries in the head, brachial arteries in the upper arm, femoral arteries in the thigh, popliteal arteries behind the knees, posterior tibial arteries near the medial tarsal regions, and dorsalis pedis arteries in the feet. A variety of commercial electronic devices are also available to measure pulse.","{'bd91bc43-2cc0-4be1-9494-ce8709070bae': 'After blood is ejected from the heart, elastic fibers in the arteries help maintain a high-pressure gradient as they expand to accommodate the blood, then recoil to keep pressure on the blood. This expansion and recoiling effect, known as the pulse, can be palpated manually or measured electronically. Although the effect diminishes as the distance from the heart increases, elements of the systolic and diastolic components of the pulse are still evident down to the level of the arterioles.', 'f9b46739-1a9d-4291-a1da-2758614336e7': 'Because pulse indicates heart rate, it is measured clinically to provide clues to a patient’s state of health. It is recorded as beats per minute. Both the rate and the strength of the pulse are important clinically. A high or irregular pulse rate can be caused by physical activity or other temporary factors, but it may also indicate a heart condition. The pulse strength indicates the strength of ventricular contraction and cardiac output. If the pulse is strong, then systolic pressure is high. If it is weak, systolic pressure has fallen, and medical intervention may be warranted.', '5a8da6ce-883c-46bc-8246-5937f1cc5eb6': 'Pulse can be palpated manually by lightly pressing the tips of the fingers across an artery that runs close to the body surface. While this procedure is normally performed using the radial artery in the wrist or the common carotid artery in the neck, any superficial artery that can be palpated may be used (Figure 20.2.2). Common sites to find a pulse include temporal and facial arteries in the head, brachial arteries in the upper arm, femoral arteries in the thigh, popliteal arteries behind the knees, posterior tibial arteries near the medial tarsal regions, and dorsalis pedis arteries in the feet. A variety of commercial electronic devices are also available to measure pulse.'}"
+Figure 20.2.3,Anatomy_And_Physio/images/Figure 20.2.3.jpg,"Figure 20.2.3 – Blood Pressure Measurement: When pressure in a sphygmomanometer cuff is released, a clinician can hear the Korotkoff sounds. In this graph, a blood pressure tracing is aligned to a measurement of systolic and diastolic pressures.","Although there are five recognized Korotkoff sounds, only two are normally recorded. Initially, no sounds are heard since there is no blood flowing through the vessels, but as air pressure steadily drops, the cuff relaxes, and blood flow becomes pulsatile (turbulent) as it is pushed through the opening vessel.  As shown in Figure 20.2.3, the first sound heard through the stethoscope—the first Korotkoff sound—indicates systolic blood pressure. The clinician measuring the blood pressure will continue to hear tapping sounds for a time, but as more air is released from the cuff, the blood vessel lumen completely opens, and blood is eventually able to flow freely through the brachial artery. Once blood flows freely, all sounds disappear. The point at which the sound disappears is recorded as the patient’s diastolic pressure. Thus, the diastolic pressure is recorded when a clinician expects to hear another sound but does not.","{'a8f10f5e-db31-4c65-9e67-446a23def46b': 'Blood pressure is one of the critical parameters measured on virtually every patient in every healthcare setting. The technique used today was developed more than 100 years ago by a pioneering Russian physician, Dr. Nikolai Korotkoff. Turbulent blood flow through the vessels can be heard as a soft ticking sound while measuring blood pressure; these sounds are known as Korotkoff sounds. The technique of measuring blood pressure requires the use of a sphygmomanometer (a blood pressure cuff attached to a measuring device) and a stethoscope. The technique is as follows:', 'd62eec1d-94c1-4b15-bdde-0c127cd95070': 'Although there are five recognized Korotkoff sounds, only two are normally recorded. Initially, no sounds are heard since there is no blood flowing through the vessels, but as air pressure steadily drops, the cuff relaxes, and blood flow becomes pulsatile (turbulent) as it is pushed through the opening vessel.\xa0 As shown in Figure 20.2.3, the first sound heard through the stethoscope—the first Korotkoff sound—indicates systolic blood pressure. The clinician measuring the blood pressure will continue to hear tapping sounds for a time, but as more air is released from the cuff, the blood vessel lumen completely opens, and blood is eventually able to flow freely through the brachial artery. Once blood flows freely, all sounds disappear. The point at which the sound disappears is recorded as the patient’s diastolic pressure. Thus, the diastolic pressure is recorded when a clinician expects to hear another sound but does not.', '09dabe5b-ebe9-4545-bb9e-21bbe978ea5a': 'The majority of hospitals and clinics have automated equipment for measuring blood pressure that work on the same principles. An even more recent innovation is a small instrument that wraps around a patient’s wrist. The patient then holds the wrist over the heart while the device measures blood flow and records pressure.'}"
+Figure 20.2.1,Anatomy_And_Physio/images/Figure 20.2.1.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures.",Arterial blood pressure in the larger vessels varies between systolic and diastolic pressures. Pulse pressure and mean arterial pressure are calculated values based upon the systolic and diastolic pressures (Figure 20.2.1).,"{'e07da81a-8522-4db3-8fb9-a8d75c2e3933': 'Arterial blood pressure in the larger vessels varies between systolic and diastolic pressures. Pulse pressure and mean arterial pressure are calculated values based upon the systolic and diastolic pressures (Figure 20.2.1).', '56188638-73ca-46c1-af42-55701e546ab5': 'Recall that blood moves from higher pressure to lower pressure. It is pumped from the heart into the arteries at high pressure. Since pressure in the veins is normally relatively low, for blood to flow back into the heart, the pressure in the atria during atrial diastole must be even lower. It normally approaches zero, except when the atria contract (see Figure 20.2.1).'}"
+Figure 20.1.1,Anatomy_And_Physio/images/Figure 20.1.1.jpg,"Figure 20.1.1 – Cardiovascular Circulation: The pulmonary circuit moves blood from the right side of the heart to the lungs and back to the heart. The systemic circuit moves blood from the left side of the heart to the head and body and returns it to the right side of the heart to repeat the cycle. The arrows indicate the direction of blood flow, and the colors show the relative levels of oxygen concentration.","Arteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit (Figure 20.1.1). Systemic arteries provide blood rich in oxygen to the body’s tissues. The blood returned to the heart through systemic veins has less oxygen, since much of the oxygen carried by the arteries has been delivered to the cells. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation. Although arteries and veins differ structurally and functionally, they share certain features.","{'4501e605-a274-42c5-8a93-4a1318d2d419': 'The pumping action of the heart propels the blood into the arteries, from an area of higher pressure toward an area of lower pressure. If blood is to flow from the veins back into the heart, the pressure in the veins must be greater than the pressure in the atria of the heart. Two factors help maintain this pressure gradient between the veins and the heart. First, the pressure in the atria during diastole is very low, often approaching zero when the atria are relaxed (atrial diastole). Second, two physiologic “pumps” increase pressure in the venous system. The use of the term “pump” implies a physical device that speeds flow. These physiological pumps are less obvious.', 'fb770a96-cf5b-479a-8f4f-b9366db9526a': 'Blood is carried through the body via blood vessels. An artery is a blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels. Eventually, the smallest arteries, vessels called arterioles, further branch into tiny capillaries, where nutrients and wastes are exchanged. Capillaries come together to form venules, small blood vessels that carry blood to a vein, a larger blood vessel that returns blood to the heart.', '03b959e7-b265-4583-9849-eaee23effc46': 'Arteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit (Figure 20.1.1). Systemic arteries provide blood rich in oxygen to the body’s tissues. The blood returned to the heart through systemic veins has less oxygen, since much of the oxygen carried by the arteries has been delivered to the cells. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation. Although arteries and veins differ structurally and functionally, they share certain features.'}"
+Figure 20.1.3,Anatomy_And_Physio/images/Figure 20.1.3.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries.","An artery is a blood vessel that conducts blood away from the heart. All arteries have relatively thick walls that can withstand the high pressure of blood ejected from the heart. However, those close to the heart have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics. This type of artery is known as an elastic artery (Figure 20.1.3). Vessels larger than 10 mm in diameter, such as the aorta, pulmonary trunk, common carotid, common iliac and subclavian arteries are typically elastic. Their abundant elastic fibers allow them to expand, as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure. The elastic recoil of the vascular wall helps to maintain the pressure gradient that drives the blood through the arterial system. Between beats, when the heart is relaxed, diastolic pressure is provided by this elastic recoil. An elastic artery is also known as a conducting artery, because the large diameter of the lumen enables it to accept a large volume of blood from the heart and conduct it to smaller branches.","{'298e84e1-f731-4374-a77c-4d82d1f488e2': 'An artery is a blood vessel that conducts blood away from the heart. All arteries have relatively thick walls that can withstand the high pressure of blood ejected from the heart. However, those close to the heart have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics. This type of artery is known as an elastic artery (Figure 20.1.3). Vessels larger than 10 mm in diameter, such as the aorta, pulmonary trunk, common carotid, common iliac and subclavian arteries are typically elastic. Their abundant elastic fibers allow them to expand, as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure. The elastic recoil of the vascular wall helps to maintain the pressure gradient that drives the blood through the arterial system. Between beats, when the heart is relaxed, diastolic pressure is provided by this elastic recoil. An elastic artery is also known as a conducting artery, because the large diameter of the lumen enables it to accept a large volume of blood from the heart and conduct it to smaller branches.', '5494049c-8db8-420d-ba6d-2c8b2c548b1f': 'Farther from the heart, where the surge of blood has dampened, the percentage of elastic fibers in an artery tunica intima decreases and the amount of smooth muscle in its tunica media increases. The artery at this point is described as a muscular artery also called a distributing artery because the relatively thick tunica media allows precise control of blood vessel diameter to control blood flow to different areas or organs\xa0.\xa0The diameter of muscular arteries typically ranges from 0.1 mm to 10 mm. Their thick tunica media allows muscular arteries to play a leading role in vasoconstriction. In contrast, their decreased quantity of elastic fibers limits their ability to expand. Fortunately, because the blood pressure has eased by the time it reaches these more distant vessels, elasticity has become less important.', 'a0d9b2f5-9aab-4189-8829-8cef1f421898': 'Notice that although the distinctions between elastic and muscular arteries are important, there is no “line of demarcation” where an elastic artery suddenly becomes muscular. Rather, there is a gradual transition as the vascular tree repeatedly branches. In turn, muscular arteries branch to distribute blood to the vast network of arterioles.', 'bf283cd9-6c46-4488-8a0f-e2467cc436f1': 'An arteriole is a very small artery that leads to a capillary. Larger arterioles have the same three tunics as the larger vessels, but the thickness of each is greatly diminished. The critical endothelial lining of the tunica intima is intact. The tunica media is restricted to one or two smooth muscle cell layers in thickness. The tunica externa remains but is very thin (see Figure 20.1.3). The smallest arterioles do not have a tunica externa and the tunica media is limited to a single incomplete layer of smooth cells.', '660cc565-798d-4a4e-b649-f8ceeeabd6f4': 'With a lumen averaging 30 micrometers or less in diameter, arterioles are critical in slowing down—or resisting—blood flow and, thus, causing a substantial drop in blood pressure. Because of this, you may see them referred to as resistance vessels. The muscle fibers in arterioles are normally slightly contracted, causing arterioles to maintain a consistent muscle tone—in this case referred to as vascular tone—in a similar manner to the muscular tone of skeletal muscle. In reality, all blood vessels exhibit vascular tone due to the partial contraction of smooth muscle. The importance of the arterioles is that they will be the primary site of both resistance and regulation of blood pressure. The precise diameter of the lumen of an arteriole at any given moment is determined by neural and chemical controls, and vasoconstriction and vasodilation in the arterioles are the primary mechanisms for distribution of blood flow due to local metabolic demands.'}"
+Figure 20.1.3,Anatomy_And_Physio/images/Figure 20.1.3.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries.","An artery is a blood vessel that conducts blood away from the heart. All arteries have relatively thick walls that can withstand the high pressure of blood ejected from the heart. However, those close to the heart have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics. This type of artery is known as an elastic artery (Figure 20.1.3). Vessels larger than 10 mm in diameter, such as the aorta, pulmonary trunk, common carotid, common iliac and subclavian arteries are typically elastic. Their abundant elastic fibers allow them to expand, as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure. The elastic recoil of the vascular wall helps to maintain the pressure gradient that drives the blood through the arterial system. Between beats, when the heart is relaxed, diastolic pressure is provided by this elastic recoil. An elastic artery is also known as a conducting artery, because the large diameter of the lumen enables it to accept a large volume of blood from the heart and conduct it to smaller branches.","{'298e84e1-f731-4374-a77c-4d82d1f488e2': 'An artery is a blood vessel that conducts blood away from the heart. All arteries have relatively thick walls that can withstand the high pressure of blood ejected from the heart. However, those close to the heart have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics. This type of artery is known as an elastic artery (Figure 20.1.3). Vessels larger than 10 mm in diameter, such as the aorta, pulmonary trunk, common carotid, common iliac and subclavian arteries are typically elastic. Their abundant elastic fibers allow them to expand, as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure. The elastic recoil of the vascular wall helps to maintain the pressure gradient that drives the blood through the arterial system. Between beats, when the heart is relaxed, diastolic pressure is provided by this elastic recoil. An elastic artery is also known as a conducting artery, because the large diameter of the lumen enables it to accept a large volume of blood from the heart and conduct it to smaller branches.', '5494049c-8db8-420d-ba6d-2c8b2c548b1f': 'Farther from the heart, where the surge of blood has dampened, the percentage of elastic fibers in an artery tunica intima decreases and the amount of smooth muscle in its tunica media increases. The artery at this point is described as a muscular artery also called a distributing artery because the relatively thick tunica media allows precise control of blood vessel diameter to control blood flow to different areas or organs\xa0.\xa0The diameter of muscular arteries typically ranges from 0.1 mm to 10 mm. Their thick tunica media allows muscular arteries to play a leading role in vasoconstriction. In contrast, their decreased quantity of elastic fibers limits their ability to expand. Fortunately, because the blood pressure has eased by the time it reaches these more distant vessels, elasticity has become less important.', 'a0d9b2f5-9aab-4189-8829-8cef1f421898': 'Notice that although the distinctions between elastic and muscular arteries are important, there is no “line of demarcation” where an elastic artery suddenly becomes muscular. Rather, there is a gradual transition as the vascular tree repeatedly branches. In turn, muscular arteries branch to distribute blood to the vast network of arterioles.', 'bf283cd9-6c46-4488-8a0f-e2467cc436f1': 'An arteriole is a very small artery that leads to a capillary. Larger arterioles have the same three tunics as the larger vessels, but the thickness of each is greatly diminished. The critical endothelial lining of the tunica intima is intact. The tunica media is restricted to one or two smooth muscle cell layers in thickness. The tunica externa remains but is very thin (see Figure 20.1.3). The smallest arterioles do not have a tunica externa and the tunica media is limited to a single incomplete layer of smooth cells.', '660cc565-798d-4a4e-b649-f8ceeeabd6f4': 'With a lumen averaging 30 micrometers or less in diameter, arterioles are critical in slowing down—or resisting—blood flow and, thus, causing a substantial drop in blood pressure. Because of this, you may see them referred to as resistance vessels. The muscle fibers in arterioles are normally slightly contracted, causing arterioles to maintain a consistent muscle tone—in this case referred to as vascular tone—in a similar manner to the muscular tone of skeletal muscle. In reality, all blood vessels exhibit vascular tone due to the partial contraction of smooth muscle. The importance of the arterioles is that they will be the primary site of both resistance and regulation of blood pressure. The precise diameter of the lumen of an arteriole at any given moment is determined by neural and chemical controls, and vasoconstriction and vasodilation in the arterioles are the primary mechanisms for distribution of blood flow due to local metabolic demands.'}"
+Figure 20.1.4,Anatomy_And_Physio/images/Figure 20.1.4.jpg,"Figure 20.1.4 – Types of Capillaries: The three major types of capillaries: continuous, fenestrated, and sinusoid.","For capillaries to function, their walls must be leaky, allowing substances to pass through. There are three major types of capillaries, which differ according to their degree of “leakiness:” continuous, fenestrated, and sinusoid capillaries (Figure 20.1.4).","{'c83c86bc-eb5e-4c4b-91f4-d3ff2b34feb6': 'A capillary is a microscopic channel that supplies blood to the tissues themselves, a process called perfusion. Exchange of gases and other substances occurs in the capillaries between the blood and the surrounding cells and their tissue fluid (interstitial fluid). The diameter of a capillary lumen ranges from 5–10 micrometers; the smallest are just barely wide enough for an erythrocyte to squeeze through. Flow through capillaries is often described as microcirculation.', '87619b03-5890-439d-9798-91449ba43f6b': 'The wall of a capillary consists of the endothelial layer surrounded by a basement membrane with occasional smooth muscle fibers. There is some variation in wall structure: In a large capillary, several endothelial cells bordering each other may line the lumen; in a small capillary, there may be only a single cell layer that wraps around to contact itself.', '5a3bf30f-0c82-439e-b2cb-3adbb3b94420': 'For capillaries to function, their walls must be leaky, allowing substances to pass through. There are three major types of capillaries, which differ according to their degree of “leakiness:” continuous, fenestrated, and sinusoid capillaries (Figure 20.1.4).'}"
+Figure 20.1.5,Anatomy_And_Physio/images/Figure 20.1.5.jpg,"Figure 20.1.5 – Capillary Bed: In a capillary bed, arterioles give rise to metarterioles. Precapillary sphincters located at the junction of a metarteriole with a capillary regulate blood flow. A thoroughfare channel connects the metarteriole to a venule. An arteriovenous anastomosis, which directly connects the arteriole with the venule, is shown at the bottom.","The precapillary sphincters, circular smooth muscle cells that surround the capillary at its origin with the metarteriole, tightly regulate the flow of blood from a metarteriole to the capillaries it supplies. Their function is critical: If all of the capillary beds in the body were to open simultaneously, they would collectively hold every drop of blood in the body and there would be none in the arteries, arterioles, venules, veins, or the heart itself. Normally, the precapillary sphincters are closed. When the surrounding tissues need oxygen and have excess waste products, the precapillary sphincters open, allowing blood to flow through and exchange to occur before closing once more (Figure 20.1.5). If all of the precapillary sphincters in a capillary bed are closed, blood will flow from the metarteriole directly into a thoroughfare channel and then into the venous circulation, bypassing the capillary bed entirely. This creates what is known as a vascular shunt. In addition, an arteriovenous anastomosis may bypass the capillary bed and lead directly to the venous system.","{'77094a86-4eb7-4c0e-8708-522e93224770': 'A metarteriole is a type of vessel that has structural characteristics of both an arteriole and a capillary. Slightly larger than the typical capillary, the smooth muscle of the tunica media of the metarteriole is not continuous but forms rings of smooth muscle (sphincters) at the entrance to the capillaries. Each metarteriole arises from a terminal arteriole and branches to supply blood to a capillary bed that may consist of 10–100 capillaries.', '3277e483-6dea-4b27-b011-e37b6ea6a7be': 'The precapillary sphincters, circular smooth muscle cells that surround the capillary at its origin with the metarteriole, tightly regulate the flow of blood from a metarteriole to the capillaries it supplies. Their function is critical: If all of the capillary beds in the body were to open simultaneously, they would collectively hold every drop of blood in the body and there would be none in the arteries, arterioles, venules, veins, or the heart itself. Normally, the precapillary sphincters are closed. When the surrounding tissues need oxygen and have excess waste products, the precapillary sphincters open, allowing blood to flow through and exchange to occur before closing once more (Figure 20.1.5). If all of the precapillary sphincters in a capillary bed are closed, blood will flow from the metarteriole directly into a thoroughfare channel and then into the venous circulation, bypassing the capillary bed entirely. This creates what is known as a vascular shunt. In addition, an arteriovenous anastomosis may bypass the capillary bed and lead directly to the venous system.', 'fbb5341c-dd2f-4068-a435-aa360c676f93': 'Although you might expect blood flow through a capillary bed to be smooth, in reality, it moves with an irregular, pulsating flow. This pattern is called vasomotion and is regulated by chemical signals that are triggered in response to changes in internal conditions, such as oxygen, carbon dioxide, hydrogen ion, and lactic acid levels. For example, during strenuous exercise when oxygen levels decrease and carbon dioxide, hydrogen ion, and lactic acid levels all increase, the capillary beds in skeletal muscle are open, as they would be in the digestive system when nutrients are present in the digestive tract. During sleep or rest periods, vessels in both areas are largely closed; they open only occasionally to allow oxygen and nutrient supplies to travel to the tissues to maintain basic life processes.'}"
+Figure 20.1.6,Anatomy_And_Physio/images/Figure 20.1.6.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins.","A venule is an extremely small vein, generally 8–100 micrometers in diameter. Postcapillary venules join multiple capillaries exiting from a capillary bed. Multiple venules join to form veins. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica externa (Figure 20.1.6). Venules as well as capillaries are the primary sites of emigration or diapedesis, in which the white blood cells adhere to the endothelial lining of the vessels and then squeeze through adjacent cells to enter the tissue fluid.","{'f5122ffe-0cfd-43cb-a316-4e81ba8838ae': 'A venule is an extremely small vein, generally 8–100 micrometers in diameter. Postcapillary venules join multiple capillaries exiting from a capillary bed. Multiple venules join to form veins. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica externa (Figure 20.1.6). Venules as well as capillaries are the primary sites of emigration or diapedesis, in which the white blood cells adhere to the endothelial lining of the vessels and then squeeze through adjacent cells to enter the tissue fluid.', 'e2c886d0-7025-473e-8df3-aab2a4d4fb1c': 'A vein is a blood vessel that conducts blood toward the heart. Compared to arteries, veins are thin-walled vessels with large and irregular lumens (see Figure 20.1.6). Because they are low-pressure vessels, larger veins are commonly equipped with valves that promote the unidirectional flow of blood toward the heart and prevent backflow toward the capillaries caused by the inherent low blood pressure in veins as well as the pull of gravity. Table 20.2 compares the features of arteries and veins.'}"
+Figure 20.1.6,Anatomy_And_Physio/images/Figure 20.1.6.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins.","A venule is an extremely small vein, generally 8–100 micrometers in diameter. Postcapillary venules join multiple capillaries exiting from a capillary bed. Multiple venules join to form veins. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica externa (Figure 20.1.6). Venules as well as capillaries are the primary sites of emigration or diapedesis, in which the white blood cells adhere to the endothelial lining of the vessels and then squeeze through adjacent cells to enter the tissue fluid.","{'f5122ffe-0cfd-43cb-a316-4e81ba8838ae': 'A venule is an extremely small vein, generally 8–100 micrometers in diameter. Postcapillary venules join multiple capillaries exiting from a capillary bed. Multiple venules join to form veins. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica externa (Figure 20.1.6). Venules as well as capillaries are the primary sites of emigration or diapedesis, in which the white blood cells adhere to the endothelial lining of the vessels and then squeeze through adjacent cells to enter the tissue fluid.', 'e2c886d0-7025-473e-8df3-aab2a4d4fb1c': 'A vein is a blood vessel that conducts blood toward the heart. Compared to arteries, veins are thin-walled vessels with large and irregular lumens (see Figure 20.1.6). Because they are low-pressure vessels, larger veins are commonly equipped with valves that promote the unidirectional flow of blood toward the heart and prevent backflow toward the capillaries caused by the inherent low blood pressure in veins as well as the pull of gravity. Table 20.2 compares the features of arteries and veins.'}"
+Figure 20.1.8,Anatomy_And_Physio/images/Figure 20.1.8.jpg,Figure 20.1.8 Distribution of Blood Flow,"In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.","{'87280829-f55d-4513-8c1f-79a61c6cbfd2': 'In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.', '9e203800-1a20-48db-8231-59d3f8c1882a': 'When blood flow needs to be redistributed to other portions of the body, the vasomotor center located in the medulla oblongata sends sympathetic stimulation to the smooth muscles in the walls of the veins, causing constriction—or in this case, venoconstriction. Less dramatic than the vasoconstriction seen in smaller arteries and arterioles, venoconstriction may be likened to a “stiffening” of the vessel wall. This increases pressure on the blood within the veins, speeding its return to the heart. As you will note in Figure 20.1.8, approximately 21 percent of the venous blood is located in venous networks within the liver, bone marrow, and integument. This volume of blood is referred to as venous reserve. Through venoconstriction, this “reserve” volume of blood can get back to the heart more quickly for redistribution to other parts of the circulation.', '9554db93-76e0-443c-8326-7704934be962': 'Vascular surgery is a specialty in which the physician deals primarily with diseases of the vascular portion of the cardiovascular system. This includes repair and replacement of diseased or damaged vessels, removal of plaque from vessels, minimally invasive procedures including the insertion of venous catheters, and traditional surgery. Following completion of medical school, the physician generally completes a 5-year surgical residency followed by an additional 1 to 2 years of vascular specialty training. In the United States, most vascular surgeons are members of the Society of Vascular Surgery.', '93606693-bd95-499f-828d-c829ab6d1f1b': 'Vascular technicians are specialists in imaging technologies that provide information on the health of the vascular system. They may also assist physicians in treating disorders involving the arteries and veins. This profession often overlaps with cardiovascular technology, which would also include treatments involving the heart. Although recognized by the American Medical Association, there are currently no licensing requirements for vascular technicians, and licensing is voluntary. Vascular technicians typically have an Associate’s degree or certificate, involving 18 months to 2 years of training. The United States Bureau of Labor projects this profession to grow by 29 percent from 2010 to 2020.', '6324b513-f5ca-43f3-bc3f-713c82c3c165': 'In this chapter, you will learn about the vascular part of the cardiovascular system, that is, the vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.', '6f29d03a-fc04-410c-8d91-64cf08a9d064': 'The human heart is the first functional organ to develop. It begins beating and pumping blood around day 21 or 22, a mere three weeks after fertilization. This emphasizes the critical nature of the heart in distributing blood through the vessels and the vital exchange of nutrients, oxygen, and wastes both to and from the developing baby. The critical early development of the heart is reflected by the prominent heart bulge that appears on the anterior surface of the embryo.', '16bc0617-eadc-47d0-a3e8-f7be01f16f7d': 'The heart forms from an embryonic tissue called mesoderm around 18 to 19 days after fertilization. Mesoderm is one of the three primary germ layers that differentiates early in development that collectively gives rise to all subsequent tissues and organs. The heart begins to develop near the head of the embryo in a region known as the cardiogenic area. Following chemical signals called factors from the underlying endoderm (another of the three primary germ layers), the cardiogenic area begins to form two strands called the cardiogenic cords. As the cardiogenic cords develop, a lumen rapidly develops within them. At this point, they are referred to as endocardial tubes (Figure 19.5.1). The two tubes migrate together and fuse to form a single primitive heart tube. The primitive heart tube quickly forms five distinct regions. From head to tail, these include the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. Initially, all venous blood flows into the sinus venosus, and contractions propel the blood from tail to head, or from the sinus venosus to the truncus arteriosus. This is a very different pattern from that of an adult.', '3a152ed4-6e43-4221-9852-d3425f978969': 'The five regions of the primitive heart tube develop into recognizable structures in a fully developed heart. The truncus arteriosus will eventually divide and give rise to the ascending aorta and pulmonary trunk. The bulbus cordis develops into the right ventricle. The primitive ventricle forms the left ventricle. The primitive atrium becomes the anterior portions of both the right and left atria, and the two auricles. The sinus venosus develops into the posterior portion of the right atrium, the SA node, and the coronary sinus.', '12638f00-56a6-41a6-90e5-520a9b8a0f69': 'As the primitive heart tube elongates, it begins to fold within the pericardium, eventually forming an S shape, which places the chambers and major vessels into an alignment similar to the adult heart. This process occurs between days 23 and 28. The remainder of the heart development pattern includes development of septa and valves, and remodeling of the actual chambers. Partitioning of the atria and ventricles by the interatrial septum, interventricular septum, and atrioventricular septum is complete by the end of the fifth week, although the fetal blood shunts remain until birth or shortly after. The atrioventricular valves form between weeks five and eight, and the semilunar valves form between weeks five and nine.', '0f982ce5-26d4-44fb-b849-e2d152743ea9': 'The autorhythmicity inherent in cardiac cells keeps the heart beating at a regular pace; however, the heart is regulated by and responds to outside influences as well. Neural and endocrine controls are vital to the regulation of cardiac function. In addition, the heart is sensitive to several environmental factors, including electrolytes.'}"
+Figure 20.1.8,Anatomy_And_Physio/images/Figure 20.1.8.jpg,Figure 20.1.8 Distribution of Blood Flow,"In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.","{'87280829-f55d-4513-8c1f-79a61c6cbfd2': 'In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.', '9e203800-1a20-48db-8231-59d3f8c1882a': 'When blood flow needs to be redistributed to other portions of the body, the vasomotor center located in the medulla oblongata sends sympathetic stimulation to the smooth muscles in the walls of the veins, causing constriction—or in this case, venoconstriction. Less dramatic than the vasoconstriction seen in smaller arteries and arterioles, venoconstriction may be likened to a “stiffening” of the vessel wall. This increases pressure on the blood within the veins, speeding its return to the heart. As you will note in Figure 20.1.8, approximately 21 percent of the venous blood is located in venous networks within the liver, bone marrow, and integument. This volume of blood is referred to as venous reserve. Through venoconstriction, this “reserve” volume of blood can get back to the heart more quickly for redistribution to other parts of the circulation.', '9554db93-76e0-443c-8326-7704934be962': 'Vascular surgery is a specialty in which the physician deals primarily with diseases of the vascular portion of the cardiovascular system. This includes repair and replacement of diseased or damaged vessels, removal of plaque from vessels, minimally invasive procedures including the insertion of venous catheters, and traditional surgery. Following completion of medical school, the physician generally completes a 5-year surgical residency followed by an additional 1 to 2 years of vascular specialty training. In the United States, most vascular surgeons are members of the Society of Vascular Surgery.', '93606693-bd95-499f-828d-c829ab6d1f1b': 'Vascular technicians are specialists in imaging technologies that provide information on the health of the vascular system. They may also assist physicians in treating disorders involving the arteries and veins. This profession often overlaps with cardiovascular technology, which would also include treatments involving the heart. Although recognized by the American Medical Association, there are currently no licensing requirements for vascular technicians, and licensing is voluntary. Vascular technicians typically have an Associate’s degree or certificate, involving 18 months to 2 years of training. The United States Bureau of Labor projects this profession to grow by 29 percent from 2010 to 2020.', '6324b513-f5ca-43f3-bc3f-713c82c3c165': 'In this chapter, you will learn about the vascular part of the cardiovascular system, that is, the vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.', '6f29d03a-fc04-410c-8d91-64cf08a9d064': 'The human heart is the first functional organ to develop. It begins beating and pumping blood around day 21 or 22, a mere three weeks after fertilization. This emphasizes the critical nature of the heart in distributing blood through the vessels and the vital exchange of nutrients, oxygen, and wastes both to and from the developing baby. The critical early development of the heart is reflected by the prominent heart bulge that appears on the anterior surface of the embryo.', '16bc0617-eadc-47d0-a3e8-f7be01f16f7d': 'The heart forms from an embryonic tissue called mesoderm around 18 to 19 days after fertilization. Mesoderm is one of the three primary germ layers that differentiates early in development that collectively gives rise to all subsequent tissues and organs. The heart begins to develop near the head of the embryo in a region known as the cardiogenic area. Following chemical signals called factors from the underlying endoderm (another of the three primary germ layers), the cardiogenic area begins to form two strands called the cardiogenic cords. As the cardiogenic cords develop, a lumen rapidly develops within them. At this point, they are referred to as endocardial tubes (Figure 19.5.1). The two tubes migrate together and fuse to form a single primitive heart tube. The primitive heart tube quickly forms five distinct regions. From head to tail, these include the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. Initially, all venous blood flows into the sinus venosus, and contractions propel the blood from tail to head, or from the sinus venosus to the truncus arteriosus. This is a very different pattern from that of an adult.', '3a152ed4-6e43-4221-9852-d3425f978969': 'The five regions of the primitive heart tube develop into recognizable structures in a fully developed heart. The truncus arteriosus will eventually divide and give rise to the ascending aorta and pulmonary trunk. The bulbus cordis develops into the right ventricle. The primitive ventricle forms the left ventricle. The primitive atrium becomes the anterior portions of both the right and left atria, and the two auricles. The sinus venosus develops into the posterior portion of the right atrium, the SA node, and the coronary sinus.', '12638f00-56a6-41a6-90e5-520a9b8a0f69': 'As the primitive heart tube elongates, it begins to fold within the pericardium, eventually forming an S shape, which places the chambers and major vessels into an alignment similar to the adult heart. This process occurs between days 23 and 28. The remainder of the heart development pattern includes development of septa and valves, and remodeling of the actual chambers. Partitioning of the atria and ventricles by the interatrial septum, interventricular septum, and atrioventricular septum is complete by the end of the fifth week, although the fetal blood shunts remain until birth or shortly after. The atrioventricular valves form between weeks five and eight, and the semilunar valves form between weeks five and nine.', '0f982ce5-26d4-44fb-b849-e2d152743ea9': 'The autorhythmicity inherent in cardiac cells keeps the heart beating at a regular pace; however, the heart is regulated by and responds to outside influences as well. Neural and endocrine controls are vital to the regulation of cardiac function. In addition, the heart is sensitive to several environmental factors, including electrolytes.'}"
+Figure 19.5.1,Anatomy_And_Physio/images/Figure 19.5.1.jpg,Figure 19.5.1 – Development of the Human Heart: This diagram outlines the embryological development of the human heart during the first eight weeks and the subsequent formation of the four heart chambers.,"The heart forms from an embryonic tissue called mesoderm around 18 to 19 days after fertilization. Mesoderm is one of the three primary germ layers that differentiates early in development that collectively gives rise to all subsequent tissues and organs. The heart begins to develop near the head of the embryo in a region known as the cardiogenic area. Following chemical signals called factors from the underlying endoderm (another of the three primary germ layers), the cardiogenic area begins to form two strands called the cardiogenic cords. As the cardiogenic cords develop, a lumen rapidly develops within them. At this point, they are referred to as endocardial tubes (Figure 19.5.1). The two tubes migrate together and fuse to form a single primitive heart tube. The primitive heart tube quickly forms five distinct regions. From head to tail, these include the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. Initially, all venous blood flows into the sinus venosus, and contractions propel the blood from tail to head, or from the sinus venosus to the truncus arteriosus. This is a very different pattern from that of an adult.","{'87280829-f55d-4513-8c1f-79a61c6cbfd2': 'In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.', '9e203800-1a20-48db-8231-59d3f8c1882a': 'When blood flow needs to be redistributed to other portions of the body, the vasomotor center located in the medulla oblongata sends sympathetic stimulation to the smooth muscles in the walls of the veins, causing constriction—or in this case, venoconstriction. Less dramatic than the vasoconstriction seen in smaller arteries and arterioles, venoconstriction may be likened to a “stiffening” of the vessel wall. This increases pressure on the blood within the veins, speeding its return to the heart. As you will note in Figure 20.1.8, approximately 21 percent of the venous blood is located in venous networks within the liver, bone marrow, and integument. This volume of blood is referred to as venous reserve. Through venoconstriction, this “reserve” volume of blood can get back to the heart more quickly for redistribution to other parts of the circulation.', '9554db93-76e0-443c-8326-7704934be962': 'Vascular surgery is a specialty in which the physician deals primarily with diseases of the vascular portion of the cardiovascular system. This includes repair and replacement of diseased or damaged vessels, removal of plaque from vessels, minimally invasive procedures including the insertion of venous catheters, and traditional surgery. Following completion of medical school, the physician generally completes a 5-year surgical residency followed by an additional 1 to 2 years of vascular specialty training. In the United States, most vascular surgeons are members of the Society of Vascular Surgery.', '93606693-bd95-499f-828d-c829ab6d1f1b': 'Vascular technicians are specialists in imaging technologies that provide information on the health of the vascular system. They may also assist physicians in treating disorders involving the arteries and veins. This profession often overlaps with cardiovascular technology, which would also include treatments involving the heart. Although recognized by the American Medical Association, there are currently no licensing requirements for vascular technicians, and licensing is voluntary. Vascular technicians typically have an Associate’s degree or certificate, involving 18 months to 2 years of training. The United States Bureau of Labor projects this profession to grow by 29 percent from 2010 to 2020.', '6324b513-f5ca-43f3-bc3f-713c82c3c165': 'In this chapter, you will learn about the vascular part of the cardiovascular system, that is, the vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.', '6f29d03a-fc04-410c-8d91-64cf08a9d064': 'The human heart is the first functional organ to develop. It begins beating and pumping blood around day 21 or 22, a mere three weeks after fertilization. This emphasizes the critical nature of the heart in distributing blood through the vessels and the vital exchange of nutrients, oxygen, and wastes both to and from the developing baby. The critical early development of the heart is reflected by the prominent heart bulge that appears on the anterior surface of the embryo.', '16bc0617-eadc-47d0-a3e8-f7be01f16f7d': 'The heart forms from an embryonic tissue called mesoderm around 18 to 19 days after fertilization. Mesoderm is one of the three primary germ layers that differentiates early in development that collectively gives rise to all subsequent tissues and organs. The heart begins to develop near the head of the embryo in a region known as the cardiogenic area. Following chemical signals called factors from the underlying endoderm (another of the three primary germ layers), the cardiogenic area begins to form two strands called the cardiogenic cords. As the cardiogenic cords develop, a lumen rapidly develops within them. At this point, they are referred to as endocardial tubes (Figure 19.5.1). The two tubes migrate together and fuse to form a single primitive heart tube. The primitive heart tube quickly forms five distinct regions. From head to tail, these include the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. Initially, all venous blood flows into the sinus venosus, and contractions propel the blood from tail to head, or from the sinus venosus to the truncus arteriosus. This is a very different pattern from that of an adult.', '3a152ed4-6e43-4221-9852-d3425f978969': 'The five regions of the primitive heart tube develop into recognizable structures in a fully developed heart. The truncus arteriosus will eventually divide and give rise to the ascending aorta and pulmonary trunk. The bulbus cordis develops into the right ventricle. The primitive ventricle forms the left ventricle. The primitive atrium becomes the anterior portions of both the right and left atria, and the two auricles. The sinus venosus develops into the posterior portion of the right atrium, the SA node, and the coronary sinus.', '12638f00-56a6-41a6-90e5-520a9b8a0f69': 'As the primitive heart tube elongates, it begins to fold within the pericardium, eventually forming an S shape, which places the chambers and major vessels into an alignment similar to the adult heart. This process occurs between days 23 and 28. The remainder of the heart development pattern includes development of septa and valves, and remodeling of the actual chambers. Partitioning of the atria and ventricles by the interatrial septum, interventricular septum, and atrioventricular septum is complete by the end of the fifth week, although the fetal blood shunts remain until birth or shortly after. The atrioventricular valves form between weeks five and eight, and the semilunar valves form between weeks five and nine.', '0f982ce5-26d4-44fb-b849-e2d152743ea9': 'The autorhythmicity inherent in cardiac cells keeps the heart beating at a regular pace; however, the heart is regulated by and responds to outside influences as well. Neural and endocrine controls are vital to the regulation of cardiac function. In addition, the heart is sensitive to several environmental factors, including electrolytes.'}"
+Figure 19.4.1,Anatomy_And_Physio/images/Figure 19.4.1.jpg,"Figure 19.4.1 – Major Factors Influencing Cardiac Output: Cardiac output is influenced by heart rate and stroke volume, both of which are also variable.","Remember, however, that these numbers refer to CO from each ventricle separately, not the total for the heart. In a healthy heart the CO from each ventricle is the same. CO is influenced by HR and by SV. If SV decreases, CO can be maintained by increasing HR. Factors that influence HR are referred to as chronotropic factors. Chrono- refers to time. Positive chronotropic factors increase HR and negative chronotropic factors decrease HR. HR is influenced by the autonomic nervous system, chemicals, and other factors. The factors influencing CO are summarized in Figure 19.4.1.","{'d107ca3d-b634-4eb2-af19-dfe0619162dd': 'SV is normally measured using an echocardiogram to record EDV and ESV, and calculating the difference: SV = EDV – ESV. SV can also be measured using a specialized catheter, but this is an invasive procedure and far more dangerous to the patient. A mean SV for a resting 70-kg (150-lb) individual would be approximately 70 mL.\xa0 This is because typical EDV and ESV values are approximately 120 mL and 50 mL, respectively and 70 mL = 120 mL – 50 mL. Normal range for SV would be 55–100 mL. An average resting HR would be approximately 75 bpm but could range from 60–100 in some individuals. There are several important variables, including size of the heart, physical and mental condition (via hormones and the ANS) of the individual, gender, contractility, duration of contraction, preload or EDV, and afterload or resistance that can affect SV and HR.', 'b432a74b-4483-4c6e-9a21-7043655d5b13': 'Using these numbers, the mean resting CO is 5.25 L/min, with a range of 4.0–8.0 L/min.\xa0 The CO of 5.25 L/min, was calculated using the following values.', '32755430-c711-457f-b1e2-bb50cf7fe0d5': 'CO L/min = 75 beats/min x 0.070 L/beat (where 0.070 L is equal to 70 mL).', '87700fde-ea67-47aa-9d2d-f03d6a2ec965': 'Remember, however, that these numbers refer to CO from each ventricle separately, not the total for the heart. In a healthy heart the CO from each ventricle is the same. CO is influenced by HR and by SV. If SV decreases, CO can be maintained by increasing HR. Factors that influence HR are referred to as chronotropic factors. Chrono- refers to time. Positive chronotropic factors increase HR and negative chronotropic factors decrease HR. HR is influenced by the autonomic nervous system, chemicals, and other factors. The factors influencing CO are summarized in Figure 19.4.1.', '04b8dbc7-cedb-48d7-b26c-3b5fb5c2761e': 'SVs are also used to calculate ejection fraction, which is the portion of the blood that is pumped or ejected from the heart with each contraction. To calculate ejection fraction, SV is divided by EDV. Despite the name, the ejection fraction is normally expressed as a percentage. Ejection fractions range from approximately 55–70 percent, with a mean of 58 percent.\xa0 For example, if the average EDV is 120 mL and the SV is 70 mL, the ejection fraction of 58% is calculated as follows:'}"
+Figure 19.4.2,Anatomy_And_Physio/images/Figure 19.4.2.jpg,Figure 19.4.2 – Autonomic Innervation of the Heart: Cardioacceleratory and cardioinhibitory areas are components of the paired cardiac centers located in the medulla oblongata of the brain. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus (parasympathetic) nerves that slow cardiac activity.,"Nervous control over HR is centralized within the two paired cardiovascular centers of the medulla oblongata (Figure 19.4.2). The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioacceleratory nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve, cranial nerve X. Both sympathetic and parasympathetic stimulations flow through a paired complex network of nerve fibers known as the cardiac plexus near the base of the heart. The cardioacceleratory center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia (the cervical ganglia plus superior thoracic ganglia T1–T4) to both the SA and AV nodes to increase heart rate, plus additional fibers to the atrial and ventricular myocardium to increase force of contraction (see section on Contractility). The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm.","{'3a2ba175-bac5-4b82-a4d5-38692b073df2': 'Initially, physiological conditions that cause HR to increase also trigger an increase in SV. During exercise, the rate of blood returning to the heart increases. However as the HR rises, there is less time spent in diastole and consequently less time for the ventricles to fill with blood. Even though there is less filling time, SV will initially remain high. However, as HR continues to increase, SV gradually decreases due to decreased filling time. CO will initially stabilize as the increasing HR compensates for the decreasing SV, but at very high rates, CO will eventually decrease as increasing rates are no longer able to compensate for the decreasing SV. Consider this phenomenon in a healthy young individual. Initially, as HR increases from resting to approximately 120 bpm, CO will rise. As HR increases from 120 to 160 bpm, CO remains stable, since the increase in rate is offset by decreasing ventricular filling time and, consequently, SV. As HR continues to rise above 160 bpm, CO actually decreases as SV falls faster than HR increases. So although aerobic exercises are critical to maintain the health of the heart, individuals are cautioned to monitor their HR to ensure they stay within the target heart rate range of between 120 and 160 bpm, so CO is maintained.\xa0 It is also important to note that the coronary circulation nourishes the heart during diastole so as the HR increases the ability of the coronary circulation to nourish the myocardium decreases. The target HR is loosely defined as the range in which both the heart and lungs receive the maximum benefit from the aerobic workout and is dependent upon age.', '8c46e421-bec3-4fb6-8e2a-b3ee9fcf267b': 'Nervous control over HR is centralized within the two paired cardiovascular centers of the medulla oblongata (Figure 19.4.2). The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioacceleratory nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve, cranial nerve X. Both sympathetic and parasympathetic stimulations flow through a paired complex network of nerve fibers known as the cardiac plexus near the base of the heart. The cardioacceleratory center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia (the cervical ganglia plus superior thoracic ganglia T1–T4) to both the SA and AV nodes to increase heart rate, plus additional fibers to the atrial and ventricular myocardium to increase force of contraction (see section on Contractility). The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm.', 'ac451541-5066-4721-bd14-150b91bcdac2': 'At the nodes sympathetic stimulation causes the release of the neurotransmitter norepinephrine (NE) at the neuromuscular junction of the cardiac nerves. NE binds to the beta-1 receptors and opens chemical- or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions. NE shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increase in HR. Some cardiac medications (for example, beta blockers) work by blocking these receptors, thereby slowing HR and are one possible treatment for hypertension. Overprescription of these drugs may lead to bradycardia and even stoppage of the heart.', 'f04b5d8f-f228-4ea0-9458-04efe71dbd43': 'Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve (cranial nerve X). The vagus nerve sends branches to both the SA and AV nodes to decrease HR. Parasympathetic stimulation releases the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. ACh slows HR by opening chemical- or ligand-gated potassium ion channels to slow the rate of spontaneous depolarization and increase the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 100 bpm. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove one’s foot from the break and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 100 bpm. Any increases beyond this rate would require sympathetic stimulation. Figure 19.4.3 illustrates the effects of parasympathetic and sympathetic stimulation on the normal sinus rhythm.', '192aeeb5-b2c1-447f-95d7-d79d56af45f9': 'The cardiovascular center receives input from the limbic system as well as a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors. Collectively, these inputs normally enable the cardiovascular centers to regulate heart function precisely, a process known as cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. Any such increase in physical activity would logically warrant increased blood flow. The cardiac centers monitor these increased rates of firing, and suppress parasympathetic stimulation and increase sympathetic stimulation as needed in order to increase blood flow.', '05a0226b-bbbc-40f4-a01d-ff473311364b': 'Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the rightatrium. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic stimulation. As pressure and stretch decrease, the rate of baroreceptor firing decreases, and the cardiac centers increase sympathetic stimulation and decrease parasympathetic stimulation.', '3e4d4a73-108b-4c0e-b55d-e1ece43921fe': 'There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase HR.', 'c1f0ea85-2059-4eb8-b91c-b1316965b307': 'Increased metabolic byproducts associated with increased activity, such as carbon dioxide, hydrogen ions, and lactic acid, plus falling oxygen levels, are detected by a suite of chemoreceptors innervated by the glossopharyngeal and vagus nerves. These chemoreceptors provide feedback to the cardiovascular centers about the need for increased or decreased blood flow, based on the relative levels of these substances.', '2c0062cc-e5df-43dc-8c2c-01add95e7541': 'The limbic system can also significantly impact HR related to emotional state. During periods of stress, it is not unusual to identify higher than normal HRs, often accompanied by a surge in the stress hormone cortisol. Individuals experiencing extreme anxiety may manifest panic attacks with symptoms that resemble those of heart attacks. These events are typically transient and treatable. Meditation techniques have been developed to ease anxiety and have been shown to lower HR effectively. Doing simple deep and slow breathing exercises with one’s eyes closed can also significantly reduce this anxiety and HR.'}"
+Figure 19.4.3,Anatomy_And_Physio/images/Figure 19.4.3.jpg,"Figure 19.4.3 – Effects of Parasympathetic and Sympathetic Stimulation on Normal Sinus Rhythm: The wave of depolarization in a normal sinus rhythm shows a stable resting HR. Following parasympathetic stimulation, HR slows. Following sympathetic stimulation, HR increases.","Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve (cranial nerve X). The vagus nerve sends branches to both the SA and AV nodes to decrease HR. Parasympathetic stimulation releases the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. ACh slows HR by opening chemical- or ligand-gated potassium ion channels to slow the rate of spontaneous depolarization and increase the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 100 bpm. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove one’s foot from the break and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 100 bpm. Any increases beyond this rate would require sympathetic stimulation. Figure 19.4.3 illustrates the effects of parasympathetic and sympathetic stimulation on the normal sinus rhythm.","{'3a2ba175-bac5-4b82-a4d5-38692b073df2': 'Initially, physiological conditions that cause HR to increase also trigger an increase in SV. During exercise, the rate of blood returning to the heart increases. However as the HR rises, there is less time spent in diastole and consequently less time for the ventricles to fill with blood. Even though there is less filling time, SV will initially remain high. However, as HR continues to increase, SV gradually decreases due to decreased filling time. CO will initially stabilize as the increasing HR compensates for the decreasing SV, but at very high rates, CO will eventually decrease as increasing rates are no longer able to compensate for the decreasing SV. Consider this phenomenon in a healthy young individual. Initially, as HR increases from resting to approximately 120 bpm, CO will rise. As HR increases from 120 to 160 bpm, CO remains stable, since the increase in rate is offset by decreasing ventricular filling time and, consequently, SV. As HR continues to rise above 160 bpm, CO actually decreases as SV falls faster than HR increases. So although aerobic exercises are critical to maintain the health of the heart, individuals are cautioned to monitor their HR to ensure they stay within the target heart rate range of between 120 and 160 bpm, so CO is maintained.\xa0 It is also important to note that the coronary circulation nourishes the heart during diastole so as the HR increases the ability of the coronary circulation to nourish the myocardium decreases. The target HR is loosely defined as the range in which both the heart and lungs receive the maximum benefit from the aerobic workout and is dependent upon age.', '8c46e421-bec3-4fb6-8e2a-b3ee9fcf267b': 'Nervous control over HR is centralized within the two paired cardiovascular centers of the medulla oblongata (Figure 19.4.2). The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioacceleratory nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve, cranial nerve X. Both sympathetic and parasympathetic stimulations flow through a paired complex network of nerve fibers known as the cardiac plexus near the base of the heart. The cardioacceleratory center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia (the cervical ganglia plus superior thoracic ganglia T1–T4) to both the SA and AV nodes to increase heart rate, plus additional fibers to the atrial and ventricular myocardium to increase force of contraction (see section on Contractility). The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm.', 'ac451541-5066-4721-bd14-150b91bcdac2': 'At the nodes sympathetic stimulation causes the release of the neurotransmitter norepinephrine (NE) at the neuromuscular junction of the cardiac nerves. NE binds to the beta-1 receptors and opens chemical- or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions. NE shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increase in HR. Some cardiac medications (for example, beta blockers) work by blocking these receptors, thereby slowing HR and are one possible treatment for hypertension. Overprescription of these drugs may lead to bradycardia and even stoppage of the heart.', 'f04b5d8f-f228-4ea0-9458-04efe71dbd43': 'Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve (cranial nerve X). The vagus nerve sends branches to both the SA and AV nodes to decrease HR. Parasympathetic stimulation releases the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. ACh slows HR by opening chemical- or ligand-gated potassium ion channels to slow the rate of spontaneous depolarization and increase the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 100 bpm. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove one’s foot from the break and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 100 bpm. Any increases beyond this rate would require sympathetic stimulation. Figure 19.4.3 illustrates the effects of parasympathetic and sympathetic stimulation on the normal sinus rhythm.', '192aeeb5-b2c1-447f-95d7-d79d56af45f9': 'The cardiovascular center receives input from the limbic system as well as a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors. Collectively, these inputs normally enable the cardiovascular centers to regulate heart function precisely, a process known as cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. Any such increase in physical activity would logically warrant increased blood flow. The cardiac centers monitor these increased rates of firing, and suppress parasympathetic stimulation and increase sympathetic stimulation as needed in order to increase blood flow.', '05a0226b-bbbc-40f4-a01d-ff473311364b': 'Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the rightatrium. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic stimulation. As pressure and stretch decrease, the rate of baroreceptor firing decreases, and the cardiac centers increase sympathetic stimulation and decrease parasympathetic stimulation.', '3e4d4a73-108b-4c0e-b55d-e1ece43921fe': 'There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase HR.', 'c1f0ea85-2059-4eb8-b91c-b1316965b307': 'Increased metabolic byproducts associated with increased activity, such as carbon dioxide, hydrogen ions, and lactic acid, plus falling oxygen levels, are detected by a suite of chemoreceptors innervated by the glossopharyngeal and vagus nerves. These chemoreceptors provide feedback to the cardiovascular centers about the need for increased or decreased blood flow, based on the relative levels of these substances.', '2c0062cc-e5df-43dc-8c2c-01add95e7541': 'The limbic system can also significantly impact HR related to emotional state. During periods of stress, it is not unusual to identify higher than normal HRs, often accompanied by a surge in the stress hormone cortisol. Individuals experiencing extreme anxiety may manifest panic attacks with symptoms that resemble those of heart attacks. These events are typically transient and treatable. Meditation techniques have been developed to ease anxiety and have been shown to lower HR effectively. Doing simple deep and slow breathing exercises with one’s eyes closed can also significantly reduce this anxiety and HR.'}"
+Figure 19.3.1,Anatomy_And_Physio/images/Figure 19.3.1.jpg,"Figure 19.3.1 – Overview of the Cardiac Cycle: The cardiac cycle begins with atrial systole and progresses to ventricular systole, atrial diastole, and ventricular diastole, when the cycle begins again. Correlations to the ECG are highlighted.","The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle (Figure 19.3.1). The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole. Both the atria and ventricles undergo systole and diastole, and it is essential that these components be carefully regulated and coordinated to ensure blood is pumped efficiently to the body.","{'758fd97f-301b-4b8f-8da0-342af4daac5f': 'Many of the same factors that regulate HR also impact cardiac function by altering SV. While a number of variables are involved, SV is ultimately dependent upon the difference between EDV and ESV. The three primary factors to consider are preload, or the stretch on the ventricles prior to contraction; the contractility, or the force or strength of the contraction itself; and afterload, the force the ventricles must generate to pump blood against the resistance in the vessels. These factors are summarized in Table 19.1 and Table 19.2.', '86472935-e501-4e63-a8bd-2c3c48224f40': 'The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle (Figure 19.3.1). The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole. Both the atria and ventricles undergo systole and diastole, and it is essential that these components be carefully regulated and coordinated to ensure blood is pumped efficiently to the body.'}"
+Figure 19.3.3,Anatomy_And_Physio/images/Figure 19.3.3.jpg,"Figure 19.3.3 – Heart Sounds and the Cardiac Cycle: In this illustration, the x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure.","In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a “lub,” or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a “dub” (Figure 19.3.3). In both cases, as the valves close, the openings within the atrioventricular septum guarded by the valves will become reduced, and blood flow through the opening will become more turbulent until the valves are fully closed. There is a third heart sound, S3, but it is rarely heard in healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests. Some cardiologists refer to the collective S1, S2, and S3 sounds as the “Kentucky gallop,” because they mimic those produced by a galloping horse. The fourth heart sound, S4, results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the “Tennessee gallop,” because of their similarity to the sound produced by a galloping horse with a different gait. A few individuals may have both S3 and S4, and this combined sound is referred to as S7.","{'e71a0889-ea71-42e6-8a98-3eb42c92a4da': 'One of the simplest, yet effective, diagnostic techniques applied to assess the state of a patient’s heart is auscultation using a stethoscope.', 'd74d9cb5-43cf-4d15-b6d1-5d8b76bf1de3': 'In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a “lub,” or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a “dub” (Figure 19.3.3). In both cases, as the valves close, the openings within the atrioventricular septum guarded by the valves will become reduced, and blood flow through the opening will become more turbulent until the valves are fully closed. There is a third heart sound, S3, but it is rarely heard in healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests. Some cardiologists refer to the collective S1, S2, and S3 sounds as the “Kentucky gallop,” because they mimic those produced by a galloping horse. The fourth heart sound, S4, results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the “Tennessee gallop,” because of their similarity to the sound produced by a galloping horse with a different gait. A few individuals may have both S3 and S4, and this combined sound is referred to as S7.', '2b3862d7-37b6-494f-8a74-777fb25f89b1': 'The term murmur is used to describe an unusual sound coming from the heart that is caused by the turbulent flow of blood, usually due to valve problesms. For example an incompetent valve does not close completely leading to a “swish” sound as the blood flows backwards through the valve. A high pitch sound results as blood moves through a stiff (stenotic) valve.\xa0 Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the most difficult sound to detect, and the least serious. The most severe is a 6. Phonocardiograms or auscultograms can be used to record both normal and abnormal sounds using specialized electronic stethoscopes.', '484ef81e-5ae4-435a-a718-57a56aa7b615': 'During auscultation, it is common practice for the clinician to ask the patient to breathe deeply. This procedure not only allows for listening to airflow, but it may also amplify heart murmurs. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs. Figure 19.3.4 indicates proper placement of the bell of the stethoscope to facilitate auscultation.'}"
+Figure 19.3.4,Anatomy_And_Physio/images/Figure 19.3.4.jpg,"Figure 19.3.4 – Stethoscope Placement for Auscultation: Proper placement of the bell of the stethoscope facilitates auscultation. At each of the four locations on the chest, a different valve can be heard.","During auscultation, it is common practice for the clinician to ask the patient to breathe deeply. This procedure not only allows for listening to airflow, but it may also amplify heart murmurs. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs. Figure 19.3.4 indicates proper placement of the bell of the stethoscope to facilitate auscultation.","{'e71a0889-ea71-42e6-8a98-3eb42c92a4da': 'One of the simplest, yet effective, diagnostic techniques applied to assess the state of a patient’s heart is auscultation using a stethoscope.', 'd74d9cb5-43cf-4d15-b6d1-5d8b76bf1de3': 'In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a “lub,” or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a “dub” (Figure 19.3.3). In both cases, as the valves close, the openings within the atrioventricular septum guarded by the valves will become reduced, and blood flow through the opening will become more turbulent until the valves are fully closed. There is a third heart sound, S3, but it is rarely heard in healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests. Some cardiologists refer to the collective S1, S2, and S3 sounds as the “Kentucky gallop,” because they mimic those produced by a galloping horse. The fourth heart sound, S4, results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the “Tennessee gallop,” because of their similarity to the sound produced by a galloping horse with a different gait. A few individuals may have both S3 and S4, and this combined sound is referred to as S7.', '2b3862d7-37b6-494f-8a74-777fb25f89b1': 'The term murmur is used to describe an unusual sound coming from the heart that is caused by the turbulent flow of blood, usually due to valve problesms. For example an incompetent valve does not close completely leading to a “swish” sound as the blood flows backwards through the valve. A high pitch sound results as blood moves through a stiff (stenotic) valve.\xa0 Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the most difficult sound to detect, and the least serious. The most severe is a 6. Phonocardiograms or auscultograms can be used to record both normal and abnormal sounds using specialized electronic stethoscopes.', '484ef81e-5ae4-435a-a718-57a56aa7b615': 'During auscultation, it is common practice for the clinician to ask the patient to breathe deeply. This procedure not only allows for listening to airflow, but it may also amplify heart murmurs. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs. Figure 19.3.4 indicates proper placement of the bell of the stethoscope to facilitate auscultation.'}"
+Figure 19.2.1,Anatomy_And_Physio/images/Figure 19.2.1.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)","Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell (Figure 19.2.1a). These contractile elements are virtually identical to skeletal muscle. T (transverse) tubules penetrate from the surface plasma membrane, the sarcolemma, to the interior of the cell, allowing the electrical impulse to reach the interior. The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. In addition, the sarcoplasmic reticulum stores few calcium ions, so most of the calcium ions must come from outside the cells. The result is a slower onset of contraction. Mitochondria are plentiful, providing energy for the contractions of the heart.  Typically, cardiomyocytes have a single, central nucleus, but two or more nuclei may be found in some cells.","{'cd9a0103-2d16-419c-a7d9-29f738700dea': 'Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell (Figure 19.2.1a). These contractile elements are virtually identical to skeletal muscle. T (transverse) tubules penetrate from the surface plasma membrane, the sarcolemma, to the interior of the cell, allowing the electrical impulse to reach the interior. The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. In addition, the sarcoplasmic reticulum stores few calcium ions, so most of the calcium ions must come from outside the cells. The result is a slower onset of contraction. Mitochondria are plentiful, providing energy for the contractions of the heart.\xa0 Typically, cardiomyocytes have a single, central nucleus, but two or more nuclei may be found in some cells.', '36cb583b-6e1e-4164-a4ce-12a5fb14d0f1': 'Cardiac muscle cells branch freely. A junction between two adjoining cells is marked by a critical structure called an intercalated disc, which helps support the synchronized contraction of the muscle (Figure 19.2.1b). The sarcolemmas from adjacent cells bind together at the intercalated discs. They consist of desmosomes, specialized linking proteoglycans, tight junctions, and large numbers of gap junctions that allow the passage of ions between the cells and help to synchronize the contraction (Figure 19.2.1c). Intercellular connective tissue also helps to bind the cells together. The importance of strongly binding these cells together is necessitated by the forces exerted by contraction.'}"
+Figure 19.2.1,Anatomy_And_Physio/images/Figure 19.2.1.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)","Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell (Figure 19.2.1a). These contractile elements are virtually identical to skeletal muscle. T (transverse) tubules penetrate from the surface plasma membrane, the sarcolemma, to the interior of the cell, allowing the electrical impulse to reach the interior. The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. In addition, the sarcoplasmic reticulum stores few calcium ions, so most of the calcium ions must come from outside the cells. The result is a slower onset of contraction. Mitochondria are plentiful, providing energy for the contractions of the heart.  Typically, cardiomyocytes have a single, central nucleus, but two or more nuclei may be found in some cells.","{'cd9a0103-2d16-419c-a7d9-29f738700dea': 'Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell (Figure 19.2.1a). These contractile elements are virtually identical to skeletal muscle. T (transverse) tubules penetrate from the surface plasma membrane, the sarcolemma, to the interior of the cell, allowing the electrical impulse to reach the interior. The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. In addition, the sarcoplasmic reticulum stores few calcium ions, so most of the calcium ions must come from outside the cells. The result is a slower onset of contraction. Mitochondria are plentiful, providing energy for the contractions of the heart.\xa0 Typically, cardiomyocytes have a single, central nucleus, but two or more nuclei may be found in some cells.', '36cb583b-6e1e-4164-a4ce-12a5fb14d0f1': 'Cardiac muscle cells branch freely. A junction between two adjoining cells is marked by a critical structure called an intercalated disc, which helps support the synchronized contraction of the muscle (Figure 19.2.1b). The sarcolemmas from adjacent cells bind together at the intercalated discs. They consist of desmosomes, specialized linking proteoglycans, tight junctions, and large numbers of gap junctions that allow the passage of ions between the cells and help to synchronize the contraction (Figure 19.2.1c). Intercellular connective tissue also helps to bind the cells together. The importance of strongly binding these cells together is necessitated by the forces exerted by contraction.'}"
+Figure 19.2.2,Anatomy_And_Physio/images/Figure 19.2.2.jpg,"Figure 19.2.2 -Conduction System of the Heart: Specialized conducting components of the heart include the sinoatrial node, the internodal pathways, the atrioventricular node, the atrioventricular bundle, the right and left bundle branches, and the Purkinje fibers.","If embryonic heart cells are separated into a Petri dish and kept alive, each is capable of generating its own electrical impulse followed by contraction. When two independently beating embryonic cardiac muscle cells are placed together, the cell with the higher inherent rate sets the pace, and the impulse spreads from the faster to the slower cell to trigger a contraction. As more cells are joined together, the fastest cell continues to assume control of the rate. A fully developed adult heart maintains the capability of generating its own electrical impulse, triggered by the fastest cells, as part of the cardiac conduction system. The components of the cardiac conduction system include the sinoatrial node, the atrioventricular node, the atrioventricular bundle, the atrioventricular bundle branches, and the Purkinje cells (Figure 19.2.2).","{'e4ec84e1-51f5-484a-9508-401158df795b': 'The wave of contraction that allows the heart to work as a unit, called a functional syncytium, begins with the pacemaker cells. This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called autorhythmicity; they do this at set intervals which determine heart rate. Because they are connected with gap junctions to surrounding muscle fibers, the specialized fibers of the heart’s conduction system, the pacemaker cells are able to transfer the depolarization to the other cardiac muscle fibers in a manner that allows the heart to contract in a coordinated manner.', '7a9504a1-ab9a-44b2-8c91-583be6faa933': 'If embryonic heart cells are separated into a Petri dish and kept alive, each is capable of generating its own electrical impulse followed by contraction. When two independently beating embryonic cardiac muscle cells are placed together, the cell with the higher inherent rate sets the pace, and the impulse spreads from the faster to the slower cell to trigger a contraction. As more cells are joined together, the fastest cell continues to assume control of the rate. A fully developed adult heart maintains the capability of generating its own electrical impulse, triggered by the fastest cells, as part of the cardiac conduction system. The components of the cardiac conduction system include the sinoatrial node, the atrioventricular node, the atrioventricular bundle, the atrioventricular bundle branches, and the Purkinje cells (Figure 19.2.2).'}"
+Figure 19.2.6,Anatomy_And_Physio/images/Figure 19.2.6.jpg,"Figure 19.2.6 – Standard Placement of ECG Leads: In a 12-lead ECG, six electrodes are placed on the chest, and four electrodes are placed on the limbs.","By careful placement of surface electrodes on the body, it is possible to record the complex, composite electrical signal of the heart. This tracing of the electrical signal is the electrocardiogram (ECG), also commonly abbreviated EKG (K coming kardiology, from the German term for cardiology). Careful analysis of the ECG reveals a detailed picture of both normal and abnormal heart function, and is an indispensable clinical diagnostic tool. The standard electrocardiograph (the instrument that generates an ECG) uses 3, 5, or 12 leads. The greater the number of leads an electrocardiograph uses, the more information the ECG provides. The term “lead” may be used to refer to the cable from the electrode to the electrical recorder, but it typically describes the voltage difference between two electrodes (bipolar leads). The 12-lead electrocardiograph uses 10 electrodes placed in standard locations on the patient’s skin (Figure 19.2.6), the chest electrodes are unipolar and the appendage leads are bipolar. In continuous ambulatory electrocardiographs, the patient wears a small, portable, battery-operated device known as a Holter monitor, or simply a Holter, that continuously monitors heart electrical activity, typically for a period of 24 hours during the patient’s normal routine.","{'0ca8057d-320a-474f-bbbf-c4a8b2934782': 'By careful placement of surface electrodes on the body, it is possible to record the complex, composite electrical signal of the heart. This tracing of the electrical signal is the electrocardiogram (ECG), also commonly abbreviated EKG (K coming kardiology, from the German term for cardiology). Careful analysis of the ECG reveals a detailed picture of both normal and abnormal heart function, and is an indispensable clinical diagnostic tool. The standard electrocardiograph (the instrument that generates an ECG) uses 3, 5, or 12 leads. The greater the number of leads an electrocardiograph uses, the more information the ECG provides. The term “lead” may be used to refer to the cable from the electrode to the electrical recorder, but it typically describes the voltage difference between two electrodes (bipolar leads). The 12-lead electrocardiograph uses 10 electrodes placed in standard locations on the patient’s skin (Figure 19.2.6), the chest electrodes are unipolar and the appendage leads are bipolar. In continuous ambulatory electrocardiographs, the patient wears a small, portable, battery-operated device known as a Holter monitor, or simply a Holter, that continuously monitors heart electrical activity, typically for a period of 24 hours during the patient’s normal routine.', 'db6ee1fe-5a3f-44d5-9eaa-d142717edc7b': 'A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.', '64287e19-09f7-4fd3-b897-2915e7bdea12': 'There are five prominent components (points) on the ECG: the P wave, the QRS complex, and the T wave. The small P wave represents the depolarization of the atria. The atria begin contracting approximately 25 ms after the start of the P wave. The large QRS complex represents the depolarization of the ventricles, which requires a much stronger electrical signal because of the larger size of the ventricular cardiac muscle. The ventricles begin to contract as the QRS reaches the peak of the R wave. Lastly, the T wave represents the repolarization of the ventricles. The repolarization of the atria occurs during the QRS complex, which masks it on an ECG.', '64b66c71-5f60-425d-98e7-64b686569238': 'The major segments and intervals of an ECG tracing are indicated in Figure 19.2.7. Segments are defined as the regions between two waves. Intervals include one segment plus one or more waves. For example, the PR segment begins at the end of the P wave and ends at the beginning of the QRS complex. The PR interval starts at the beginning of the P wave and ends with the beginning of the QRS complex. The PR interval is more clinically relevant, as it measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. Since the Q wave may be difficult to view in some tracings, the measurement is often extended to the R that is more easily visible. Should there be a delay in passage of the impulse from the SA node to the AV node, it would be visible in the PR interval. Figure 19.2.8 correlates events of heart contraction to the corresponding segments and intervals of an ECG.'}"
+Figure 19.2.7,Anatomy_And_Physio/images/Figure 19.2.7.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments.","A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.","{'0ca8057d-320a-474f-bbbf-c4a8b2934782': 'By careful placement of surface electrodes on the body, it is possible to record the complex, composite electrical signal of the heart. This tracing of the electrical signal is the electrocardiogram (ECG), also commonly abbreviated EKG (K coming kardiology, from the German term for cardiology). Careful analysis of the ECG reveals a detailed picture of both normal and abnormal heart function, and is an indispensable clinical diagnostic tool. The standard electrocardiograph (the instrument that generates an ECG) uses 3, 5, or 12 leads. The greater the number of leads an electrocardiograph uses, the more information the ECG provides. The term “lead” may be used to refer to the cable from the electrode to the electrical recorder, but it typically describes the voltage difference between two electrodes (bipolar leads). The 12-lead electrocardiograph uses 10 electrodes placed in standard locations on the patient’s skin (Figure 19.2.6), the chest electrodes are unipolar and the appendage leads are bipolar. In continuous ambulatory electrocardiographs, the patient wears a small, portable, battery-operated device known as a Holter monitor, or simply a Holter, that continuously monitors heart electrical activity, typically for a period of 24 hours during the patient’s normal routine.', 'db6ee1fe-5a3f-44d5-9eaa-d142717edc7b': 'A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.', '64287e19-09f7-4fd3-b897-2915e7bdea12': 'There are five prominent components (points) on the ECG: the P wave, the QRS complex, and the T wave. The small P wave represents the depolarization of the atria. The atria begin contracting approximately 25 ms after the start of the P wave. The large QRS complex represents the depolarization of the ventricles, which requires a much stronger electrical signal because of the larger size of the ventricular cardiac muscle. The ventricles begin to contract as the QRS reaches the peak of the R wave. Lastly, the T wave represents the repolarization of the ventricles. The repolarization of the atria occurs during the QRS complex, which masks it on an ECG.', '64b66c71-5f60-425d-98e7-64b686569238': 'The major segments and intervals of an ECG tracing are indicated in Figure 19.2.7. Segments are defined as the regions between two waves. Intervals include one segment plus one or more waves. For example, the PR segment begins at the end of the P wave and ends at the beginning of the QRS complex. The PR interval starts at the beginning of the P wave and ends with the beginning of the QRS complex. The PR interval is more clinically relevant, as it measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. Since the Q wave may be difficult to view in some tracings, the measurement is often extended to the R that is more easily visible. Should there be a delay in passage of the impulse from the SA node to the AV node, it would be visible in the PR interval. Figure 19.2.8 correlates events of heart contraction to the corresponding segments and intervals of an ECG.'}"
+Figure 19.2.7,Anatomy_And_Physio/images/Figure 19.2.7.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments.","A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.","{'0ca8057d-320a-474f-bbbf-c4a8b2934782': 'By careful placement of surface electrodes on the body, it is possible to record the complex, composite electrical signal of the heart. This tracing of the electrical signal is the electrocardiogram (ECG), also commonly abbreviated EKG (K coming kardiology, from the German term for cardiology). Careful analysis of the ECG reveals a detailed picture of both normal and abnormal heart function, and is an indispensable clinical diagnostic tool. The standard electrocardiograph (the instrument that generates an ECG) uses 3, 5, or 12 leads. The greater the number of leads an electrocardiograph uses, the more information the ECG provides. The term “lead” may be used to refer to the cable from the electrode to the electrical recorder, but it typically describes the voltage difference between two electrodes (bipolar leads). The 12-lead electrocardiograph uses 10 electrodes placed in standard locations on the patient’s skin (Figure 19.2.6), the chest electrodes are unipolar and the appendage leads are bipolar. In continuous ambulatory electrocardiographs, the patient wears a small, portable, battery-operated device known as a Holter monitor, or simply a Holter, that continuously monitors heart electrical activity, typically for a period of 24 hours during the patient’s normal routine.', 'db6ee1fe-5a3f-44d5-9eaa-d142717edc7b': 'A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.', '64287e19-09f7-4fd3-b897-2915e7bdea12': 'There are five prominent components (points) on the ECG: the P wave, the QRS complex, and the T wave. The small P wave represents the depolarization of the atria. The atria begin contracting approximately 25 ms after the start of the P wave. The large QRS complex represents the depolarization of the ventricles, which requires a much stronger electrical signal because of the larger size of the ventricular cardiac muscle. The ventricles begin to contract as the QRS reaches the peak of the R wave. Lastly, the T wave represents the repolarization of the ventricles. The repolarization of the atria occurs during the QRS complex, which masks it on an ECG.', '64b66c71-5f60-425d-98e7-64b686569238': 'The major segments and intervals of an ECG tracing are indicated in Figure 19.2.7. Segments are defined as the regions between two waves. Intervals include one segment plus one or more waves. For example, the PR segment begins at the end of the P wave and ends at the beginning of the QRS complex. The PR interval starts at the beginning of the P wave and ends with the beginning of the QRS complex. The PR interval is more clinically relevant, as it measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. Since the Q wave may be difficult to view in some tracings, the measurement is often extended to the R that is more easily visible. Should there be a delay in passage of the impulse from the SA node to the AV node, it would be visible in the PR interval. Figure 19.2.8 correlates events of heart contraction to the corresponding segments and intervals of an ECG.'}"
+Figure 19.1.1,Anatomy_And_Physio/images/Figure 19.1.1.jpg,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base.","The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 19.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.","{'9eb3a7b6-7f3d-4ee5-90ea-f9498f3e3fa2': 'The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 19.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.', 'a0938f1b-cdd2-4608-9f7a-e68184e58e22': 'The shape of the heart is similar to a inverted pear, rather broad at the superior surface and tapering to the apex (see Figure 19.1.1). A typical heart is approximately the size of your fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness. Given the size difference between most members of the sexes, the weight of a female heart is approximately 250–300 grams (9 to 11 ounces), and the weight of a male heart is approximately 300–350 grams (11 to 12 ounces). The heart of a well-trained athlete, especially one specializing in aerobic sports, can be considerably larger than this. Cardiac muscle responds to exercise in a manner similar to that of skeletal muscle. That is, exercise results in the addition of protein myofilaments that increase the size of the individual cells without increasing their numbers, a concept called hypertrophy. Hearts of athletes can pump blood more effectively at lower rates than those of nonathletes. Enlarged hearts are not always a result of exercise; they can result from pathologies, such as hypertrophic cardiomyopathy. The cause of such an abnormally enlarged heart muscle is unknown, but the condition is often undiagnosed and can cause sudden death in apparently otherwise healthy young people.'}"
+Figure 19.1.1,Anatomy_And_Physio/images/Figure 19.1.1.jpg,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base.","The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 19.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.","{'9eb3a7b6-7f3d-4ee5-90ea-f9498f3e3fa2': 'The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 19.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.', 'a0938f1b-cdd2-4608-9f7a-e68184e58e22': 'The shape of the heart is similar to a inverted pear, rather broad at the superior surface and tapering to the apex (see Figure 19.1.1). A typical heart is approximately the size of your fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness. Given the size difference between most members of the sexes, the weight of a female heart is approximately 250–300 grams (9 to 11 ounces), and the weight of a male heart is approximately 300–350 grams (11 to 12 ounces). The heart of a well-trained athlete, especially one specializing in aerobic sports, can be considerably larger than this. Cardiac muscle responds to exercise in a manner similar to that of skeletal muscle. That is, exercise results in the addition of protein myofilaments that increase the size of the individual cells without increasing their numbers, a concept called hypertrophy. Hearts of athletes can pump blood more effectively at lower rates than those of nonathletes. Enlarged hearts are not always a result of exercise; they can result from pathologies, such as hypertrophic cardiomyopathy. The cause of such an abnormally enlarged heart muscle is unknown, but the condition is often undiagnosed and can cause sudden death in apparently otherwise healthy young people.'}"
+Figure 19.1.2,Anatomy_And_Physio/images/Figure 19.1.2.jpg,"Figure 19.1.2 – Dual System of the Human Blood Circulation: Blood flows from the right atrium to the right ventricle, where it is pumped into the pulmonary circuit. The blood in the pulmonary artery branches is low in oxygen but relatively high in carbon dioxide. Gas exchange occurs in the pulmonary capillaries (oxygen into the blood, carbon dioxide out), and blood high in oxygen and low in carbon dioxide is returned to the left atrium. From here, blood enters the left ventricle, which pumps it into the systemic circuit. Following exchange in the systemic capillaries (oxygen and nutrients out of the capillaries and carbon dioxide and wastes in), blood returns to the right atrium and the cycle is repeated.","The blood exiting the systemic capillaries is lower in oxygen concentration than when it entered. The capillaries will ultimately unite to form venules, joining to form ever-larger veins, eventually flowing into the two major systemic veins, the superior vena cava and the inferior vena cava, which return blood to the right atrium. The blood in the superior and inferior venae cavae flows into the right atrium, which pumps blood into the right ventricle. This process of blood circulation continues as long as the individual remains alive. Understanding the flow of blood through the pulmonary and systemic circuits is critical to all health professions (Figure 19.1.2).","{'35f8bcad-ad5b-4467-8dcb-49b4c9da431c': 'The human heart consists of four chambers: The left side and the right side each have one atrium and one ventricle. Each of the upper chambers, the right atrium (plural = atria) and the left atrium, act as receiving chambers and the combination of gravity and atrial contraction move blood into the lower chambers, the right ventricle and the left ventricle. The ventricles serve as the primary pumping chambers of the heart, propelling blood to the lungs or to the rest of the body.', 'f4ceda0f-3dec-4dab-8482-2f3d77daa75a': 'There are two distinct but linked circuits in the human circulation called the pulmonary and systemic circuits. Although both circuits transport blood and everything it carries (see section 18.1), we can initially view the circuits from the point of view of gases. The pulmonary circuit transports blood to and from the lungs, where it picks up oxygen and delivers carbon dioxide for exhalation. The systemic circuit transports oxygenated blood to virtually all of the tissues of the body and returns relatively deoxygenated blood and carbon dioxide to the heart to be sent back to the pulmonary circulation. These two circulations function simultaneously and thus the heart functions as a dual pump.', '48fe3562-7b56-4c08-b9e2-3e8f9d58aa60': 'The right ventricle pumps deoxygenated blood into the pulmonary trunk, which leads toward the lungs and bifurcates into the left and right pulmonary arteries. Arteries carry blood away from the heart. These vessels in turn branch many times before reaching the pulmonary capillaries, where gas exchange occurs: Carbon dioxide diffuses out of the blood and oxygen diffuses into the blood. The pulmonary trunk arteries and their branches are the only arteries in the post-natal body that carry relatively deoxygenated blood. Highly oxygenated blood returning from the pulmonary capillaries in the lungs passes through a series of vessels that join together to form the pulmonary veins—the only post-natal veins in the body that carry highly oxygenated blood. Veins carry blood toward the heart. The pulmonary veins conduct blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and on to the many branches of the systemic circuit. Eventually, these vessels will lead to the systemic capillaries, where exchange with the tissue fluid and cells of the body occurs. In this case, oxygen and nutrients out of the systemic capillaries to be used by the cells in their metabolic processes, and carbon dioxide and waste products diffuse into the blood.', '9a54c580-a6fc-425a-bb78-e0ef37736c33': 'The blood exiting the systemic capillaries is lower in oxygen concentration than when it entered. The capillaries will ultimately unite to form venules, joining to form ever-larger veins, eventually flowing into the two major systemic veins, the superior vena cava and the inferior vena cava, which return blood to the right atrium. The blood in the superior and inferior venae cavae flows into the right atrium, which pumps blood into the right ventricle. This process of blood circulation continues as long as the individual remains alive. Understanding the flow of blood through the pulmonary and systemic circuits is critical to all health professions (Figure 19.1.2).'}"
+Figure 19.1.8,Anatomy_And_Physio/images/Figure 19.1.8.jpg,"Figure 19.1.8 – Internal Structures of the Heart: This anterior view of the heart shows the four chambers, the major vessels and their early branches, as well as the four valves. The presence of the pulmonary trunk and aorta covers the interatrial septum, and the atrioventricular septum is cut away to show the atrioventricular valves.","Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because the right and left pair of chambers simultaneously pump blood into the pulmonary and systemic circulations respectively. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in Figure 19.1.8.","{'6d2cbdf8-2789-49b3-92a7-80bbe5efb859': 'Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because the right and left pair of chambers simultaneously pump blood into the pulmonary and systemic circulations respectively. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in Figure 19.1.8.', 'bed19af1-b335-48b1-85b4-0ef388984c57': 'Cardiologists are medical doctors that specialize in the diagnosis and treatment of diseases of the heart. After completing 4 years of medical school, cardiologists complete a three-year residency in internal medicine followed by an additional three or more years in cardiology. Following this 10-year period of medical training and clinical experience, they qualify for a rigorous two-day examination administered by the Board of Internal Medicine that tests their academic training and clinical abilities, including diagnostics and treatment. After successful completion of this examination, a physician becomes a board-certified cardiologist. Some board-certified cardiologists may be invited to become a Fellow of the American College of Cardiology (FACC). This professional recognition is awarded to outstanding physicians based upon merit, including outstanding credentials, achievements, and community contributions to cardiovascular medicine.', 'bb1391c5-d022-4755-8d04-3c48d0a1c02b': 'Cardiovascular technologists/technicians are trained professionals who perform a variety of imaging techniques, such as sonograms or echocardiograms, used by physicians to diagnose and treat diseases of the heart. Nearly all of these positions require an associate degree, and these technicians earn a median salary of $49,410 as of May 2010, according to the U.S. Bureau of Labor Statistics. Growth within the field is fast, projected at 29 percent from 2010 to 2020.', '6dbe0764-8519-437c-82c8-5b28f424e586': 'There is a considerable overlap and complementary skills between cardiac technicians and vascular technicians, and so the term cardiovascular technician is often used. Special certifications within the field require documenting appropriate experience and completing additional and often expensive certification examinations. These subspecialties include Certified Rhythm Analysis Technician (CRAT), Certified Cardiographic Technician (CCT), Registered Congenital Cardiac Sonographer (RCCS), Registered Cardiac Electrophysiology Specialist (RCES), Registered Cardiovascular Invasive Specialist (RCIS), Registered Cardiac Sonographer (RCS), Registered Vascular Specialist (RVS), and Registered Phlebology Sonographer (RPhS).'}"
+Figure 18.6.1,Anatomy_And_Physio/images/Figure 18.6.1.jpg,"Figure 18.6.1 – Erythroblastosis Fetalis: The first exposure of an Rh− mother to Rh+ erythrocytes during pregnancy induces sensitization. Anti-Rh antibodies begin to circulate in the mother’s bloodstream. A second exposure occurs with a subsequent pregnancy with an Rh+ fetus in the uterus. Maternal anti-Rh antibodies may cross the placenta and enter the fetal bloodstream, causing agglutination and hemolysis of fetal erythrocytes.","In contrast to the ABO group antibodies, which are preformed, antibodies to the Rh antigen are produced only in Rh− individuals after exposure to the antigen. This process, called sensitization, occurs following a transfusion with Rh-incompatible blood or, more commonly, with the birth of an Rh+ baby to an Rh− mother. Problems are rare in a first pregnancy, since the baby’s Rh+ cells rarely cross the placenta (the organ of gas and nutrient exchange between the baby and the mother). However, during or immediately after birth, the Rh− mother can be exposed to the baby’s Rh+ cells (Figure 18.6.1). Research has shown that this occurs in about 13−14 percent of such pregnancies. After exposure, the mother’s immune system begins to generate anti-Rh antibodies. If the mother should then conceive another Rh+ baby, the Rh antibodies she has produced can cross the placenta into the fetal bloodstream and destroy the fetal RBCs. This condition, known as hemolytic disease of the newborn (HDN) or erythroblastosis fetalis, may cause anemia in mild cases, but the agglutination and hemolysis can be so severe that without treatment the fetus may die in the womb or shortly after birth.","{'507d3b7c-5d48-4373-bf8d-e361ba01d9b5': 'The Rh blood group is classified according to the presence or absence of a second erythrocyte antigen identified as Rh. (It was first discovered in a type of primate known as a rhesus macaque, which is often used in research, because its blood is similar to that of humans.) Although dozens of Rh antigens have been identified, only one, designated D, is clinically important. Those who have the Rh D antigen present on their erythrocytes—about 85 percent of Americans—are described as Rh positive (Rh+) and those who lack it are Rh negative (Rh−). Note that the Rh group is distinct from the ABO group, so any individual, no matter their ABO blood type, may have or lack this Rh antigen. When identifying a patient’s blood type, the Rh group is designated by adding the word positive or negative to the ABO type. For example, A positive (A+) means ABO group A blood with the Rh antigen present, and AB negative (AB−) means ABO group AB blood without the Rh antigen.', '46aea82a-dbd3-4819-9a97-27b5c692cd4c': 'Table 18.2 summarizes the distribution of the ABO and Rh blood types within the United States.', '100b1cd3-d262-4cc6-905a-95a8b517a81b': 'In contrast to the ABO group antibodies, which are preformed, antibodies to the Rh antigen are produced only in Rh− individuals after exposure to the antigen. This process, called sensitization, occurs following a transfusion with Rh-incompatible blood or, more commonly, with the birth of an Rh+ baby to an Rh− mother. Problems are rare in a first pregnancy, since the baby’s Rh+ cells rarely cross the placenta (the organ of gas and nutrient exchange between the baby and the mother). However, during or immediately after birth, the Rh− mother can be exposed to the baby’s Rh+ cells (Figure 18.6.1). Research has shown that this occurs in about 13−14 percent of such pregnancies. After exposure, the mother’s immune system begins to generate anti-Rh antibodies. If the mother should then conceive another Rh+ baby, the Rh antibodies she has produced can cross the placenta into the fetal bloodstream and destroy the fetal RBCs. This condition, known as hemolytic disease of the newborn (HDN) or erythroblastosis fetalis, may cause anemia in mild cases, but the agglutination and hemolysis can be so severe that without treatment the fetus may die in the womb or shortly after birth.', '491df4c8-8b64-4e73-b14c-cae67433446e': 'A drug known as RhoGAM, short for Rh immune globulin, can temporarily prevent the development of Rh antibodies in the Rh− mother, thereby averting this potentially serious disease for the fetus. RhoGAM antibodies destroy any fetal Rh+ erythrocytes that may cross the placental barrier. RhoGAM is normally administered to Rh− mothers during weeks 26−28 of pregnancy and within 72 hours following birth. It has proven remarkably effective in decreasing the incidence of HDN. Earlier we noted that the incidence of HDN in an Rh+ subsequent pregnancy to an Rh− mother is about 13–14 percent without preventive treatment. Since the introduction of RhoGAM in 1968, the incidence has dropped to about 0.1 percent in the United States.'}"
+Figure 18.6.2,Anatomy_And_Physio/images/Figure 18.6.2.jpg,"Figure 18.6.2 – Cross Matching Blood Types: This sample of a commercially produced “bedside” card enables quick typing of both a recipient’s and donor’s blood before transfusion. The card contains three reaction sites or wells. One is coated with an anti-A antibody, one with an anti-B antibody, and one with an anti-D antibody (tests for the presence of Rh factor D). Mixing a drop of blood and saline into each well enables the blood to interact with a preparation of type-specific antibodies. Agglutination of RBCs in a given site indicates a positive identification of the blood antigens, in this case A and Rh antigens for blood type A+. For the purpose of transfusion, the donor’s and recipient’s blood types must match.","Clinicians are able to determine a patient’s blood type quickly and easily using commercially prepared antibodies. An unknown blood sample is allocated into separate wells. Into one well a small amount of anti-A antibody is added, and to another a small amount of anti-B antibody. If the antigen is present, the antibodies will cause visible agglutination of the cells (Figure 18.6.2). The blood should also be tested for Rh antibodies.","{'0de4754f-18d3-49ea-a092-cef42cc0a19f': 'Clinicians are able to determine a patient’s blood type quickly and easily using commercially prepared antibodies. An unknown blood sample is allocated into separate wells. Into one well a small amount of anti-A antibody is added, and to another a small amount of anti-B antibody. If the antigen is present, the antibodies will cause visible agglutination of the cells (Figure 18.6.2). The blood should also be tested for Rh antibodies.'}"
+Figure 18.6.3,Anatomy_And_Physio/images/Figure 18.6.3.jpg,Figure 18.6.3 – ABO Blood Group: This chart summarizes the characteristics of the blood types in the ABO blood group. See the text for more on the concept of a universal donor or recipient.,"A patient with blood type AB+ is known as the universal recipient. This patient can theoretically receive any type of blood, because the patient’s own blood—having both A and B antigens on the erythrocyte surface—does not produce anti-A or anti-B antibodies. In addition, an Rh+ patient can receive both Rh+ and Rh− blood.  Figure 18.6.3 summarizes the blood types and transfusion compatibility.","{'ea678cd7-4f8e-4f2d-844d-16db963fb6c2': 'To avoid transfusion reactions, it is best to transfuse only matching blood types; that is, a type B+ recipient should ideally receive blood only from a type B+ donor and so on. That said, in emergency situations, when acute hemorrhage threatens the patient’s life, there may not be time for cross matching to identify blood type. In these cases, blood from a universal donor—an individual with type O− blood—may be transfused. Recall that type O erythrocytes do not display A or B antigens. Thus, anti-A or anti-B antibodies that might be circulating in the patient’s blood plasma will not encounter any erythrocyte surface antigens on the donated blood and therefore will not be provoked into a response. Ideally, the transfusion is not whole blood, but only red blood cells and saline, avoiding the problem of type A or type B antibodies in the donor’s plasma being transfused to the patient. If whole blood is transfused instead, and the the O− donor had prior exposure to Rh antigen, Rh antibodies may be present in the donated blood. Also, introducing type O blood into an individual with type A, B, or AB blood would introduce antibodies against both A and B antigens, as these are always circulating in the type O blood plasma. This may cause problems for the recipient, but because the volume of blood transfused is much lower than the volume of the patient’s own blood, the adverse effects of the relatively few infused plasma antibodies are typically limited. For these reasons, it is preferable to cross match a patient’s blood before transfusing, or only transfuse red blood cells and saline. In a true life-threatening emergency situation, this is not always possible, and the universal donor (O-) whole blood could be used.', '8622fa9e-d68f-434f-8a12-a72dd7f885c2': 'A patient with blood type AB+ is known as the universal recipient. This patient can theoretically receive any type of blood, because the patient’s own blood—having both A and B antigens on the erythrocyte surface—does not produce anti-A or anti-B antibodies. In addition, an Rh+ patient can receive both Rh+ and Rh− blood.\xa0 Figure 18.6.3 summarizes the blood types and transfusion compatibility.', 'c64dc1cc-f9c8-4efa-962f-e1354692006d': 'At the scene of multiple-vehicle accidents, military engagements, and natural or human-caused disasters, many victims may suffer simultaneously from acute hemorrhage, yet type O blood may not be immediately available. In these circumstances, medics may at least try to replace some of the volume of blood that has been lost. This is done by intravenous administration of a saline solution that provides fluids and electrolytes in proportions equivalent to those of normal blood plasma. Research is ongoing to develop a safe and effective artificial blood that would carry out the oxygen-carrying function of blood without the RBCs, enabling transfusions in the field without concern for incompatibility. These blood substitutes normally contain hemoglobin- as well as perfluorocarbon-based oxygen carriers.'}"
+Figure 18.5.1,Anatomy_And_Physio/images/Figure 18.5.1.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)","More sophisticated and durable repairs made beyond the plug formation are collectively called coagulation, the formation of a blood clot. The process is sometimes characterized as a cascade, because one event prompts the next as in a multi-level waterfall. The result is the production of a gelatinous but robust clot made up of a mesh of fibrin—an insoluble filamentous protein derived from fibrinogen, the plasma protein introduced earlier—in which platelets and blood cells are trapped. Figure 18.5.1 summarizes the three steps of hemostasis following injury.","{'7ef07214-8dee-4a31-b3d5-8255176d4074': 'More sophisticated and durable repairs made beyond the plug formation are collectively called coagulation, the formation of a blood clot. The process is sometimes characterized as a cascade, because one event prompts the next as in a multi-level waterfall. The result is the production of a gelatinous but robust clot made up of a mesh of fibrin—an insoluble filamentous protein derived from fibrinogen, the plasma protein introduced earlier—in which platelets and blood cells are trapped. Figure 18.5.1 summarizes the three steps of hemostasis following injury.', '9417cf49-8269-4192-905d-7a9a5b347494': 'The stabilized clot is acted upon by contractile proteins within the platelets. As these proteins contract, they pull on the fibrin threads, bringing the edges of the clot more tightly together, somewhat as we do when tightening loose shoelaces (see Figure 18.5.1a). This process also wrings out of the clot a small amount of fluid called serum, which is blood plasma without its clotting factors.', 'fa566517-0fdb-4d99-90ac-91e2e3861753': 'To restore normal blood flow as the vessel heals, the clot must eventually be removed. Fibrinolysis is the gradual degradation of the clot. Again, there is a fairly complicated series of reactions that involves factor XII and protein-catabolizing enzymes. During this process, the inactive protein plasminogen is converted into the active plasmin, which gradually breaks down the fibrin of the clot. Additionally, bradykinin, a vasodilator, is released, reversing the effects of the serotonin and prostaglandins from the platelets. This allows the smooth muscle in the walls of the vessels to relax and helps to restore the circulation.'}"
+Figure 18.5.1,Anatomy_And_Physio/images/Figure 18.5.1.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)","More sophisticated and durable repairs made beyond the plug formation are collectively called coagulation, the formation of a blood clot. The process is sometimes characterized as a cascade, because one event prompts the next as in a multi-level waterfall. The result is the production of a gelatinous but robust clot made up of a mesh of fibrin—an insoluble filamentous protein derived from fibrinogen, the plasma protein introduced earlier—in which platelets and blood cells are trapped. Figure 18.5.1 summarizes the three steps of hemostasis following injury.","{'7ef07214-8dee-4a31-b3d5-8255176d4074': 'More sophisticated and durable repairs made beyond the plug formation are collectively called coagulation, the formation of a blood clot. The process is sometimes characterized as a cascade, because one event prompts the next as in a multi-level waterfall. The result is the production of a gelatinous but robust clot made up of a mesh of fibrin—an insoluble filamentous protein derived from fibrinogen, the plasma protein introduced earlier—in which platelets and blood cells are trapped. Figure 18.5.1 summarizes the three steps of hemostasis following injury.', '9417cf49-8269-4192-905d-7a9a5b347494': 'The stabilized clot is acted upon by contractile proteins within the platelets. As these proteins contract, they pull on the fibrin threads, bringing the edges of the clot more tightly together, somewhat as we do when tightening loose shoelaces (see Figure 18.5.1a). This process also wrings out of the clot a small amount of fluid called serum, which is blood plasma without its clotting factors.', 'fa566517-0fdb-4d99-90ac-91e2e3861753': 'To restore normal blood flow as the vessel heals, the clot must eventually be removed. Fibrinolysis is the gradual degradation of the clot. Again, there is a fairly complicated series of reactions that involves factor XII and protein-catabolizing enzymes. During this process, the inactive protein plasminogen is converted into the active plasmin, which gradually breaks down the fibrin of the clot. Additionally, bradykinin, a vasodilator, is released, reversing the effects of the serotonin and prostaglandins from the platelets. This allows the smooth muscle in the walls of the vessels to relax and helps to restore the circulation.'}"
+Figure 18.4.1,Anatomy_And_Physio/images/Figure 18.4.1.jpg,"Figure 18.4.1 – Emigration: Leukocytes exit the blood vessel and then move through the connective tissue of the dermis toward the site of a wound. Some leukocytes, such as the eosinophil and neutrophil, are characterized as granular leukocytes. They release chemicals from their granules that destroy pathogens; they are also capable of phagocytosis. The monocyte, an agranular leukocyte, differentiates into a macrophage that then phagocytizes the pathogens.","One of the most distinctive characteristics of leukocytes is their movement. Whereas erythrocytes spend their days circulating within the blood vessels, leukocytes routinely leave the bloodstream to perform their defensive functions in the body’s tissues. For leukocytes, the vascular network is a highway they travel and then exit to reach their destination. These cells are sometimes given distinct names depending on their function, such as macrophage or microglia, . As shown in Figure 18.4.1, they leave the capillaries—the smallest blood vessels—or other small vessels through a process known as emigration (from the Latin for “removal”) or diapedesis (dia- = “through”; -pedan = “to leap”) in which they squeeze through adjacent cells in a blood vessel wall.","{'ae177a48-6a58-4f8f-945f-03e1e6b41ab1': 'Although leukocytes and erythrocytes both originate from hematopoietic stem cells in the bone marrow, they are very different from each other in many significant ways. For instance, leukocytes are far less numerous than erythrocytes: Typically there are only 5000 to 10,000 per µL. They are also larger than erythrocytes and are the only formed elements that are complete cells, possessing a nucleus and organelles. And although there is just one type of erythrocyte, there are many types of leukocytes. Most of these types have a much shorter lifespan than that of erythrocytes, some as short as a few hours or even a few minutes in the case of acute infection.', 'b5572700-1075-4a8c-9427-0e317c9b138c': 'One of the most distinctive characteristics of leukocytes is their movement. Whereas erythrocytes spend their days circulating within the blood vessels, leukocytes routinely leave the bloodstream to perform their defensive functions in the body’s tissues. For leukocytes, the vascular network is a highway they travel and then exit to reach their destination. These cells are sometimes given distinct names\xa0depending on their function, such as macrophage or microglia, . As shown in Figure 18.4.1, they leave the capillaries—the smallest blood vessels—or other small vessels through a process known as emigration (from the Latin for “removal”) or diapedesis (dia- = “through”; -pedan = “to leap”) in which they squeeze through adjacent cells in a blood vessel wall.', 'd4bcc9b6-f6f1-4d4d-9790-7b249a18e3b1': 'Once they have exited the capillaries, some leukocytes will take up fixed positions in lymphatic tissue, bone marrow, the spleen, the thymus, or other organs. Others will move about through the tissue spaces very much like amoebas, continuously extending their plasma membranes, sometimes wandering freely, and sometimes moving toward the direction in which they are drawn by chemical signals. This attracting of leukocytes occurs because of positive chemotaxis (literally “movement in response to chemicals”), a phenomenon in which injured or infected cells and nearby leukocytes emit the equivalent of a chemical “emergency” call, attracting more leukocytes to the site. In clinical medicine, the differential counts of the types and percentages of leukocytes present are often key indicators in making a diagnosis and selecting a treatment.'}"
+Figure 18.4.3,Anatomy_And_Physio/images/Figure 18.4.3.jpg,Figure 18.4.3 – Platelets: Platelets are derived from cells called megakaryocytes.,"You may occasionally see platelets referred to as thrombocytes, but because this name suggests they are a type of cell, it is not accurate. A platelet is not a cell but rather a fragment of the cytoplasm of a cell called a megakaryocyte that is surrounded by a plasma membrane. Megakaryocytes are descended from myeloid stem cells (see Chapter 18.2 Production of the Formed Elements) and are large, typically 50–100 µm in diameter, and contain an enlarged, lobed nucleus. As noted earlier, thrombopoietin, a glycoprotein secreted by the kidneys and liver, stimulates the proliferation of megakaryoblasts, which mature into megakaryocytes. These remain within bone marrow tissue (Figure 18.4.3) and ultimately form platelet-precursor extensions that extend through the walls of bone marrow capillaries to release into the circulation thousands of cytoplasmic fragments, each enclosed by a bit of plasma membrane. These enclosed fragments are platelets. Each megakarocyte releases 2000–3000 platelets during its lifespan. Following platelet release, megakaryocyte remnants, which are little more than a cell nucleus, are consumed by macrophages.","{'e7b30914-aeac-4b48-a9b8-9b49a79d6159': 'You may occasionally see platelets referred to as thrombocytes, but because this name suggests they are a type of cell, it is not accurate. A platelet is not a cell but rather a fragment of the cytoplasm of a cell called a megakaryocyte that is surrounded by a plasma membrane. Megakaryocytes are descended from myeloid stem cells (see Chapter 18.2 Production of the Formed Elements) and are large, typically 50–100 µm in diameter, and contain an enlarged, lobed nucleus. As noted earlier, thrombopoietin, a glycoprotein secreted by the kidneys and liver, stimulates the proliferation of megakaryoblasts, which mature into megakaryocytes. These remain within bone marrow tissue (Figure 18.4.3) and ultimately form platelet-precursor extensions that extend through the walls of bone marrow capillaries to release into the circulation thousands of cytoplasmic fragments, each enclosed by a bit of plasma membrane. These enclosed fragments are platelets. Each megakarocyte releases 2000–3000 platelets during its lifespan. Following platelet release, megakaryocyte remnants, which are little more than a cell nucleus, are consumed by macrophages.', '9ebb6be2-dcbb-4c77-b8ec-81daf9b3ea9a': 'Platelets are relatively small, 2–4 µm in diameter, but numerous, with typically 150,000–160,000 per µL of blood. After entering the circulation, approximately one-third migrate to the spleen for storage for later release in response to any rupture in a blood vessel. They then become activated to perform their primary function, which is to limit blood loss. Platelets remain only about 10 days, then are phagocytized by macrophages.', '4de50435-046f-4142-9498-2a9e903e001a': 'Platelets are critical to hemostasis, the stoppage of blood flow following damage to a vessel. They also secrete a variety of growth factors essential for growth and repair of tissue, particularly connective tissue. Infusions of concentrated platelets are now being used in some therapies to stimulate healing.'}"
+Figure 18.3.1,Anatomy_And_Physio/images/Figure 18.3.1.jpg,Figure 18.3.1 Summary of Formed Elements in Blood,"The erythrocyte, commonly known as a red blood cell (or RBC), is by far the most common formed element: A single drop of blood contains millions of erythrocytes and only thousands of leukocytes (Figure 18.3.1). Specifically, males have about 5.4 million erythrocytes per microliter (µL) of blood, and females have approximately 4.8 million per µL. In fact, erythrocytes are estimated to make up about 25 percent of the total cells in the body. They are small cells, with a mean diameter of 7–8 micrometers (µm). The primary function of erythrocytes is to pick up oxygen from the lungs and transport it to the body’s tissues, and to pick up carbon dioxide at the tissues and transport it to the lungs. Although leukocytes typically leave the blood vessels to perform their defensive functions, movement of erythrocytes from the blood vessels is abnormal.","{'2e74e85a-15f9-4672-931e-05a69f33265e': 'Thrombocytosis is a condition in which there are too many platelets. This may trigger formation of unwanted blood clots (thrombosis), a potentially fatal disorder. If there is an insufficient number of platelets, called thrombocytopenia, blood may not clot properly, and excessive bleeding may result.', 'd859e7dd-ef03-4ac4-acfa-69ad513b8035': 'Discuss the structure and function of erythrocytes (red blood cells) and hemoglobin', '937447af-b002-456c-8d4a-2f12c818d073': 'The erythrocyte, commonly known as a red blood cell (or RBC), is by far the most common formed element: A single drop of blood contains millions of erythrocytes and only thousands of leukocytes (Figure 18.3.1). Specifically, males have about 5.4 million erythrocytes per microliter (µL) of blood, and females have approximately 4.8 million per µL. In fact, erythrocytes are estimated to make up about 25 percent of the total cells in the body. They are small cells, with a mean diameter of 7–8 micrometers (µm). The primary function of erythrocytes is to pick up oxygen from the lungs and transport it to the body’s tissues, and to pick up carbon dioxide at the tissues and transport it to the lungs. Although leukocytes typically leave the blood vessels to perform their defensive functions, movement of erythrocytes from the blood vessels is abnormal.'}"
+Figure 18.3.2,Anatomy_And_Physio/images/Figure 18.3.2.jpg,"Figure 18.3.2 – Shape of Red Blood Cells: Erythrocytes are biconcave discs with very shallow centers. This shape optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels.","The erythrocytes’ function of transporting blood gases is complimented by their structure, such as their lack of organelles, particularly mitochondria, their biconcave shape, and the presence of a flexible cytoskeletal protein element called spectrin.  Since erythrocytes lack mitochondria and must rely on anaerobic metabolism, they do not utilize any of the oxygen they are transporting as they deliver it to the tissues. Erythrocytes are biconcave disks; that is, they are plump at their periphery and very thin in the center (Figure 18.3.2). Since they lack most organelles, there is more interior space for the presence of the hemoglobin molecules that, as you will see shortly, transport gases. The biconcave shape also provides a greater surface area across which gas exchange can occur, relative to its volume; a sphere of a similar diameter would have a lower surface area-to-volume ratio. In the capillaries, the oxygen carried by the erythrocytes can diffuse into the plasma and then through the capillary walls to reach the cells, whereas some of the carbon dioxide produced by the cells as a waste product diffuses into the capillaries to be picked up by the erythrocytes. Capillary beds are extremely narrow, slowing the passage of the erythrocytes and providing an extended opportunity for gas exchange to occur. However, the space within capillaries can be so small that, despite their own small size, erythrocytes travel in single-file and sometimes fold in on themselves to pass through. Fortunately, their structural proteins like spectrin, are flexible, allowing them to fold and then spring back again when they enter a wider vessel.","{'4d5966d2-3c02-4e05-bd3a-90f76fb21b80': 'As an erythrocyte matures in the red bone marrow, it extrudes its nucleus and most of its other organelles. During the first day or two that it is in the circulation, an immature erythrocyte, known as a reticulocyte, will still typically contain remnants of organelles. Reticulocytes should comprise approximately 1–2 percent of the erythrocyte count and provide a rough estimate of the rate of RBC production. Abnormally low or high levels of reticulocytes indicate deviations in the production of these erythrocytes. These organelle remnants are quickly shed, so circulating erythrocytes have few internal cellular structural components. They lack endoplasmic reticula and do not synthesize proteins.', '530cd335-8433-4eee-9d9a-6f9bc07d0498': 'The erythrocytes’ function of transporting blood gases is complimented by their structure, such as their lack of organelles, particularly mitochondria, their biconcave shape, and the presence of a flexible cytoskeletal protein element called spectrin.\xa0 Since erythrocytes lack mitochondria and must rely on anaerobic metabolism, they do not utilize any of the oxygen they are transporting as they deliver it to the tissues. Erythrocytes are biconcave disks; that is, they are plump at their periphery and very thin in the center (Figure 18.3.2). Since they lack most organelles, there is more interior space for the presence of the hemoglobin molecules that, as you will see shortly, transport gases. The biconcave shape also provides a greater surface area across which gas exchange can occur, relative to its volume; a sphere of a similar diameter would have a lower surface area-to-volume ratio. In the capillaries, the oxygen carried by the erythrocytes can diffuse into the plasma and then through the capillary walls to reach the cells, whereas some of the carbon dioxide produced by the cells as a waste product diffuses into the capillaries to be picked up by the erythrocytes. Capillary beds are extremely narrow, slowing the passage of the erythrocytes and providing an extended opportunity for gas exchange to occur. However, the space within capillaries can be so small that, despite their own small size, erythrocytes travel in single-file and sometimes fold in on themselves to pass through. Fortunately, their structural proteins like spectrin, are flexible, allowing them to fold and then spring back again when they enter a wider vessel.'}"
+Figure 18.3.3,Anatomy_And_Physio/images/Figure 18.3.3.jpg,"Figure 18.3.3 – Hemoglobin: (a) A molecule of hemoglobin contains four globin proteins, each of which is bound to one molecule of the iron-containing pigment heme. (b) A single erythrocyte can contain 300 million hemoglobin molecules, and thus more than 1 billion oxygen molecules.","Hemoglobin is a large molecule made up of proteins and iron. It consists of four folded chains of the protein globin, designated alpha 1 and 2, and beta 1 and 2 (Figure 18.3.3a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains an iron ion (Fe2+) (Figure 18.3.3b).","{'9bb81ad5-5a6f-40f5-9608-69ac040f4209': 'Hemoglobin is a large molecule made up of proteins and iron. It consists of four folded chains of the protein globin, designated alpha 1 and 2, and beta 1 and 2 (Figure 18.3.3a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains an iron ion (Fe2+) (Figure 18.3.3b).', '678a897f-2d3e-4d91-95de-9b6cd811492d': 'Each iron ion in the heme can bind to one oxygen molecule, therefore, each hemoglobin molecule can transport four oxygen molecules. An individual erythrocyte may contain about 300 million hemoglobin molecules, and can bind to and transport up to 1.2 billion oxygen molecules.', 'd729ec16-fb34-44b0-9e27-d6ec567c9020': 'In the lungs, hemoglobin picks up oxygen, which binds to the iron ions, forming oxyhemoglobin. The bright red, oxygenated hemoglobin travels to the capillaries of the body tissues, where it releases some of the oxygen molecules, becoming darker red deoxyhemoglobin. Oxygen release depends on the need for oxygen in the surrounding tissues, so hemoglobin rarely leaves all of its oxygen behind. At the time time, carbon dioxide (CO2) enters the bloodstream. About 76 percent of the CO2 dissolves in the plasma, some of it remaining as dissolved CO2, and the remainder forming bicarbonate (CO2 + H2O <==> H2CO3 <==> HCO3– + H+), where HCO3– is bicarbonate ion. About 23–24 percent of it binds to the amino acids in hemoglobin, forming a molecule known as carbaminohemoglobin. From the capillaries, the hemoglobin carries CO2 back to the lungs.', '7866843a-060b-49ea-8e89-00907f04ad67': 'Changes in the levels of RBCs can have significant effects on the body’s ability to effectively deliver oxygen to the tissues. An overproduction of RBCs produces a condition called polycythemia. The primary drawback with polycythemia is not a failure to deliver enough oxygen to the tissues, but rather the increased viscosity of the blood, which makes it more difficult for the heart to circulate the blood. Ineffective hematopoiesis results in insufficient numbers of RBCs and results in one of several forms of anemia. In patients with insufficient hemoglobin, the tissues may not receive sufficient oxygen, resulting in another form of anemia.', '31798f41-320d-44ee-b313-040cd1dd4c22': 'In determining oxygenation of tissues, the value of greatest interest in healthcare is the percent saturation; that is, the percentage of hemoglobin sites occupied by oxygen in a patient’s blood. Clinically this value is commonly referred to simply as “percent sat.” Percent saturation is normally monitored using a device known as a pulse oximeter, which is applied to a thin part of the body, typically the tip of the patient’s finger. The device works by sending two different wavelengths of light (one red, the other infrared) through the finger and measuring the light with a photodetector as it exits. Hemoglobin absorbs light differentially depending upon its saturation with oxygen. The machine calibrates the amount of light received by the photodetector against the amount absorbed by the partially oxygenated hemoglobin and presents the data as percent saturation. Normal pulse oximeter readings range from 95–100 percent. Lower percentages reflect hypoxemia, or low blood oxygen. The term hypoxia is more generic and simply refers to low oxygen levels. Oxygen levels are also directly monitored from free oxygen in the plasma typically following an arterial stick. When this method is applied, the amount of oxygen present is expressed in terms of partial pressure of oxygen or simply pO2 and is typically recorded in units of millimeters of mercury, mm Hg.', '1db2397b-ee12-4ed8-8bed-9eb524c14b54': 'Receptors for oxygenation saturation are found in the kidneys, which is an ideal site to monitor saturation, since the kidneys filter about 180 liters (~380 pints) of blood in an average adult each day. In response to hypoxemia, less oxygen is diffused into the kidney, resulting in hypoxia of the kidney cells where oxygen concentration is actually monitored. Interstitial fibroblasts within the kidney secrete erythropoietin (EPO), leading to increased erythrocyte production and eventually restoring oxygen levels. In a negative-feedback loop, as oxygen saturation rises, EPO secretion falls, and vice versa, thereby maintaining homeostasis. Populations dwelling at high elevations, with inherently lower levels of oxygen in the atmosphere, naturally maintain a hematocrit higher than people living at sea level. Consequently, people traveling to high elevations may experience symptoms of hypoxemia, such as fatigue, headache, and shortness of breath, for a few days after their arrival. In response to the hypoxemia, the kidneys secrete EPO to step up the production of erythrocytes until homeostasis is achieved once again. To avoid the symptoms of hypoxemia, or altitude sickness, mountain climbers typically rest for several days to a week or more at a series of camps situated at increasing elevations to allow EPO levels and, consequently, erythrocyte counts to rise. When climbing the tallest peaks, such as Mt. Everest and K2 in the Himalayas, many mountain climbers rely upon bottled oxygen as they near the summit.'}"
+Figure 18.3.4,Anatomy_And_Physio/images/Figure 18.3.4.jpg,"Figure 18.3.4 – Erythrocyte Lifecycle: Erythrocytes are produced in the bone marrow and sent into the circulation. At the end of their lifecycle, they are destroyed by macrophages, and their components are recycled.",The erythrocyte lifecycle is summarized in Figure 18.3.4.,"{'4975ac06-035d-4b79-8e52-396bca9e6c36': 'Production of erythrocytes in the marrow occurs at the staggering rate of more than 2 million cells per second. For this production to occur, a number of raw materials must be present in adequate amounts. These include the same nutrients that are essential to the production and maintenance of any cell, such as glucose, lipids, and amino acids. However, erythrocyte production also requires several trace elements:', '59bc9280-c431-4aaf-86a6-68463eab668a': 'Erythrocytes live up to 120 days in the circulation, after which the worn-out cells are removed by a type of myeloid phagocytic cell called a macrophage, located primarily within the bone marrow, liver, and spleen. The components of the degraded erythrocytes’ hemoglobin are further processed as follows:', '6fec579b-541f-45f8-91f3-5258df1c6c2e': 'The breakdown pigments formed from the destruction of hemoglobin can be seen in a variety of situations. At the site of an injury, green biliverdin from damaged RBCs produces some of the dramatic colors associated with bruising. With a failing liver, bilirubin cannot be removed effectively from circulation and causes the body to assume a yellowish tinge associated with jaundice. Stercobilins within the feces produce the typical brown color associated with this waste. And the yellow of urine is associated with the urobilins.', '3722881c-134c-4634-983d-caf8a27c9616': 'The erythrocyte lifecycle is summarized in Figure 18.3.4.'}"
+Figure 18.2.1,Anatomy_And_Physio/images/Figure 18.2.1.jpg,"Figure 18.2.1. Hematopoietic System of Bone Marrow. Hemopoiesis is the proliferation and differentiation of the formed elements of blood. Lymphoid stem cells give rise to lymphocytes including T cells, B cells, and natural killer (NK) cells. Myeloid stem cells give rise to all the other formed elements.","Hemopoiesis begins when the hemopoietic stem cell is exposed to appropriate chemical stimuli collectively called hemopoietic growth factors, which prompt it to divide and differentiate. One daughter cell remains a hemopoietic stem cell, allowing hemopoiesis to continue. The other daughter cell becomes either of two types of more specialized stem cells (Figure 18.2.1):","{'80ec4c42-1cd6-4c79-94ff-b74b22b8f6a4': 'All formed elements arise from stem cells of the red bone marrow. Recall that stem cells undergo mitosis plus cytokinesis (cellular division) to give rise to new daughter cells. One of these daughter cells remains a stem cell and the other differentiates into one of any number of diverse cell types. Stem cells may be viewed as occupying a hierarchal system, with some loss of the ability to diversify at each step. The totipotent stem cell is the zygote, or fertilized egg. The totipotent (toti- = “all”) stem cell gives rise to all cells of the human body. The next level is the pluripotent stem cell, which gives rise to multiple types of cells of the body and some of the supporting fetal membranes. Beneath this level, the mesenchymal cell is a stem cell that develops only into types of connective tissue, including fibrous connective tissue, bone, cartilage, and blood, but not epithelium, muscle, and nervous tissue. One step lower on the hierarchy of stem cells is the hemopoietic stem cell, or hemocytoblast. All of the formed elements of blood originate from this specific type of cell.', 'f6746a42-73e6-49d9-922b-c4088e5fcd02': 'Hemopoiesis begins when the hemopoietic stem cell is exposed to appropriate chemical stimuli collectively called hemopoietic growth factors, which prompt it to divide and differentiate. One daughter cell remains a hemopoietic stem cell, allowing hemopoiesis to continue. The other daughter cell becomes either of two types of more specialized stem cells (Figure 18.2.1):', 'fcb69648-6043-417e-b9dc-295f8891eff9': 'Lymphoid and myeloid stem cells do not immediately divide and differentiate into mature formed elements. As you can see in Figure 1, there are several intermediate stages of precursor cells, many of which can be recognized by their names, which have the suffix -blast. For instance, megakaryoblasts are the precursors of megakaryocytes, and proerythroblasts become reticulocytes, which eject their nucleus and most other organelles before maturing into erythrocytes.'}"
+Figure 18.1.1,Anatomy_And_Physio/images/Figure 18.1.1.jpg,"Figure 18.1.1. Composition of Blood: The cellular elements of blood include a vast number of erythrocytes and comparatively fewer leukocytes and platelets. Plasma is the fluid in which the formed elements are suspended. A sample of blood spun in a centrifuge reveals that plasma is the least dense component. It floats at the top of the tube separated from the densest elements, the erythrocytes, which are separated by a buffy coat of leukocytes and platelets. Hematocrit is the percentage of the total sample that is comprised of erythrocytes. Depressed and elevated hematocrit levels are shown for comparison.","One such test examines hematocrit, which measures the percentage of RBCs (erythrocytes) in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.1.1). Because the densest elements in blood are the erythrocytes, these settle at the bottom of the hematocrit tube. Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs (leukocytes) and the platelets (thrombocytes). This layer is referred to as the buffy coat, and it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, straw-colored fluid, which constitutes the remainder of the sample.","{'35e364d9-51b9-4866-b242-ce53915500b3': 'If you have had a blood test, it was likely drawn from a superficial vein in your arm, which was then sent to a lab for analysis. Some of the most common blood tests—for instance, those measuring lipid or glucose levels in plasma—determine which substances are present within blood and in what quantities. Other blood tests check for the composition of the blood itself, including the quantities and types of formed elements.', '766fdf27-fb7d-4b96-8f77-3b7567d1b6fd': 'One such test examines hematocrit, which measures the percentage of RBCs (erythrocytes) in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.1.1). Because the densest elements in blood are the erythrocytes, these settle at the bottom of the hematocrit tube. Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs (leukocytes) and the platelets (thrombocytes). This layer is referred to as the buffy coat, and it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, straw-colored fluid, which constitutes the remainder of the sample.', 'fef4a08c-0d1b-42ad-998e-bebcddca43f7': 'The volume of erythrocytes after centrifugation is also commonly referred to as packed cell volume. Typically, blood contains about 45 percent erythrocytes, however, samples can vary significantly from about 36–50 percent. Normal hematocrit values for females range from 37 to 47%, with a mean value of 41%; for males, hematocrit ranges from 42 to 52%, with a mean of 47%. The percentage of other formed elements, the WBCs and platelets, is extremely small so it is not normally considered with the hematocrit. Therefore, the mean plasma percentage is the percent of blood that is not erythrocytes: for females, approximately 59% (or 100 minus 41), and for males, approximately 53% (or 100 minus 47).'}"
+Figure 17.9.1,Anatomy_And_Physio/images/Figure 17.9.1.jpg,Figure 17.9.1 – Pancreas   Pancreas endocrine function involves the secretion of insulin (produced by beta cells) and glucagon (produced by alpha cells) within the pancreatic islets. These two hormones regulate the rate of glucose metabolism in the body. The micrograph reveals pancreatic islets. LM × 760. Also shown are the exocrine acinar cells. (Micrograph provided by the Regents of University of Michigan Medical School © 2012.,"The pancreas is a long, slender organ, most of which is located posterior to the bottom half of the stomach (Figure 17.9.1). Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas also has endocrine cells. Its pancreatic islets—clusters of cells formerly known as the islets of Langerhans—secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide (PP).","{'c1cd38d7-82fa-4186-8f15-2e1d2f2ebbc2': 'The liver is responsible for secreting at least four important hormones or hormone precursors: insulin-like growth factor (somatomedin), angiotensinogen, thrombopoetin, and hepcidin. Insulin-like growth factor-1 is the immediate stimulus for growth in the body, especially of the bones. Angiotensinogen is the precursor to angiotensin, mentioned earlier, which increases blood pressure. Thrombopoetin stimulates the production of the blood’s platelets. Hepcidins block the release of iron from cells in the body, helping to regulate iron homeostasis in our body fluids.', 'a30e9e1a-7e9f-4d7a-9686-1e0995738842': 'The major hormones discussed above\xa0are summarized in Table 17.8.', '2ac8010d-86e9-4b7e-bff1-6459879ec653': 'Explain the role of the pancreatic endocrine cells in the regulation of blood glucose', 'a0440ffa-dbdd-48c2-8a5c-b2d58c68ad4c': 'The pancreas is a long, slender organ, most of which is located posterior to the bottom half of the stomach (Figure 17.9.1). Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas also has endocrine cells. Its pancreatic islets—clusters of cells formerly known as the islets of Langerhans—secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide (PP).'}"
+Figure 17.6.1,Anatomy_And_Physio/images/Figure 17.6.1.jpg,"Figure 17.6.1 – Adrenal Glands: Both adrenal glands sit atop the kidneys and are composed of an outer cortex and an inner medulla, all surrounded by a connective tissue capsule. The cortex can be subdivided into additional zones, all of which produce different types of hormones. LM × 204. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","The adrenal glands are glandular and neuroendocrine tissue adhering to the top of the kidneys by a fibrous capsule (Figure 17.6.1). The adrenal glands have a rich blood supply and have one of the highest rates of blood flow in the body. They are supplied by several arteries branching off the aorta, including the suprarenal and renal arteries. Blood first flows through the adrenal cortex and then drains into the adrenal medulla. Adrenal hormones are released into the circulation via the left and right suprarenal veins.","{'b97d9a75-fd61-4c15-9f73-790c88a33bf6': 'This section briefly discusses the hormonal role of the gonads—the male testes and female ovaries—which produce the sex cells (sperm and ova) and secrete the gonadal hormones. The roles of the gonadotropins released from the anterior pituitary, follicle stimulating hormone (FSH) and luteinizing hormone (LH), were discussed earlier in the section regarding the pituitary gland and the hypothalamus.', '7bfffc6f-f57c-4925-b7fb-2a7eb2760e28': 'The primary hormone produced by the male testes is testosterone, a steroid hormone important in the development of the male reproductive system, the maturation of sperm cells, and the development of male secondary sex characteristics such as a deepened voice, body hair, and increased muscle mass. Testosterone is also produced in the female ovaries, but at a much reduced level. The testes also produce the peptide hormone inhibin, which inhibits the secretion of FSH from the anterior pituitary gland. FSH stimulates spermatogenesis.', 'b027ebc3-21dd-4f7a-aa0b-79cd85efbd8a': 'The primary hormones produced by the ovaries are estrogens, which include estradiol, estriol, and estrone. Estrogens play an important role in a larger number of physiological processes, including the development of the female reproductive system, regulation of the menstrual cycle, the development of female secondary sex characteristics such as increased adipose tissue and the development of breast tissue, and the maintenance of pregnancy. Another significant ovarian hormone is progesterone, which contributes to regulation of the menstrual cycle and is important in preparing the body for pregnancy as well as maintaining pregnancy. In addition, the granulosa cells of the ovarian follicles produce inhibin, which—as in males—inhibits the secretion of FSH. During the initial stages of pregnancy, an organ called the placenta develops within the uterus. The placenta supplies oxygen and nutrients to the fetus, excretes waste products, and produces and secretes estrogens and progesterone. The placenta produces human chorionic gonadotropin (hCG) as well. The hCG hormone promotes progesterone synthesis and reduces the mother’s immune function to protect the fetus from immune rejection. It also secretes human placental lactogen (hPL), which plays a role in preparing the breasts for lactation, and relaxin, which is thought to help soften and widen the pubic symphysis in preparation for childbirth. The hormones related to sex characteristics and reproduction\xa0are summarized in Table 17.6.', '906d921c-48c9-45aa-a5b9-1889500e1a13': 'The use of performance-enhancing drugs is banned by all major collegiate and professional sports organizations in the United States because they impart an unfair advantage to athletes who take them. In addition, the drugs can cause significant and dangerous side effects. For example, anabolic steroid use can increase cholesterol levels, raise blood pressure, and damage the liver. Altered testosterone levels (both too low or too high) have been implicated in causing structural damage to the heart, and increasing the risk for cardiac arrhythmias, heart attacks, congestive heart failure, and sudden death. Paradoxically, steroids can have a feminizing effect in males, including atrophied\xa0testicles and enlarged breast tissue. In females, their use can cause masculinizing effects such as an enlarged clitoris and growth of facial hair. In both sexes, their use can promote increased aggression (commonly known as “roid-rage”), depression, sleep disturbances, severe acne, and infertility.', 'edf99b01-6759-4ad1-8b18-84abccfcedde': 'Summarize the site of production, regulation, and effects of the hormone of the pineal glands', 'e06bef48-4df8-4f1b-81a3-24d864e587d0': 'The pineal gland, found inferior but somewhat posterior to the thalamus, is a tiny endocrine gland whose functions are not entirely understood. The pinealocyte cells that make up the pineal gland are known to produce and secrete the amine hormone melatonin, which is derived from serotonin.', 'c3346c8a-c035-4ea1-84ab-4f53749a753f': 'The secretion of melatonin varies according to the level of light received from the environment. When photons of light stimulate the retinas of the eyes, a nerve impulse is sent to a region of the hypothalamus called the suprachiasmatic nucleus (SCN), which is important in regulating biological rhythms. From the SCN, the nerve signal is carried to the spinal cord and eventually to the pineal gland, where the production of melatonin is inhibited. As a result, blood levels of melatonin fall, promoting wakefulness. In contrast, as light levels decline—such as during the evening—melatonin production increases, boosting blood levels and causing drowsiness.', '1fc74f3e-149b-4b9d-870e-e3998f8846a1': 'The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. High melatonin levels in children may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty until melatonin production declines. Finally, an antioxidant role of melatonin is the subject of current research.', '53a63e52-3935-4dd6-b364-1de0d7308aec': 'Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep.', '28a3c560-b941-41df-bfe4-4c2c491e238a': 'The adrenal glands\xa0are\xa0glandular and neuroendocrine tissue adhering to the top of the kidneys by a fibrous capsule (Figure 17.6.1). The adrenal glands have a rich blood supply and have\xa0one of the highest rates of blood flow in the body. They are supplied by several arteries branching off the aorta, including the suprarenal and renal arteries. Blood first flows through the adrenal cortex and then drains into the adrenal medulla. Adrenal hormones are released into the circulation via the left and right suprarenal veins.', '994ad022-d497-40ee-8fc2-97d6a0fa2bf5': 'The adrenal gland consists of an outer cortex of glandular tissue and an inner medulla of nervous tissue. The cortex itself is divided into three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. Each region secretes its own set of hormones.', '4c240921-dd0f-4aa0-aa19-56c334e30aa9': 'The adrenal cortex, as a component of the hypothalamic-pituitary-adrenal (HPA) axis, secretes steroid hormones important for the regulation of the long-term stress response, blood pressure and blood volume, nutrient uptake and storage, fluid and electrolyte balance, and inflammation. The HPA axis involves the hypothalamus stimulating the\xa0release of adrenocorticotropic hormone (ACTH) from the pituitary. ACTH then stimulates the adrenal cortex to produce the hormone from the cortex (corticosteroids). This pathway will be discussed in more detail below.', '86e775d6-9aef-48bd-acdf-13e645d77c28': 'The adrenal medulla is neuroendocrine tissue composed of postganglionic sympathetic neurons. It is really an extension of the autonomic nervous system. This neuroendocrine pathway, controlled by the hypothalamus, involves\xa0stimulation of the medulla by impulses from preganglionic sympathetic neurons originating in the\xa0thoracic spinal cord. Stimulation causes the medulla to secrete the amine hormones epinephrine and norepinephrine.', 'd3ac5a60-065a-4b2f-867b-bd6f42c34a45': 'One of the major functions of the adrenal gland is to respond to stress. Stress can be either physical, psychological or both. Physical stresses may include\xa0injury, exposure to severe temperatures\xa0or malnutrition. Psychological stresses include the perception of a physical threat, a fight with a loved one, or just a bad day at school.', '6865c046-6617-4d55-bf20-11306b460dda': 'The body responds in different ways to short-term stress and long-term stress following a pattern known as the general adaptation syndrome (GAS). Stage one of GAS is called the alarm reaction. This is short-term stress, the fight-or-flight response, mediated by the hormones epinephrine and norepinephrine from the adrenal medulla. Their function is to prepare the body for extreme physical exertion. Once this stress is relieved, the body quickly returns to normal. The section on the adrenal medulla covers this response in more detail.', 'b577e139-d82d-450c-a0df-34e399a9046b': 'If the stress is not soon relieved, the body adapts to the stress in the second stage called the stage of resistance. If a person is starving for example, the body may send signals to the gastrointestinal tract to maximize the absorption of nutrients from food.', '9ca66844-1c0b-4430-bcc0-4265524214c4': 'If the stress continues for a longer term however, the body responds with symptoms quite different than the fight-or-flight response. During the stage of exhaustion, individuals may begin to suffer depression, the suppression of their immune response, severe fatigue, or even a fatal heart attack. These symptoms are mediated by the hormones of the adrenal cortex, especially cortisol, released as a result of signals from the HPA axis.', '55c8e657-0fbb-4f8c-bfc2-2bea98a2c28e': 'Adrenal hormones also have several non–stress-related functions, including the increase of blood sodium and glucose levels, which will be described in detail below.'}"
+Figure 17.5.1,Anatomy_And_Physio/images/Figure 17.5.1.jpg,Figure 17.5.1 – Parathyroid Glands: The small parathyroid glands are embedded in the posterior surface of the thyroid gland. LM × 760. (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (Figure 17.5.1). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels. The gland also contains oxyphil cells but their function is not clear.","{'15a5a4e8-7e3d-426b-ae08-6273fd88e7fc': 'Several disorders are caused by the dysregulation of the hormones produced by the adrenal glands. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. It is caused by hypersecretion of cortisol. The most common source of Cushing’s disease is a pituitary tumor that secretes ACTH in abnormally high amounts. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss. Long term glucocorticoid use for inflammatory conditions such as rheumatoid arthritis or to prevent transplant rejection can cause symptoms similar to those in Cushing’s disease.', 'c0d62a1e-8300-4c4b-9e6e-e01932da4d4b': 'In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food. Treatment involves injections of glucocorticoids.', 'f8965a16-9adc-481f-99fa-5c14bcf1773d': 'The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (Figure 17.5.1). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels.\xa0The gland also contains\xa0oxyphil cells but their function is not clear.', 'a861b29a-af74-480d-a873-b9c7f77b4d94': 'The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (Figure 17.5.2). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.', '092fc75b-07fb-4294-9076-5df51b2ec114': 'Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium phosphate deposits may collect in the body’s tissues and organs (extraosseous calcification), impairing their functioning.', 'a33e60ef-2a36-4081-aabe-7aa811b48071': 'In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism, which may develop following injury or surgery involving the thyroid gland. Low blood calcium increases membrane permeability to sodium, resulting in muscle twitching, cramping, spasms, or convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal.', 'af089285-5851-4f5d-9343-c0185b9a3f2c': 'A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.4.1). The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells. These follicles are the center of thyroid hormone production and that production is dependent on the hormones’ essential and unique component: iodine.'}"
+Figure 17.5.2,Anatomy_And_Physio/images/Figure 17.5.2.jpg,"Figure 17.5.2 – Parathyroid Hormone in Maintaining Blood Calcium Homeostasis: Parathyroid hormone increases blood calcium levels when they drop too low. Conversely, calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too high. These two mechanisms constantly maintain blood calcium concentration at homeostasis.","The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (Figure 17.5.2). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.","{'15a5a4e8-7e3d-426b-ae08-6273fd88e7fc': 'Several disorders are caused by the dysregulation of the hormones produced by the adrenal glands. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. It is caused by hypersecretion of cortisol. The most common source of Cushing’s disease is a pituitary tumor that secretes ACTH in abnormally high amounts. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss. Long term glucocorticoid use for inflammatory conditions such as rheumatoid arthritis or to prevent transplant rejection can cause symptoms similar to those in Cushing’s disease.', 'c0d62a1e-8300-4c4b-9e6e-e01932da4d4b': 'In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food. Treatment involves injections of glucocorticoids.', 'f8965a16-9adc-481f-99fa-5c14bcf1773d': 'The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (Figure 17.5.1). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels.\xa0The gland also contains\xa0oxyphil cells but their function is not clear.', 'a861b29a-af74-480d-a873-b9c7f77b4d94': 'The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (Figure 17.5.2). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.', '092fc75b-07fb-4294-9076-5df51b2ec114': 'Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium phosphate deposits may collect in the body’s tissues and organs (extraosseous calcification), impairing their functioning.', 'a33e60ef-2a36-4081-aabe-7aa811b48071': 'In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism, which may develop following injury or surgery involving the thyroid gland. Low blood calcium increases membrane permeability to sodium, resulting in muscle twitching, cramping, spasms, or convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal.', 'af089285-5851-4f5d-9343-c0185b9a3f2c': 'A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.4.1). The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells. These follicles are the center of thyroid hormone production and that production is dependent on the hormones’ essential and unique component: iodine.'}"
+Figure 17.4.1,Anatomy_And_Physio/images/Figure 17.4.1.jpg,Figure 17.4.1 – Thyroid Gland: The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.4.1). The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells. These follicles are the center of thyroid hormone production and that production is dependent on the hormones’ essential and unique component: iodine.","{'15a5a4e8-7e3d-426b-ae08-6273fd88e7fc': 'Several disorders are caused by the dysregulation of the hormones produced by the adrenal glands. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. It is caused by hypersecretion of cortisol. The most common source of Cushing’s disease is a pituitary tumor that secretes ACTH in abnormally high amounts. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss. Long term glucocorticoid use for inflammatory conditions such as rheumatoid arthritis or to prevent transplant rejection can cause symptoms similar to those in Cushing’s disease.', 'c0d62a1e-8300-4c4b-9e6e-e01932da4d4b': 'In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food. Treatment involves injections of glucocorticoids.', 'f8965a16-9adc-481f-99fa-5c14bcf1773d': 'The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (Figure 17.5.1). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels.\xa0The gland also contains\xa0oxyphil cells but their function is not clear.', 'a861b29a-af74-480d-a873-b9c7f77b4d94': 'The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (Figure 17.5.2). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.', '092fc75b-07fb-4294-9076-5df51b2ec114': 'Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium phosphate deposits may collect in the body’s tissues and organs (extraosseous calcification), impairing their functioning.', 'a33e60ef-2a36-4081-aabe-7aa811b48071': 'In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism, which may develop following injury or surgery involving the thyroid gland. Low blood calcium increases membrane permeability to sodium, resulting in muscle twitching, cramping, spasms, or convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal.', 'af089285-5851-4f5d-9343-c0185b9a3f2c': 'A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.4.1). The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells. These follicles are the center of thyroid hormone production and that production is dependent on the hormones’ essential and unique component: iodine.'}"
+Figure 17.4.2,Anatomy_And_Physio/images/Figure 17.4.2.jpg,Figure 17.4.2 – Classic Negative Feedback Loop: A classic negative feedback loop controls the regulation of thyroid hormone levels.,"The release of T3 and T4 from the thyroid gland is regulated by thyroid-stimulating hormone (TSH). As shown in Figure 17.4.2, low blood levels of T3 and T4 stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus, which triggers secretion of TSH from the anterior pituitary. In turn, TSH stimulates the thyroid gland to secrete T3 and T4. The levels of TRH, TSH, T3, and T4 are regulated by a negative feedback system in which increasing levels of T3 and T4 decrease the production and secretion of TSH.","{'70abe358-5377-43ec-a272-6aa058f0a52b': 'The release of T3 and T4 from the thyroid gland is regulated by thyroid-stimulating hormone (TSH). As shown in Figure 17.4.2, low blood levels of T3 and T4 stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus, which triggers secretion of TSH from the anterior pituitary. In turn, TSH stimulates the thyroid gland to secrete T3 and T4. The levels of TRH, TSH, T3, and T4 are regulated by a negative feedback system in which increasing levels of T3 and T4 decrease the production and secretion of TSH.'}"
+Figure 17.3.1,Anatomy_And_Physio/images/Figure 17.3.1.jpg,"Figure 17.3.1 – Hypothalamus–Pituitary Complex: The hypothalamus region lies inferior and anterior to the thalamus. It connects to the pituitary gland by the stalk-like infundibulum. The pituitary gland consists of an anterior and posterior lobe, with each lobe secreting different hormones in response to signals from the hypothalamus.","The hypothalamus is a structure of the diencephalon of the brain located anterior and inferior to the thalamus (Figure 17.3.1). It has both neural and endocrine functions, producing and secreting many hormones. In addition, the hypothalamus is anatomically and functionally related to the pituitary gland (or hypophysis), a bean-sized organ suspended from it by a stem called the infundibulum (or pituitary stalk). The pituitary gland is cradled within the sella turcica of the sphenoid bone of the skull. It consists of two lobes that arise from distinct parts of embryonic tissue: the posterior pituitary (neurohypophysis) is neural tissue, whereas the anterior pituitary (also known as the adenohypophysis [adeno=glandular]) is glandular tissue. The hormones secreted by the posterior and anterior pituitary, and the intermediate zone between the lobes are summarized in Table 17.3.","{'3bc28650-b423-440a-8a10-7645cfaa235b': 'The thyroid gland also secretes a hormone called calcitonin that is produced by the parafollicular cells (also called C cells) that are located\xa0between follicles. Calcitonin is released in response to a rise in blood calcium levels. It appears to have a function in decreasing blood calcium concentrations by:', '278d2a87-05f4-4a0c-8650-c85670320043': 'However, these functions are usually not significant in maintaining calcium homeostasis, so the importance of calcitonin is not entirely understood. Pharmaceutical preparations of calcitonin are sometimes prescribed to reduce osteoclast activity in people with osteoporosis and to reduce the degradation of cartilage in people with osteoarthritis. The hormones secreted by thyroid are summarized in Table 17.4.', '0645f378-81df-42d3-a869-4c921838130c': 'Calcium is critical for many other biological processes. It is a second messenger in many signaling pathways, and is essential for muscle contraction, nerve impulse transmission, and blood clotting. Given these roles, it is not surprising that blood calcium levels are tightly regulated by the endocrine system. The organs primarily involved in the regulation are the parathyroid glands.', 'a5d39613-1046-42c3-bc98-2ec3d92986c7': 'The hypothalamus–pituitary complex can be thought of as the “command center” of the endocrine system. This complex secretes several hormones that directly produce responses in target tissues, as well as hormones that regulate the synthesis and secretion of hormones of other glands. In addition, the hypothalamus–pituitary complex coordinates the messages of the endocrine and nervous systems. In many cases stimuli received by the nervous system must pass through the hypothalamus–pituitary complex to release\xa0hormones that can initiate a response.', '4259c26c-0fd7-49b2-b9f3-afbfe6625c60': 'The hypothalamus is a structure of the diencephalon of the brain located anterior and inferior to the thalamus (Figure 17.3.1). It has both neural and endocrine functions, producing and secreting many hormones. In addition, the hypothalamus is anatomically and functionally related to the pituitary gland (or hypophysis), a bean-sized organ suspended from it by a stem called the infundibulum (or pituitary stalk). The pituitary gland is cradled within the sella turcica of the sphenoid bone of the skull. It consists of two lobes that arise from distinct parts of embryonic tissue: the posterior pituitary (neurohypophysis) is neural tissue, whereas the anterior pituitary (also known as the adenohypophysis [adeno=glandular]) is glandular tissue. The hormones secreted by the posterior and anterior pituitary, and the intermediate zone between the lobes are summarized in Table 17.3.'}"
+Figure 17.3.2,Anatomy_And_Physio/images/Figure 17.3.2.jpg,Figure 17.3.2 – Posterior Pituitary: Neurosecretory cells in the hypothalamus release oxytocin (OT) or ADH into the posterior lobe of the pituitary gland. These hormones are stored or released into the blood via the capillary plexus.,"The posterior pituitary is actually an extension of the neurons of the paraventricular and supraoptic nuclei of the hypothalamus. The cell bodies of these nuclei are located in the hypothalamus, but their axons descend as the hypothalamic–hypophyseal tract within the infundibulum, and end in axon terminals within the posterior pituitary (Figure 17.3.2).","{'4d99c28e-c616-4c83-90b9-07f6bfab3abc': 'The posterior pituitary is actually an extension of the neurons of the paraventricular and supraoptic nuclei of the hypothalamus. The cell bodies of these nuclei are located in the hypothalamus, but their axons descend as the hypothalamic–hypophyseal tract within the infundibulum, and end in axon terminals\xa0within\xa0the posterior pituitary (Figure 17.3.2).', '3f8c57f9-0e47-4aa8-9e27-79495c78e894': 'The posterior pituitary gland does not produce hormones, but rather stores and secretes hormones produced by the hypothalamus. Neurons of the paraventricular nucleus produce the hormone oxytocin, whereas neurons of the supraoptic nucleus produce ADH. These hormones travel along the axons into axon terminals within the posterior pituitary. In response to action potentials from\xa0the same hypothalamic neurons that produced them, these hormones are released from vesicles within the axon terminals into the bloodstream.'}"
+Figure 17.3.3,Anatomy_And_Physio/images/Figure 17.3.3.jpg,Figure 17.3.3 – Anterior Pituitary: The anterior pituitary manufactures seven hormones. The hypothalamus produces separate hormones that stimulate or inhibit hormone production in the anterior pituitary. Hormones from the hypothalamus reach the anterior pituitary via the hypophyseal portal system.,"Within the infundibulum is a bridge of capillaries that connects the hypothalamus to the anterior pituitary. This network, called the hypophyseal portal system, allows hypothalamic hormones to be transported to the anterior pituitary without becoming diluted in systemic circulation. This portal system begins with a primary capillary plexus originating from the superior hypophyseal artery, a branches of the internal carotid artery. Blood from the first capillary bed supplies a secondary capillary plexus in the anterior pituitary via the hypophyseal portal veins (see Figure 17.3.3). Hypothalamic releasing and inhibiting hormones are released into the primary capillary plexus which drain into the portal veins carrying them to the secondary capillary plexus where they stimulate (or inhibit) the endocrine cells of the anterior pituitary. Hormones produced by the anterior pituitary (in response to hypothalamic releasing hormones) enter the secondary capillary plexus continuing into general circulation.","{'f25da362-3171-4fe5-986e-12265057e2f7': 'The anterior pituitary originates\xa0from epithelial tissue derived from an invagination of the oral mucusa\xa0in the embryo which migrates toward the brain during fetal development. There are three regions: the pars distalis is the most anterior, the pars intermedia is adjacent to the posterior pituitary, and the pars tuberalis is a slender “tube” that wraps the infundibulum.', '52781a84-011b-4532-be95-49fe252d9c19': 'Recall that the posterior pituitary does not synthesize hormones, but merely stores them. In contrast, the anterior pituitary does manufacture hormones. Like the posterior pituitary the release of hormones from the anterior pituitary is controlled by the hypothalamus.\xa0This control is mediated by secretion of releasing or inhibiting hormones into the blood.', 'fbfba720-27b1-49dc-bd9f-0c5de7ddd361': 'Within the infundibulum is a bridge of capillaries that connects the hypothalamus to the anterior pituitary. This network, called the hypophyseal portal system, allows hypothalamic hormones to be transported to the anterior pituitary without becoming diluted in\xa0systemic circulation. This portal system begins with a primary capillary plexus originating from the superior hypophyseal artery, a branches of the internal carotid artery. Blood from the first capillary bed supplies a secondary capillary plexus in the anterior pituitary via the hypophyseal portal veins\xa0(see Figure 17.3.3). Hypothalamic releasing and inhibiting hormones are released into the\xa0primary capillary plexus which drain into the portal veins carrying them to the secondary capillary plexus where they stimulate (or inhibit) the endocrine cells of the anterior pituitary. Hormones produced by the anterior pituitary (in response to hypothalamic releasing hormones) enter the secondary capillary plexus\xa0continuing into general\xa0circulation.', '69eedf71-8895-4cfa-a137-f828be32669c': 'The anterior pituitary produces seven hormones. These are growth hormone (GH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), beta endorphin, and prolactin. Of the hormones of the anterior pituitary, TSH, ACTH, FSH, and LH are collectively referred to as tropic hormones (trope- = “turning”) because they stimulate or inhibit secretion of hormones from other glands.'}"
+Figure 17.3.5,Anatomy_And_Physio/images/Figure 17.3.5.jpg,Figure 17.3.5 – Major Pituitary Hormones: Major pituitary hormones and their target organs.,"The cells in the zone between the pituitary lobes secrete a hormone known as melanocyte-stimulating hormone (MSH) that is formed by cleavage of the pro-opiomelanocortin (POMC) precursor protein. Local production of MSH in the skin is responsible for melanin production in response to UV light exposure. The role of MSH made by the pituitary is more complicated. For instance, people with lighter skin generally have the same amount of MSH as people with darker skin. Nevertheless, this hormone is capable of darkening of the skin by inducing melanin production in the skin’s melanocytes. Women also show increased MSH production during pregnancy; in combination with estrogens, it can lead to darker skin pigmentation, especially the skin of the areolas and labia minora. Figure 17.3.5 is a summary of the pituitary hormones and their principal effects.","{'8fc88617-a6e2-4296-9744-ae8e51cf7d02': 'The cells in the zone between the pituitary lobes secrete a hormone known as melanocyte-stimulating hormone (MSH) that is formed by cleavage of the pro-opiomelanocortin (POMC) precursor protein. Local production of MSH in the skin is responsible for melanin production in response to UV light exposure. The role of MSH made by the pituitary is more complicated. For instance, people with lighter skin generally have the same amount of MSH as people with darker skin. Nevertheless, this hormone is capable of darkening of the skin by inducing melanin production in the skin’s melanocytes. Women also show increased MSH production during pregnancy; in combination with estrogens, it can lead to darker skin pigmentation, especially the skin of the areolas and labia minora. Figure 17.3.5 is a summary of the pituitary hormones and their principal effects.', 'cf9fdd50-9a38-46d7-97ab-a25963fd4413': 'When released into the blood, a hormone circulates freely throughout the body.\xa0 However, a hormone will only affect the activity of its target cells; that is, cells with receptors for that particular hormone. Once the hormone binds to the receptor, a chain of events is initiated that leads to the target cell’s response.\xa0 The major hormones of the human body and their effects are identified in Table 17.2.'}"
+Figure 17.2.1,Anatomy_And_Physio/images/Figure 17.2.1.jpg,"Figure 17.2.1:  Amine, Peptide, Protein, and Steroid Hormone Structure","The hormones of the human body can be structurally divided into three major groups: amino acid derivatives (amines), peptides, and steroids (Figure 17.2.1). These chemical groups affect a hormone’s distribution, the type of receptors it binds to, and other aspects of its function..","{'d2b3970c-b484-4bff-961e-5ac3010b2741': 'The hormones of the human body can be structurally divided into three major groups: amino acid derivatives (amines), peptides, and steroids (Figure 17.2.1). These chemical groups affect a hormone’s distribution, the type of receptors it binds to, and other aspects of its function..'}"
+Figure 17.1.1,Anatomy_And_Physio/images/Figure 17.1.1.jpg,Figure 17.1.1 – Endocrine System: Endocrine glands and cells are located throughout the body and play an important role in homeostasis.,"The major endocrine glands found in the human body include the pituitary gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pineal gland, testes, and ovaries (Figure 17.1.1). While some of the glands are pure endocrine (e.g., thyroid gland), others serve both endocrine and exocrine function. For example, the pancreas contains cells that secrete digestive enzymes and juices into the small intestine (exocrine function) and cells that secrete the hormones insulin and glucagon, which regulate blood glucose levels.","{'d28ba82f-7f02-4f84-90fa-552ae50ca97e': 'Hormones are released by secretory cells that are derived from epithelial tissue.\xa0 Often, these cells are clustered together, forming endocrine glands.\xa0 Unlike exocrine glands, which have a duct for conveying secretions to the outside of the body (e.g., sweat gland), endocrine glands secrete substances directly into the surrounding interstitial fluid.\xa0 From there, hormones then enter the bloodstream for distribution throughout the body.', 'cca80d1f-25de-44ed-b65f-b286d42ae3ab': 'The major endocrine glands found in the human body include the pituitary gland, thyroid gland,\xa0parathyroid glands, thymus gland, adrenal glands, pineal gland, testes, and ovaries\xa0(Figure 17.1.1). While some of the glands are pure endocrine (e.g., thyroid gland), others serve both endocrine and\xa0exocrine function. For example, the pancreas contains cells that secrete digestive enzymes and juices into the small intestine (exocrine function) and cells that secrete the hormones insulin and glucagon, which regulate blood glucose levels.', 'fef9ac7d-3dfd-4913-a7d2-02b51646389c': 'In addition to the endocrine glands,\xa0major organs of the body show endocrine function including the\xa0hypothalamus, heart, kidneys, stomach, small intestine, and liver.\xa0 Moreover, adipose tissue has long been known to produce hormones, and recent research has revealed a role for bone tissue in hormone production and secretion.'}"
+Figure 16.4.1,Anatomy_And_Physio/images/Figure 16.4.1.jpg,"Figure 16.4.1 – Autonomic Connections to Heart and Blood Vessels: The nicotinic receptor is found on all autonomic ganglia, but the cardiovascular connections are particular, and do not conform to the usual competitive projections that would just cancel each other out when stimulated by nicotine. The opposing signals to the heart would both depolarize and hyperpolarize the heart cells that establish the rhythm of the heartbeat, likely causing arrhythmia. Only the sympathetic system governs systemic blood pressure so nicotine would cause an increase.","The system in which this can be problematic is in the cardiovascular system, which is why smoking is a risk factor for cardiovascular disease. First, there is no significant parasympathetic regulation of blood pressure. Only a limited number of blood vessels are affected by parasympathetic input, so nicotine will preferentially cause the vascular tone to become more sympathetic, which means blood pressure will be increased. Second, the autonomic control of the heart is special. Unlike skeletal or smooth muscles, cardiac muscle is intrinsically active, meaning that it generates its own action potentials. The autonomic system does not cause the heart to beat, it just speeds it up (sympathetic) or slows it down (parasympathetic). The mechanisms for this are not mutually exclusive, so the heart receives conflicting signals, and the rhythm of the heart can be affected (Figure 16.4.1).","{'6058bc8d-d0cc-4b3e-8b78-6f0a05755db5': 'One important drug that affects the autonomic system broadly is not a pharmaceutical therapeutic agent associated with the system. This drug is nicotine. The effects of nicotine on the autonomic nervous system are important in considering the role smoking can play in health.', 'c1046963-92e3-4060-91d3-a48fc02d79f5': 'All ganglionic neurons of the autonomic system, in both sympathetic and parasympathetic ganglia, are activated by ACh released from preganglionic fibers. The ACh receptors on these neurons are of the nicotinic type, meaning that they are ligand-gated ion channels. When the neurotransmitter released from the preganglionic fiber binds to the receptor protein, a channel opens to allow positive ions to cross the cell membrane. The result is depolarization of the ganglia. Nicotine acts as an ACh analog at these synapses, so when someone takes in the drug, it binds to these ACh receptors and activates the ganglionic neurons, causing them to depolarize.', '27ab9439-ae65-4553-b903-36f3110c96ef': 'Ganglia of both divisions are activated equally by the drug. For many target organs in the body, this results in no net change. The competing inputs to the system cancel each other out and nothing significant happens. For example, the sympathetic system will cause sphincters in the digestive tract to contract, limiting digestive propulsion, but the parasympathetic system will cause the contraction of other muscles in the digestive tract, which will try to push the contents of the digestive system along. The end result is that the food does not really move along and the digestive system has not appreciably changed.', '9b1ec2e5-6106-404d-91b9-e254f1db4753': 'The system in which this can be problematic is in the cardiovascular system, which is why smoking is a risk factor for cardiovascular disease. First, there is no significant parasympathetic regulation of blood pressure. Only a limited number of blood vessels are affected by parasympathetic input, so nicotine will preferentially cause the vascular tone to become more sympathetic, which means blood pressure will be increased. Second, the autonomic control of the heart is special. Unlike skeletal or smooth muscles, cardiac muscle is intrinsically active, meaning that it generates its own action potentials. The autonomic system does not cause the heart to beat, it just speeds it up (sympathetic) or slows it down (parasympathetic). The mechanisms for this are not mutually exclusive, so the heart receives conflicting signals, and the rhythm of the heart can be affected (Figure 16.4.1).'}"
+Figure 16.4.3,Anatomy_And_Physio/images/Figure 16.4.3.jpg,"Figure 16.4.3 – Belladonna Plant: The plant from the genus Atropa, which is known as belladonna or deadly nightshade, was used cosmetically to dilate pupils, but can be fatal when ingested. The berries on the plant may seem attractive as a fruit, but they contain the same anticholinergic compounds as the rest of the plant.","Atropine and scopolamine are part of a class of muscarinic antagonists that come from the Atropa genus of plants that include belladonna or deadly nightshade (Figure 16.4.3). The name of one of these plants, belladonna, refers to the fact that extracts from this plant were used cosmetically for dilating the pupil. The active chemicals from this plant block the muscarinic receptors in the iris and allow the pupil to dilate, which is considered attractive because it makes the eyes appear larger. Humans are instinctively attracted to anything with larger eyes, which comes from the fact that the ratio of eye-to-head size is different in infants (or baby animals) and can elicit an emotional response. The cosmetic use of belladonna extract was essentially acting on this response. Atropine is no longer used in this cosmetic capacity for reasons related to the other name for the plant, which is deadly nightshade. Suppression of parasympathetic function, especially when it becomes systemic, can be fatal. Autonomic regulation is disrupted and anticholinergic symptoms develop. The berries of this plant are highly toxic, but can be mistaken for other berries. The antidote for atropine or scopolamine poisoning is pilocarpine.","{'f7f7b2da-bb59-404c-982e-90c29e2d2994': 'Drugs affecting parasympathetic functions can be classified into those that increase or decrease activity at postganglionic terminals. Parasympathetic postganglionic fibers release ACh, and the receptors on the targets are muscarinic receptors. There are several types of muscarinic receptors, M1–M5, but the drugs are not usually specific to the specific types. Parasympathetic drugs can be either muscarinic agonists or antagonists, or have indirect effects on the cholinergic system. Drugs that enhance cholinergic effects are called parasympathomimetic drugs, whereas those that inhibit cholinergic effects are referred to as anticholinergic drugs.', 'd8e485f7-6ee2-4b4d-a8fd-e122eee61842': 'Pilocarpine is a nonspecific muscarinic agonist commonly used to treat disorders of the eye. It reverses mydriasis, such as is caused by phenylephrine, and can be administered after an eye exam. Along with constricting the pupil through the smooth muscle of the iris, pilocarpine will also cause the ciliary muscle to contract. This will open perforations at the base of the cornea, allowing for the drainage of aqueous humor from the anterior compartment of the eye and, therefore, reducing intraocular pressure related to glaucoma.', '724b0975-e0d0-4e89-84f0-262e54ba429a': 'Atropine and scopolamine are part of a class of muscarinic antagonists that come from the Atropa genus of plants that include belladonna or deadly nightshade (Figure 16.4.3). The name of one of these plants, belladonna, refers to the fact that extracts from this plant were used cosmetically for dilating the pupil. The active chemicals from this plant block the muscarinic receptors in the iris and allow the pupil to dilate, which is considered attractive because it makes the eyes appear larger. Humans are instinctively attracted to anything with larger eyes, which comes from the fact that the ratio of eye-to-head size is different in infants (or baby animals) and can elicit an emotional response. The cosmetic use of belladonna extract was essentially acting on this response. Atropine is no longer used in this cosmetic capacity for reasons related to the other name for the plant, which is deadly nightshade. Suppression of parasympathetic function, especially when it becomes systemic, can be fatal. Autonomic regulation is disrupted and anticholinergic symptoms develop. The berries of this plant are highly toxic, but can be mistaken for other berries. The antidote for atropine or scopolamine poisoning is pilocarpine.', 'f837880c-ccdc-41db-8055-a3b37f6d017a': 'The pupillary light reflex (Figure 16.3.1) begins when light hits the retina and causes a signal to travel along the optic nerve. This is visual sensation, because the afferent branch of this reflex is simply sharing the special sense pathway. Bright light hitting the retina leads to the parasympathetic response, through the oculomotor nerve, followed by the postganglionic fiber from the ciliary ganglion, which stimulates the circular fibers of the iris to contract and constrict the pupil. When light hits the retina in one eye, both pupils contract. When that light is removed, both pupils dilate again back to the resting position. When the stimulus is unilateral (presented to only one eye), the response is bilateral (both eyes). The same is not true for somatic reflexes. If you touch a hot radiator, you only pull that arm back, not both. Central control of autonomic reflexes is different than for somatic reflexes. The hypothalamus, along with other CNS locations, controls the autonomic system.'}"
+Figure 16.3.1,Anatomy_And_Physio/images/Figure 16.3.1.jpg,"Figure 16.3.1 – Pupillary Reflex Pathways: The pupil is under competing autonomic control in response to light levels hitting the retina. The sympathetic system will dilate the pupil when the retina is not receiving enough light, and the parasympathetic system will constrict the pupil when too much light hits the retina.","The pupillary light reflex (Figure 16.3.1) begins when light hits the retina and causes a signal to travel along the optic nerve. This is visual sensation, because the afferent branch of this reflex is simply sharing the special sense pathway. Bright light hitting the retina leads to the parasympathetic response, through the oculomotor nerve, followed by the postganglionic fiber from the ciliary ganglion, which stimulates the circular fibers of the iris to contract and constrict the pupil. When light hits the retina in one eye, both pupils contract. When that light is removed, both pupils dilate again back to the resting position. When the stimulus is unilateral (presented to only one eye), the response is bilateral (both eyes). The same is not true for somatic reflexes. If you touch a hot radiator, you only pull that arm back, not both. Central control of autonomic reflexes is different than for somatic reflexes. The hypothalamus, along with other CNS locations, controls the autonomic system.","{'f7f7b2da-bb59-404c-982e-90c29e2d2994': 'Drugs affecting parasympathetic functions can be classified into those that increase or decrease activity at postganglionic terminals. Parasympathetic postganglionic fibers release ACh, and the receptors on the targets are muscarinic receptors. There are several types of muscarinic receptors, M1–M5, but the drugs are not usually specific to the specific types. Parasympathetic drugs can be either muscarinic agonists or antagonists, or have indirect effects on the cholinergic system. Drugs that enhance cholinergic effects are called parasympathomimetic drugs, whereas those that inhibit cholinergic effects are referred to as anticholinergic drugs.', 'd8e485f7-6ee2-4b4d-a8fd-e122eee61842': 'Pilocarpine is a nonspecific muscarinic agonist commonly used to treat disorders of the eye. It reverses mydriasis, such as is caused by phenylephrine, and can be administered after an eye exam. Along with constricting the pupil through the smooth muscle of the iris, pilocarpine will also cause the ciliary muscle to contract. This will open perforations at the base of the cornea, allowing for the drainage of aqueous humor from the anterior compartment of the eye and, therefore, reducing intraocular pressure related to glaucoma.', '724b0975-e0d0-4e89-84f0-262e54ba429a': 'Atropine and scopolamine are part of a class of muscarinic antagonists that come from the Atropa genus of plants that include belladonna or deadly nightshade (Figure 16.4.3). The name of one of these plants, belladonna, refers to the fact that extracts from this plant were used cosmetically for dilating the pupil. The active chemicals from this plant block the muscarinic receptors in the iris and allow the pupil to dilate, which is considered attractive because it makes the eyes appear larger. Humans are instinctively attracted to anything with larger eyes, which comes from the fact that the ratio of eye-to-head size is different in infants (or baby animals) and can elicit an emotional response. The cosmetic use of belladonna extract was essentially acting on this response. Atropine is no longer used in this cosmetic capacity for reasons related to the other name for the plant, which is deadly nightshade. Suppression of parasympathetic function, especially when it becomes systemic, can be fatal. Autonomic regulation is disrupted and anticholinergic symptoms develop. The berries of this plant are highly toxic, but can be mistaken for other berries. The antidote for atropine or scopolamine poisoning is pilocarpine.', 'f837880c-ccdc-41db-8055-a3b37f6d017a': 'The pupillary light reflex (Figure 16.3.1) begins when light hits the retina and causes a signal to travel along the optic nerve. This is visual sensation, because the afferent branch of this reflex is simply sharing the special sense pathway. Bright light hitting the retina leads to the parasympathetic response, through the oculomotor nerve, followed by the postganglionic fiber from the ciliary ganglion, which stimulates the circular fibers of the iris to contract and constrict the pupil. When light hits the retina in one eye, both pupils contract. When that light is removed, both pupils dilate again back to the resting position. When the stimulus is unilateral (presented to only one eye), the response is bilateral (both eyes). The same is not true for somatic reflexes. If you touch a hot radiator, you only pull that arm back, not both. Central control of autonomic reflexes is different than for somatic reflexes. The hypothalamus, along with other CNS locations, controls the autonomic system.'}"
+Figure 16.2.1,Anatomy_And_Physio/images/Figure 16.2.1.jpg,"Figure 16.2.1 – Comparison of Somatic and Visceral Reflexes: The afferent inputs to somatic and visceral reflexes are essentially the same, whereas the efferent branches are different. Somatic reflexes, for instance, involve a direct connection from the ventral horn of the spinal cord to the skeletal muscle. Visceral reflexes involve a projection from the central neuron to a ganglion, followed by a second projection from the ganglion to the target effector.","One difference between a somatic reflex, such as the withdrawal reflex, and a visceral reflex, which is an autonomic reflex, is in the efferent branch. The output of a somatic reflex is the lower motor neuron in the ventral horn of the spinal cord that projects directly to a skeletal muscle to cause its contraction. The output of a visceral reflex is a two-step pathway starting with the preganglionic fiber emerging from a lateral horn neuron in the spinal cord, or a cranial nucleus neuron in the brain stem, to a ganglion—followed by the postganglionic fiber projecting to a target effector. The other part of a reflex, the afferent branch, is often the same between the two systems. Sensory neurons receiving input from the periphery—with cell bodies in the sensory ganglia, either of a cranial nerve or a dorsal root ganglion adjacent to the spinal cord—project into the CNS to initiate the reflex (Figure 16.2.1). The Latin root “effere” means “to carry.” Adding the prefix “ef-” suggests the meaning “to carry away,” whereas adding the prefix “af-” suggests “to carry toward or inward.”","{'1d294549-f391-4c1c-b6cc-108f3c0a2916': 'One difference between a somatic reflex, such as the withdrawal reflex, and a visceral reflex, which is an autonomic reflex, is in the efferent branch. The output of a somatic reflex is the lower motor neuron in the ventral horn of the spinal cord that projects directly to a skeletal muscle to cause its contraction. The output of a visceral reflex is a two-step pathway starting with the preganglionic fiber emerging from a lateral horn neuron in the spinal cord, or a cranial nucleus neuron in the brain stem, to a ganglion—followed by the postganglionic fiber projecting to a target effector. The other part of a reflex, the afferent branch, is often the same between the two systems. Sensory neurons receiving input from the periphery—with cell bodies in the sensory ganglia, either of a cranial nerve or a dorsal root ganglion adjacent to the spinal cord—project into the CNS to initiate the reflex (Figure 16.2.1). The Latin root “effere” means “to carry.” Adding the prefix “ef-” suggests the meaning “to carry away,” whereas adding the prefix “af-” suggests “to carry toward or inward.”'}"
+Figure 16.1.1,Anatomy_And_Physio/images/Figure 16.1.1.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.,"A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.","{'4bc5886f-9ffe-4daa-9ea4-732c326849d5': 'To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.', '43e147e0-5762-4d8c-af33-3fe109c0c86e': 'The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.', 'c662cbe4-bcbf-44d3-9e22-c13e7142b157': 'A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.', 'c7faa5a6-9f77-41f0-a85a-1f5101c07d4a': 'To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.', '179dbfe6-f754-42db-a8e5-6084f7fb698d': 'In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.', 'a3d582bb-4d47-47ec-a961-cefa16c43cfe': 'Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).', 'da6763fc-2d9a-4253-8447-4d9f36d01d75': 'Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.', '66a98272-6be6-47cb-b3cf-0b95159a42a0': 'An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)', '99a7324c-cdb1-4ad3-976a-987a24da276e': 'One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.', 'aa1313a1-9c09-4a23-b50a-ceb7747a190f': 'The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.'}"
+Figure 16.1.2,Anatomy_And_Physio/images/Figure 16.1.2.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured).","To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.","{'4bc5886f-9ffe-4daa-9ea4-732c326849d5': 'To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.', '43e147e0-5762-4d8c-af33-3fe109c0c86e': 'The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.', 'c662cbe4-bcbf-44d3-9e22-c13e7142b157': 'A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.', 'c7faa5a6-9f77-41f0-a85a-1f5101c07d4a': 'To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.', '179dbfe6-f754-42db-a8e5-6084f7fb698d': 'In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.', 'a3d582bb-4d47-47ec-a961-cefa16c43cfe': 'Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).', 'da6763fc-2d9a-4253-8447-4d9f36d01d75': 'Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.', '66a98272-6be6-47cb-b3cf-0b95159a42a0': 'An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)', '99a7324c-cdb1-4ad3-976a-987a24da276e': 'One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.', 'aa1313a1-9c09-4a23-b50a-ceb7747a190f': 'The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.'}"
+Figure 16.1.2,Anatomy_And_Physio/images/Figure 16.1.2.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured).","To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.","{'4bc5886f-9ffe-4daa-9ea4-732c326849d5': 'To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.', '43e147e0-5762-4d8c-af33-3fe109c0c86e': 'The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.', 'c662cbe4-bcbf-44d3-9e22-c13e7142b157': 'A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.', 'c7faa5a6-9f77-41f0-a85a-1f5101c07d4a': 'To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.', '179dbfe6-f754-42db-a8e5-6084f7fb698d': 'In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.', 'a3d582bb-4d47-47ec-a961-cefa16c43cfe': 'Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).', 'da6763fc-2d9a-4253-8447-4d9f36d01d75': 'Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.', '66a98272-6be6-47cb-b3cf-0b95159a42a0': 'An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)', '99a7324c-cdb1-4ad3-976a-987a24da276e': 'One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.', 'aa1313a1-9c09-4a23-b50a-ceb7747a190f': 'The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.'}"
+Figure 16.1.2,Anatomy_And_Physio/images/Figure 16.1.2.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured).","To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.","{'4bc5886f-9ffe-4daa-9ea4-732c326849d5': 'To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.', '43e147e0-5762-4d8c-af33-3fe109c0c86e': 'The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.', 'c662cbe4-bcbf-44d3-9e22-c13e7142b157': 'A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.', 'c7faa5a6-9f77-41f0-a85a-1f5101c07d4a': 'To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.', '179dbfe6-f754-42db-a8e5-6084f7fb698d': 'In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.', 'a3d582bb-4d47-47ec-a961-cefa16c43cfe': 'Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).', 'da6763fc-2d9a-4253-8447-4d9f36d01d75': 'Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.', '66a98272-6be6-47cb-b3cf-0b95159a42a0': 'An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)', '99a7324c-cdb1-4ad3-976a-987a24da276e': 'One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.', 'aa1313a1-9c09-4a23-b50a-ceb7747a190f': 'The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.'}"
+Figure 16.1.1,Anatomy_And_Physio/images/Figure 16.1.1.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.,"A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.","{'4bc5886f-9ffe-4daa-9ea4-732c326849d5': 'To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.', '43e147e0-5762-4d8c-af33-3fe109c0c86e': 'The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.', 'c662cbe4-bcbf-44d3-9e22-c13e7142b157': 'A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.', 'c7faa5a6-9f77-41f0-a85a-1f5101c07d4a': 'To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.', '179dbfe6-f754-42db-a8e5-6084f7fb698d': 'In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.', 'a3d582bb-4d47-47ec-a961-cefa16c43cfe': 'Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).', 'da6763fc-2d9a-4253-8447-4d9f36d01d75': 'Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.', '66a98272-6be6-47cb-b3cf-0b95159a42a0': 'An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)', '99a7324c-cdb1-4ad3-976a-987a24da276e': 'One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.', 'aa1313a1-9c09-4a23-b50a-ceb7747a190f': 'The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.'}"
+Figure 16.1.3,Anatomy_And_Physio/images/Figure 16.1.3.jpg,"Figure 16.1.3 – Connections of Parasympathetic Division of the Autonomic Nervous System: Neurons from brain-stem nuclei, or from the lateral horn of the sacral spinal cord, project to terminal ganglia near or within the various organs of the body. Axons from these ganglionic neurons then project the short distance to those target effectors.","The connections, or “circuits,” of the parasympathetic division are similar to the general layout of the sympathetic division with a few specific differences (Figure 16.1.3). The preganglionic fibers from the cranial region travel in cranial nerves, whereas preganglionic fibers from the sacral region travel in spinal nerves. The targets of these fibers are terminal ganglia, which are located near—or even within—the target effector. These ganglia are often referred to as intramural ganglia when they are found within the walls of the target organ. The postganglionic fiber projects from the terminal ganglia a short distance to the target effector, or to the specific target tissue within the organ. Comparing the relative lengths of axons in the parasympathetic system, the preganglionic fibers are long and the postganglionic fibers are short because the ganglia are close to—and sometimes within—the target effectors.","{'ebd72446-f7a8-41df-a347-457040ee89b7': 'The parasympathetic division of the autonomic nervous system is named because its central neurons are located on either side of the thoracolumbar region of the spinal cord (para- = “beside” or “near”). The parasympathetic system can also be referred to as the craniosacral system (or outflow) because the preganglionic neurons are located in nuclei of the brain stem and the lateral horn of the sacral spinal cord.', '743b88b6-2263-491a-ad12-3ffb1df5d985': 'The connections, or “circuits,” of the parasympathetic division are similar to the general layout of the sympathetic division with a few specific differences (Figure 16.1.3). The preganglionic fibers from the cranial region travel in cranial nerves, whereas preganglionic fibers from the sacral region travel in spinal nerves. The targets of these fibers are terminal ganglia, which are located near—or even within—the target effector. These ganglia are often referred to as intramural ganglia when they are found within the walls of the target organ. The postganglionic fiber projects from the terminal ganglia a short distance to the target effector, or to the specific target tissue within the organ. Comparing the relative lengths of axons in the parasympathetic system, the preganglionic fibers are long and the postganglionic fibers are short because the ganglia are close to—and sometimes within—the target effectors.', 'a4da97fd-41e6-4bc1-99e1-ce1632097f02': 'The cranial component of the parasympathetic system is based in particular nuclei of the brain stem. In the midbrain, the Edinger–Westphal nucleus is part of the oculomotor complex, and axons from those neurons travel with the fibers in the oculomotor nerve (cranial nerve III) that innervate the extraocular muscles. The preganglionic parasympathetic fibers within cranial nerve III terminate in the ciliary ganglion, which is located in the posterior orbit. The postganglionic parasympathetic fibers then project to the smooth muscle of the iris to control pupillary size. In the upper medulla, the salivatory nuclei contain neurons with axons that project through the facial and glossopharyngeal nerves to ganglia that control salivary glands. Tear production is influenced by parasympathetic fibers in the facial nerve, which activate a ganglion, and ultimately the lacrimal (tear) gland. Neurons in the dorsal nucleus of the vagus nerve and the nucleus ambiguus project through the vagus nerve (cranial nerve X) to the terminal ganglia of the thoracic and abdominal cavities. Parasympathetic preganglionic fibers primarily influence the heart, bronchi, and esophagus in the thoracic cavity and the stomach, liver, pancreas, gall bladder, and small intestine of the abdominal cavity. The postganglionic fibers from the ganglia activated by the vagus nerve are often incorporated into the structure of the organ, such as the mesenteric plexus of the digestive tract organs and the intramural ganglia.'}"
+Figure 16.1.4,Anatomy_And_Physio/images/Figure 16.1.4.jpg,"Figure 16.1.4 – Autonomic Varicosities: The connection between autonomic fibers and target effectors is not the same as the typical synapse, such as the neuromuscular junction. Instead of a synaptic end bulb, a neurotransmitter is released from swellings along the length of a fiber that makes an extended network of connections in the target effector.","What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.1,Anatomy_And_Physio/images/Figure 15.5.1.jpg,Figure 15.5.1 – The Eye in the Orbit: The eye is located within the orbit and surrounded by soft tissues that protect and support its function. The orbit is surrounded by cranial bones of the skull.,"Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.2,Anatomy_And_Physio/images/Figure 15.5.2.jpg,Figure 15.5.2 – Extraocular Muscles: The extraocular muscles move the eye within the orbit.,"Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.3,Anatomy_And_Physio/images/Figure 15.5.3.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea.","The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.3,Anatomy_And_Physio/images/Figure 15.5.3.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea.","The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.3,Anatomy_And_Physio/images/Figure 15.5.3.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea.","The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.4,Anatomy_And_Physio/images/Figure 15.5.4.jpg,"Figure 15.5.4 – Photoreceptor: (a) All photoreceptors have inner segments containing the nucleus and other important organelles and outer segments with membrane arrays containing the photosensitive opsin molecules. Rod outer segments are long columnar shapes with stacks of membrane-bound discs that contain the rhodopsin pigment. Cone outer segments are short, tapered shapes with folds of membrane in place of the discs in the rods. (b) Tissue of the retina shows a dense layer of nuclei of the rods and cones. LM × 800. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.5,Anatomy_And_Physio/images/Figure 15.5.5.jpg,"Figure 15.5.5 – Retinal Isomers: The retinal molecule has two isomers, (a) one before a photon interacts with it and (b) one that is altered through photoisomerization.","Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.5.6,Anatomy_And_Physio/images/Figure 15.5.6.jpg,Figure 15.5.6 – Comparison of Color Sensitivity of Photopigments: Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths.,"The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.","{'56440a47-0d0d-453e-bfd2-45123f9ee59c': 'Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.', '5e87ee4b-3507-4c26-8c4d-4a5d8f47f670': 'The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).', '83daf676-97eb-454c-988e-b6d3ae4e6b5a': 'The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.', 'adfb5a31-7112-465f-b3c8-e94425701ddd': 'The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.', 'ea354296-0dbf-43da-90ac-8de372cecc65': 'Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).', '631ebf12-c456-47e2-8a9a-988a0a1c9950': 'Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.', 'e330f2e1-440c-479d-aec8-86a22fc6ae1f': 'What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).', 'd6023c5c-3e39-4dbf-b295-beea5a580bb9': 'The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.', '3a51e17c-ad37-4eb2-9a56-0a615f22ef1e': 'Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.', '51699243-d160-45db-a6bd-a4de9eb932d6': 'This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.', 'c185e975-dd32-4af6-b6c1-94b0c80947b4': 'However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.', '8995e60b-3a9c-4590-9d6d-c769e9aff185': 'Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.', 'a01ad384-3eee-43fe-bd27-283c43ad74b4': 'Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).', 'f7de08a6-97a1-4bd8-bfdf-afd601c02a92': 'The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.', '199e7162-00ac-4e78-bcc8-815a41220839': 'The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.', '68c2db6d-0eb7-4bd0-8650-11e965c431bc': 'The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.', 'db371f50-4f66-473f-a084-bc9eaf3213fd': 'The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.', 'e8550904-56fa-47bc-a265-29f0df045a8d': 'Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.', 'c75c913d-90f9-454a-8425-df448a9214b9': 'Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.', 'a774893d-b349-4c37-a13b-64287ae7fe52': 'At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.', 'a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461': 'Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).', '2e9c3505-a77b-436e-8028-b9dfe27db7dc': 'The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.', '895d91b7-6fb2-4ed0-8c50-f136be1be78d': 'The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.', '25d054d2-2edc-4f7f-bea1-5fb3257701d1': 'The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.'}"
+Figure 15.4.1,Anatomy_And_Physio/images/Figure 15.4.1.jpg,"Figure 15.4.1 – Linear Acceleration Coding by Maculae: The maculae are specialized for sensing linear acceleration, such as when gravity acts on the tilting head, or if the head starts moving in a straight line. The difference in inertia between the hair cell stereocilia and the otolithic membrane in which they are embedded leads to a shearing force that causes the stereocilia to bend in the direction of that linear acceleration.","The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.4.2,Anatomy_And_Physio/images/Figure 15.4.2.jpg,"Figure 15.4.2 – Rotational Coding by Semicircular Canals: Rotational movement of the head is encoded by the hair cells in the base of the semicircular canals. As one of the canals moves in an arc with the head, the internal fluid moves in the opposite direction, causing the cupula and stereocilia to bend. The movement of two canals within a plane results in information about the direction in which the head is moving, and activation of all six canals can give a very precise indication of head movement in three dimensions.","The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.4.3,Anatomy_And_Physio/images/Figure 15.4.3.jpg,"Figure 15.4.3 – Vestibulo-ocular Reflex: Connections between the vestibular system and the cranial nerves controlling eye movement keep the eyes centered on a visual stimulus, even though the head is moving. During head movement, the eye muscles move the eyes in the opposite direction as the head movement, keeping the visual stimulus centered in the field of view.","Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.1,Anatomy_And_Physio/images/Figure 15.3.1.jpg,"Figure 15.3.1 – Structures of the Ear: The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively.","Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.2,Anatomy_And_Physio/images/Figure 15.3.2.jpg,"Figure 15.3.2 – Transmission of Sound Waves to Cochlea: A sound wave causes the tympanic membrane to vibrate. This vibration is amplified as it moves across the malleus, incus, and stapes. The amplified vibration is picked up by the oval window causing pressure waves in the fluid of the scala vestibuli and scala tympani. The complexity of the pressure waves is determined by the changes in amplitude and frequency of the sound waves entering the ear.","The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.3,Anatomy_And_Physio/images/Figure 15.3.3.jpg,"Figure 15.3.3 – Cross Section of the Cochlea: The three major spaces within the cochlea are highlighted. The scala tympani and scala vestibuli lie on either side of the cochlear duct. The organ of Corti, containing the mechanoreceptor hair cells, is adjacent to the scala tympani, where it sits atop the basilar membrane.","A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.4,Anatomy_And_Physio/images/Figure 15.3.4.jpg,"Figure 15.3.4 – Hair Cell: The hair cell is a mechanoreceptor with an array of stereocilia emerging from its apical surface. The stereocilia are tethered together by proteins that open ion channels when the array is bent toward the tallest member of their array, and closed when the array is bent toward the shortest member of their array.","The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.6,Anatomy_And_Physio/images/Figure 15.3.6.jpg,"Figure 15.3.6 – Frequency Coding in the Cochlea: The standing sound wave generated in the cochlea by the movement of the oval window deflects the basilar membrane on the basis of the frequency of sound. Therefore, hair cells at the base of the cochlea are activated only by high frequencies, whereas those at the apex of the cochlea are activated only by low frequencies.","As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.3.7,Anatomy_And_Physio/images/Figure 15.3.7.jpg,Figure 15.3.7 – Auditory Brain Stem Mechanisms of Sound Localization: Localizing sound in the horizontal plane is achieved by processing in the medullary nuclei of the auditory system. Connections between neurons on either side are able to compare very slight differences in sound stimuli that arrive at either ear and represent interaural time and intensity differences.,"Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.2.1,Anatomy_And_Physio/images/Figure 15.2.1.jpg,Figure 15.2.1 – The Olfactory System: (a) The olfactory system begins in the peripheral structures of the nasal cavity. (b) The olfactory receptor neurons are within the olfactory epithelium. (c) Axons of the olfactory receptor neurons project through the cribriform plate of the ethmoid bone and synapse with the neurons of the olfactory bulb (tissue source: simian). LM × 812. (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 15.1.1,Anatomy_And_Physio/images/Figure 15.1.1.jpg,"Figure 15.1.1 – The Tongue: The tongue is covered with small bumps, called papillae, which contain taste buds that are sensitive to chemicals in ingested food or drink. Different types of papillae are found in different regions of the tongue. The taste buds contain specialized gustatory receptor cells that respond to chemical stimuli dissolved in the saliva. These receptor cells activate sensory neurons that are part of the facial and glossopharyngeal nerves. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.","{'352396ed-338f-4bd0-b217-412a472cacfd': 'Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.', '9d6eb5ef-f84b-4d90-b288-c3b1a38bad66': 'The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.', 'c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79': 'The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.', 'b35784a8-e8db-4f42-bc3e-2bfc4a9325b7': 'Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.', '9ad4c4e8-7c9d-490a-bc82-03d7871ab430': 'Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.', 'd555a927-2599-4a3f-9abe-dbf1c72d5ee7': 'Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.', '7cc44b14-80ad-4b6f-9500-051f2114964b': 'The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.', '7521af5b-943f-44ce-a020-b579e05ee6f1': 'The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.', '7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3': 'A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.', 'e595c5d8-bf26-4dae-bec0-7c85131744be': 'The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.', '11dab03c-88a0-494f-8878-1a18abd7d68b': 'As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.', 'c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21': 'The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.', 'fecbd5ef-cc31-4dd1-8212-26557abe2eeb': 'Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.', '514e7c3f-bf35-4646-b2b7-2943b0c9906e': 'Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.', '148997ac-bb14-474f-9e20-274a6c01afba': 'Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.', '3a3a5225-177f-4763-b407-1e1833fa42ca': 'The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.', '247bf358-8176-4f69-a8c1-eb62c7a93392': 'The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.', 'aec1881f-4ab8-4894-8b6f-65bdf124fec8': 'Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.', '3045b11f-acb2-4736-a2ff-9b7171ed07b2': 'Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.', 'ab48314c-12bf-4fe5-9485-0e8e9462c9d3': 'Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.', 'f6b6de0d-c919-4893-abeb-68525b02cc29': 'Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.', '61891638-6d15-486d-a998-a2cc04d9ccbf': 'The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.', '7048622e-513d-4562-95ba-38cc250c441e': 'Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.', 'f1a8d4b0-a38c-4424-b34e-5e3a668efbcd': 'One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.', '5125f605-3690-46f2-a5f0-37e7599da2fc': 'Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.', '7585d2fa-c58f-45d2-a537-bfb000e1593e': 'The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.', '93b7131c-174b-4bb1-898d-51b91c499452': 'Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.', '7ab87957-aaf4-48fb-9533-e1a82aebbc83': 'The sensory pathway for gustation travels along the facial, \xa0glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.'}"
+Figure 14.5.2,Anatomy_And_Physio/images/Figure 14.5.2.jpg,Figure 14.5.2 – The Sensory Homunculus: A cartoon representation of the sensory homunculus arranged adjacent to the cortical region in which the processing takes place.,"As described earlier, many of the sensory axons are positioned in the same way as their corresponding receptor cells in the body. This allows identification of the position of a stimulus on the basis of which receptor cells are sending information. The cerebral cortex also maintains this sensory topography in the particular areas of the cortex that correspond to the position of the receptor cells. The somatosensory cortex provides an example in which, in essence, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex. This mapping is often depicted using a sensory homunculus (Figure 14.5.2).","{'6ecb27f0-4561-414a-b887-3cba544639f7': 'As described earlier, many of the sensory axons are positioned in the same way as their corresponding receptor cells in the body. This allows identification of the position of a stimulus on the basis of which receptor cells are sending information. The cerebral cortex also maintains this sensory topography in the particular areas of the cortex that correspond to the position of the receptor cells. The somatosensory cortex provides an example in which, in essence, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex. This mapping is often depicted using a sensory homunculus (Figure 14.5.2).', 'de3a35ae-763c-4373-9d6c-3fda4be6a361': 'The term homunculus comes from the Latin word for “little man” and refers to a map of the human body that is laid across a portion of the cerebral cortex. In the somatosensory cortex, the external genitals, feet, and lower legs are represented on the medial face of the gyrus within the longitudinal fissure. As the gyrus curves out of the fissure and along the surface of the parietal lobe, the body map continues through the thighs, hips, trunk, shoulders, arms, and hands. The head and face are just lateral to the fingers as the gyrus approaches the lateral sulcus. The representation of the body in this topographical map is medial to lateral from the lower to upper body. It is a continuation of the topographical arrangement seen in the dorsal column system, where axons from the lower body are carried in the fasciculus gracilis, whereas axons from the upper body are carried in the fasciculus cuneatus. As the dorsal column system continues into the medial lemniscus, these relationships are maintained. Also, the head and neck axons running from the trigeminal nuclei to the thalamus run adjacent to the upper body fibers. The connections through the thalamus maintain topography such that the anatomic information is preserved. Note that this correspondence does not result in a perfectly miniature scale version of the body, but rather exaggerates the more sensitive areas of the body, such as the fingers and lower face. Less sensitive areas of the body, such as the shoulders and back, are mapped to smaller areas on the cortex.', 'f31a6c48-dc98-40d2-9ee9-1800be7997cd': 'The cortex has been described as having specific regions that are responsible for processing specific information; there is the visual cortex, somatosensory cortex, gustatory cortex, etc. However, our experience of these senses is not divided. Instead, we experience what can be referred to as a seamless percept. Our perceptions of the various sensory modalities—though distinct in their content—are integrated by the brain so that we experience the world as a continuous whole.', 'eef40952-c5ea-45eb-92e2-341901269957': 'In the cerebral cortex, sensory processing begins at the primary sensory cortex, then proceeds to an association area, and finally, into a multimodal integration area. For example, somatosensory information inputs directly into the primary somatosensory cortex in the post-central gyrus of the parietal lobe where general awareness of sensation (location and type of sensation) begins. In the somatosensory association cortex details are integrated into a whole. In the highest level of association cortex details are integrated from entirely different modalities to form complete representations as we experience them.', 'ad034bdc-75ca-4151-81cb-cbc7de2d00d8': 'The defining characteristic of the somatic nervous system is that it controls skeletal muscles. Somatic senses inform the nervous system about the external environment, but the response to that is through voluntary muscle movement. The term “voluntary” suggests that there is a conscious decision to make a movement. However, some aspects of the somatic system use voluntary muscles without conscious control. One example is the ability of our breathing to switch to unconscious control while we are focused on another task. However, the muscles that are responsible for the basic process of breathing are also utilized for speech, which is entirely voluntary.', '10736676-31fb-4e71-9cde-288a75050d77': 'Let’s start with sensory stimuli that have been registered through receptor cells and the information relayed to the CNS along ascending pathways. In the cerebral cortex, the initial processing of sensory perception progresses to associative processing and then integration in multimodal areas of cortex. These levels of processing can lead to the incorporation of sensory perceptions into memory, but more importantly, they lead to a response. The completion of cortical processing through the primary, associative, and integrative sensory areas initiates a similar progression of motor processing, usually in different cortical areas.', '2ebc0fd8-1022-45ba-bdcf-cffe5668b162': 'Whereas the sensory cortical areas are located in the occipital, temporal, and parietal lobes, motor functions are largely controlled by the frontal lobe. The most anterior regions of the frontal lobe—the prefrontal areas—are important for executive functions, which are those cognitive functions that lead to goal-directed behaviors. These higher cognitive processes include working memory, which has been called a “mental scratch pad,” that can help organize and represent information that is not in the immediate environment. The prefrontal lobe is responsible for aspects of attention, such as inhibiting distracting thoughts and actions so that a person can focus on a goal and direct behavior toward achieving that goal.', 'a7f901b5-7f67-4e7c-a2c3-9a5f51037901': 'The functions of the prefrontal cortex are integral to the personality of an individual, because it is largely responsible for what a person intends to do and how they accomplish those plans. A famous case of damage to the prefrontal cortex is that of Phineas Gage, dating back to 1848. He was a railroad worker who had a metal spike impale his prefrontal cortex (Figure 14.5.3). He survived the accident, but according to second-hand accounts, his personality changed drastically. Friends described him as no longer acting like himself. Whereas he was a hardworking, amiable man before the accident, he turned into an irritable, temperamental, and lazy man after the accident. Many of the accounts of his change may have been inflated in the retelling, and some behavior was likely attributable to alcohol used as a pain medication. However, the accounts suggest that some aspects of his personality did change. Also, there is new evidence that though his life changed dramatically, he was able to become a functioning stagecoach driver, suggesting that the brain has the ability to recover even from major trauma such as this.', '36dae701-8b3f-4599-adf0-78c9462c69d9': 'In generating motor responses, the executive functions of the prefrontal cortex will need to initiate actual movements. One way to define the prefrontal area is any region of the frontal lobe that does not elicit movement when electrically stimulated. These are primarily in the anterior part of the frontal lobe. The regions of the frontal lobe that remain are the regions of the cortex that produce movement. The prefrontal areas project into the secondary motor cortices, which include the premotor cortex and the supplemental motor area.', '30baf4cd-1d06-4d10-9f98-ef48f88d2238': 'Two important regions that assist in planning and coordinating movements are located adjacent to the primary motor cortex. The premotor cortex is more lateral, whereas the supplemental motor area is more medial and superior. The premotor area aids in controlling movements of the core muscles to maintain posture during movement, whereas the supplemental motor area is hypothesized to be responsible for planning and coordinating movement. The supplemental motor area also manages sequential movements that are based on prior experience (that is, learned movements). Neurons in these areas are most active leading up to the initiation of movement. For example, these areas might prepare the body for the movements necessary to drive a car in anticipation of a traffic light changing.', 'a87ffb3b-ce0f-4bd2-9eb8-bcb7883536a2': 'Adjacent to these two regions are two specialized motor planning centers. The frontal eye fields are responsible for moving the eyes in response to visual stimuli. There are direct connections between the frontal eye fields and the superior colliculus. Also, anterior to the premotor cortex and primary motor cortex is Broca’s area. This area is responsible for controlling movements of the structures of speech production. The area is named after a French surgeon and anatomist who studied patients who could not produce speech. They did not have impairments to understanding speech, only to producing speech sounds, suggesting a damaged or underdeveloped Broca’s area.', '585f0697-9010-4343-99f2-a6a569903067': 'The primary motor cortex is located in the precentral gyrus of the frontal lobe. A neurosurgeon, Walter Penfield, described much of the basic understanding of the primary motor cortex by electrically stimulating the surface of the cerebrum. Penfield would probe the surface of the cortex while the patient was only under local anesthesia so that he could observe responses to the stimulation. This led to the belief that the precentral gyrus directly stimulated muscle movement. We now know that the primary motor cortex receives input from several areas that aid in planning movement, and its principle output stimulates spinal cord neurons to stimulate skeletal muscle contraction.', 'fd27de35-aec6-4dfe-baee-e7f5efbcd3d9': 'The primary motor cortex is arranged in a similar fashion to the primary somatosensory cortex, in that it has a topographical map of the body, creating a motor homunculus (see Chapter 14.2 Figure 14.2.5). The neurons responsible for musculature in the feet and lower legs are in the medial wall of the precentral gyrus, with the thighs, trunk, and shoulder at the crest of the longitudinal fissure. The hand and face are in the lateral face of the gyrus. Also, the relative space allotted for the different regions is exaggerated in muscles that have greater enervation. The greatest amount of cortical space is given to muscles that perform fine, agile movements, such as the muscles of the fingers and the lower face that are parts of small motor units. The “power muscles” that perform coarser movements, such as the buttock and back muscles, occupy much less space on the motor cortex.'}"
+Figure 14.5.3,Anatomy_And_Physio/images/Figure 14.5.3.jpg,"Figure 14.5.3 – Phineas Gage: The victim of an accident while working on a railroad in 1848, Phineas Gage had a large iron rod impaled through the prefrontal cortex of his frontal lobe. After the accident, his personality appeared to change, but he eventually learned to cope with the trauma and lived as a coach driver even after such a traumatic event. (credit b: John M. Harlow, MD)","The functions of the prefrontal cortex are integral to the personality of an individual, because it is largely responsible for what a person intends to do and how they accomplish those plans. A famous case of damage to the prefrontal cortex is that of Phineas Gage, dating back to 1848. He was a railroad worker who had a metal spike impale his prefrontal cortex (Figure 14.5.3). He survived the accident, but according to second-hand accounts, his personality changed drastically. Friends described him as no longer acting like himself. Whereas he was a hardworking, amiable man before the accident, he turned into an irritable, temperamental, and lazy man after the accident. Many of the accounts of his change may have been inflated in the retelling, and some behavior was likely attributable to alcohol used as a pain medication. However, the accounts suggest that some aspects of his personality did change. Also, there is new evidence that though his life changed dramatically, he was able to become a functioning stagecoach driver, suggesting that the brain has the ability to recover even from major trauma such as this.","{'6ecb27f0-4561-414a-b887-3cba544639f7': 'As described earlier, many of the sensory axons are positioned in the same way as their corresponding receptor cells in the body. This allows identification of the position of a stimulus on the basis of which receptor cells are sending information. The cerebral cortex also maintains this sensory topography in the particular areas of the cortex that correspond to the position of the receptor cells. The somatosensory cortex provides an example in which, in essence, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex. This mapping is often depicted using a sensory homunculus (Figure 14.5.2).', 'de3a35ae-763c-4373-9d6c-3fda4be6a361': 'The term homunculus comes from the Latin word for “little man” and refers to a map of the human body that is laid across a portion of the cerebral cortex. In the somatosensory cortex, the external genitals, feet, and lower legs are represented on the medial face of the gyrus within the longitudinal fissure. As the gyrus curves out of the fissure and along the surface of the parietal lobe, the body map continues through the thighs, hips, trunk, shoulders, arms, and hands. The head and face are just lateral to the fingers as the gyrus approaches the lateral sulcus. The representation of the body in this topographical map is medial to lateral from the lower to upper body. It is a continuation of the topographical arrangement seen in the dorsal column system, where axons from the lower body are carried in the fasciculus gracilis, whereas axons from the upper body are carried in the fasciculus cuneatus. As the dorsal column system continues into the medial lemniscus, these relationships are maintained. Also, the head and neck axons running from the trigeminal nuclei to the thalamus run adjacent to the upper body fibers. The connections through the thalamus maintain topography such that the anatomic information is preserved. Note that this correspondence does not result in a perfectly miniature scale version of the body, but rather exaggerates the more sensitive areas of the body, such as the fingers and lower face. Less sensitive areas of the body, such as the shoulders and back, are mapped to smaller areas on the cortex.', 'f31a6c48-dc98-40d2-9ee9-1800be7997cd': 'The cortex has been described as having specific regions that are responsible for processing specific information; there is the visual cortex, somatosensory cortex, gustatory cortex, etc. However, our experience of these senses is not divided. Instead, we experience what can be referred to as a seamless percept. Our perceptions of the various sensory modalities—though distinct in their content—are integrated by the brain so that we experience the world as a continuous whole.', 'eef40952-c5ea-45eb-92e2-341901269957': 'In the cerebral cortex, sensory processing begins at the primary sensory cortex, then proceeds to an association area, and finally, into a multimodal integration area. For example, somatosensory information inputs directly into the primary somatosensory cortex in the post-central gyrus of the parietal lobe where general awareness of sensation (location and type of sensation) begins. In the somatosensory association cortex details are integrated into a whole. In the highest level of association cortex details are integrated from entirely different modalities to form complete representations as we experience them.', 'ad034bdc-75ca-4151-81cb-cbc7de2d00d8': 'The defining characteristic of the somatic nervous system is that it controls skeletal muscles. Somatic senses inform the nervous system about the external environment, but the response to that is through voluntary muscle movement. The term “voluntary” suggests that there is a conscious decision to make a movement. However, some aspects of the somatic system use voluntary muscles without conscious control. One example is the ability of our breathing to switch to unconscious control while we are focused on another task. However, the muscles that are responsible for the basic process of breathing are also utilized for speech, which is entirely voluntary.', '10736676-31fb-4e71-9cde-288a75050d77': 'Let’s start with sensory stimuli that have been registered through receptor cells and the information relayed to the CNS along ascending pathways. In the cerebral cortex, the initial processing of sensory perception progresses to associative processing and then integration in multimodal areas of cortex. These levels of processing can lead to the incorporation of sensory perceptions into memory, but more importantly, they lead to a response. The completion of cortical processing through the primary, associative, and integrative sensory areas initiates a similar progression of motor processing, usually in different cortical areas.', '2ebc0fd8-1022-45ba-bdcf-cffe5668b162': 'Whereas the sensory cortical areas are located in the occipital, temporal, and parietal lobes, motor functions are largely controlled by the frontal lobe. The most anterior regions of the frontal lobe—the prefrontal areas—are important for executive functions, which are those cognitive functions that lead to goal-directed behaviors. These higher cognitive processes include working memory, which has been called a “mental scratch pad,” that can help organize and represent information that is not in the immediate environment. The prefrontal lobe is responsible for aspects of attention, such as inhibiting distracting thoughts and actions so that a person can focus on a goal and direct behavior toward achieving that goal.', 'a7f901b5-7f67-4e7c-a2c3-9a5f51037901': 'The functions of the prefrontal cortex are integral to the personality of an individual, because it is largely responsible for what a person intends to do and how they accomplish those plans. A famous case of damage to the prefrontal cortex is that of Phineas Gage, dating back to 1848. He was a railroad worker who had a metal spike impale his prefrontal cortex (Figure 14.5.3). He survived the accident, but according to second-hand accounts, his personality changed drastically. Friends described him as no longer acting like himself. Whereas he was a hardworking, amiable man before the accident, he turned into an irritable, temperamental, and lazy man after the accident. Many of the accounts of his change may have been inflated in the retelling, and some behavior was likely attributable to alcohol used as a pain medication. However, the accounts suggest that some aspects of his personality did change. Also, there is new evidence that though his life changed dramatically, he was able to become a functioning stagecoach driver, suggesting that the brain has the ability to recover even from major trauma such as this.', '36dae701-8b3f-4599-adf0-78c9462c69d9': 'In generating motor responses, the executive functions of the prefrontal cortex will need to initiate actual movements. One way to define the prefrontal area is any region of the frontal lobe that does not elicit movement when electrically stimulated. These are primarily in the anterior part of the frontal lobe. The regions of the frontal lobe that remain are the regions of the cortex that produce movement. The prefrontal areas project into the secondary motor cortices, which include the premotor cortex and the supplemental motor area.', '30baf4cd-1d06-4d10-9f98-ef48f88d2238': 'Two important regions that assist in planning and coordinating movements are located adjacent to the primary motor cortex. The premotor cortex is more lateral, whereas the supplemental motor area is more medial and superior. The premotor area aids in controlling movements of the core muscles to maintain posture during movement, whereas the supplemental motor area is hypothesized to be responsible for planning and coordinating movement. The supplemental motor area also manages sequential movements that are based on prior experience (that is, learned movements). Neurons in these areas are most active leading up to the initiation of movement. For example, these areas might prepare the body for the movements necessary to drive a car in anticipation of a traffic light changing.', 'a87ffb3b-ce0f-4bd2-9eb8-bcb7883536a2': 'Adjacent to these two regions are two specialized motor planning centers. The frontal eye fields are responsible for moving the eyes in response to visual stimuli. There are direct connections between the frontal eye fields and the superior colliculus. Also, anterior to the premotor cortex and primary motor cortex is Broca’s area. This area is responsible for controlling movements of the structures of speech production. The area is named after a French surgeon and anatomist who studied patients who could not produce speech. They did not have impairments to understanding speech, only to producing speech sounds, suggesting a damaged or underdeveloped Broca’s area.', '585f0697-9010-4343-99f2-a6a569903067': 'The primary motor cortex is located in the precentral gyrus of the frontal lobe. A neurosurgeon, Walter Penfield, described much of the basic understanding of the primary motor cortex by electrically stimulating the surface of the cerebrum. Penfield would probe the surface of the cortex while the patient was only under local anesthesia so that he could observe responses to the stimulation. This led to the belief that the precentral gyrus directly stimulated muscle movement. We now know that the primary motor cortex receives input from several areas that aid in planning movement, and its principle output stimulates spinal cord neurons to stimulate skeletal muscle contraction.', 'fd27de35-aec6-4dfe-baee-e7f5efbcd3d9': 'The primary motor cortex is arranged in a similar fashion to the primary somatosensory cortex, in that it has a topographical map of the body, creating a motor homunculus (see Chapter 14.2 Figure 14.2.5). The neurons responsible for musculature in the feet and lower legs are in the medial wall of the precentral gyrus, with the thighs, trunk, and shoulder at the crest of the longitudinal fissure. The hand and face are in the lateral face of the gyrus. Also, the relative space allotted for the different regions is exaggerated in muscles that have greater enervation. The greatest amount of cortical space is given to muscles that perform fine, agile movements, such as the muscles of the fingers and the lower face that are parts of small motor units. The “power muscles” that perform coarser movements, such as the buttock and back muscles, occupy much less space on the motor cortex.'}"
+Figure 14.2.5,Anatomy_And_Physio/images/Figure 14.2.5.jpg,"Figure 14.2.5 – Cerebrospinal Fluid Circulation: The choroid plexus in the four ventricles produce CSF, which is circulated through the ventricular system and then enters the subarachnoid space through the median and lateral apertures. The CSF is then reabsorbed into the blood at the arachnoid granulations, where the arachnoid membrane emerges into the dural sinuses.","The primary motor cortex is arranged in a similar fashion to the primary somatosensory cortex, in that it has a topographical map of the body, creating a motor homunculus (see Chapter 14.2 Figure 14.2.5). The neurons responsible for musculature in the feet and lower legs are in the medial wall of the precentral gyrus, with the thighs, trunk, and shoulder at the crest of the longitudinal fissure. The hand and face are in the lateral face of the gyrus. Also, the relative space allotted for the different regions is exaggerated in muscles that have greater enervation. The greatest amount of cortical space is given to muscles that perform fine, agile movements, such as the muscles of the fingers and the lower face that are parts of small motor units. The “power muscles” that perform coarser movements, such as the buttock and back muscles, occupy much less space on the motor cortex.","{'6ecb27f0-4561-414a-b887-3cba544639f7': 'As described earlier, many of the sensory axons are positioned in the same way as their corresponding receptor cells in the body. This allows identification of the position of a stimulus on the basis of which receptor cells are sending information. The cerebral cortex also maintains this sensory topography in the particular areas of the cortex that correspond to the position of the receptor cells. The somatosensory cortex provides an example in which, in essence, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex. This mapping is often depicted using a sensory homunculus (Figure 14.5.2).', 'de3a35ae-763c-4373-9d6c-3fda4be6a361': 'The term homunculus comes from the Latin word for “little man” and refers to a map of the human body that is laid across a portion of the cerebral cortex. In the somatosensory cortex, the external genitals, feet, and lower legs are represented on the medial face of the gyrus within the longitudinal fissure. As the gyrus curves out of the fissure and along the surface of the parietal lobe, the body map continues through the thighs, hips, trunk, shoulders, arms, and hands. The head and face are just lateral to the fingers as the gyrus approaches the lateral sulcus. The representation of the body in this topographical map is medial to lateral from the lower to upper body. It is a continuation of the topographical arrangement seen in the dorsal column system, where axons from the lower body are carried in the fasciculus gracilis, whereas axons from the upper body are carried in the fasciculus cuneatus. As the dorsal column system continues into the medial lemniscus, these relationships are maintained. Also, the head and neck axons running from the trigeminal nuclei to the thalamus run adjacent to the upper body fibers. The connections through the thalamus maintain topography such that the anatomic information is preserved. Note that this correspondence does not result in a perfectly miniature scale version of the body, but rather exaggerates the more sensitive areas of the body, such as the fingers and lower face. Less sensitive areas of the body, such as the shoulders and back, are mapped to smaller areas on the cortex.', 'f31a6c48-dc98-40d2-9ee9-1800be7997cd': 'The cortex has been described as having specific regions that are responsible for processing specific information; there is the visual cortex, somatosensory cortex, gustatory cortex, etc. However, our experience of these senses is not divided. Instead, we experience what can be referred to as a seamless percept. Our perceptions of the various sensory modalities—though distinct in their content—are integrated by the brain so that we experience the world as a continuous whole.', 'eef40952-c5ea-45eb-92e2-341901269957': 'In the cerebral cortex, sensory processing begins at the primary sensory cortex, then proceeds to an association area, and finally, into a multimodal integration area. For example, somatosensory information inputs directly into the primary somatosensory cortex in the post-central gyrus of the parietal lobe where general awareness of sensation (location and type of sensation) begins. In the somatosensory association cortex details are integrated into a whole. In the highest level of association cortex details are integrated from entirely different modalities to form complete representations as we experience them.', 'ad034bdc-75ca-4151-81cb-cbc7de2d00d8': 'The defining characteristic of the somatic nervous system is that it controls skeletal muscles. Somatic senses inform the nervous system about the external environment, but the response to that is through voluntary muscle movement. The term “voluntary” suggests that there is a conscious decision to make a movement. However, some aspects of the somatic system use voluntary muscles without conscious control. One example is the ability of our breathing to switch to unconscious control while we are focused on another task. However, the muscles that are responsible for the basic process of breathing are also utilized for speech, which is entirely voluntary.', '10736676-31fb-4e71-9cde-288a75050d77': 'Let’s start with sensory stimuli that have been registered through receptor cells and the information relayed to the CNS along ascending pathways. In the cerebral cortex, the initial processing of sensory perception progresses to associative processing and then integration in multimodal areas of cortex. These levels of processing can lead to the incorporation of sensory perceptions into memory, but more importantly, they lead to a response. The completion of cortical processing through the primary, associative, and integrative sensory areas initiates a similar progression of motor processing, usually in different cortical areas.', '2ebc0fd8-1022-45ba-bdcf-cffe5668b162': 'Whereas the sensory cortical areas are located in the occipital, temporal, and parietal lobes, motor functions are largely controlled by the frontal lobe. The most anterior regions of the frontal lobe—the prefrontal areas—are important for executive functions, which are those cognitive functions that lead to goal-directed behaviors. These higher cognitive processes include working memory, which has been called a “mental scratch pad,” that can help organize and represent information that is not in the immediate environment. The prefrontal lobe is responsible for aspects of attention, such as inhibiting distracting thoughts and actions so that a person can focus on a goal and direct behavior toward achieving that goal.', 'a7f901b5-7f67-4e7c-a2c3-9a5f51037901': 'The functions of the prefrontal cortex are integral to the personality of an individual, because it is largely responsible for what a person intends to do and how they accomplish those plans. A famous case of damage to the prefrontal cortex is that of Phineas Gage, dating back to 1848. He was a railroad worker who had a metal spike impale his prefrontal cortex (Figure 14.5.3). He survived the accident, but according to second-hand accounts, his personality changed drastically. Friends described him as no longer acting like himself. Whereas he was a hardworking, amiable man before the accident, he turned into an irritable, temperamental, and lazy man after the accident. Many of the accounts of his change may have been inflated in the retelling, and some behavior was likely attributable to alcohol used as a pain medication. However, the accounts suggest that some aspects of his personality did change. Also, there is new evidence that though his life changed dramatically, he was able to become a functioning stagecoach driver, suggesting that the brain has the ability to recover even from major trauma such as this.', '36dae701-8b3f-4599-adf0-78c9462c69d9': 'In generating motor responses, the executive functions of the prefrontal cortex will need to initiate actual movements. One way to define the prefrontal area is any region of the frontal lobe that does not elicit movement when electrically stimulated. These are primarily in the anterior part of the frontal lobe. The regions of the frontal lobe that remain are the regions of the cortex that produce movement. The prefrontal areas project into the secondary motor cortices, which include the premotor cortex and the supplemental motor area.', '30baf4cd-1d06-4d10-9f98-ef48f88d2238': 'Two important regions that assist in planning and coordinating movements are located adjacent to the primary motor cortex. The premotor cortex is more lateral, whereas the supplemental motor area is more medial and superior. The premotor area aids in controlling movements of the core muscles to maintain posture during movement, whereas the supplemental motor area is hypothesized to be responsible for planning and coordinating movement. The supplemental motor area also manages sequential movements that are based on prior experience (that is, learned movements). Neurons in these areas are most active leading up to the initiation of movement. For example, these areas might prepare the body for the movements necessary to drive a car in anticipation of a traffic light changing.', 'a87ffb3b-ce0f-4bd2-9eb8-bcb7883536a2': 'Adjacent to these two regions are two specialized motor planning centers. The frontal eye fields are responsible for moving the eyes in response to visual stimuli. There are direct connections between the frontal eye fields and the superior colliculus. Also, anterior to the premotor cortex and primary motor cortex is Broca’s area. This area is responsible for controlling movements of the structures of speech production. The area is named after a French surgeon and anatomist who studied patients who could not produce speech. They did not have impairments to understanding speech, only to producing speech sounds, suggesting a damaged or underdeveloped Broca’s area.', '585f0697-9010-4343-99f2-a6a569903067': 'The primary motor cortex is located in the precentral gyrus of the frontal lobe. A neurosurgeon, Walter Penfield, described much of the basic understanding of the primary motor cortex by electrically stimulating the surface of the cerebrum. Penfield would probe the surface of the cortex while the patient was only under local anesthesia so that he could observe responses to the stimulation. This led to the belief that the precentral gyrus directly stimulated muscle movement. We now know that the primary motor cortex receives input from several areas that aid in planning movement, and its principle output stimulates spinal cord neurons to stimulate skeletal muscle contraction.', 'fd27de35-aec6-4dfe-baee-e7f5efbcd3d9': 'The primary motor cortex is arranged in a similar fashion to the primary somatosensory cortex, in that it has a topographical map of the body, creating a motor homunculus (see Chapter 14.2 Figure 14.2.5). The neurons responsible for musculature in the feet and lower legs are in the medial wall of the precentral gyrus, with the thighs, trunk, and shoulder at the crest of the longitudinal fissure. The hand and face are in the lateral face of the gyrus. Also, the relative space allotted for the different regions is exaggerated in muscles that have greater enervation. The greatest amount of cortical space is given to muscles that perform fine, agile movements, such as the muscles of the fingers and the lower face that are parts of small motor units. The “power muscles” that perform coarser movements, such as the buttock and back muscles, occupy much less space on the motor cortex.'}"
+Figure 14.5.4,Anatomy_And_Physio/images/Figure 14.5.4.jpg,"Figure 14.5.4 – Corticospinal Tract: The major descending tract that controls skeletal muscle movements is the corticospinal tract. It is composed of two neurons, the upper motor neuron and the lower motor neuron. The upper motor neuron has its cell body in the primary motor cortex of the frontal lobe and synapses on the lower motor neuron, which is in the ventral horn of the spinal cord and projects to the skeletal muscle in the periphery.","The corticospinal tract descends from the cortex through the deep white matter of the cerebrum. It then passes between the caudate nucleus and putamen of the basal nuclei as a bundle called the internal capsule. The tract then passes through the midbrain as the cerebral peduncles, after which it burrows through the pons. Upon entering the medulla, the tracts make up the large white matter tract referred to as the pyramids (Figure 14.5.4). The defining landmark of the medullary-spinal border is the pyramidal decussation, which is where most of the fibers in the corticospinal tract cross over to the opposite side of the brain. At this point, the tract separates into two parts, which have control over different domains of the musculature.","{'ea3feeb7-f36f-4427-818e-6ddb3ea5d701': 'The motor output from the cortex descends into the brain stem and to the spinal cord to control the musculature through motor neurons. Neurons located in the primary motor cortex, named Betz cells, are large cortical neurons that synapse with lower motor neurons in the spinal cord or the brain stem. The two descending pathways travelled by the axons of Betz cells are the corticospinal tract and the corticobulbar tract. Both tracts are named for their origin in the cortex and their targets—either the spinal cord or the brain stem (the term “bulbar” refers to the brain stem as the bulb, or enlargement, at the top of the spinal cord).', 'd4f2c6b6-c3f7-4c81-90b1-5952fb6c8385': 'These two descending pathways are responsible for the conscious or voluntary movements of skeletal muscles. Any motor command from the primary motor cortex is sent down the axons of the Betz cells to activate upper motor neurons in either the cranial motor nuclei or in the ventral horn of the spinal cord. The axons of the corticobulbar tract are ipsilateral, meaning they project from the cortex to the motor nucleus on the same side of the nervous system. Conversely, the axons of the corticospinal tract are largely contralateral, meaning that they cross the midline of the brain stem or spinal cord and synapse on the opposite side of the body. Therefore, the right motor cortex of the cerebrum controls muscles on the left side of the body, and vice versa.', '3e609b08-9717-4e43-af52-a63b8592ce1a': 'The corticospinal tract descends from the cortex through the deep white matter of the cerebrum. It then passes between the caudate nucleus and putamen of the basal nuclei as a bundle called the internal capsule. The tract then passes through the midbrain as the cerebral peduncles, after which it burrows through the pons. Upon entering the medulla, the tracts make up the large white matter tract referred to as the pyramids (Figure 14.5.4). The defining landmark of the medullary-spinal border is the pyramidal decussation, which is where most of the fibers in the corticospinal tract cross over to the opposite side of the brain. At this point, the tract separates into two parts, which have control over different domains of the musculature.'}"
+Figure 14.5.5,Anatomy_And_Physio/images/Figure 14.5.5.jpg,Figure 14.5.5 Locations of Spinal Fiber Tracts,"Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 14.5.5). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.","{'303e8f2c-0cce-4bde-8017-60cd71018521': 'Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 14.5.5). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.'}"
+Figure 14.4.1,Anatomy_And_Physio/images/Figure 14.4.1.jpg,"Figure 14.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 14.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.","{'e5a4f24f-a3c8-469f-afaf-63cc74ccda9e': 'The description of the CNS is concentrated on the structures of the brain, but the spinal cord is another major organ of the system. Whereas the brain develops out of expansions of the neural tube into primary and then secondary vesicles, the spinal cord maintains the tube structure and is only specialized into certain regions. As the spinal cord continues to develop in the newborn, anatomical features mark its surface. The anterior midline is marked by the anterior median fissure, and the posterior midline is marked by the posterior median sulcus. Axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.', 'a175454a-33cf-4813-a5c4-905ed80c5960': 'On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions. This comes from the initial development of the spinal cord, which is divided into the basal plate and the alar plate. The basal plate is closest to the ventral midline of the neural tube, which will become the anterior face of the spinal cord and gives rise to motor neurons. The alar plate is on the dorsal side of the neural tube and gives rise to neurons that will receive sensory input from the periphery.', '8a61d477-9082-4d4e-ae3a-9f390416a71b': 'The length of the spinal cord is divided into regions that correspond to the regions of the vertebral column. The name of a spinal cord region corresponds to the level at which spinal nerves pass through the intervertebral foramina. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, then the lumbar, and finally the sacral region. The spinal cord is not the full length of the vertebral column because the spinal cord does not grow significantly longer after the first or second year, but the skeleton continues to grow. The nerves that emerge from the spinal cord pass through the intervertebral formina at the respective levels. As the vertebral column grows, these nerves grow with it and result in a long bundle of nerves that resembles a horse’s tail and is named the cauda equina. The sacral spinal cord is at the level of the upper lumbar vertebral bones. The spinal nerves extend from their various levels to the proper level of the vertebral column.', '28eef0a4-5a1a-4870-9077-ac2eb76889cb': 'In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 14.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.', '2eee94d5-62af-47df-9314-2868d9b12260': 'Some of the largest neurons of the spinal cord are the multipolar motor neurons in the anterior horn. The fibers that cause contraction of skeletal muscles are the axons of these neurons. The motor neuron that causes contraction of the big toe, for example, is located in the sacral spinal cord. The axon that has to reach all the way to the belly of that muscle may be a meter in length. The neuronal cell body that maintains that long fiber must be quite large, possibly several hundred micrometers in diameter, making it one of the largest cells in the body.', 'ad57367c-16ab-4391-ad93-c3b1a053d768': 'Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.', '64998010-25bc-42a2-b469-cc39bc03d673': 'The brain and the spinal cord are the central nervous system, and they represent the main organs of the nervous system. The spinal cord is a single structure, whereas the adult brain is described in terms of four major regions: the cerebrum, the diencephalon, the brain stem, and the cerebellum. A person’s conscious experiences are based on neural activity in the brain. The regulation of homeostasis is governed by a specialized region in the brain. The coordination of reflexes depends on the integration of sensory and motor pathways in the spinal cord.'}"
+Figure 14.3.1,Anatomy_And_Physio/images/Figure 14.3.1.jpg,"Figure 14.3.1 – The Cerebrum: The cerebrum is a large component of the CNS in humans, and the most obvious aspect of it is the folded surface called the cerebral cortex.","The iconic gray mantle of the human brain, which appears to make up most of the mass of the brain, is the cerebrum (Figure 14.3.1). The wrinkled portion is the cerebral cortex, and the rest of the structure is beneath that outer covering. There is a large separation between the two sides of the cerebrum called the longitudinal fissure. It separates the cerebrum into two distinct halves, a right and left cerebral hemisphere. Deep within the cerebrum, the white matter of the corpus callosum provides the major pathway for communication between the two hemispheres of the cerebral cortex.","{'7d29f70b-1694-4e31-89ca-a24bd3faf2e1': 'The iconic gray mantle of the human brain, which appears to make up most of the mass of the brain, is the cerebrum (Figure 14.3.1). The wrinkled portion is the cerebral cortex, and the rest of the structure is beneath that outer covering. There is a large separation between the two sides of the cerebrum called the longitudinal fissure. It separates the cerebrum into two distinct halves, a right and left cerebral hemisphere. Deep within the cerebrum, the white matter of the corpus callosum provides the major pathway for communication between the two hemispheres of the cerebral cortex.', '92464a38-cf21-4adc-8825-8b9d7b2b1e43': 'Many of the higher neurological functions, such as memory, emotion, and consciousness, are the result of cerebral function. The complexity of the cerebrum is different across vertebrate species. The cerebrum of the most primitive vertebrates is not much more than the connection for the sense of smell. In mammals, the cerebrum comprises the outer gray matter that is the cortex (from the Latin word meaning “bark of a tree”) and several deep nuclei that belong to three important functional groups. The basal nuclei are responsible for cognitive processing, the most important function being that associated with planning movements. The basal forebrain contains nuclei that are important in learning and memory. The limbic cortex is the region of the cerebral cortex that is part of the limbic system, a collection of structures involved in emotion, memory, and behavior.'}"
+Figure 14.3.6,Anatomy_And_Physio/images/Figure 14.3.6.jpg,"Figure 14.3.6 – Frontal Section of Cerebral Cortex and Basal Nuclei: The major components of the basal nuclei, shown in a frontal section of the brain, are the caudate (just lateral to the lateral ventricle), the putamen (inferior to the caudate and separated by the large white-matter structure called the internal capsule), and the globus pallidus (medial to the putamen).","The major structures of the basal nuclei that control movement are the caudate, putamen, and globus pallidus, which are located deep in the cerebrum. The caudate is a long nucleus that follows the basic C-shape of the cerebrum from the frontal lobe, through the parietal and occipital lobes, into the temporal lobe. The putamen is mostly deep in the anterior regions of the frontal and parietal lobes. Together, the caudate and putamen are called the striatum. The globus pallidus is a layered nucleus that lies just medial to the putamen; they are called the lenticular nuclei because they look like curved pieces fitting together like lenses. The globus pallidus has two subdivisions, the external and internal segments, which are lateral and medial, respectively. These nuclei are depicted in a frontal section of the brain in Figure 14.3.6.","{'16896b61-5fe4-4ac6-939f-126541f58fe2': 'The cerebrum, particularly the cerebral cortex, is the location of important cognitive functions that are the focus of the mental status exam. The regionalization of the cortex, initially described on the basis of anatomical evidence of cytoarchitecture, reveals the distribution of functionally distinct areas. Cortical regions can be described as primary sensory or motor areas, association areas, or multimodal integration areas. The functions attributed to these regions include attention, memory, language, speech, sensation, judgment, and abstract reasoning.', '54e04788-cc9e-4df6-8ef1-f2f780c65490': 'The mental status exam addresses these cognitive abilities through a series of subtests designed to elicit particular behaviors ascribed to these functions. The loss of neurological function can illustrate the location of damage to the cerebrum. Memory functions are attributed to the temporal lobe, particularly the medial temporal lobe structures known as the hippocampus and amygdala, along with the adjacent cortex. Evidence of the importance of these structures comes from the side effects of a bilateral temporal lobectomy that were studied in detail in patient HM.', 'c1083d03-b929-4061-ab4e-6d516a569208': 'Losses of language and speech functions, known as aphasias, are associated with damage to the important integration areas in the left hemisphere known as Broca’s or Wernicke’s areas, as well as the connections in the white matter between them. Different types of aphasia are named for the particular structures that are damaged. Assessment of the functions of the sensorium includes praxis and gnosis. The subtests related to these functions depend on multimodal integration, as well as language-dependent processing.', '5ea3868d-be19-4626-a70b-59fd364f8759': 'The prefrontal cortex contains structures important for planning, judgment, reasoning, and working memory. Damage to these areas can result in changes to personality, mood, and behavior. The famous case of Phineas Gage suggests a role for this cortex in personality, as does the outdated practice of prefrontal lobectomy.', 'c5b0b93b-2ec5-4605-b4cb-0c6318141483': 'Beneath the cerebral cortex are sets of nuclei known as subcortical nuclei that augment cortical processes. The nuclei of the basal forebrain serve as the primary location for acetylcholine production, which modulates the overall activity of the cortex, possibly leading to greater attention to sensory stimuli. Alzheimer’s disease is associated with a loss of neurons in the basal forebrain. The hippocampus and amygdala are medial-lobe structures that, along with the adjacent cortex, are involved in long-term memory formation and emotional responses. The basal nuclei are a set of nuclei in the cerebrum responsible for comparing cortical processing with the general state of activity in the nervous system to influence the likelihood of movement taking place. For example, while a student is sitting in a classroom listening to a lecture, the basal nuclei will keep the urge to jump up and scream from actually happening. (The basal nuclei are also referred to as the basal ganglia, although that is potentially confusing because the term ganglia is typically used for peripheral structures.)', 'aae9b0cd-8286-4b99-a5e5-439793411804': 'The major structures of the basal nuclei that control movement are the caudate, putamen, and globus pallidus, which are located deep in the cerebrum. The caudate is a long nucleus that follows the basic C-shape of the cerebrum from the frontal lobe, through the parietal and occipital lobes, into the temporal lobe. The putamen is mostly deep in the anterior regions of the frontal and parietal lobes. Together, the caudate and putamen are called the striatum. The globus pallidus is a layered nucleus that lies just medial to the putamen; they are called the lenticular nuclei because they look like curved pieces fitting together like lenses. The globus pallidus has two subdivisions, the external and internal segments, which are lateral and medial, respectively. These nuclei are depicted in a frontal section of the brain in Figure 14.3.6.', 'ea8d5f85-d67e-4c6d-8bce-6852bad3edc5': 'The basal nuclei in the cerebrum are connected with a few more nuclei in the brain stem that together act as a functional group that forms a motor pathway. Two streams of information processing take place in the basal nuclei. All input to the basal nuclei is from the cortex into the striatum (Figure 14.3.7). The direct pathway is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr). The GPi/SNr then projects to the thalamus, which projects back to the cortex. The indirect pathway is the projection of axons from the striatum to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to GPi/SNr. The two streams both target the GPi/SNr, but one has a direct projection and the other goes through a few intervening nuclei. The direct pathway causes the disinhibition of the thalamus (inhibition of one cell on a target cell that then inhibits the first cell), whereas the indirect pathway causes, or reinforces, the normal inhibition of the thalamus. The thalamus then can either excite the cortex (as a result of the direct pathway) or fail to excite the cortex (as a result of the indirect pathway).', '322a5003-a694-4622-b955-3d81dc9b1669': 'The switch between the two pathways is the substantia nigra pars compacta, which projects to the striatum and releases the neurotransmitter dopamine. Dopamine receptors are either excitatory (D1-type receptors) or inhibitory (D2-type receptors). The direct pathway is activated by dopamine, and the indirect pathway is inhibited by dopamine. When the substantia nigra pars compacta is firing, it signals to the basal nuclei that the body is in an active state, and movement will be more likely. When the substantia nigra pars compacta is silent, the body is in a passive state, and movement is inhibited. To illustrate this situation, while a student is sitting listening to a lecture, the substantia nigra pars compacta would be silent and the student less likely to get up and walk around. Likewise, while the professor is lecturing, and walking around at the front of the classroom, the professor’s substantia nigra pars compacta would be active, in keeping with his or her activity level.', '03bc117c-88ba-48fd-bbe3-8e58d79cf246': 'However, there are well-documented cases of language functions lost from damage to the right side of the brain. The deficits seen in damage to the left side of the brain are classified as aphasia, a loss of speech function; damage on the right side can affect the use of language. Right-side damage can result in a loss of ability to understand figurative aspects of speech, such as jokes, irony, or metaphors. Nonverbal aspects of speech can be affected by damage to the right side, such as facial expression or body language, and right-side damage can lead to a “flat affect” in speech, or a loss of emotional expression in speech—sounding like a robot when talking. Damage to language areas on the right side causes a condition called aprosodia where the patient has difficulty understanding or expressing the figurative part of speech.'}"
+Figure 14.3.7,Anatomy_And_Physio/images/Figure 14.3.7.jpg,"Figure 14.3.7 – Connections of Basal Nuclei: Input to the basal nuclei is from the cerebral cortex, which is an excitatory connection releasing glutamate as a neurotransmitter. This input is to the striatum, or the caudate and putamen. In the direct pathway, the striatum projects to the internal segment of the globus pallidus and the substantia nigra pars reticulata (GPi/SNr). This is an inhibitory pathway, in which GABA is released at the synapse, and the target cells are hyperpolarized and less likely to fire. The output from the basal nuclei is to the thalamus, which is an inhibitory projection using GABA.","The basal nuclei in the cerebrum are connected with a few more nuclei in the brain stem that together act as a functional group that forms a motor pathway. Two streams of information processing take place in the basal nuclei. All input to the basal nuclei is from the cortex into the striatum (Figure 14.3.7). The direct pathway is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr). The GPi/SNr then projects to the thalamus, which projects back to the cortex. The indirect pathway is the projection of axons from the striatum to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to GPi/SNr. The two streams both target the GPi/SNr, but one has a direct projection and the other goes through a few intervening nuclei. The direct pathway causes the disinhibition of the thalamus (inhibition of one cell on a target cell that then inhibits the first cell), whereas the indirect pathway causes, or reinforces, the normal inhibition of the thalamus. The thalamus then can either excite the cortex (as a result of the direct pathway) or fail to excite the cortex (as a result of the indirect pathway).","{'16896b61-5fe4-4ac6-939f-126541f58fe2': 'The cerebrum, particularly the cerebral cortex, is the location of important cognitive functions that are the focus of the mental status exam. The regionalization of the cortex, initially described on the basis of anatomical evidence of cytoarchitecture, reveals the distribution of functionally distinct areas. Cortical regions can be described as primary sensory or motor areas, association areas, or multimodal integration areas. The functions attributed to these regions include attention, memory, language, speech, sensation, judgment, and abstract reasoning.', '54e04788-cc9e-4df6-8ef1-f2f780c65490': 'The mental status exam addresses these cognitive abilities through a series of subtests designed to elicit particular behaviors ascribed to these functions. The loss of neurological function can illustrate the location of damage to the cerebrum. Memory functions are attributed to the temporal lobe, particularly the medial temporal lobe structures known as the hippocampus and amygdala, along with the adjacent cortex. Evidence of the importance of these structures comes from the side effects of a bilateral temporal lobectomy that were studied in detail in patient HM.', 'c1083d03-b929-4061-ab4e-6d516a569208': 'Losses of language and speech functions, known as aphasias, are associated with damage to the important integration areas in the left hemisphere known as Broca’s or Wernicke’s areas, as well as the connections in the white matter between them. Different types of aphasia are named for the particular structures that are damaged. Assessment of the functions of the sensorium includes praxis and gnosis. The subtests related to these functions depend on multimodal integration, as well as language-dependent processing.', '5ea3868d-be19-4626-a70b-59fd364f8759': 'The prefrontal cortex contains structures important for planning, judgment, reasoning, and working memory. Damage to these areas can result in changes to personality, mood, and behavior. The famous case of Phineas Gage suggests a role for this cortex in personality, as does the outdated practice of prefrontal lobectomy.', 'c5b0b93b-2ec5-4605-b4cb-0c6318141483': 'Beneath the cerebral cortex are sets of nuclei known as subcortical nuclei that augment cortical processes. The nuclei of the basal forebrain serve as the primary location for acetylcholine production, which modulates the overall activity of the cortex, possibly leading to greater attention to sensory stimuli. Alzheimer’s disease is associated with a loss of neurons in the basal forebrain. The hippocampus and amygdala are medial-lobe structures that, along with the adjacent cortex, are involved in long-term memory formation and emotional responses. The basal nuclei are a set of nuclei in the cerebrum responsible for comparing cortical processing with the general state of activity in the nervous system to influence the likelihood of movement taking place. For example, while a student is sitting in a classroom listening to a lecture, the basal nuclei will keep the urge to jump up and scream from actually happening. (The basal nuclei are also referred to as the basal ganglia, although that is potentially confusing because the term ganglia is typically used for peripheral structures.)', 'aae9b0cd-8286-4b99-a5e5-439793411804': 'The major structures of the basal nuclei that control movement are the caudate, putamen, and globus pallidus, which are located deep in the cerebrum. The caudate is a long nucleus that follows the basic C-shape of the cerebrum from the frontal lobe, through the parietal and occipital lobes, into the temporal lobe. The putamen is mostly deep in the anterior regions of the frontal and parietal lobes. Together, the caudate and putamen are called the striatum. The globus pallidus is a layered nucleus that lies just medial to the putamen; they are called the lenticular nuclei because they look like curved pieces fitting together like lenses. The globus pallidus has two subdivisions, the external and internal segments, which are lateral and medial, respectively. These nuclei are depicted in a frontal section of the brain in Figure 14.3.6.', 'ea8d5f85-d67e-4c6d-8bce-6852bad3edc5': 'The basal nuclei in the cerebrum are connected with a few more nuclei in the brain stem that together act as a functional group that forms a motor pathway. Two streams of information processing take place in the basal nuclei. All input to the basal nuclei is from the cortex into the striatum (Figure 14.3.7). The direct pathway is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr). The GPi/SNr then projects to the thalamus, which projects back to the cortex. The indirect pathway is the projection of axons from the striatum to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to GPi/SNr. The two streams both target the GPi/SNr, but one has a direct projection and the other goes through a few intervening nuclei. The direct pathway causes the disinhibition of the thalamus (inhibition of one cell on a target cell that then inhibits the first cell), whereas the indirect pathway causes, or reinforces, the normal inhibition of the thalamus. The thalamus then can either excite the cortex (as a result of the direct pathway) or fail to excite the cortex (as a result of the indirect pathway).', '322a5003-a694-4622-b955-3d81dc9b1669': 'The switch between the two pathways is the substantia nigra pars compacta, which projects to the striatum and releases the neurotransmitter dopamine. Dopamine receptors are either excitatory (D1-type receptors) or inhibitory (D2-type receptors). The direct pathway is activated by dopamine, and the indirect pathway is inhibited by dopamine. When the substantia nigra pars compacta is firing, it signals to the basal nuclei that the body is in an active state, and movement will be more likely. When the substantia nigra pars compacta is silent, the body is in a passive state, and movement is inhibited. To illustrate this situation, while a student is sitting listening to a lecture, the substantia nigra pars compacta would be silent and the student less likely to get up and walk around. Likewise, while the professor is lecturing, and walking around at the front of the classroom, the professor’s substantia nigra pars compacta would be active, in keeping with his or her activity level.', '03bc117c-88ba-48fd-bbe3-8e58d79cf246': 'However, there are well-documented cases of language functions lost from damage to the right side of the brain. The deficits seen in damage to the left side of the brain are classified as aphasia, a loss of speech function; damage on the right side can affect the use of language. Right-side damage can result in a loss of ability to understand figurative aspects of speech, such as jokes, irony, or metaphors. Nonverbal aspects of speech can be affected by damage to the right side, such as facial expression or body language, and right-side damage can lead to a “flat affect” in speech, or a loss of emotional expression in speech—sounding like a robot when talking. Damage to language areas on the right side causes a condition called aprosodia where the patient has difficulty understanding or expressing the figurative part of speech.'}"
+Figure 14.3.8,Anatomy_And_Physio/images/Figure 14.3.8.jpg,"Figure 14.3.8 – The Diencephalon: The diencephalon is composed primarily of the thalamus and hypothalamus, which together define the walls of the third ventricle. The thalami are two elongated, ovoid structures on either side of the midline that make contact in the middle. The hypothalamus is inferior and anterior to the thalamus, culminating in a sharp angle to which the pituitary gland is attached.","The diencephalon is deep beneath the cerebrum and constitutes the walls of the third ventricle. The diencephalon can be described as any region of the brain with “thalamus” in its name. The two major regions of the diencephalon are the thalamus itself and the hypothalamus (Figure 14.3.8). There are other structures, such as the epithalamus, which contains the pineal gland, or the subthalamus, which includes the subthalamic nucleus that is part of the basal nuclei.","{'f541c9e8-3e4f-4713-b672-dbcb297c4d95': 'The diencephalon is the one region of the adult brain that retains its name from embryologic development. The etymology of the word diencephalon translates to “through brain.” It is the connection between the cerebrum and the rest of the nervous system, with one exception. The rest of the brain, the spinal cord, and the PNS all send information to the cerebrum through the diencephalon. Output from the cerebrum passes through the diencephalon. The single exception is the system associated with olfaction, or the sense of smell, which connects directly with the cerebrum. In the earliest vertebrate species, the cerebrum was not much more than olfactory bulbs that received peripheral information about the chemical environment (to call it smell in these organisms is imprecise because they lived in the ocean).', '39ad87e4-5150-4453-9da9-159f231d2d5d': 'The diencephalon is deep beneath the cerebrum and constitutes the walls of the third ventricle. The diencephalon can be described as any region of the brain with “thalamus” in its name. The two major regions of the diencephalon are the thalamus itself and the hypothalamus (Figure 14.3.8). There are other structures, such as the epithalamus, which contains the pineal gland, or the subthalamus, which includes the subthalamic nucleus that is part of the basal nuclei.'}"
+Figure 14.3.9,Anatomy_And_Physio/images/Figure 14.3.9.jpg,"Figure 14.3.9 – The Brain Stem: The brain stem comprises three regions: the midbrain, the pons, and the medulla.","The midbrain and the pons and medulla of the hindbrain are collectively referred to as the “brain stem” (Figure 14.3.9). The structure emerges from the ventral surface of the forebrain as a tapering cone that connects the brain to the spinal cord. Attached to the brain stem, but considered a separate region of the adult brain, is the cerebellum. The midbrain coordinates sensory representations of the visual, auditory, and somatosensory perceptual spaces. The pons is the main connection with the cerebellum. The pons and the medulla regulate several crucial functions, including the cardiovascular and respiratory systems.","{'290fde74-cd01-4641-b270-3d854b35b57c': 'The midbrain and the pons and medulla of the hindbrain\xa0are collectively referred to as the “brain stem” (Figure 14.3.9). The structure emerges from the ventral surface of the forebrain as a tapering cone that connects the brain to the spinal cord. Attached to the brain stem, but considered a separate region of the adult brain, is the cerebellum. The midbrain coordinates sensory representations of the visual, auditory, and somatosensory perceptual spaces. The pons is the main connection with the cerebellum. The pons and the medulla regulate several crucial functions, including the cardiovascular and respiratory systems.', '831f5657-42c1-49fe-9341-1597fd24e843': 'The cranial nerves connect through the brain stem and provide the brain with the sensory input and motor output associated with the head and neck, including most of the special senses. The major ascending and descending pathways between the spinal cord and brain, specifically the cerebrum, pass through the brain stem.'}"
+Figure 14.3.10,Anatomy_And_Physio/images/Figure 14.3.10.jpg,"Figure 14.3.10 – The Cerebellum: The cerebellum is situated on the posterior surface of the brain stem. Descending input from the cerebellum enters through the large white matter structure of the pons. Ascending input from the periphery and spinal cord enters through the fibers of the inferior olive. Output goes to the midbrain, which sends a descending signal to the spinal cord.","The cerebellum, as the name suggests, is the “little brain.” It is covered in gyri and sulci like the cerebrum, and looks like a miniature version of that part of the brain (Figure 14.3.10). The cerebellum is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord. It accounts for approximately 10 percent of the mass of the brain.","{'5e05d3c3-6b4f-48f1-a62e-e66f7d0fdb21': 'The cerebellum, as the name suggests, is the “little brain.” It is covered in gyri and sulci like the cerebrum, and looks like a miniature version of that part of the brain (Figure 14.3.10). The cerebellum is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord. It accounts for approximately 10 percent of the mass of the brain.', 'c03f5447-a406-4f54-a13c-3d762c88fc7c': 'Descending fibers from the cerebrum have branches that connect to neurons in the pons. Those neurons project into the cerebellum, providing a copy of motor commands sent to the spinal cord. Sensory information from the periphery, which enters through spinal or cranial nerves, is copied to a nucleus in the medulla known as the inferior olive. Fibers from this nucleus enter the cerebellum and are compared with the descending commands from the cerebrum. If the primary motor cortex of the frontal lobe sends a command down to the spinal cord to initiate walking, a copy of that instruction is sent to the cerebellum. Sensory feedback from the muscles and joints, proprioceptive information about the movements of walking, and sensations of balance are sent to the cerebellum through the inferior olive and the cerebellum compares them. If walking is not coordinated, perhaps because the ground is uneven or a strong wind is blowing, then the cerebellum sends out a corrective command to compensate for the difference between the original cortical command and the sensory feedback. The output of the cerebellum is into the midbrain, which then sends a descending input to the spinal cord to correct the messages going to skeletal muscles.'}"
+Figure 14.2.3,Anatomy_And_Physio/images/Figure 14.2.3.jpg,Figure 14.2.3 – Hemorrhagic Stroke: (a) A hemorrhage into the tissue of the cerebrum results in a large accumulation of blood with an additional edema in the adjacent tissue. The hemorrhagic area causes the entire brain to be disfigured as suggested here by the lateral ventricles being squeezed into the opposite hemisphere. (b) A CT scan shows an intraparenchymal hemorrhage within the parietal lobe. (credit b: James Heilman),"A hemorrhagic stroke is bleeding into the brain because of a damaged blood vessel. Accumulated blood fills a region of the cranial vault and presses against the tissue in the brain (Figure 14.2.3). Physical pressure on the brain can cause the loss of function, as well as the squeezing of local arteries resulting in compromised blood flow beyond the site of the hemorrhage. As blood pools in the nervous tissue and the vasculature is damaged, the blood-brain barrier can break down and allow additional fluid to accumulate in the region, which is known as edema.","{'7df28724-a000-4101-8b98-7a73b149d4c8': 'A lack of oxygen to the CNS can be devastating, and the cardiovascular system has specific regulatory reflexes to ensure that the blood supply is not interrupted. There are multiple routes for blood to get into the CNS, with specializations to protect that blood supply and to maximize the ability of the brain to get an uninterrupted perfusion.', 'e844d8ef-c084-417c-b3b8-1fdb3cc8f67f': 'Damage to the nervous system can be limited to individual structures or can be distributed across broad areas of the brain and spinal cord. Localized, limited injury to the nervous system is most often the result of circulatory problems. Neurons are very sensitive to oxygen deprivation and will start to deteriorate within 1 or 2 minutes, and permanent damage (cell death) could result within a few hours. The loss of blood flow to part of the brain is known as a stroke, or a cerebrovascular accident (CVA).', 'c67173af-0214-4b79-919b-8bfcdb692868': 'There are two main types of stroke, depending on how the blood supply is compromised: ischemic and hemorrhagic. An ischemic stroke is the loss of blood flow to an area because vessels are blocked or narrowed. This is often caused by an embolus, which may be a blood clot or fat deposit. Ischemia may also be the result of thickening of the blood vessel wall, or a drop in blood volume in the brain known as hypovolemia.', '7cf3272e-f862-4ef6-940d-58ab807be4a1': 'A related type of CVA is known as a transient ischemic attack (TIA), which is similar to a stroke although it does not last as long. The diagnostic definition of a stroke includes effects that last at least 24 hours. Any stroke symptoms that are resolved within a 24-hour period because of restoration of adequate blood flow are classified as a TIA.', '1e13bdf2-0ffc-487f-a8f2-8bab0c1811a3': 'A hemorrhagic stroke is bleeding into the brain because of a damaged blood vessel. Accumulated blood fills a region of the cranial vault and presses against the tissue in the brain (Figure 14.2.3). Physical pressure on the brain can cause the loss of function, as well as the squeezing of local arteries resulting in compromised blood flow beyond the site of the hemorrhage. As blood pools in the nervous tissue and the vasculature is damaged, the blood-brain barrier can break down and allow additional fluid to accumulate in the region, which is known as edema.'}"
+Figure 14.2.4,Anatomy_And_Physio/images/Figure 14.2.4.jpg,"Figure 14.2.4 – Meningeal Layers of Superior Sagittal Sinus: The layers of the meninges in the longitudinal fissure of the superior sagittal sinus are shown, with the dura mater adjacent to the inner surface of the cranium, the pia mater adjacent to the surface of the brain, and the arachnoid and subarachnoid space between them. An arachnoid villus is shown emerging into the dural sinus to allow CSF to filter back into the blood for drainage.","The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which protect the brain. The dura mater is a thick fibrous layer and a strong protective sheath over the entire brain and spinal cord. It is anchored to the inner surface of the cranium and vertebral cavity. The arachnoid mater is a membrane of thin fibrous tissue that forms a loose sac around the CNS. Beneath the arachnoid is a thin, filamentous mesh called the arachnoid trabeculae, which looks like a spider web, giving this layer its name. Directly adjacent to the surface of the CNS is the pia mater, a thin fibrous membrane that follows the convolutions of gyri and sulci in the cerebral cortex and fits into other grooves and indentations (Figure 14.2.4).","{'091f1ceb-f059-456b-bba5-8dd08e612d0e': 'The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which protect the brain. The dura mater is a thick fibrous layer and a strong protective sheath over the entire brain and spinal cord. It is anchored to the inner surface of the cranium and vertebral cavity. The arachnoid mater is a membrane of thin fibrous tissue that forms a loose sac around the CNS. Beneath the arachnoid is a thin, filamentous mesh called the arachnoid trabeculae, which looks like a spider web, giving this layer its name. Directly adjacent to the surface of the CNS is the pia mater, a thin fibrous membrane that follows the convolutions of gyri and sulci in the cerebral cortex and fits into other grooves and indentations (Figure 14.2.4).'}"
+Figure 14.1.1,Anatomy_And_Physio/images/Figure 14.1.1.jpg,"Figure 14.1.1 – Early Embryonic Development of Nervous System: The neuroectoderm begins to fold inward to form the neural groove. As the two sides of the neural groove converge, they form the neural tube, which lies beneath the ectoderm. The anterior end of the neural tube will develop into the brain, and the posterior portion will become the spinal cord. The neural crest develops into peripheral structures.","As the embryo develops, a portion of the ectoderm differentiates into a specialized region of neuroectoderm, which is the precursor for the tissue of the nervous system. Molecular signals induce cells in this region to differentiate into the neuroepithelium, forming a neural plate. The cells then begin to change shape, causing the tissue to buckle and fold inward (Figure 14.1.1). A neural groove forms, visible as a line along the dorsal surface of the embryo. The ridge-like edge on either side of the neural groove is referred as the neural fold. As the neural folds come together and converge, the underlying structure forms into a tube just beneath the ectoderm called the neural tube. Cells from the neural folds then separate from the ectoderm to form a cluster of cells referred to as the neural crest, which runs lateral to the neural tube. The neural crest migrates away from the nascent, or embryonic, central nervous system (CNS) that will form along the neural groove and develops into several parts of the peripheral nervous system (PNS), including the enteric nervous tissue. Many tissues that are not part of the nervous system also arise from the neural crest, such as craniofacial cartilage and bone, and melanocytes.","{'5d0585f7-5c74-4b78-aa01-04c804be2091': 'To begin, a sperm cell and an egg cell fuse to become a fertilized egg. The fertilized egg cell, or zygote, starts dividing to generate the cells that make up an entire organism. Sixteen days after fertilization, the developing embryo’s cells belong to one of three germ layers that give rise to the different tissues in the body. The endoderm, or inner tissue, is responsible for generating the lining tissues of various spaces within the body, such as the mucosae of the digestive and respiratory systems. The mesoderm, or middle tissue, gives rise to most of the muscle and connective tissues. Finally the ectoderm, or outer tissue, develops into the integumentary system (the skin) and the nervous system. It is probably not difficult to see that the outer tissue of the embryo becomes the outer covering of the body. But how is it responsible for the nervous system?', 'bf17f6b8-3291-4e83-a6c8-ee987289f9eb': 'As the embryo develops, a portion of the ectoderm differentiates into a specialized region of neuroectoderm, which is the precursor for the tissue of the nervous system. Molecular signals induce cells in this region to differentiate into the neuroepithelium, forming a neural plate. The cells then begin to change shape, causing the tissue to buckle and fold inward (Figure 14.1.1). A neural groove forms, visible as a line along the dorsal surface of the embryo. The ridge-like edge on either side of the neural groove is referred as the neural fold. As the neural folds come together and converge, the underlying structure forms into a tube just beneath the ectoderm called the neural tube. Cells from the neural folds then separate from the ectoderm to form a cluster of cells referred to as the neural crest, which runs lateral to the neural tube. The neural crest migrates away from the nascent, or embryonic, central nervous system (CNS) that will form along the neural groove and develops into several parts of the peripheral nervous system (PNS), including the enteric nervous tissue. Many tissues that are not part of the nervous system also arise from the neural crest, such as craniofacial cartilage and bone, and melanocytes.', '527121d7-93ac-465c-823f-6e3e7f1e54df': 'At this point, the early nervous system is a simple, hollow tube. It runs from the anterior end of the embryo to the posterior end. Beginning at 25 days, the anterior end develops into the brain, and the posterior portion becomes the spinal cord. This is the most basic arrangement of tissue in the nervous system, and it gives rise to the more complex structures by the fourth week of development.'}"
+Figure 14.1.2,Anatomy_And_Physio/images/Figure 14.1.2.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions.","The prosencephalonforebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain.” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 14.1.2a).","{'f771cf9c-17b0-4947-8239-67e8e4b9d19d': 'As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of sac-like vesicles. Similar to a child’s balloon animal, the long, straight neural tube begins to take on a new shape. Three vesicles form at the first stage, which are called primary vesicles. These vesicles are given names that are based on Greek words, the main root word being enkephalon, which means “brain” (en- = “inside”; kephalon = “head”). The prefix to each generally corresponds to its position along the length of the developing nervous system.', '60ef3aae-aa6a-44a8-91f0-33c08c9d3023': 'The prosencephalonforebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain.” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 14.1.2a).', '04f5a2d3-cf5e-4e4a-afa0-a6aa79f06d3a': 'The brain continues to develop, and the vesicles differentiate further (see Figure 14.1.2b). The three primary vesicles become five secondary vesicles. The prosencephalon enlarges into two new vesicles called the telencephalon and the diencephalon. The telecephalon will become the cerebrum. The diencephalon gives rise to several adult structures; two that will be important are the thalamus and the hypothalamus. In the embryonic diencephalon, a structure known as the eye cup develops, which will eventually become the retina, the nervous tissue of the eye called the retina. This is a rare example of nervous tissue developing as part of the CNS structures in the embryo, but becoming a peripheral structure in the fully formed nervous system.', '72e830d8-ca77-43ff-8e94-3b30dd5837e4': 'The mesencephalon does not differentiate into any finer divisions. The midbrain is an established region of the brain at the primary vesicle stage of development and remains that way. The rest of the brain develops around it and constitutes a large percentage of the mass of the brain. Dividing the brain into forebrain, midbrain, and hindbrain is useful in considering its developmental pattern, but the midbrain is a small proportion of the entire brain, relatively speaking.', 'e0a490c7-aea8-4e6b-9f61-7efbd826d924': 'The rhombencephalon develops into the metencephalon and myelencephalon. The metencephalon corresponds to the adult structure known as the pons and also gives rise to the cerebellum. The cerebellum (from the Latin meaning “little brain”) accounts for about 10 percent of the mass of the brain and is an important structure in itself. The most significant connection between the cerebellum and the rest of the brain is at the pons, because the pons and cerebellum develop out of the same vesicle. The myelencephalon corresponds to the adult structure known as the medulla oblongata. The structures that come from the mesencephalon and rhombencephalon, except for the cerebellum, are collectively considered the brain stem, which specifically includes the midbrain, pons, and medulla.'}"
+Figure 14.1.2,Anatomy_And_Physio/images/Figure 14.1.2.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions.","The prosencephalonforebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain.” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 14.1.2a).","{'f771cf9c-17b0-4947-8239-67e8e4b9d19d': 'As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of sac-like vesicles. Similar to a child’s balloon animal, the long, straight neural tube begins to take on a new shape. Three vesicles form at the first stage, which are called primary vesicles. These vesicles are given names that are based on Greek words, the main root word being enkephalon, which means “brain” (en- = “inside”; kephalon = “head”). The prefix to each generally corresponds to its position along the length of the developing nervous system.', '60ef3aae-aa6a-44a8-91f0-33c08c9d3023': 'The prosencephalonforebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain.” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 14.1.2a).', '04f5a2d3-cf5e-4e4a-afa0-a6aa79f06d3a': 'The brain continues to develop, and the vesicles differentiate further (see Figure 14.1.2b). The three primary vesicles become five secondary vesicles. The prosencephalon enlarges into two new vesicles called the telencephalon and the diencephalon. The telecephalon will become the cerebrum. The diencephalon gives rise to several adult structures; two that will be important are the thalamus and the hypothalamus. In the embryonic diencephalon, a structure known as the eye cup develops, which will eventually become the retina, the nervous tissue of the eye called the retina. This is a rare example of nervous tissue developing as part of the CNS structures in the embryo, but becoming a peripheral structure in the fully formed nervous system.', '72e830d8-ca77-43ff-8e94-3b30dd5837e4': 'The mesencephalon does not differentiate into any finer divisions. The midbrain is an established region of the brain at the primary vesicle stage of development and remains that way. The rest of the brain develops around it and constitutes a large percentage of the mass of the brain. Dividing the brain into forebrain, midbrain, and hindbrain is useful in considering its developmental pattern, but the midbrain is a small proportion of the entire brain, relatively speaking.', 'e0a490c7-aea8-4e6b-9f61-7efbd826d924': 'The rhombencephalon develops into the metencephalon and myelencephalon. The metencephalon corresponds to the adult structure known as the pons and also gives rise to the cerebellum. The cerebellum (from the Latin meaning “little brain”) accounts for about 10 percent of the mass of the brain and is an important structure in itself. The most significant connection between the cerebellum and the rest of the brain is at the pons, because the pons and cerebellum develop out of the same vesicle. The myelencephalon corresponds to the adult structure known as the medulla oblongata. The structures that come from the mesencephalon and rhombencephalon, except for the cerebellum, are collectively considered the brain stem, which specifically includes the midbrain, pons, and medulla.'}"
+Figure 14.1.3,Anatomy_And_Physio/images/Figure 14.1.3.jpg,"Figure 14.1.3 – Human Neuraxis: The mammalian nervous system is arranged with the neural tube running along an anterior to posterior axis, from nose to tail for a four-legged animal like a dog. Humans, as two-legged animals, have a bend in the neuraxis between the brain stem and the diencephalon, along with a bend in the neck, so that the eyes and the face are oriented forward.","Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension of the nervous system, which is called the neuraxis. The embryonic nervous system in mammals can be said to have a standard arrangement. Humans (and other primates, to some degree) make this complicated by standing up and walking on two legs. The anterior–posterior dimension of the neuraxis overlays the superior–inferior dimension of the body. However, there is a major curve between the brain stem and forebrain, which is called the cephalic flexure. Because of this, the neuraxis starts in an inferior position—the end of the spinal cord—and ends in an anterior position, the front of the cerebrum. If this is confusing, just imagine a four-legged animal standing up on two legs. Without the flexure in the brain stem, and at the top of the neck, that animal would be looking straight up instead of straight in front (Figure 14.1.3).","{'e4028384-f37a-4f88-8519-72cb6e724574': 'Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension of the nervous system, which is called the neuraxis. The embryonic nervous system in mammals can be said to have a standard arrangement. Humans (and other primates, to some degree) make this complicated by standing up and walking on two legs. The anterior–posterior dimension of the neuraxis overlays the superior–inferior dimension of the body. However, there is a major curve between the brain stem and forebrain, which is called the cephalic flexure. Because of this, the neuraxis starts in an inferior position—the end of the spinal cord—and ends in an anterior position, the front of the cerebrum. If this is confusing, just imagine a four-legged animal standing up on two legs. Without the flexure in the brain stem, and at the top of the neck, that animal would be looking straight up instead of straight in front (Figure 14.1.3).', 'a74b4c4d-57ea-4604-92e2-765162ac4e20': 'In summary, the primary vesicles help to establish the basic regions of the nervous system: forebrain, midbrain, and hindbrain. These divisions are useful in certain situations, but they are not equivalent regions. The midbrain is small compared with the hindbrain and particularly the forebrain. The secondary vesicles go on to establish the major regions of the adult nervous system that will be followed in this text. The telencephalon is the cerebrum, which is the major portion of the human brain. The diencephalon continues to be referred to by this Greek name, because there is no better term for it (dia- = “through”). The diencephalon is between the cerebrum and the rest of the nervous system and can be described as the region through which all projections have to pass between the cerebrum and everything else. The brain stem includes the midbrain, pons, and medulla, which correspond to the mesencephalon, metencephalon, and myelencephalon. The cerebellum, being a large portion of the brain, is considered a separate region. Table 14.1 connects the different stages of development to the adult structures of the CNS.', '513030b4-82e4-493f-9292-f41f432a4526': 'One other benefit of considering embryonic development is that certain connections are more obvious because of how these adult structures are related. The retina, which began as part of the diencephalon, is primarily connected to the diencephalon. The eyes are just inferior to the anterior-most part of the cerebrum, but the optic nerve extends back to the thalamus as the optic tract, with branches into a region of the hypothalamus. There is also a connection of the optic tract to the midbrain, but the mesencephalon is adjacent to the diencephalon, so that is not difficult to imagine. The cerebellum originates out of the metencephalon, and its largest white matter connection is to the pons, also from the metencephalon. There are connections between the cerebellum and both the medulla and midbrain, which are adjacent structures in the secondary vesicle stage of development. In the adult brain, the cerebellum seems close to the cerebrum, but there is no direct connection between them.', '694733bd-abc5-4495-a940-8de451dcce40': 'Another aspect of the adult CNS structures that relates to embryonic development is the ventricles—open spaces within the CNS where cerebrospinal fluid circulates. They are the remnant of the hollow center of the neural tube. The four ventricles and the tubular spaces associated with them can be linked back to the hollow center of the embryonic brain (see Table 14.1).', 'e4849212-7f8a-4761-b621-00b206316681': 'The twelve cranial nerves are typically covered in introductory anatomy courses, and memorizing their names is facilitated by numerous mnemonics developed by students over the years of this practice. But knowing the names of the nerves in order often leaves much to be desired in understanding what the nerves do. The nerves can be categorized by functions, and subtests of the cranial nerve exam can clarify these functional groupings.', '7d51da22-8a64-4dd4-a73f-60d263750eb9': 'Three of the nerves are strictly responsible for special senses whereas four others contain fibers for special and general senses. Three nerves are connected to the extraocular muscles resulting in the control of gaze. Four nerves connect to muscles of the face, oral cavity, and pharynx, controlling facial expressions, mastication, swallowing, and speech. Four nerves make up the cranial component of the parasympathetic nervous system responsible for pupillary constriction, salivation, and the regulation of the organs of the thoracic and upper abdominal cavities. Finally, one nerve controls the muscles of the neck, assisting with spinal control of the movement of the head and neck.', 'afe6ae40-163b-4c12-ac79-f1147173362a': 'The cranial nerve exam allows directed tests of forebrain and brain stem structures. The twelve cranial nerves serve the head and neck. The vagus nerve (cranial nerve X) has autonomic functions in the thoracic and superior abdominal cavities. The special senses are served through the cranial nerves, as well as the general senses of the head and neck. The movement of the eyes, face, tongue, throat, and neck are all under the control of cranial nerves. Preganglionic parasympathetic nerve fibers that control pupillary size, salivary glands, and the thoracic and upper abdominal viscera are found in four of the nerves. Tests of these functions can provide insight into damage to specific regions of the brain stem and may uncover deficits in adjacent regions.'}"
+Figure 13.7.1,Anatomy_And_Physio/images/Figure 13.7.1.jpg,"Figure 13.7.1 – The Snellen Chart: The Snellen chart for visual acuity presents a limited number of Roman letters in lines of decreasing size. The line with letters that subtend 5 minutes of an arc from 20 feet represents the smallest letters that a person with normal acuity should be able to read at that distance. The different sizes of letters in the other lines represent rough approximations of what a person of normal acuity can read at different distances. For example, the line that represents 20/200 vision would have larger letters so that they are legible to the person with normal acuity at 200 feet.","Testing vision relies on the tests that are common in an optometry office. The Snellen chart (Figure 13.7.1) demonstrates visual acuity by presenting standard Roman letters in a variety of sizes. The result of this test is a rough generalization of the acuity of a person based on the normal accepted acuity, such that a letter that subtends a visual angle of 5 minutes of an arc at 20 feet can be seen. To have 20/60 vision, for example, means that the smallest letters that a person can see at a 20-foot distance could be seen by a person with normal acuity from 60 feet away. Testing the extent of the visual field means that the examiner can establish the boundaries of peripheral vision as simply as holding their hands out to either side and asking the patient when the fingers are no longer visible without moving the eyes to track them. If it is necessary, further tests can establish the perceptions in the visual fields. Physical inspection of the optic disk, or where the optic nerve emerges from the eye, can be accomplished by looking through the pupil with an ophthalmoscope.","{'3c679572-063f-47a2-94b3-fef7436baf45': 'The olfactory, optic, and vestibulocochlear nerves (cranial nerves I, II, and VIII) are dedicated to four of the special senses: smell, vision, equilibrium, and hearing, respectively. Taste sensation is relayed to the brain stem through fibers of the facial and glossopharyngeal nerves. The trigeminal nerve is a mixed nerve that carries the general somatic senses from the head, similar to those coming through spinal nerves from the rest of the body.', '4e1bbea3-dfd0-4cf5-975f-5001366b04cd': 'Testing smell is straightforward, as common smells are presented to one nostril at a time. The patient should be able to recognize the smell of coffee or mint, indicating the proper functioning of the olfactory system. Loss of the sense of smell is called anosmia and can be lost following blunt trauma to the head or through aging. The short axons of the first cranial nerve regenerate on a regular basis. The neurons in the olfactory epithelium have a limited life span, and new cells grow to replace the ones that die off. The axons from these neurons grow back into the CNS by following the existing axons—representing one of the few examples of such growth in the mature nervous system. If all of the fibers are sheared when the brain moves within the cranium, such as in a motor vehicle accident, then no axons can find their way back to the olfactory bulb to re-establish connections. If the nerve is not completely severed, the anosmia may be temporary as new neurons can eventually reconnect.', '76ab2ba5-7d05-485f-afe3-86e3a85d715d': 'Olfaction is not the pre-eminent sense, but its loss can be quite detrimental. The enjoyment of food is largely based on our sense of smell. Anosmia means that food will not seem to have the same taste, though the gustatory sense is intact, and food will often be described as being bland. However, the taste of food can be improved by adding ingredients (e.g., salt) that stimulate the gustatory sense.', 'b4384c49-897c-4ce1-85c0-aae7a4b42eef': 'Testing vision relies on the tests that are common in an optometry office. The Snellen chart (Figure 13.7.1) demonstrates visual acuity by presenting standard Roman letters in a variety of sizes. The result of this test is a rough generalization of the acuity of a person based on the normal accepted acuity, such that a letter that subtends a visual angle of 5 minutes of an arc at 20 feet can be seen. To have 20/60 vision, for example, means that the smallest letters that a person can see at a 20-foot distance could be seen by a person with normal acuity from 60 feet away. Testing the extent of the visual field means that the examiner can establish the boundaries of peripheral vision as simply as holding their hands out to either side and asking the patient when the fingers are no longer visible without moving the eyes to track them. If it is necessary, further tests can establish the perceptions in the visual fields. Physical inspection of the optic disk, or where the optic nerve emerges from the eye, can be accomplished by looking through the pupil with an ophthalmoscope.', '6fcd0341-5b05-418f-a2d8-0e33cdd23008': 'The optic nerves from both sides enter the cranium through the respective optic canals and meet at the optic chiasm at which fibers sort such that the two halves of the visual field are processed by the opposite sides of the brain. Deficits in visual field perception often suggest damage along the length of the optic pathway between the orbit and the diencephalon. For example, loss of peripheral vision may be the result of a pituitary tumor pressing on the optic chiasm (Figure 13.7.2). The pituitary, seated in the sella turcica of the sphenoid bone, is directly inferior to the optic chiasm. The axons that decussate in the chiasm are from the medial retinae of either eye, and therefore carry information from the peripheral visual field.', 'a2cc97ae-4ae4-4514-9764-8795217ccb9f': 'The vestibulocochlear nerve (CN VIII) carries both equilibrium and auditory sensations from the inner ear to the medulla. Though the two senses are not directly related, anatomy is mirrored in the two systems. Problems with balance, such as vertigo, and deficits in hearing may both point to problems with the inner ear. Within the petrous region of the temporal bone is the bony labyrinth of the inner ear. The vestibule is the portion for equilibrium, composed of the utricle, saccule, and the three semicircular canals. The cochlea is responsible for transducing sound waves into a neural signal. The sensory nerves from these two structures travel side-by-side as the vestibulocochlear nerve, though they are really separate divisions. They both emerge from the inner ear, pass through the internal auditory meatus, and synapse in nuclei of the superior medulla. Though they are part of distinct sensory systems, the vestibular nuclei and the cochlear nuclei are close neighbors with adjacent inputs. Deficits in one or both systems could occur from damage that encompasses structures close to both. Damage to structures near the two nuclei can result in deficits to one or both systems.', '34af1773-b25f-4a2f-b042-6982bce1e999': 'Balance or hearing deficits may be the result of damage to the middle or inner ear structures. Ménière’s\xa0disease is a disorder that can affect both equilibrium and audition in a variety of ways. The patient can suffer from vertigo, a low-frequency ringing in the ears, or a loss of hearing. From patient to patient, the exact presentation of the disease can be different. Additionally, within a single patient, the symptoms and signs may change as the disease progresses. Use of the neurological exam subtests for the vestibulocochlear nerve illuminates the changes a patient may go through. The disease appears to be the result of accumulation, or over-production, of fluid in the inner ear, in either the vestibule or cochlea.', 'a9a8354c-d58b-4f82-a2b2-dea90d453a5e': 'Tests of equilibrium are important for coordination and gait and are related to other aspects of the neurological exam. The vestibulo-ocular reflex involves the cranial nerves for gaze control. Balance and equilibrium, as tested by the Romberg test, are part of spinal and cerebellar processes and involved in those components of the neurological exam, as discussed later.', '703e2288-b2ea-43d6-a73c-4599d405c072': 'Hearing is tested by using a tuning fork in a couple of different ways. The Rinne test involves using a tuning fork to distinguish between conductive hearing and sensorineural hearing. Conductive hearing relies on vibrations being conducted through the ossicles of the middle ear. Sensorineural hearing is the transmission of sound stimuli through the neural components of the inner ear and cranial nerve. A vibrating tuning fork is placed on the mastoid process and the patient indicates when the sound produced from this is no longer present. Then the fork is immediately moved to just next to the ear canal so the sound travels through the air. If the sound is not heard through the ear, meaning the sound is conducted better through the temporal bone than through the ossicles, a conductive hearing deficit is present. The Weber test also uses a tuning fork to differentiate between conductive versus sensorineural hearing loss. In this test, the tuning fork is placed at the top of the skull, and the sound of the tuning fork reaches both inner ears by travelling through bone. In a healthy patient, the sound would appear equally loud in both ears. With unilateral conductive hearing loss, however, the tuning fork sounds louder in the ear with hearing loss. This is because the sound of the tuning fork has to compete with background noise coming from the outer ear, but in conductive hearing loss, the background noise is blocked in the damaged ear, allowing the tuning fork to sound relatively louder in that ear. With unilateral sensorineural hearing loss, however, damage to the cochlea or associated nervous tissue means that the tuning fork sounds quieter in that ear.', '0da86847-c1ee-4f4c-98f1-d098f8d04e41': 'The trigeminal system of the head and neck is the equivalent of the ascending spinal cord systems of the dorsal column and the spinothalamic pathways. Somatosensation of the face is conveyed along the nerve to enter the brain stem at the level of the pons. Synapses of those axons, however, are distributed across nuclei found throughout the brain stem. The mesencephalic nucleus processes proprioceptive information of the face, which is the movement and position of facial muscles. It is the sensory component of the jaw-jerk reflex, a stretch reflex of the masseter muscle. The chief nucleus, located in the pons, receives information about light touch as well as proprioceptive information about the mandible, which are both relayed to the thalamus and, ultimately, to the postcentral gyrus of the parietal lobe. The spinal trigeminal nucleus, located in the medulla, receives information about crude touch, pain, and temperature to be relayed to the thalamus and cortex. Essentially, the projection through the chief nucleus is analogous to the dorsal column pathway for the body, and the projection through the spinal trigeminal nucleus is analogous to the spinothalamic pathway.', '17fc745f-14c8-4361-8e4b-55e31a33d245': 'Subtests for the sensory component of the trigeminal system are the same as those for the sensory exam targeting the spinal nerves. The primary sensory subtest for the trigeminal system is sensory discrimination. A cotton-tipped applicator, which is cotton attached to the end of a thin wooden stick, can be used easily for this. The wood of the applicator can be snapped so that a pointed end is opposite the soft cotton-tipped end. The cotton end provides a touch stimulus, while the pointed end provides a painful, or sharp, stimulus. While the patient’s eyes are closed, the examiner touches the two ends of the applicator to the patient’s face, alternating randomly between them. The patient must identify whether the stimulus is sharp or dull. These stimuli are processed by the trigeminal system separately. Contact with the cotton tip of the applicator is a light touch, relayed by the chief nucleus, but contact with the pointed end of the applicator is a painful stimulus relayed by the spinal trigeminal nucleus. Failure to discriminate these stimuli can localize problems within the brain stem. If a patient cannot recognize a painful stimulus, that might indicate damage to the spinal trigeminal nucleus in the medulla. The medulla also contains important regions that regulate the cardiovascular, respiratory, and digestive systems, as well as being the pathway for ascending and descending tracts between the brain and spinal cord. Damage, such as a stroke, that results in changes in sensory discrimination may indicate these unrelated regions are affected as well.'}"
+Figure 13.7.2,Anatomy_And_Physio/images/Figure 13.7.2.jpg,"Figure 13.7.2 – Pituitary Tumor: The pituitary gland is located in the sella turcica of the sphenoid bone within the cranial floor, placing it immediately inferior to the optic chiasm. If the pituitary gland develops a tumor, it can press against the fibers crossing in the chiasm. Those fibers are conveying peripheral visual information to the opposite side of the brain, so the patient will experience “tunnel vision”—meaning that only the central visual field will be perceived.","The optic nerves from both sides enter the cranium through the respective optic canals and meet at the optic chiasm at which fibers sort such that the two halves of the visual field are processed by the opposite sides of the brain. Deficits in visual field perception often suggest damage along the length of the optic pathway between the orbit and the diencephalon. For example, loss of peripheral vision may be the result of a pituitary tumor pressing on the optic chiasm (Figure 13.7.2). The pituitary, seated in the sella turcica of the sphenoid bone, is directly inferior to the optic chiasm. The axons that decussate in the chiasm are from the medial retinae of either eye, and therefore carry information from the peripheral visual field.","{'3c679572-063f-47a2-94b3-fef7436baf45': 'The olfactory, optic, and vestibulocochlear nerves (cranial nerves I, II, and VIII) are dedicated to four of the special senses: smell, vision, equilibrium, and hearing, respectively. Taste sensation is relayed to the brain stem through fibers of the facial and glossopharyngeal nerves. The trigeminal nerve is a mixed nerve that carries the general somatic senses from the head, similar to those coming through spinal nerves from the rest of the body.', '4e1bbea3-dfd0-4cf5-975f-5001366b04cd': 'Testing smell is straightforward, as common smells are presented to one nostril at a time. The patient should be able to recognize the smell of coffee or mint, indicating the proper functioning of the olfactory system. Loss of the sense of smell is called anosmia and can be lost following blunt trauma to the head or through aging. The short axons of the first cranial nerve regenerate on a regular basis. The neurons in the olfactory epithelium have a limited life span, and new cells grow to replace the ones that die off. The axons from these neurons grow back into the CNS by following the existing axons—representing one of the few examples of such growth in the mature nervous system. If all of the fibers are sheared when the brain moves within the cranium, such as in a motor vehicle accident, then no axons can find their way back to the olfactory bulb to re-establish connections. If the nerve is not completely severed, the anosmia may be temporary as new neurons can eventually reconnect.', '76ab2ba5-7d05-485f-afe3-86e3a85d715d': 'Olfaction is not the pre-eminent sense, but its loss can be quite detrimental. The enjoyment of food is largely based on our sense of smell. Anosmia means that food will not seem to have the same taste, though the gustatory sense is intact, and food will often be described as being bland. However, the taste of food can be improved by adding ingredients (e.g., salt) that stimulate the gustatory sense.', 'b4384c49-897c-4ce1-85c0-aae7a4b42eef': 'Testing vision relies on the tests that are common in an optometry office. The Snellen chart (Figure 13.7.1) demonstrates visual acuity by presenting standard Roman letters in a variety of sizes. The result of this test is a rough generalization of the acuity of a person based on the normal accepted acuity, such that a letter that subtends a visual angle of 5 minutes of an arc at 20 feet can be seen. To have 20/60 vision, for example, means that the smallest letters that a person can see at a 20-foot distance could be seen by a person with normal acuity from 60 feet away. Testing the extent of the visual field means that the examiner can establish the boundaries of peripheral vision as simply as holding their hands out to either side and asking the patient when the fingers are no longer visible without moving the eyes to track them. If it is necessary, further tests can establish the perceptions in the visual fields. Physical inspection of the optic disk, or where the optic nerve emerges from the eye, can be accomplished by looking through the pupil with an ophthalmoscope.', '6fcd0341-5b05-418f-a2d8-0e33cdd23008': 'The optic nerves from both sides enter the cranium through the respective optic canals and meet at the optic chiasm at which fibers sort such that the two halves of the visual field are processed by the opposite sides of the brain. Deficits in visual field perception often suggest damage along the length of the optic pathway between the orbit and the diencephalon. For example, loss of peripheral vision may be the result of a pituitary tumor pressing on the optic chiasm (Figure 13.7.2). The pituitary, seated in the sella turcica of the sphenoid bone, is directly inferior to the optic chiasm. The axons that decussate in the chiasm are from the medial retinae of either eye, and therefore carry information from the peripheral visual field.', 'a2cc97ae-4ae4-4514-9764-8795217ccb9f': 'The vestibulocochlear nerve (CN VIII) carries both equilibrium and auditory sensations from the inner ear to the medulla. Though the two senses are not directly related, anatomy is mirrored in the two systems. Problems with balance, such as vertigo, and deficits in hearing may both point to problems with the inner ear. Within the petrous region of the temporal bone is the bony labyrinth of the inner ear. The vestibule is the portion for equilibrium, composed of the utricle, saccule, and the three semicircular canals. The cochlea is responsible for transducing sound waves into a neural signal. The sensory nerves from these two structures travel side-by-side as the vestibulocochlear nerve, though they are really separate divisions. They both emerge from the inner ear, pass through the internal auditory meatus, and synapse in nuclei of the superior medulla. Though they are part of distinct sensory systems, the vestibular nuclei and the cochlear nuclei are close neighbors with adjacent inputs. Deficits in one or both systems could occur from damage that encompasses structures close to both. Damage to structures near the two nuclei can result in deficits to one or both systems.', '34af1773-b25f-4a2f-b042-6982bce1e999': 'Balance or hearing deficits may be the result of damage to the middle or inner ear structures. Ménière’s\xa0disease is a disorder that can affect both equilibrium and audition in a variety of ways. The patient can suffer from vertigo, a low-frequency ringing in the ears, or a loss of hearing. From patient to patient, the exact presentation of the disease can be different. Additionally, within a single patient, the symptoms and signs may change as the disease progresses. Use of the neurological exam subtests for the vestibulocochlear nerve illuminates the changes a patient may go through. The disease appears to be the result of accumulation, or over-production, of fluid in the inner ear, in either the vestibule or cochlea.', 'a9a8354c-d58b-4f82-a2b2-dea90d453a5e': 'Tests of equilibrium are important for coordination and gait and are related to other aspects of the neurological exam. The vestibulo-ocular reflex involves the cranial nerves for gaze control. Balance and equilibrium, as tested by the Romberg test, are part of spinal and cerebellar processes and involved in those components of the neurological exam, as discussed later.', '703e2288-b2ea-43d6-a73c-4599d405c072': 'Hearing is tested by using a tuning fork in a couple of different ways. The Rinne test involves using a tuning fork to distinguish between conductive hearing and sensorineural hearing. Conductive hearing relies on vibrations being conducted through the ossicles of the middle ear. Sensorineural hearing is the transmission of sound stimuli through the neural components of the inner ear and cranial nerve. A vibrating tuning fork is placed on the mastoid process and the patient indicates when the sound produced from this is no longer present. Then the fork is immediately moved to just next to the ear canal so the sound travels through the air. If the sound is not heard through the ear, meaning the sound is conducted better through the temporal bone than through the ossicles, a conductive hearing deficit is present. The Weber test also uses a tuning fork to differentiate between conductive versus sensorineural hearing loss. In this test, the tuning fork is placed at the top of the skull, and the sound of the tuning fork reaches both inner ears by travelling through bone. In a healthy patient, the sound would appear equally loud in both ears. With unilateral conductive hearing loss, however, the tuning fork sounds louder in the ear with hearing loss. This is because the sound of the tuning fork has to compete with background noise coming from the outer ear, but in conductive hearing loss, the background noise is blocked in the damaged ear, allowing the tuning fork to sound relatively louder in that ear. With unilateral sensorineural hearing loss, however, damage to the cochlea or associated nervous tissue means that the tuning fork sounds quieter in that ear.', '0da86847-c1ee-4f4c-98f1-d098f8d04e41': 'The trigeminal system of the head and neck is the equivalent of the ascending spinal cord systems of the dorsal column and the spinothalamic pathways. Somatosensation of the face is conveyed along the nerve to enter the brain stem at the level of the pons. Synapses of those axons, however, are distributed across nuclei found throughout the brain stem. The mesencephalic nucleus processes proprioceptive information of the face, which is the movement and position of facial muscles. It is the sensory component of the jaw-jerk reflex, a stretch reflex of the masseter muscle. The chief nucleus, located in the pons, receives information about light touch as well as proprioceptive information about the mandible, which are both relayed to the thalamus and, ultimately, to the postcentral gyrus of the parietal lobe. The spinal trigeminal nucleus, located in the medulla, receives information about crude touch, pain, and temperature to be relayed to the thalamus and cortex. Essentially, the projection through the chief nucleus is analogous to the dorsal column pathway for the body, and the projection through the spinal trigeminal nucleus is analogous to the spinothalamic pathway.', '17fc745f-14c8-4361-8e4b-55e31a33d245': 'Subtests for the sensory component of the trigeminal system are the same as those for the sensory exam targeting the spinal nerves. The primary sensory subtest for the trigeminal system is sensory discrimination. A cotton-tipped applicator, which is cotton attached to the end of a thin wooden stick, can be used easily for this. The wood of the applicator can be snapped so that a pointed end is opposite the soft cotton-tipped end. The cotton end provides a touch stimulus, while the pointed end provides a painful, or sharp, stimulus. While the patient’s eyes are closed, the examiner touches the two ends of the applicator to the patient’s face, alternating randomly between them. The patient must identify whether the stimulus is sharp or dull. These stimuli are processed by the trigeminal system separately. Contact with the cotton tip of the applicator is a light touch, relayed by the chief nucleus, but contact with the pointed end of the applicator is a painful stimulus relayed by the spinal trigeminal nucleus. Failure to discriminate these stimuli can localize problems within the brain stem. If a patient cannot recognize a painful stimulus, that might indicate damage to the spinal trigeminal nucleus in the medulla. The medulla also contains important regions that regulate the cardiovascular, respiratory, and digestive systems, as well as being the pathway for ascending and descending tracts between the brain and spinal cord. Damage, such as a stroke, that results in changes in sensory discrimination may indicate these unrelated regions are affected as well.'}"
+Figure 13.7.3,Anatomy_And_Physio/images/Figure 13.7.3.jpg,"Figure 13.7.3 – Saccadic Eye Movements: Saccades are rapid, conjugate movements of the eyes to survey a complicated visual stimulus, or to follow a moving visual stimulus. This image represents the shifts in gaze typical of a person studying a face. Notice the concentration of gaze on the major features of the face and the large number of paths traced between the eyes or around the mouth.","Purely vertical movements of the eyes are not very common. Movements are often at an angle, so some horizontal components are necessary, adding the medial and lateral rectus muscles to the movement. The rapid movement of the eyes used to locate and direct the fovea onto visual stimuli is called a saccade. Notice that the paths that are traced in Figure 13.7.3 are not strictly vertical. The movements between the nose and the mouth are closest, but still have a slant to them. Also, the superior and inferior rectus muscles are not perfectly oriented with the line of sight. The origin for both muscles is medial to their insertions, so elevation and depression may require the lateral rectus muscles to compensate for the slight adduction inherent in the contraction of those muscles, requiring MLF activity as well.","{'a61ff612-0358-409f-aa80-0b691f190ba2': 'The three nerves that control the extraocular muscles are the oculomotor, trochlear, and abducens nerves, which are the third, fourth, and sixth cranial nerves. As the name suggests, the abducens nerve is responsible for abducting the eye, which it controls through contraction of the lateral rectus muscle. The trochlear nerve controls the superior oblique muscle to rotate the eye along its axis in the orbit medially, which is called intorsion, and is a component of focusing the eyes on an object close to the face. The oculomotor nerve controls all the other extraocular muscles, as well as a muscle of the upper eyelid. Movements of the two eyes need to be coordinated to locate and track visual stimuli accurately. When moving the eyes to locate an object in the horizontal plane, or to track movement horizontally in the visual field, the lateral rectus muscle of one eye and medial rectus muscle of the other eye are both active. The lateral rectus is controlled by neurons of the abducens nucleus in the superior medulla, whereas the medial rectus is controlled by neurons in the oculomotor nucleus of the midbrain.', '437167ab-5cd7-46d7-9f09-74ebd5b457d9': 'Coordinated movement of both eyes through different nuclei requires integrated processing through the brain stem. In the midbrain, the superior colliculus integrates visual stimuli with motor responses to initiate eye movements. The paramedian pontine reticular formation (PPRF) will initiate a rapid eye movement, or saccade, to bring the eyes to bear on a visual stimulus quickly. These areas are connected to the oculomotor, trochlear, and abducens nuclei by the medial longitudinal fasciculus (MLF) that runs through the majority of the brain stem. The MLF allows for conjugate gaze, or the movement of the eyes in the same direction, during horizontal movements that require the lateral and medial rectus muscles. Control of conjugate gaze strictly in the vertical direction is contained within the oculomotor complex. To elevate the eyes, the oculomotor nerve on either side stimulates the contraction of both superior rectus muscles; to depress the eyes, the oculomotor nerve on either side stimulates the contraction of both inferior rectus muscles.', '9471df54-4576-4b75-816d-a472e9206d5d': 'Purely vertical movements of the eyes are not very common. Movements are often at an angle, so some horizontal components are necessary, adding the medial and lateral rectus muscles to the movement. The rapid movement of the eyes used to locate and direct the fovea onto visual stimuli is called a saccade. Notice that the paths that are traced in Figure 13.7.3 are not strictly vertical. The movements between the nose and the mouth are closest, but still have a slant to them. Also, the superior and inferior rectus muscles are not perfectly oriented with the line of sight. The origin for both muscles is medial to their insertions, so elevation and depression may require the lateral rectus muscles to compensate for the slight adduction inherent in the contraction of those muscles, requiring MLF activity as well.', 'b4a5dd84-365e-4cba-aa75-4cf1d51a5014': 'Testing eye movement is simply a matter of having the patient track the tip of a pen as it is passed through the visual field. This may appear similar to testing visual field deficits related to the optic nerve, but the difference is that the patient is asked to not move the eyes while the examiner moves a stimulus into the peripheral visual field. Here, the extent of movement is the point of the test. The examiner is watching for conjugate movements representing proper function of the related nuclei and the MLF. Failure of one eye to abduct while the other adducts in a horizontal movement is referred to as internuclear ophthalmoplegia. When this occurs, the patient will experience diplopia, or double vision, as the two eyes are temporarily pointed at different stimuli. Diplopia is not restricted to failure of the lateral rectus, because any of the extraocular muscles may fail to move one eye in perfect conjugation with the other.', '10cdf71f-828b-4ce5-a89e-defe1f67537d': 'The final aspect of testing eye movements is to move the tip of the pen in toward the patient’s face. As visual stimuli move closer to the face, the two medial recti muscles cause the eyes to move in the one nonconjugate movement that is part of gaze control. When the two eyes move to look at something closer to the face, they both adduct, which is referred to as convergence. To keep the stimulus in focus, the eye also needs to change the shape of the lens, which is controlled through the parasympathetic fibers of the oculomotor nerve. The change in focal power of the eye is referred to as accommodation. Accommodation ability changes with age; focusing on nearer objects, such as the written text of a book or on a computer screen, may require corrective lenses later in life. Coordination of the skeletal muscles for convergence and coordination of the smooth muscles of the ciliary body for accommodation are referred to as the accommodation–convergence reflex.', '533c5600-b0c4-4499-9bd1-a782dde0b99f': 'A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of the retina. The vestibulo-ocular reflex (VOR) coordinates all of the components (Figure 13.7.4), both sensory and motor, that make this possible. If the head rotates in one direction—for example, to the right—the horizontal pair of semicircular canals in the inner ear indicate the movement by increased activity on the right and decreased activity on the left. The information is sent to the abducens nuclei and oculomotor nuclei on either side to coordinate the lateral and medial rectus muscles. The left lateral rectus and right medial rectus muscles will contract, rotating the eyes in the opposite direction of the head, while nuclei controlling the right lateral rectus and left medial rectus muscles will be inhibited to reduce antagonism of the contracting muscles. These actions stabilize the visual field by compensating for the head rotation with opposite rotation of the eyes in the orbits. Deficits in the VOR may be related to vestibular damage, such as in Ménière’s disease, or from dorsal brain stem damage that would affect the eye movement nuclei or their connections through the MLF.'}"
+Figure 13.7.4,Anatomy_And_Physio/images/Figure 13.7.4.jpg,"Figure 13.7.4 – Vestibulo-ocular Reflex: If the head is turned in one direction, the coordination of that movement with the fixation of the eyes on a visual stimulus involves a circuit that ties the vestibular sense with the eye movement nuclei through the MLF.","A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of the retina. The vestibulo-ocular reflex (VOR) coordinates all of the components (Figure 13.7.4), both sensory and motor, that make this possible. If the head rotates in one direction—for example, to the right—the horizontal pair of semicircular canals in the inner ear indicate the movement by increased activity on the right and decreased activity on the left. The information is sent to the abducens nuclei and oculomotor nuclei on either side to coordinate the lateral and medial rectus muscles. The left lateral rectus and right medial rectus muscles will contract, rotating the eyes in the opposite direction of the head, while nuclei controlling the right lateral rectus and left medial rectus muscles will be inhibited to reduce antagonism of the contracting muscles. These actions stabilize the visual field by compensating for the head rotation with opposite rotation of the eyes in the orbits. Deficits in the VOR may be related to vestibular damage, such as in Ménière’s disease, or from dorsal brain stem damage that would affect the eye movement nuclei or their connections through the MLF.","{'a61ff612-0358-409f-aa80-0b691f190ba2': 'The three nerves that control the extraocular muscles are the oculomotor, trochlear, and abducens nerves, which are the third, fourth, and sixth cranial nerves. As the name suggests, the abducens nerve is responsible for abducting the eye, which it controls through contraction of the lateral rectus muscle. The trochlear nerve controls the superior oblique muscle to rotate the eye along its axis in the orbit medially, which is called intorsion, and is a component of focusing the eyes on an object close to the face. The oculomotor nerve controls all the other extraocular muscles, as well as a muscle of the upper eyelid. Movements of the two eyes need to be coordinated to locate and track visual stimuli accurately. When moving the eyes to locate an object in the horizontal plane, or to track movement horizontally in the visual field, the lateral rectus muscle of one eye and medial rectus muscle of the other eye are both active. The lateral rectus is controlled by neurons of the abducens nucleus in the superior medulla, whereas the medial rectus is controlled by neurons in the oculomotor nucleus of the midbrain.', '437167ab-5cd7-46d7-9f09-74ebd5b457d9': 'Coordinated movement of both eyes through different nuclei requires integrated processing through the brain stem. In the midbrain, the superior colliculus integrates visual stimuli with motor responses to initiate eye movements. The paramedian pontine reticular formation (PPRF) will initiate a rapid eye movement, or saccade, to bring the eyes to bear on a visual stimulus quickly. These areas are connected to the oculomotor, trochlear, and abducens nuclei by the medial longitudinal fasciculus (MLF) that runs through the majority of the brain stem. The MLF allows for conjugate gaze, or the movement of the eyes in the same direction, during horizontal movements that require the lateral and medial rectus muscles. Control of conjugate gaze strictly in the vertical direction is contained within the oculomotor complex. To elevate the eyes, the oculomotor nerve on either side stimulates the contraction of both superior rectus muscles; to depress the eyes, the oculomotor nerve on either side stimulates the contraction of both inferior rectus muscles.', '9471df54-4576-4b75-816d-a472e9206d5d': 'Purely vertical movements of the eyes are not very common. Movements are often at an angle, so some horizontal components are necessary, adding the medial and lateral rectus muscles to the movement. The rapid movement of the eyes used to locate and direct the fovea onto visual stimuli is called a saccade. Notice that the paths that are traced in Figure 13.7.3 are not strictly vertical. The movements between the nose and the mouth are closest, but still have a slant to them. Also, the superior and inferior rectus muscles are not perfectly oriented with the line of sight. The origin for both muscles is medial to their insertions, so elevation and depression may require the lateral rectus muscles to compensate for the slight adduction inherent in the contraction of those muscles, requiring MLF activity as well.', 'b4a5dd84-365e-4cba-aa75-4cf1d51a5014': 'Testing eye movement is simply a matter of having the patient track the tip of a pen as it is passed through the visual field. This may appear similar to testing visual field deficits related to the optic nerve, but the difference is that the patient is asked to not move the eyes while the examiner moves a stimulus into the peripheral visual field. Here, the extent of movement is the point of the test. The examiner is watching for conjugate movements representing proper function of the related nuclei and the MLF. Failure of one eye to abduct while the other adducts in a horizontal movement is referred to as internuclear ophthalmoplegia. When this occurs, the patient will experience diplopia, or double vision, as the two eyes are temporarily pointed at different stimuli. Diplopia is not restricted to failure of the lateral rectus, because any of the extraocular muscles may fail to move one eye in perfect conjugation with the other.', '10cdf71f-828b-4ce5-a89e-defe1f67537d': 'The final aspect of testing eye movements is to move the tip of the pen in toward the patient’s face. As visual stimuli move closer to the face, the two medial recti muscles cause the eyes to move in the one nonconjugate movement that is part of gaze control. When the two eyes move to look at something closer to the face, they both adduct, which is referred to as convergence. To keep the stimulus in focus, the eye also needs to change the shape of the lens, which is controlled through the parasympathetic fibers of the oculomotor nerve. The change in focal power of the eye is referred to as accommodation. Accommodation ability changes with age; focusing on nearer objects, such as the written text of a book or on a computer screen, may require corrective lenses later in life. Coordination of the skeletal muscles for convergence and coordination of the smooth muscles of the ciliary body for accommodation are referred to as the accommodation–convergence reflex.', '533c5600-b0c4-4499-9bd1-a782dde0b99f': 'A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of the retina. The vestibulo-ocular reflex (VOR) coordinates all of the components (Figure 13.7.4), both sensory and motor, that make this possible. If the head rotates in one direction—for example, to the right—the horizontal pair of semicircular canals in the inner ear indicate the movement by increased activity on the right and decreased activity on the left. The information is sent to the abducens nuclei and oculomotor nuclei on either side to coordinate the lateral and medial rectus muscles. The left lateral rectus and right medial rectus muscles will contract, rotating the eyes in the opposite direction of the head, while nuclei controlling the right lateral rectus and left medial rectus muscles will be inhibited to reduce antagonism of the contracting muscles. These actions stabilize the visual field by compensating for the head rotation with opposite rotation of the eyes in the orbits. Deficits in the VOR may be related to vestibular damage, such as in Ménière’s disease, or from dorsal brain stem damage that would affect the eye movement nuclei or their connections through the MLF.'}"
+Figure 13.7.5,Anatomy_And_Physio/images/Figure 13.7.5.jpg,"Figure 13.7.5 – Muscles Controlled by the Accessory Nerve: The accessory nerve innervates the sternocleidomastoid and trapezius muscles, both of which attach to the head and to the trunk and shoulders. They can act as antagonists in head flexion and extension, and as synergists in lateral flexion toward the shoulder.","The accessory nerve, also referred to as the spinal accessory nerve, innervates the sternocleidomastoid and trapezius muscles (Figure 13.7.5). When both the sternocleidomastoids contract, the head flexes forward; individually, they cause rotation to the opposite side. The trapezius can act as an antagonist, causing extension and hyperextension of the neck. These two superficial muscles are important for changing the position of the head. Both muscles also receive input from cervical spinal nerves. Along with the spinal accessory nerve, these nerves contribute to elevating the scapula and clavicle through the trapezius, which is tested by asking the patient to shrug both shoulders, and watching for asymmetry. For the sternocleidomastoid, those spinal nerves are primarily sensory projections, whereas the trapezius also has lateral insertions to the clavicle and scapula, and receives motor input from the spinal cord. Calling the nerve the spinal accessory nerve suggests that it is aiding the spinal nerves. Though that is not precisely how the name originated, it does help make the association between the function of this nerve in controlling these muscles and the role these muscles play in movements of the trunk or shoulders.","{'50ba3b52-c284-478d-a52c-0052057ed384': 'The accessory nerve, also referred to as the spinal accessory nerve, innervates the sternocleidomastoid and trapezius muscles (Figure 13.7.5). When both the sternocleidomastoids contract, the head flexes forward; individually, they cause rotation to the opposite side. The trapezius can act as an antagonist, causing extension and hyperextension of the neck. These two superficial muscles are important for changing the position of the head. Both muscles also receive input from cervical spinal nerves. Along with the spinal accessory nerve, these nerves contribute to elevating the scapula and clavicle through the trapezius, which is tested by asking the patient to shrug both shoulders, and watching for asymmetry. For the sternocleidomastoid, those spinal nerves are primarily sensory projections, whereas the trapezius also has lateral insertions to the clavicle and scapula, and receives motor input from the spinal cord. Calling the nerve the spinal accessory nerve suggests that it is aiding the spinal nerves. Though that is not precisely how the name originated, it does help make the association between the function of this nerve in controlling these muscles and the role these muscles play in movements of the trunk or shoulders.', '136b8810-0e68-4cf9-b5e3-ae82f53491f2': 'To test these muscles, the patient is asked to flex and extend the neck or shrug the shoulders against resistance, testing the strength of the muscles. Lateral flexion of the neck toward the shoulder tests both at the same time. Any difference on one side versus the other would suggest damage on the weaker side. These strength tests are common for the skeletal muscles controlled by spinal nerves and are a significant component of the motor exam. Deficits associated with the accessory nerve may have an effect on orienting the head, as described with the VOR.'}"
+Figure 13.6.1,Anatomy_And_Physio/images/Figure 13.6.1.jpg,Figure 13.6.1 Locations of Spinal Fiber Tracts,"Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 13.6.1). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.","{'1f516b61-a8ec-4a3a-8d73-d177351c369b': 'The cranial nerves can be separated into four major groups associated with the subtests of the cranial nerve exam. First are the sensory nerves, then the nerves that control eye movement, the nerves of the oral cavity and superior pharynx, and the nerve that controls movements of the neck.', '8c0b8e15-739d-496c-9f71-5f0c96811b6c': 'The olfactory, optic, and vestibulocochlear nerves are strictly sensory nerves for smell, sight, and balance and hearing, whereas the trigeminal, facial, and glossopharyngeal nerves carry somatosensation of the face, and taste—separated between the anterior two-thirds of the tongue and the posterior one-third. Special senses are tested by presenting the particular stimuli to each receptive organ. General senses can be tested through sensory discrimination of touch versus painful stimuli.', '536ffd27-8945-4690-ad55-94ca68685085': 'The oculomotor, trochlear, and abducens nerves control the extraocular muscles and are connected by the medial longitudinal fasciculus to coordinate gaze. Testing conjugate gaze is as simple as having the patient follow a visual target, like a pen tip, through the visual field ending with an approach toward the face to test convergence and accommodation. Along with the vestibular functions of the eighth nerve, the vestibulo-ocular reflex stabilizes gaze during head movements by coordinating equilibrium sensations with the eye movement systems.', 'a50d3ed3-d6f8-4bd3-82a9-0c43b2149e7c': 'The trigeminal nerve controls the muscles of chewing, which are tested for stretch reflexes. Motor functions of the facial nerve are usually obvious if facial expressions are compromised, but can be tested by having the patient raise their eyebrows, smile, and frown. Movements of the tongue, soft palate, or superior pharynx can be observed directly while the patient swallows, while the gag reflex is elicited, or while the patient says repetitive consonant sounds. The motor control of the gag reflex is largely controlled by fibers in the vagus nerve and constitutes a test of that nerve because the parasympathetic functions of that nerve are involved in visceral regulation, such as regulating the heartbeat and digestion.', '2be3e49d-f0d2-4253-b82a-c34142b0677b': 'Movement of the head and neck using the sternocleidomastoid and trapezius muscles is controlled by the accessory nerve. Flexing of the neck and strength testing of those muscles reviews the function of that nerve.', '2851e578-d7d9-40d4-afd4-ad6f7df86b35': 'Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 13.6.1). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.'}"
+Figure 13.6.2,Anatomy_And_Physio/images/Figure 13.6.2.jpg,Figure 13.6.2 – Dermatomes: The surface of the skin can be divided into topographic regions that relate to the location of sensory endings in the skin based on the spinal nerve that contains those fibers. (credit: modification of work by Mikael Häggström),"The sensory exam tests the somatic senses, meaning those that are consciously perceived. Testing of the senses begins with examining the regions known as dermatomes that connect to the cortical region where somatosensation is perceived in the postcentral gyrus. To test the sensory fields, a simple stimulus of the light touch of the soft end of a cotton-tipped applicator is applied at various locations on the skin. The spinal nerves, which contain sensory fibers with dendritic endings in the skin, connect with the skin in a topographically organized manner, illustrated as dermatomes (Figure 13.6.2). For example, the fibers of eighth cervical nerve innervate the medial surface of the forearm and extend out to the fingers. In addition to testing perception at different positions on the skin, it is necessary to test sensory perception within the dermatome from distal to proximal locations in the appendages, or lateral to medial locations in the trunk. In testing the eighth cervical nerve, the patient would be asked if the touch of the cotton to the fingers or the medial forearm was perceptible, and whether there were any differences in the sensations.","{'5a83a657-5263-4453-8847-db7e29b3baf6': 'The general senses are distributed throughout the body, relying on nervous tissue incorporated into various organs. Somatic senses are incorporated mostly into the skin, muscles, or tendons, whereas the visceral senses come from nervous tissue incorporated into the majority of organs such as the heart or stomach. The somatic senses are those that usually make up the conscious perception of the how the body interacts with the environment. The visceral senses are most often below the limit of conscious perception because they are involved in homeostatic regulation through the autonomic nervous system.', 'e098e753-6a72-46a7-9b3b-fe94481cc1d7': 'The sensory exam tests the somatic senses, meaning those that are consciously perceived. Testing of the senses begins with examining the regions known as dermatomes that connect to the cortical region where somatosensation is perceived in the postcentral gyrus. To test the sensory fields, a simple stimulus of the light touch of the soft end of a cotton-tipped applicator is applied at various locations on the skin. The spinal nerves, which contain sensory fibers with dendritic endings in the skin, connect with the skin in a topographically organized manner, illustrated as dermatomes (Figure 13.6.2). For example, the fibers of eighth cervical nerve innervate the medial surface of the forearm and extend out to the fingers. In addition to testing perception at different positions on the skin, it is necessary to test sensory perception within the dermatome from distal to proximal locations in the appendages, or lateral to medial locations in the trunk. In testing the eighth cervical nerve, the patient would be asked if the touch of the cotton to the fingers or the medial forearm was perceptible, and whether there were any differences in the sensations.', '60c09a01-c6ef-4722-8140-e506eaecb136': 'Other modalities of somatosensation can be tested using a few simple tools. The perception of pain can be tested using the broken end of the cotton-tipped applicator. The perception of vibratory stimuli can be testing using an oscillating tuning fork placed against prominent bone features such as the distal head of the ulna on the medial aspect of the elbow. When the tuning fork is still, the metal against the skin can be perceived as a cold stimulus. Using the cotton tip of the applicator, or even just a fingertip, the perception of tactile movement can be assessed as the stimulus is drawn across the skin for approximately 2–3 cm. The patient would be asked in what direction the stimulus is moving. All of these tests are repeated in distal and proximal locations and for different dermatomes to assess the spatial specificity of perception. The sense of position and motion, proprioception, is tested by moving the fingers or toes and asking the patient if they sense the movement. If the distal locations are not perceived, the test is repeated at increasingly proximal joints.', '5eeb1db7-e0d7-42ed-914f-d60940fc7cc1': 'The various stimuli used to test sensory input assess the function of the major ascending tracts of the spinal cord. The dorsal column pathway conveys fine touch, vibration, and proprioceptive information, whereas the spinothalamic pathway primarily conveys pain and temperature. Testing these stimuli provides information about whether these two major ascending pathways are functioning properly. Within the spinal cord, the two systems are segregated. The dorsal column information ascends ipsilateral to the source of the stimulus and decussates in the medulla, whereas the spinothalamic pathway decussates at the level of entry and ascends contralaterally. The differing sensory stimuli are segregated in the spinal cord so that the various subtests for these stimuli can distinguish which ascending pathway may be damaged in certain situations.', '1ae5f8b6-7567-464a-84c7-e2d670fa6549': 'Whereas the basic sensory stimuli are assessed in the subtests directed at each submodality of somatosensation, testing the ability to discriminate sensations is important. Pairing the light touch and pain subtests together makes it possible to compare the two submodalities at the same time, and therefore the two major ascending tracts at the same time. Mistaking painful stimuli for light touch, or vice versa, may point to errors in ascending projections, such as in a hemisection of the spinal cord that might come from a motor vehicle accident.', 'b209caf9-3f56-4589-a1c8-d61d992e559d': 'Another issue of sensory discrimination is not distinguishing between different submodalities, but rather location. The two-point discrimination subtest highlights the density of sensory endings, and therefore receptive fields in the skin. The sensitivity to fine touch, which can give indications of the texture and detailed shape of objects, is highest in the fingertips. To assess the limit of this sensitivity, two-point discrimination is measured by simultaneously touching the skin in two locations, such as could be accomplished with a pair of forceps. Specialized calipers for precisely measuring the distance between points are also available. The patient is asked to indicate whether one or two stimuli are present while keeping their eyes closed. The examiner will switch between using the two points and a single point as the stimulus. Failure to recognize two points may be an indication of a dorsal column pathway deficit.', '79273091-27bd-4bab-9692-e46f535c5eff': 'Similar to two-point discrimination, but assessing laterality of perception, is double simultaneous stimulation. Two stimuli, such as the cotton tips of two applicators, are touched to the same position on both sides of the body. If one side is not perceived, this may indicate damage to the contralateral posterior parietal lobe. Because there is one of each pathway on either side of the spinal cord, they are not likely to interact. If none of the other subtests suggest particular deficits with the pathways, the deficit is likely to be in the cortex where conscious perception is based. The mental status exam contains subtests that assess other functions that are primarily localized to the parietal cortex, such as stereognosis and graphesthesia.', '07f5b7f3-018f-4627-8704-f1153363e537': 'A final subtest of sensory perception that concentrates on the sense of proprioception is known as the Romberg test. The patient is asked to stand straight with feet together. Once the patient has achieved their balance in that position, they are asked to close their eyes. Without visual feedback that the body is in a vertical orientation relative to the surrounding environment, the patient must rely on the proprioceptive stimuli of joint and muscle position, as well as information from the inner ear, to maintain balance. This test can indicate deficits in dorsal column pathway proprioception, as well as problems with proprioceptive projections to the cerebellum through the spinocerebellar tract.'}"
+Figure 13.4.1,Anatomy_And_Physio/images/Figure 13.4.1.jpg,"Figure 13.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 13.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.","{'b4f9ffe5-f8d6-4d2c-a316-575bc63b53c2': 'Reflexes combine the spinal sensory and motor components with a sensory input that directly generates a motor response. The reflexes that are tested in the neurological exam are classified into two groups. A deep tendon reflex is commonly known as a stretch reflex, and is elicited by a strong tap to a tendon, such as in the knee-jerk reflex. A superficial reflex is elicited through gentle stimulation of the skin and causes contraction of the associated muscles.', 'f17779c9-f9be-46c6-9413-6aa6a8b6a6df': 'For the arm, the common reflexes to test are of the biceps, brachioradialis, triceps, and flexors for the digits. For the leg, the knee-jerk reflex of the quadriceps is common, as is the ankle reflex for the gastrocnemius and soleus. The tendon at the insertion for each of these muscles is struck with a rubber mallet. The muscle is quickly stretched, resulting in activation of the muscle spindle that sends a signal into the spinal cord through the dorsal root. The fiber synapses directly on the ventral horn motor neuron that activates the muscle, causing contraction. The reflexes are physiologically useful for stability. If a muscle is stretched, it reflexively contracts to return the muscle to compensate for the change in length. In the context of the neurological exam, reflexes indicate that the LMN is functioning properly.', '4b7a3a18-3af9-483d-b88c-61934007f472': 'The most common superficial reflex in the neurological exam is the plantar reflex that tests for the Babinski sign on the basis of the extension or flexion of the toes at the plantar surface of the foot. The plantar reflex is commonly tested in newborn infants to establish the presence of neuromuscular function. To elicit this reflex, an examiner brushes a stimulus, usually the examiner’s fingertip, along the plantar surface of the infant’s foot. An infant would present a positive Babinski sign, meaning the foot dorsiflexes and the toes extend and splay out. As a person learns to walk, the plantar reflex changes to cause curling of the toes and a moderate plantar flexion. If superficial stimulation of the sole of the foot caused extension of the foot, keeping one’s balance would be harder. The descending input of the corticospinal tract modifies the response of the plantar reflex, meaning that a negative Babinski sign is the expected response in testing the reflex. Other superficial reflexes are not commonly tested, though a series of abdominal reflexes can target function in the lower thoracic spinal segments.', 'ad7f2cc6-baa3-477d-921a-12936b46d8e0': 'Reflexes can be spinal or cranial, depending on the nerves and central components that are involved. The body uses both spinal and cranial reflexes to rapidly respond to important stimuli. All reflex arcs include five basic components; (1) a receptor, (2) a sensory neuron, (3) an integration center, (4) a motor neuron, and (5) an effector. The effector may be a skeletal muscle, as is the case in somatic reflexes. However, in autonomic (or visceral) reflexes, the effector will be cardiac muscle, smooth muscle, or a gland.', 'c73ebc6e-6806-48e0-aba0-7950d860424c': 'Somatic spinal reflexes utilize motor neurons of the ventral horn to activate skeletal muscles. The simplest example of this type of reflex is the stretch reflex. In this reflex, when a skeletal muscle is stretched, a muscle spindle receptor is activated. The sensory neuron associated with the muscle spindle synapses directly with the motor neuron in the ventral horn, allowing for an incredibly fast response called a monosynaptic reflex. The reflex helps to maintain muscles at a constant length, and is the reason your head jerks back up after drooping when you begin to fall asleep sitting up. Another common example of this reflex is the knee jerk that is elicited by a rubber hammer struck against the patellar ligament in a physical exam.', '78452dd8-66a1-4f15-adf2-0fbe80ccb619': 'Figure 13.5.1 – Stretch Reflex', '89570870-477c-4c0b-9316-3ac0aee2557e': 'A different somatic spinal nerve reflex involves the response to pain, like when you touch a hot stove and in response withdrawal your arm, typically before you have even registered the pain in your hand. This reflex is called the flexor withdrawal reflex, and it stimulates the withdrawal of the arm through a connection in the spinal cord that leads to contraction of the biceps brachii. Unlike the stretch reflex, the flexor withdrawal reflex is polysynaptic and requires 2 spinal cord synapses to activate the motor neuron. As you withdraw your hand from the stove, you do not want to slow that reflex down. As the biceps brachii contracts, the antagonistic triceps brachii that had been activated to extend the arm toward the stove now needs to relax. Because the neuromuscular junction is strictly excitatory, the biceps will contract when the motor nerve is active. Skeletal muscles do not actively relax. Instead the motor neuron needs to “quiet down,” or be inhibited. In the hot-stove withdrawal reflex, this occurs through an interneuron in the spinal cord. The interneuron’s cell body is located in the dorsal horn of the spinal cord. The interneuron receives a synapse from the axon of the sensory neuron that detects that the hand is being burned. In response to this stimulation from the sensory neuron, the interneuron then inhibits the motor neuron that controls the triceps brachii, in what is known as reciprocal inhibition. This is done by releasing a neurotransmitter or other signal that hyperpolarizes the motor neuron connected to the triceps brachii, making it less likely to initiate an action potential. With this motor neuron being inhibited, the triceps brachii relaxes. Without the antagonistic contraction, withdrawal from the hot stove is faster and keeps further tissue damage from occurring.', '4332e357-4964-4240-ae9c-c56a829efee4': 'The flexor withdrawal reflex is also at play when you step on a painful stimulus, like a tack or a child’s Lego®. The nociceptors that are activated by the painful stimulus activate the motor neurons responsible for contraction of the tibialis anterior muscle. This causes dorsiflexion of the foot. An inhibitory interneuron, activated by a collateral branch of the nociceptor fiber, will inhibit the motor neurons of the gastrocnemius and soleus muscles to cancel plantar flexion. An important difference in this reflex is that plantar flexion is most likely in progress as the foot is pressing down onto the tack. Contraction of the tibialis anterior is not the most important aspect of the reflex, as continuation of plantar flexion will result in further damage from stepping onto the tack. While all this is happening in one lower limb, a contralateral response will be stimulated to help you catch your balance with the other. This is called the crossed extensor reflex.', '76e79019-e11f-4aee-a8c5-04367133cd4f': 'In the cross extensor reflex, the same painful stimulus that initiates the flexor withdrawal reflex simultaneously initiates extension of the opposite limb. In the case of stepping on a painful object and pulling your foot away, the cross extensor reflex activated the contralateral quads and gastrocnemius and soleus to extend the leg while plantar flexing the ankle to shift body weight.', '2529a90e-04f1-47e5-889b-c1647d4b5129': 'All of the somatic spinal nerve reflexes involved so far involve reciprocal inhibition. In each case, a prime mover is stimulated and its antagonist is inhibited. However, in the\xa0golgi tendon reflex, the prime mover is inhibited its antagonist is stimulated. This is termed reciprocal activation. In the tendon reflex, prolonged or particularly forceful stretching of the muscle and its tendon trigger the relaxation of the muscle to prevent tearing through the activation of a special receptor, the golgi tendon organ. At the same time, the antagonist muscles is activated to help return the affected muscle and its tendon to their resting lengths.', 'a4e225df-5a8b-42ea-b3c1-13d09127ee33': 'Figure 13.5.3 – Golgi Tendon Reflex', '97691d60-ed1d-4945-92f5-027385492622': 'Cranial nerve somatic reflexes function similarly, but are integrated in the brainstem. A specialized cranial nerve reflex which protects the surface of the eye is the corneal reflex, or the eye blink reflex. When the cornea is stimulated by a tactile stimulus, or even by bright light in a related reflex, blinking is initiated. The sensory component travels through the trigeminal nerve, which carries somatosensory information from the face, or through the optic nerve, if the stimulus is bright light. The motor response travels through the facial nerve and innervates the orbicularis oculi on the same side. This reflex is commonly tested during a physical exam using an air puff or a gentle touch of a cotton-tipped applicator.', 'e0598d48-3a5a-45cf-a478-f95d8939527f': 'Sensory axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The motor axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.\xa0On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions.', '81c5a76b-85df-497b-9c5b-59351670efad': 'In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 13.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.', 'fd48e88d-95f8-4648-b276-f3b1e1d6e45a': 'Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts carrying sensory information to the brain. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.', 'c90f06af-cfe5-464d-9dcc-d5994cee0a90': 'The nerves connected to the spinal cord are the spinal nerves. The arrangement of these nerves is much more regular than that of the cranial nerves. All of the spinal nerves are combined sensory and motor axons that separate into two nerve roots. The sensory axons enter the spinal cord as the dorsal nerve root. The motor fibers, both somatic and autonomic, emerge as the ventral nerve root. The dorsal root ganglion for each nerve is an enlargement of the spinal nerve.', '4eb07ea7-b00f-41a6-ba3e-4b9f52d0da19': 'There are 31 spinal nerves, named for the level of the spinal cord at which each one emerges. There are eight pairs of cervical nerves designated C1 to C8, twelve thoracic nerves designated T1 to T12, five pairs of lumbar nerves designated L1 to L5, five pairs of sacral nerves designated S1 to S5, and one pair of coccygeal nerves. The nerves are numbered from the superior to inferior positions, and each emerges from the vertebral column through the intervertebral foramen at its level. The first nerve, C1, emerges between the first cervical vertebra and the occipital bone. The second nerve, C2, emerges between the first and second cervical vertebrae. The same occurs for C3 to C7, but C8 emerges between the seventh cervical vertebra and the first thoracic vertebra. For the thoracic and lumbar nerves, each one emerges between the vertebra that has the same designation and the next vertebra in the column. The sacral nerves emerge from the sacral foramina along the length of that unique vertebra.', 'a94b4006-73c4-4ccb-98eb-4ad10e408e66': 'Spinal nerves extend outward from the vertebral column to enervate the periphery. The nerves in the periphery are not straight continuations of the spinal nerves, but rather the reorganization of the axons in those nerves to follow different courses. Axons from different spinal nerves will come together into a systemic nerve. This occurs at four places along the length of the vertebral column, each identified as a nerve plexus, whereas the other spinal nerves directly correspond to nerves at their respective levels. In this instance, the word plexus is used to describe networks of nerve fibers with no associated cell bodies.', '10dfc9fe-603a-45d9-a001-c76df516acb2': 'Of the four nerve plexuses, two are found at the cervical level, one at the lumbar level, and one at the sacral level (Figure 13.3.1). The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. The other plexus from the cervical level is the brachial plexus. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The radial nerve continues through the arm and is paralleled by the ulnar nerve and the median nerve. The lumbar plexus arises from axons of the ventral rami of spinal nerves T12 through L4 and gives rise to nerves enervating the pelvic region and the anterior leg. The femoral nerve is one of the major nerves from this plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg. The sacral plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4. The most significant systemic nerve to come from this plexus is the sciatic nerve, which is a combination of the tibial nerve and the fibular nerve. The sciatic nerve extends across the hip joint and is most commonly associated with the condition sciatica, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it.', '48c376e0-51b4-441e-83e9-014d6124e1e0': 'These plexuses are described as arising from spinal nerves and giving rise to certain systemic nerves, but they contain fibers that serve sensory functions or fibers that serve motor functions. This means that some fibers extend from cutaneous or other peripheral sensory surfaces and send action potentials into the CNS. Those are axons of sensory neurons in the dorsal root ganglia that enter the spinal cord through the dorsal nerve root. Other fibers are the axons of motor neurons of the anterior horn of the spinal cord, which emerge in the ventral nerve root and send action potentials to cause skeletal muscles to contract in their target regions. For example, the radial nerve contains fibers of cutaneous sensation in the arm, as well as motor fibers that move muscles in the arm.', '25beaa95-86c5-4186-a024-6b28a78ee001': 'Spinal nerves of the thoracic region, T2 through T11, are not part of the plexuses but rather emerge and give rise to the intercostal nerves found between the ribs, which articulate with the vertebrae surrounding the spinal nerve.'}"
+Figure 13.3.1,Anatomy_And_Physio/images/Figure 13.3.1.jpg,"Figure 13.3.1 – Nerve Plexuses of the Body: There are four main nerve plexuses in the human body. The cervical plexus supplies nerves to the posterior head and neck, as well as to the diaphragm. The brachial plexus supplies nerves to the arm. The lumbar plexus supplies nerves to the anterior leg. The sacral plexus supplies nerves to the posterior leg.","Of the four nerve plexuses, two are found at the cervical level, one at the lumbar level, and one at the sacral level (Figure 13.3.1). The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. The other plexus from the cervical level is the brachial plexus. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The radial nerve continues through the arm and is paralleled by the ulnar nerve and the median nerve. The lumbar plexus arises from axons of the ventral rami of spinal nerves T12 through L4 and gives rise to nerves enervating the pelvic region and the anterior leg. The femoral nerve is one of the major nerves from this plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg. The sacral plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4. The most significant systemic nerve to come from this plexus is the sciatic nerve, which is a combination of the tibial nerve and the fibular nerve. The sciatic nerve extends across the hip joint and is most commonly associated with the condition sciatica, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it.","{'b4f9ffe5-f8d6-4d2c-a316-575bc63b53c2': 'Reflexes combine the spinal sensory and motor components with a sensory input that directly generates a motor response. The reflexes that are tested in the neurological exam are classified into two groups. A deep tendon reflex is commonly known as a stretch reflex, and is elicited by a strong tap to a tendon, such as in the knee-jerk reflex. A superficial reflex is elicited through gentle stimulation of the skin and causes contraction of the associated muscles.', 'f17779c9-f9be-46c6-9413-6aa6a8b6a6df': 'For the arm, the common reflexes to test are of the biceps, brachioradialis, triceps, and flexors for the digits. For the leg, the knee-jerk reflex of the quadriceps is common, as is the ankle reflex for the gastrocnemius and soleus. The tendon at the insertion for each of these muscles is struck with a rubber mallet. The muscle is quickly stretched, resulting in activation of the muscle spindle that sends a signal into the spinal cord through the dorsal root. The fiber synapses directly on the ventral horn motor neuron that activates the muscle, causing contraction. The reflexes are physiologically useful for stability. If a muscle is stretched, it reflexively contracts to return the muscle to compensate for the change in length. In the context of the neurological exam, reflexes indicate that the LMN is functioning properly.', '4b7a3a18-3af9-483d-b88c-61934007f472': 'The most common superficial reflex in the neurological exam is the plantar reflex that tests for the Babinski sign on the basis of the extension or flexion of the toes at the plantar surface of the foot. The plantar reflex is commonly tested in newborn infants to establish the presence of neuromuscular function. To elicit this reflex, an examiner brushes a stimulus, usually the examiner’s fingertip, along the plantar surface of the infant’s foot. An infant would present a positive Babinski sign, meaning the foot dorsiflexes and the toes extend and splay out. As a person learns to walk, the plantar reflex changes to cause curling of the toes and a moderate plantar flexion. If superficial stimulation of the sole of the foot caused extension of the foot, keeping one’s balance would be harder. The descending input of the corticospinal tract modifies the response of the plantar reflex, meaning that a negative Babinski sign is the expected response in testing the reflex. Other superficial reflexes are not commonly tested, though a series of abdominal reflexes can target function in the lower thoracic spinal segments.', 'ad7f2cc6-baa3-477d-921a-12936b46d8e0': 'Reflexes can be spinal or cranial, depending on the nerves and central components that are involved. The body uses both spinal and cranial reflexes to rapidly respond to important stimuli. All reflex arcs include five basic components; (1) a receptor, (2) a sensory neuron, (3) an integration center, (4) a motor neuron, and (5) an effector. The effector may be a skeletal muscle, as is the case in somatic reflexes. However, in autonomic (or visceral) reflexes, the effector will be cardiac muscle, smooth muscle, or a gland.', 'c73ebc6e-6806-48e0-aba0-7950d860424c': 'Somatic spinal reflexes utilize motor neurons of the ventral horn to activate skeletal muscles. The simplest example of this type of reflex is the stretch reflex. In this reflex, when a skeletal muscle is stretched, a muscle spindle receptor is activated. The sensory neuron associated with the muscle spindle synapses directly with the motor neuron in the ventral horn, allowing for an incredibly fast response called a monosynaptic reflex. The reflex helps to maintain muscles at a constant length, and is the reason your head jerks back up after drooping when you begin to fall asleep sitting up. Another common example of this reflex is the knee jerk that is elicited by a rubber hammer struck against the patellar ligament in a physical exam.', '78452dd8-66a1-4f15-adf2-0fbe80ccb619': 'Figure 13.5.1 – Stretch Reflex', '89570870-477c-4c0b-9316-3ac0aee2557e': 'A different somatic spinal nerve reflex involves the response to pain, like when you touch a hot stove and in response withdrawal your arm, typically before you have even registered the pain in your hand. This reflex is called the flexor withdrawal reflex, and it stimulates the withdrawal of the arm through a connection in the spinal cord that leads to contraction of the biceps brachii. Unlike the stretch reflex, the flexor withdrawal reflex is polysynaptic and requires 2 spinal cord synapses to activate the motor neuron. As you withdraw your hand from the stove, you do not want to slow that reflex down. As the biceps brachii contracts, the antagonistic triceps brachii that had been activated to extend the arm toward the stove now needs to relax. Because the neuromuscular junction is strictly excitatory, the biceps will contract when the motor nerve is active. Skeletal muscles do not actively relax. Instead the motor neuron needs to “quiet down,” or be inhibited. In the hot-stove withdrawal reflex, this occurs through an interneuron in the spinal cord. The interneuron’s cell body is located in the dorsal horn of the spinal cord. The interneuron receives a synapse from the axon of the sensory neuron that detects that the hand is being burned. In response to this stimulation from the sensory neuron, the interneuron then inhibits the motor neuron that controls the triceps brachii, in what is known as reciprocal inhibition. This is done by releasing a neurotransmitter or other signal that hyperpolarizes the motor neuron connected to the triceps brachii, making it less likely to initiate an action potential. With this motor neuron being inhibited, the triceps brachii relaxes. Without the antagonistic contraction, withdrawal from the hot stove is faster and keeps further tissue damage from occurring.', '4332e357-4964-4240-ae9c-c56a829efee4': 'The flexor withdrawal reflex is also at play when you step on a painful stimulus, like a tack or a child’s Lego®. The nociceptors that are activated by the painful stimulus activate the motor neurons responsible for contraction of the tibialis anterior muscle. This causes dorsiflexion of the foot. An inhibitory interneuron, activated by a collateral branch of the nociceptor fiber, will inhibit the motor neurons of the gastrocnemius and soleus muscles to cancel plantar flexion. An important difference in this reflex is that plantar flexion is most likely in progress as the foot is pressing down onto the tack. Contraction of the tibialis anterior is not the most important aspect of the reflex, as continuation of plantar flexion will result in further damage from stepping onto the tack. While all this is happening in one lower limb, a contralateral response will be stimulated to help you catch your balance with the other. This is called the crossed extensor reflex.', '76e79019-e11f-4aee-a8c5-04367133cd4f': 'In the cross extensor reflex, the same painful stimulus that initiates the flexor withdrawal reflex simultaneously initiates extension of the opposite limb. In the case of stepping on a painful object and pulling your foot away, the cross extensor reflex activated the contralateral quads and gastrocnemius and soleus to extend the leg while plantar flexing the ankle to shift body weight.', '2529a90e-04f1-47e5-889b-c1647d4b5129': 'All of the somatic spinal nerve reflexes involved so far involve reciprocal inhibition. In each case, a prime mover is stimulated and its antagonist is inhibited. However, in the\xa0golgi tendon reflex, the prime mover is inhibited its antagonist is stimulated. This is termed reciprocal activation. In the tendon reflex, prolonged or particularly forceful stretching of the muscle and its tendon trigger the relaxation of the muscle to prevent tearing through the activation of a special receptor, the golgi tendon organ. At the same time, the antagonist muscles is activated to help return the affected muscle and its tendon to their resting lengths.', 'a4e225df-5a8b-42ea-b3c1-13d09127ee33': 'Figure 13.5.3 – Golgi Tendon Reflex', '97691d60-ed1d-4945-92f5-027385492622': 'Cranial nerve somatic reflexes function similarly, but are integrated in the brainstem. A specialized cranial nerve reflex which protects the surface of the eye is the corneal reflex, or the eye blink reflex. When the cornea is stimulated by a tactile stimulus, or even by bright light in a related reflex, blinking is initiated. The sensory component travels through the trigeminal nerve, which carries somatosensory information from the face, or through the optic nerve, if the stimulus is bright light. The motor response travels through the facial nerve and innervates the orbicularis oculi on the same side. This reflex is commonly tested during a physical exam using an air puff or a gentle touch of a cotton-tipped applicator.', 'e0598d48-3a5a-45cf-a478-f95d8939527f': 'Sensory axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The motor axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.\xa0On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions.', '81c5a76b-85df-497b-9c5b-59351670efad': 'In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 13.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.', 'fd48e88d-95f8-4648-b276-f3b1e1d6e45a': 'Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts carrying sensory information to the brain. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.', 'c90f06af-cfe5-464d-9dcc-d5994cee0a90': 'The nerves connected to the spinal cord are the spinal nerves. The arrangement of these nerves is much more regular than that of the cranial nerves. All of the spinal nerves are combined sensory and motor axons that separate into two nerve roots. The sensory axons enter the spinal cord as the dorsal nerve root. The motor fibers, both somatic and autonomic, emerge as the ventral nerve root. The dorsal root ganglion for each nerve is an enlargement of the spinal nerve.', '4eb07ea7-b00f-41a6-ba3e-4b9f52d0da19': 'There are 31 spinal nerves, named for the level of the spinal cord at which each one emerges. There are eight pairs of cervical nerves designated C1 to C8, twelve thoracic nerves designated T1 to T12, five pairs of lumbar nerves designated L1 to L5, five pairs of sacral nerves designated S1 to S5, and one pair of coccygeal nerves. The nerves are numbered from the superior to inferior positions, and each emerges from the vertebral column through the intervertebral foramen at its level. The first nerve, C1, emerges between the first cervical vertebra and the occipital bone. The second nerve, C2, emerges between the first and second cervical vertebrae. The same occurs for C3 to C7, but C8 emerges between the seventh cervical vertebra and the first thoracic vertebra. For the thoracic and lumbar nerves, each one emerges between the vertebra that has the same designation and the next vertebra in the column. The sacral nerves emerge from the sacral foramina along the length of that unique vertebra.', 'a94b4006-73c4-4ccb-98eb-4ad10e408e66': 'Spinal nerves extend outward from the vertebral column to enervate the periphery. The nerves in the periphery are not straight continuations of the spinal nerves, but rather the reorganization of the axons in those nerves to follow different courses. Axons from different spinal nerves will come together into a systemic nerve. This occurs at four places along the length of the vertebral column, each identified as a nerve plexus, whereas the other spinal nerves directly correspond to nerves at their respective levels. In this instance, the word plexus is used to describe networks of nerve fibers with no associated cell bodies.', '10dfc9fe-603a-45d9-a001-c76df516acb2': 'Of the four nerve plexuses, two are found at the cervical level, one at the lumbar level, and one at the sacral level (Figure 13.3.1). The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. The other plexus from the cervical level is the brachial plexus. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The radial nerve continues through the arm and is paralleled by the ulnar nerve and the median nerve. The lumbar plexus arises from axons of the ventral rami of spinal nerves T12 through L4 and gives rise to nerves enervating the pelvic region and the anterior leg. The femoral nerve is one of the major nerves from this plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg. The sacral plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4. The most significant systemic nerve to come from this plexus is the sciatic nerve, which is a combination of the tibial nerve and the fibular nerve. The sciatic nerve extends across the hip joint and is most commonly associated with the condition sciatica, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it.', '48c376e0-51b4-441e-83e9-014d6124e1e0': 'These plexuses are described as arising from spinal nerves and giving rise to certain systemic nerves, but they contain fibers that serve sensory functions or fibers that serve motor functions. This means that some fibers extend from cutaneous or other peripheral sensory surfaces and send action potentials into the CNS. Those are axons of sensory neurons in the dorsal root ganglia that enter the spinal cord through the dorsal nerve root. Other fibers are the axons of motor neurons of the anterior horn of the spinal cord, which emerge in the ventral nerve root and send action potentials to cause skeletal muscles to contract in their target regions. For example, the radial nerve contains fibers of cutaneous sensation in the arm, as well as motor fibers that move muscles in the arm.', '25beaa95-86c5-4186-a024-6b28a78ee001': 'Spinal nerves of the thoracic region, T2 through T11, are not part of the plexuses but rather emerge and give rise to the intercostal nerves found between the ribs, which articulate with the vertebrae surrounding the spinal nerve.'}"
+Figure 13.2.1,Anatomy_And_Physio/images/Figure 13.2.1.jpg,"Figure 13.2.1 – Dorsal Root Ganglion: The cell bodies of sensory neurons, which are unipolar neurons by shape, are seen in this photomicrograph. Also, the fibrous region is composed of the axons of these neurons that are passing through the ganglion to be part of the dorsal nerve root (tissue source: canine). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","A ganglion is a group of neuron cell bodies in the periphery (a.k.a. the peripheral nervous system). Ganglia can be categorized, for the most part, as either sensory ganglia or autonomic ganglia, referring to their primary functions. The most common type of sensory ganglion is a dorsal (posterior) root ganglion. These ganglia are the cell bodies of neurons with axons that are associated with sensory endings in the periphery, such as in the skin, and that extend into the CNS through the dorsal nerve root. The ganglion is an enlargement of the nerve root. Note that nerve roots are not surrounded by the pia mater, and as such are part of the peripheral nervous system. Under microscopic inspection, it can be seen to include the cell bodies of the neurons, as well as bundles of fibers that are the dorsal nerve root (Figure 13.2.1). The cells of the dorsal root ganglion are unipolar cells, classifying them by shape. Also, the small round nuclei of satellite cells can be seen surrounding—as if they were orbiting—the neuron cell bodies.","{'c872e49e-df65-4b22-bdf5-737d17a8efff': 'A ganglion is a group of neuron cell bodies in the periphery (a.k.a. the peripheral nervous system). Ganglia can be categorized, for the most part, as either sensory ganglia or autonomic ganglia, referring to their primary functions. The most common type of sensory ganglion is a dorsal (posterior) root ganglion. These ganglia are the cell bodies of neurons with axons that are associated with sensory endings in the periphery, such as in the skin, and that extend into the CNS through the dorsal nerve root. The ganglion is an enlargement of the nerve root. Note that nerve roots are not surrounded by the pia mater, and as such are part of the peripheral nervous system. Under microscopic inspection, it can be seen to include the cell bodies of the neurons, as well as bundles of fibers that are the dorsal nerve root (Figure 13.2.1). The cells of the dorsal root ganglion are unipolar cells, classifying them by shape. Also, the small round nuclei of satellite cells can be seen surrounding—as if they were orbiting—the neuron cell bodies.', '72ad7166-3339-4d1a-8a44-139d0f0bdbc1': 'Another type of sensory ganglion is a cranial nerve ganglion. This is analogous to the dorsal root ganglion, except that it is associated with a cranial nerve (associated with the brain) instead of a spinal nerve (associated with the spinal cord). The roots of cranial nerves are within the cranium, whereas the ganglia are outside the skull. For example, the trigeminal ganglion is superficial to the temporal bone whereas its associated nerve is attached to the mid-pons region of the brain stem. Like the sensory neurons associated with the spinal cord, the sensory neurons of cranial nerve ganglia are unipolar in shape with associated satellite cells.', '15257af2-bf57-4987-9b11-29b76d74377e': 'The other major category of ganglia are those of the autonomic nervous system, which is divided into the sympathetic and parasympathetic nervous systems. The sympathetic chain ganglia constitute a row of ganglia along the vertebral column that receive central input from the lateral horn of the thoracic and upper lumbar spinal cord. At the superior end of the chain ganglia are three paravertebral ganglia in the cervical region. Three other autonomic ganglia that are related to the sympathetic chain are the prevertebral ganglia, which are located outside of the chain but have similar functions. They are referred to as prevertebral because they are anterior to the vertebral column. The neurons of these autonomic ganglia are multipolar in shape, with dendrites radiating out around the cell body where synapses from the spinal cord neurons are made. The neurons of the chain, paravertebral, and prevertebral ganglia then project to organs in the head and neck, thoracic, abdominal, and pelvic cavities to regulate the sympathetic aspect of homeostatic mechanisms.', 'a614e5e4-1b5e-458c-87c9-ee42767429ec': 'Another group of autonomic ganglia are the terminal ganglia that receive central input from cranial nerves or sacral spinal nerves and are responsible for regulating the parasympathetic aspect of homeostatic mechanisms. These two sets of ganglia, sympathetic and parasympathetic, often project to the same organs—one input from the chain ganglia and one input from a terminal ganglion—to regulate the overall function of an organ. For example, the heart receives two inputs such as these; one increases heart rate, and the other decreases it. The terminal ganglia that receive input from cranial nerves are found in the head and neck, as well as the thoracic and upper abdominal cavities, whereas the terminal ganglia that receive sacral input are in the lower abdominal and pelvic cavities.', '8fb8eaf4-0b7b-453c-b97a-a949002e1dab': 'Terminal ganglia below the head and neck are often incorporated into the wall of the target organ as a plexus. A plexus, in a general sense, is a network of branching interconnected fibers or vessels. This can apply to nervous tissue (as in this instance) or structures containing blood vessels (such as a choroid plexus). For example, the enteric plexus is the extensive network of axons and neurons in the wall of the small and large intestines. The enteric plexus is actually part of the enteric nervous system, along with the gastric plexuses and the esophageal plexus. Though the enteric nervous system receives input originating from central neurons of the autonomic nervous system, it does not require CNS input to function. In fact, it operates independently to regulate the digestive system.'}"
+Figure 13.2.3,Anatomy_And_Physio/images/Figure 13.2.3.jpg,"Figure 13.2.3 – Nerve Structure. The structure of a nerve is organized by the layers of connective tissue on the outside, around each fascicle, and surrounding the individual nerve fibers (tissue source: simian). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Bundles of axons in the PNS are referred to as nerves. These structures in the periphery are different than the central counterpart, called a tract. Unlike tracts, nerves are composed of more than just nervous tissue. They have connective tissues invested in their structure, as well as blood vessels supplying the tissues with nourishment. The outer surface of a nerve is a surrounding layer of fibrous connective tissue called the epineurium. Within the nerve, axons are further bundled into fascicles, which are each surrounded by their own layer of fibrous connective tissue called perineurium. Finally, individual axons are surrounded by loose connective tissue called the endoneurium (Figure 13.2.3). These three layers are similar to the connective tissue sheaths for muscles. Because peripheral axons are surrounded by an endoneurium it is possible for severed axons to regenerated. After they are cut the proximal severed end of the axon sprouts and one of the sprouts will find the endoneurium which is, essentially, an empty tube leading to (or near) the original target. The endoneurim is empty because the distal portion of the severed axon degenerates, a process called Wallerian (anterograde or orthograde) degeneration. Nerves are associated with the region of the CNS to which they are connected, either as cranial nerves connected to the brain or spinal nerves connected to the spinal cord.","{'74f1c6f1-9a1e-487d-b1f9-59e688a8d8bc': 'Bundles of axons in the PNS are referred to as nerves. These structures in the periphery are different than the central counterpart, called a tract. Unlike tracts, nerves are composed of more than just nervous tissue. They have connective tissues invested in their structure, as well as blood vessels supplying the tissues with nourishment. The outer surface of a nerve is a surrounding layer of fibrous connective tissue called the epineurium. Within the nerve, axons are further bundled into fascicles, which are each surrounded by their own layer of fibrous connective tissue called perineurium. Finally, individual axons are surrounded by loose connective tissue called the endoneurium (Figure 13.2.3).\xa0These three layers are similar to the connective tissue sheaths for muscles. Because peripheral axons are surrounded by an endoneurium it is possible for severed axons to regenerated. After they are cut the proximal severed end of the axon sprouts and one of the sprouts will find the endoneurium which is, essentially, an empty tube leading to (or near) the original target. The endoneurim is empty because the distal portion of the severed axon degenerates, a process called Wallerian (anterograde or orthograde) degeneration. Nerves are associated with the region of the CNS to which they are connected, either as cranial nerves connected to the brain or spinal nerves connected to the spinal cord.', '1ad95067-6a15-466d-b88a-d897ceae515f': 'A major role of sensory receptors is to help us learn about the environment around us, or about the state of our internal environment. Different types of stimuli from varying sources are received and changed into the electrochemical signals of the nervous system. This process is called sensory transduction. This occurs when a stimulus is detected by a receptor which generates a graded potential in a sensory neuron. If strong enough, the graded potential causes the sensory neuron to produce an action potential that is relayed into the central nervous system (CNS), where it is integrated with other sensory information—and sometimes higher cognitive functions—to become a conscious perception of that stimulus. The central integration may then lead to a motor response.', '9a011c65-32aa-4dbc-a460-9515689c60ad': 'Describing sensory function with the term sensation or perception is a deliberate distinction. Sensation is the activation of sensory receptors at the level of the stimulus. Perception is the central processing of sensory stimuli into a meaningful pattern involving awareness. Perception is dependent on sensation, but not all sensations are perceived. Receptors are the structures (and sometimes whole cells) that detect sensations. A receptor or receptor cell is changed directly by a stimulus. A transmembrane protein receptor is a protein in the cell membrane that mediates a physiological change in a neuron, most often through the opening of ion channels or changes in the cell signaling processes. Some transmembrane receptors are activated by chemicals called ligands. For example, a molecule in food can serve as a ligand for taste receptors. Other transmembrane proteins, which are not accurately called receptors, are sensitive to mechanical or thermal changes. Physical changes in these proteins increase ion flow across the membrane, and can generate a graded potential in the sensory neurons.'}"
+Figure 12.5.1,Anatomy_And_Physio/images/Figure 12.5.1.jpg,"Figure 12.5.1 – Cell Membrane and Transmembrane Proteins: The cell membrane is composed of a phospholipid bilayer and has many transmembrane proteins, including different types of channel proteins that serve as ion channels.","As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.","{'e52b78b5-93d4-408b-8264-ce734c9b3d66': 'Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.', 'd4e528ef-dbfe-4343-b989-db1f941c32c7': 'As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.', 'b29104fe-3be9-4af1-a374-2480a6dda8b0': 'The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.', 'b0c8eae9-6802-4845-809a-91eaccf131d6': 'Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.\xa0 Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.', 'ac7a05a9-9104-4ac1-84d5-e3084f874c58': 'Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).', 'd42859d0-f93a-45fa-b1f3-7e664144f28a': 'A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).', '671d9831-9f8e-4607-b2a7-fb267957fb6c': 'A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).', 'ea7c1456-49b7-4fc7-b36d-94677ebdbb0e': 'A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).'}"
+Figure 12.5.2,Anatomy_And_Physio/images/Figure 12.5.2.jpg,"Figure 12.5.2 – Ligand-Gated Channels: When the ligand, in this case the neurotransmitter acetylcholine, binds to a specific location on the extracellular surface of the channel protein, the pore opens to allow select ions through. The ions, in this case, are cations of sodium, calcium, and potassium.","Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).","{'e52b78b5-93d4-408b-8264-ce734c9b3d66': 'Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.', 'd4e528ef-dbfe-4343-b989-db1f941c32c7': 'As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.', 'b29104fe-3be9-4af1-a374-2480a6dda8b0': 'The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.', 'b0c8eae9-6802-4845-809a-91eaccf131d6': 'Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.\xa0 Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.', 'ac7a05a9-9104-4ac1-84d5-e3084f874c58': 'Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).', 'd42859d0-f93a-45fa-b1f3-7e664144f28a': 'A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).', '671d9831-9f8e-4607-b2a7-fb267957fb6c': 'A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).', 'ea7c1456-49b7-4fc7-b36d-94677ebdbb0e': 'A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).'}"
+Figure 12.5.3,Anatomy_And_Physio/images/Figure 12.5.3.jpg,"Figure 12.5.3 – Mechanically-Gated Channels: When a mechanical change occurs in the surrounding tissue (such as pressure or stretch) the channel is physically opened, and ions can move through the channel, down their concentration gradient.","A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).","{'e52b78b5-93d4-408b-8264-ce734c9b3d66': 'Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.', 'd4e528ef-dbfe-4343-b989-db1f941c32c7': 'As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.', 'b29104fe-3be9-4af1-a374-2480a6dda8b0': 'The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.', 'b0c8eae9-6802-4845-809a-91eaccf131d6': 'Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.\xa0 Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.', 'ac7a05a9-9104-4ac1-84d5-e3084f874c58': 'Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).', 'd42859d0-f93a-45fa-b1f3-7e664144f28a': 'A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).', '671d9831-9f8e-4607-b2a7-fb267957fb6c': 'A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).', 'ea7c1456-49b7-4fc7-b36d-94677ebdbb0e': 'A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).'}"
+Figure 12.5.4,Anatomy_And_Physio/images/Figure 12.5.4.jpg,Figure 12.5.4 – Voltage-Gated Channels: Voltage-gated channels open when the transmembrane voltage changes around them. Amino acids in the structure of the protein are sensitive to charge and cause the pore to open to the selected ion.,"A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).","{'e52b78b5-93d4-408b-8264-ce734c9b3d66': 'Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.', 'd4e528ef-dbfe-4343-b989-db1f941c32c7': 'As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.', 'b29104fe-3be9-4af1-a374-2480a6dda8b0': 'The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.', 'b0c8eae9-6802-4845-809a-91eaccf131d6': 'Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.\xa0 Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.', 'ac7a05a9-9104-4ac1-84d5-e3084f874c58': 'Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).', 'd42859d0-f93a-45fa-b1f3-7e664144f28a': 'A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).', '671d9831-9f8e-4607-b2a7-fb267957fb6c': 'A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).', 'ea7c1456-49b7-4fc7-b36d-94677ebdbb0e': 'A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).'}"
+Figure 12.5.5,Anatomy_And_Physio/images/Figure 12.5.5.jpg,"Figure 12.5.5 – Leak Channels: These channels open and close at random, allowing ions to pass through when they are open.","A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).","{'e52b78b5-93d4-408b-8264-ce734c9b3d66': 'Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.', 'd4e528ef-dbfe-4343-b989-db1f941c32c7': 'As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.', 'b29104fe-3be9-4af1-a374-2480a6dda8b0': 'The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.', 'b0c8eae9-6802-4845-809a-91eaccf131d6': 'Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.\xa0 Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.', 'ac7a05a9-9104-4ac1-84d5-e3084f874c58': 'Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).', 'd42859d0-f93a-45fa-b1f3-7e664144f28a': 'A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).', '671d9831-9f8e-4607-b2a7-fb267957fb6c': 'A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).', 'ea7c1456-49b7-4fc7-b36d-94677ebdbb0e': 'A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).'}"
+Figure 12.5.6,Anatomy_And_Physio/images/Figure 12.5.6.jpg,"Figure 12.5.6 – Measuring Charge across a Membrane with a Voltmeter: A recording electrode is inserted into the cell and a reference electrode is outside the cell. By comparing the charge measured by these two electrodes, the transmembrane voltage is determined. It is conventional to express that value for the cytosol relative to the outside.","The membrane potential is a distribution of charge across the cell membrane, measured in millivolts (mV). The standard is to compare the inside of the cell relative to the outside, so the membrane potential is a value representing the charge on the intracellular side of the membrane (based on the outside being zero, relatively speaking; Figure 12.5.6).","{'156d0d49-7725-4949-a24d-a49000ec3126': 'The membrane potential is a distribution of charge across the cell membrane, measured in millivolts (mV). The standard is to compare the inside of the cell relative to the outside, so the membrane potential is a value representing the charge on the intracellular side of the membrane (based on the outside being zero, relatively speaking; Figure 12.5.6).', 'e6cd4f2e-e67a-4bf3-801b-1fd66cb49ec0': 'There is typically an overall net neutral charge between the extracellular and intracellular environments of the neuron. However, a slight difference in charge occurs right at the membrane surface, both internally and externally. It is the difference in this very limited region that holds the power to generate electrical signals, including action potentials, in neurons and muscle cells.', '9186b399-e5e5-455f-b173-b22be07f5272': 'When the cell is at rest, ions are distributed across the membrane in a very predictable way. The concentration of Na+ outside the cell is 10 times greater than the concentration inside. Also, the concentration of K+ inside the cell is greater than outside. The cytosol contains a high concentration of anions, in the form of phosphate ions and negatively charged proteins. With the ions distributed across the membrane at these concentrations, the difference in charge is described as the resting membrane potential. The exact value measured for the resting membrane potential varies between cells, but -70 mV is a commonly reported value. This voltage would actually be much lower except for the contributions of some important proteins in the membrane. Leak channels allow Na+ to slowly move into the cell or K+ to slowly move out, and the Na+/K+ pump restores their concentration gradients across the membrane. This may appear to be a waste of energy, but each has a role in maintaining the membrane potential.'}"
+Figure 12.4.1,Anatomy_And_Physio/images/Figure 12.4.1.jpg,"Figure 12.4.1 – The Synapse: The synapse is a connection between a neuron and its target cell (which is not necessarily a neuron). The presynaptic element is the synaptic end bulb of the axon where Ca2+ enters the bulb to cause vesicle fusion and neurotransmitter release. The neurotransmitter diffuses across the synaptic cleft to bind to its receptor. The neurotransmitter is cleared from the synapse either by enzymatic degradation, neuronal reuptake, or glial reuptake.","Once in the synaptic cleft, the neurotransmitter diffuses the short distance to the postsynaptic membrane and can bind to neurotransmitter receptors. Receptors are specific for the neurotransmitter, and the two fit together like a lock and key, and so a neurotransmitter will not bind to receptors for other neurotransmitters (Figure 12.4.1).","{'e2f90c4d-01a4-4323-854c-a8df661c0f37': 'A synapse is the site of communication between a neuron and another cell. There are two types of synapses: chemical synapses and electrical synapses. In a chemical synapse, a chemical signal— a neurotransmitter—is released from the neuron and it binds to a receptor on the other cell. In an electrical synapse, the membranes of two cells directly connect through a gap junction so that ions can pass directly from one cell to the next, transmitting a signal. Both types of synapses occur in the nervous system, though chemical synapses are more common.', 'ae97fb08-c93e-4079-938e-0adc4f530157': 'An example of a chemical synapse is the neuromuscular junction (NMJ) described in the chapter on muscle tissue. In the nervous system, there are many additional\xa0synapses that utilize the\xa0same mechanisms as the NMJ. All chemical synapses have common characteristics, which can be summarized in Table 12.2:', '60258178-3614-463a-ba84-5e09ec9e1e42': 'When an action potential reaches the axon terminals, voltage-gated Ca2+ channels in the membrane of the synaptic end bulb open. Ca2+ diffuses down its concentration gradient and enters into the presynaptic neuron axon terminal (end bulb). Once Ca2+ is inside the presynaptic end bulb, it associates with proteins to trigger the exocytosis of neurotransmitter vesicles. The released neurotransmitter moves into the small gap between the cells, the synaptic cleft.', '0a4df8ac-82c3-40a5-b476-b78996c3ba7e': 'Once in the synaptic cleft, the neurotransmitter diffuses the short distance to the postsynaptic membrane and can bind\xa0to neurotransmitter receptors. Receptors are specific for the neurotransmitter, and the two fit together like a lock and key, and so a neurotransmitter will not bind to receptors for other neurotransmitters (Figure 12.4.1).'}"
+Figure 12.4.2,Anatomy_And_Physio/images/Figure 12.4.2.jpg,"Figure 12.4.2 – Receptor Types: (a) An ionotropic receptor is a channel that opens when the neurotransmitter binds to it. (b) A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in gene transcription.","The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.4.3,Anatomy_And_Physio/images/Figure 12.4.3.jpg,"Figure 12.4.3 – Graded Potentials: Graded potentials are temporary changes in the membrane voltage, the characteristics of which depend on the size of the stimulus. Some types of stimuli cause depolarization of the membrane, whereas others cause hyperpolarization. It depends on the specific ion channels that are activated in the cell membrane.","Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long. Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.4.4,Anatomy_And_Physio/images/Figure 12.4.4.jpg,"Figure 12.4.4 – Postsynaptic Potential Summation: The result of summation of postsynaptic potentials is the overall change in the membrane potential. At point A, several different excitatory postsynaptic potentials add up to a large depolarization. At point B, a mix of excitatory and inhibitory postsynaptic potentials result in a different end result for the membrane potential.","All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the initiation of an action potential.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.3.1,Anatomy_And_Physio/images/Figure 12.3.1.jpg,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.,"Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.3.1,Anatomy_And_Physio/images/Figure 12.3.1.jpg,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.,"Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.3.1,Anatomy_And_Physio/images/Figure 12.3.1.jpg,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.,"Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.3.3,Anatomy_And_Physio/images/Figure 12.3.3.jpg,"Figure 12.3.3 – The Motor Response: On the basis of the sensory input and the integration in the CNS, a motor response is formulated and executed.","A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron starts in this region, called the precentral gyrus of the frontal cortex, and has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.","{'4dc04b14-0484-4886-b1d4-5fb77399ad63': 'Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.', '8f4d207c-f054-4f99-be9a-cd235a368360': 'Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.', '1ebac4db-7e34-445e-a7e9-3807325e67d8': 'Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.', 'af4257fe-a868-4ee0-bea4-50ea366d7d22': 'The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).', 'fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc': 'Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.', '92fd77c2-f99c-440a-996f-6a02bd21accd': 'Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.', 'f7555434-c3ed-41c9-b145-b408875d4d04': 'The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', '017e0bed-5724-4a97-be66-25f58a964624': 'A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.', 'e702c110-2bc6-4ccb-8df2-c96e7952b110': 'The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.', 'db49e6b6-0e0e-4698-8783-84250db47610': 'The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.', 'b0d2be7b-b55c-4038-8b88-4f68f550eccd': 'Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.', '3623597d-9e43-4cbb-8529-cf3756d57bd7': 'Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long.\xa0Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.', '336a2867-0b22-4403-80c3-980151648764': 'When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.', 'c7f45919-9f7e-4432-86f7-27f94f4cb259': 'For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and\xa0influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.', '4107154c-3af4-42ac-89ca-c3876db1278b': 'A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.', 'b5ac4d42-92d1-4692-8411-f02004d9b982': 'All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the\xa0initiation of an action potential.', '8373b522-4ac6-40a7-9c43-863dfd473a55': 'Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.', '93ccdd69-0a3e-4241-a760-0bb26f433f96': 'Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession\xa0(temporal).\xa0Spatial and temporal summation can act together, as well. Since graded potentials dissipated\xa0with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.', '8c655bc3-52e6-4c16-a0a3-7a623210c607': 'Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.', '6aff615b-e7e6-474a-b01f-9467222936e3': 'Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.', 'a7c544a4-2f83-4181-80f8-4e5554dab05b': 'Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage).\xa0The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1).\xa0When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.', 'fc2121fd-6272-4aa3-a1e3-d88ccb17c227': 'In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter\xa0binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this\xa0synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.', '1a7ce1d6-2940-4408-8769-99caebe829f4': 'Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.', '0c3abe84-2330-4941-b44d-3c15e6f30a94': 'A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron\xa0starts in this region, called the precentral gyrus of the frontal cortex, and\xa0has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane\xa0causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.', '7f57d61d-9b6d-4589-b859-b52e03c436cf': 'There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.', '2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d': 'Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.', '3f922bf5-fd99-4e5a-9d96-5e18dd2701fa': 'Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.', 'e1ec1acb-5721-41f5-bb01-d8ff5a830337': 'Explain how neurons and glial cells work together to perform and support the nervous system functions.', '22f03c43-a459-4915-9c30-f1af753caed4': 'Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia\xa0or\xa0neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.'}"
+Figure 12.1.1,Anatomy_And_Physio/images/Figure 12.1.1.jpg,"Figure 12.1.1 – Central and Peripheral Nervous System: The CNS contains the brain and spinal cord, the PNS includes nerves.","The picture you have in your mind of the nervous system probably includes the brain, the nervous tissue contained within the cranium, and the spinal cord, the extension of nervous tissue within the vertebral column. Additionally, the nervous tissue that reach out from the brain and spinal cord to the rest of the body (nerves) are also part of the nervous system. We can anatomically divide the nervous system into two major regions: the central nervous system (CNS) is the brain and spinal cord, the peripheral nervous system (PNS) is the nerves (Figure 12.1.1). The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral canal of the vertebral column. The peripheral nervous system is so named because it is in the periphery—meaning beyond the brain and spinal cord.","{'9a5087fd-11a6-4a0a-827b-b4ff9410652c': 'The picture you have in your mind of the nervous system probably includes the brain, the nervous tissue contained within the cranium, and the spinal cord, the extension of nervous tissue within the vertebral column. Additionally, the nervous tissue\xa0that reach out from the brain and spinal cord to the rest of the body (nerves)\xa0are also part of the nervous system. We can anatomically divide the nervous system into two major regions: the\xa0central nervous system (CNS) is the brain and spinal cord, the peripheral nervous system (PNS) is the nerves (Figure 12.1.1). The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral canal of the vertebral column. The peripheral nervous system is so named because it is in the periphery—meaning beyond the brain and spinal cord.'}"
+Figure 11.4.22,Anatomy_And_Physio/images/Figure 11.4.22.jpg,"Figure 11.4.22 – Hip and Thigh Muscles: The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. The muscles that move the lower leg typically originate on the femur and insert into the bones of the knee joint. The anterior muscles of the femur extend the lower leg but also aid in flexing the thigh. The posterior muscles of the femur flex the lower leg but also aid in extending the thigh. A combination of gluteal and thigh muscles also adduct, abduct, and rotate the thigh and lower leg.","Most muscles that insert on the femur (the thigh bone) and move it, originate on the pelvic girdle. The major flexors of the hip are the psoas major and iliac which make up the iliopsoas group. Some of the largest and most powerful muscles in the body are the gluteal muscles or gluteal group. The gluteus maximus, one of the major extensors of the thigh at the hip, is the largest; deep to the gluteus maximus is the gluteus medius, and deep to the gluteus medius is the gluteus minimus, the smallest of the trio (Figure 11.4.22 and Figure 11.4.23).","{'22428a29-6ed2-4ccc-a9a9-ee76f9aa57b5': 'Most muscles that insert on the femur (the thigh bone) and move it, originate on the pelvic girdle. The major flexors of the hip are the\xa0psoas major\xa0and\xa0iliac\xa0which make up the\xa0iliopsoas group. Some of the largest and most powerful muscles in the body are the gluteal muscles or\xa0gluteal group. The\xa0gluteus maximus, one of the major extensors of the thigh at the hip,\xa0is the largest; deep to the gluteus maximus is the\xa0gluteus medius, and deep to the gluteus medius is the\xa0gluteus minimus, the smallest of the trio (Figure 11.4.22 and\xa0Figure 11.4.23).', '564e5c8f-5323-42b3-8f1f-9da95579f160': 'The\xa0tensor fascia latae\xa0is a thick, squarish muscle in the superior aspect of the lateral thigh. It acts as a synergist of the gluteus medius and iliopsoas in flexing and abducting the thigh. It also helps stabilize the lateral aspect of the knee by pulling on the\xa0iliotibial tract\xa0(band), making it taut. Deep to the gluteus maximus, the\xa0piriformis,\xa0obturator internus,\xa0obturator externus,\xa0superior gemellus,\xa0inferior gemellus, and\xa0quadratus femoris\xa0laterally rotate the thigh at the hip.', '09409c3d-3a03-4436-bf11-5d9d62f9a282': 'Deep fascia in the thigh separates it into medial, anterior, and posterior compartments. The muscles in the\xa0medial compartment of the thigh\xa0responsible for adducting the femur at the hip\xa0are the adductor group including the\xa0adductor longus,\xa0adductor brevis, and\xa0adductor magnus which\xa0all adduct and medially rotate the thigh. The adductor longus also flexes the thigh, whereas the adductor magnus extends it. Like the adductor longs, the\xa0pectineus\xa0adducts and flexes the femur at the hip. The pectineus is located in the\xa0femoral triangle, which is formed at the junction between the hip and the leg and includes the femoral nerve, the femoral artery, the femoral vein, and the deep inguinal lymph nodes. The strap-like\xa0gracilis\xa0adducts the thigh in addition to flexing the leg at the knee'}"
+Figure 11.4.27,Anatomy_And_Physio/images/Figure 11.4.27.jpg,"Figure 11.4.27 – Intrinsic Muscles of the Foot: The muscles along the dorsal side of the foot (a) generally extend the toes while the muscles of the plantar side of the foot (b, c, d) generally flex the toes. The plantar muscles exist in three layers, providing the foot the strength to counterbalance the weight of the body. In this diagram, these three layers are shown from a plantar view beginning with the bottom-most layer just under the plantar skin of the foot (b) and ending with the top-most layer (d) located just inferior to the foot and toe bones.","The foot also has intrinsic muscles, which originate and insert within it (similar to the intrinsic muscles of the hand). These muscles primarily provide support for the foot and its arch, and contribute to movements of the toes (Figure 11.4.27 and Figure 11.4.28). The principal support for the longitudinal arch of the foot is a deep fascia called plantar aponeurosis, which runs from the calcaneus bone to the toes (inflammation of this tissue is the cause of “plantar fasciitis,” which can affect runners. The intrinsic muscles of the foot include the extensor digitorum brevis on the dorsal aspect and a plantar group, which consists of four layers.","{'c4569256-1582-480a-8e00-b9971e815394': 'Similar to the thigh muscles, the muscles of the leg are divided by deep fascia into compartments, although the leg has three: anterior, lateral, and posterior.', '0fc7435f-677c-42c5-9eeb-208c2ac38de9': 'The muscles in the\xa0anterior compartment of the leg\xa0all contribute to dorsiflexion: the\xa0tibialis anterior, a long and thick muscle on the lateral surface of the tibia, the\xa0extensor hallucis longus, deep under it, and the\xa0extensor digitorum longus, lateral to it. The\xa0fibularis tertius, a small muscle that originates on the anterior surface of the fibula, is associated with the extensor digitorum longus and sometimes fused to it, but is not present in all people. Thick bands of connective tissue called the\xa0superior extensor retinaculum\xa0(transverse ligament of the ankle) and the\xa0inferior extensor retinaculum, hold the tendons of these muscles in place during dorsiflexion.', '091b671b-bab1-40c9-a19a-94bfa41bbe64': 'The\xa0lateral compartment of the leg\xa0includes two muscles which contribute to eversion and plantar flexion: the\xa0fibularis longus\xa0(peroneus longus) and the\xa0fibularis brevis\xa0(peroneus brevis). The superficial muscles in the\xa0posterior compartment of the leg\xa0all insert onto the\xa0calcaneal tendon\xa0(Achilles tendon), a strong tendon that inserts into the calcaneal bone of the ankle, all contribute to plantar flexion. The muscles in this compartment are large and strong and keep humans upright. The most superficial and visible muscle of the calf is the\xa0gastrocnemius. Deep to the gastrocnemius is the wide, flat\xa0soleus. The\xa0plantaris\xa0runs obliquely between the two; some people may have two of these muscles, whereas no plantaris is observed in about seven percent of other cadaver dissections. The plantaris tendon is a desirable substitute for the fascia lata in hernia repair, tendon transplants, and repair of ligaments. There are four deep muscles in the posterior compartment of the leg as well: the\xa0popliteus,\xa0flexor digitorum longus,\xa0flexor hallucis longus, and\xa0tibialis posterior all contribute to plantar flexion or inversion of the foot.', '16b61677-31a7-4b8f-b5bd-30df0fdc4546': 'The foot also has intrinsic muscles, which originate and insert within it (similar to the intrinsic muscles of the hand). These muscles primarily provide support for the foot and its arch, and contribute to movements of the toes (Figure 11.4.27 and Figure 11.4.28). The principal support for the longitudinal arch of the foot is a deep fascia called plantar aponeurosis, which runs from the calcaneus bone to the toes (inflammation of this tissue is the cause of “plantar fasciitis,” which can affect runners. The intrinsic muscles of the foot include\xa0the\xa0extensor digitorum\xa0brevis\xa0on the dorsal aspect and\xa0a\xa0plantar group, which consists of four layers.'}"
+Figure 11.4.1,Anatomy_And_Physio/images/Figure 11.4.1.jpg,"Figure 11.4.1 – Muscles of Facial Expression: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones.","The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression (Figure 11.4.1).","{'12062e7e-b32a-4195-9d35-6f8204164a8b': 'The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression (Figure 11.4.1).', '3e273c97-0c8f-4fee-9e3a-9df558287ba8': 'The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye. The occipitofrontalis muscle elevates the scalp and eyebrows. The muscle has a frontal belly and an occipital belly (near the occipital bone on the posterior part of the skull). In other words, there is a muscle on the forehead (frontalis) and one on the back of the head (occipitals). The two bellies are connected by a broad tendon called the epicranial aponeurosis, or galea aponeurosis (galea = “apple”). The physicians originally studying human anatomy thought the skull looked like an apple.', 'ff036b0b-ccee-41a3-926e-aeb43249dc0d': 'The buccinator muscle compresses the cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Figure 11.4.2.'}"
+Figure 11.4.2,Anatomy_And_Physio/images/Figure 11.4.2.jpg,Figure 11.4.2 Muscles in Facial Expression,"The buccinator muscle compresses the cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Figure 11.4.2.","{'12062e7e-b32a-4195-9d35-6f8204164a8b': 'The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression (Figure 11.4.1).', '3e273c97-0c8f-4fee-9e3a-9df558287ba8': 'The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye. The occipitofrontalis muscle elevates the scalp and eyebrows. The muscle has a frontal belly and an occipital belly (near the occipital bone on the posterior part of the skull). In other words, there is a muscle on the forehead (frontalis) and one on the back of the head (occipitals). The two bellies are connected by a broad tendon called the epicranial aponeurosis, or galea aponeurosis (galea = “apple”). The physicians originally studying human anatomy thought the skull looked like an apple.', 'ff036b0b-ccee-41a3-926e-aeb43249dc0d': 'The buccinator muscle compresses the cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Figure 11.4.2.'}"
+Figure 11.4.7,Anatomy_And_Physio/images/Figure 11.4.7.jpg,Figure 11.4.7 – Muscles of the Anterior Neck: The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.,"The muscles of the anterior neck assist in deglutition (swallowing) and speech by controlling the positions of the larynx (voice box), and the hyoid bone, a horseshoe-shaped bone that functions as a foundation on which the tongue can move. The muscles of the neck are categorized according to their position relative to the hyoid bone (Figure 11.4.7). Suprahyoid muscles are superior to it, and the infrahyoid muscles are located inferiorly.","{'94d24439-ce65-4e2a-bb5a-b8338c339dc0': 'The muscles of the anterior neck assist in deglutition (swallowing) and speech by controlling the positions of the larynx (voice box), and the hyoid bone, a horseshoe-shaped bone that functions as a foundation on which the tongue can move. The muscles of the neck are categorized according to their position relative to the hyoid bone (Figure 11.4.7). Suprahyoid muscles are superior to it, and the infrahyoid muscles are located inferiorly.', '920f59d0-6d6d-433b-b25d-9a2628e726ca': 'The suprahyoid muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition. These include the digastric muscle, which has anterior and posterior bellies that work to elevate the hyoid bone and larynx when one swallows; it also depresses the mandible. The stylohyoid muscle moves the hyoid bone posteriorly, elevating the larynx, and the mylohyoid muscle lifts it and helps press the tongue to the top of the mouth. The geniohyoid depresses the mandible in addition to raising and pulling the hyoid bone anteriorly.', '68437a56-042a-499f-8b24-d9b9a604113d': 'The strap-like infrahyoid muscles generally depress the hyoid bone and control the position of the larynx. The omohyoid muscle, which has superior and inferior bellies, depresses the hyoid bone in conjunction with the sternohyoid and thyrohyoid muscles. The thyrohyoid muscle also elevates the larynx’s thyroid cartilage, whereas the sternothyroid depresses it.'}"
+Figure 11.4.8,Anatomy_And_Physio/images/Figure 11.4.8.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column.","The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).","{'87629787-b1d2-48e0-b511-8dad0909579a': 'The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).', '98a0a71b-b052-46a7-999c-b8e0c73c9629': 'The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.', '6bd8d13c-a71d-4b6f-8d85-d8c7c5cb9c4e': 'The splenius muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the splenius capitis inserts onto the head region, and the splenius cervicis extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 11.4.8).', '091c86eb-35b5-4da1-98a2-18c81b554c26': 'The erector spinae group forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls extension, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.', 'f5e1155a-b3d1-4842-82b3-5f161f9d8ec4': 'The iliocostalis group includes the iliocostalis cervicis, associated with the cervical region; the iliocostalis thoracis, associated with the thoracic region; and the iliocostalis lumborum, associated with the lumbar region. The three muscles of the longissimus group are the longissimus capitis, associated with the head region; the longissimus cervicis, associated with the cervical region; and the longissimus thoracis, associated with the thoracic region. The third group, the spinalis group, comprises the spinalis capitis (head region), the spinalis cervicis (cervical region), and the spinalis thoracis (thoracic region).', '188e589d-3948-4b04-adeb-879af20b57b8': 'The transversospinales muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the semispinalis capitis, the semispinalis cervicis, and the semispinalis thoracis. The multifidus muscle of the lumbar region helps extend and laterally flex the vertebral column.', '151c4b23-ec40-4d3e-bdd2-ec4ef496926f': 'Important in the stabilization of the vertebral column is the segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the scalene muscles work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the anterior scalene muscle (anterior to the middle scalene), the middle scalene muscle (the longest, intermediate between the anterior and posterior scalenes), and the posterior scalene muscle (the smallest, posterior to the middle scalene).', '06219326-3bb3-4ecf-b53e-bff939fe0603': 'Describe the criteria used to name skeletal muscles\n\nExplain how understanding the muscle names helps describe shapes, location, and actions of various muscles', 'f356011f-7111-46ab-be13-b608c5707f5e': 'Taking the time to learn the Latin and Greek roots of the words is crucial to understanding the vocabulary of anatomy and physiology. When you understand the names of muscles it will help you remember where the muscles are located and what they do (Figure 11.3.1, Figure 11.3.2, and Table 11.2).', '8cc6ab97-961f-4588-b921-1abf2bf1d31a': 'Anatomists name the skeletal muscles according to a number of criteria, each of which describes the muscle in some way. These include naming the muscle after its shape, size, fiber direction, location, number of origins or its action.', '274949a6-64d8-4bbf-853f-3a6ccd3f5011': 'Muscle Shape: The names of some muscles reflect their shape. For example, the deltoid is a large, triangular-shaped muscle that covers the shoulder. It is so-named because the Greek letter delta is a triangle.', '654c25bd-7301-4685-a546-4b13216c23da': 'Muscle Location: The skeletal muscle’s anatomical location or its relationship to a particular bone often determines its name. For example, the frontalis muscle is located on top of the frontal bone of the skull. Other examples are muscles of the arm that include the term brachii (of the arm).\n\nSome muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).\nThe location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '7414e005-fceb-433d-be45-8c60543471f4': 'Some muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).', 'c380ee65-0951-499f-95cf-475cdbcc1fc7': 'The location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '0ff4e862-2e02-4d7f-affe-e7c487358ddf': 'Muscle Size: For the buttocks, the size of the muscles influences the names: gluteus maximus (largest), gluteus medius (medium), and the gluteus minimus (smallest). Another example are the pectoral muscles including\xa0major or\xa0minor.\n\nNames are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '3bae7ff4-ecd0-4cb4-b8eb-3ce959545be9': 'Names are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '34e391ca-808e-43a2-ad77-9dca778f2960': 'Muscle Fiber Direction:\xa0The direction of the muscle fibers and fascicles are used to describe muscles. For example, the abdominal muscles all indicate (remove indicated) the direction of the fibers such as the rectus (straight), the\xa0obliques (at an angle) and the transverse (horizontal)\xa0muscles of the abdomen.', 'a2b80e6d-fc80-47ac-91ce-4170ca4cb64b': 'Number of Muscle Origins (or muscles in a group): Some muscle names indicate the number of muscles origins, or number of muscles in a group,\xa0depending upon one’s perspective. For example, when considering the anterior thigh muscle(s), known as the quadriceps, some consider it to be a single muscle with four heads (origins) and others consider the quadriceps to be a group of four muscles. In either case, the prefix quad- refers to four. One example of this is the quadriceps, a group of four muscles located on the anterior (front) thigh.\xa0Other examples include the biceps brachii and the triceps brachii. The prefix bi indicates that the muscle has two origins and tri indicates three origins.', 'b9665524-a30f-4031-8fc5-6dee34f11483': 'The last feature by which to name a muscle is its action. When muscles are named for the movement they produce, one can find action words in their name. Some examples are flexors (decrease the angle at the joint), extensors (increase the angle at the joint), abductors (move the bone away from the midline), or adductors (move the bone toward the midline).'}"
+Figure 11.4.8,Anatomy_And_Physio/images/Figure 11.4.8.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column.","The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).","{'87629787-b1d2-48e0-b511-8dad0909579a': 'The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).', '98a0a71b-b052-46a7-999c-b8e0c73c9629': 'The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.', '6bd8d13c-a71d-4b6f-8d85-d8c7c5cb9c4e': 'The splenius muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the splenius capitis inserts onto the head region, and the splenius cervicis extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 11.4.8).', '091c86eb-35b5-4da1-98a2-18c81b554c26': 'The erector spinae group forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls extension, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.', 'f5e1155a-b3d1-4842-82b3-5f161f9d8ec4': 'The iliocostalis group includes the iliocostalis cervicis, associated with the cervical region; the iliocostalis thoracis, associated with the thoracic region; and the iliocostalis lumborum, associated with the lumbar region. The three muscles of the longissimus group are the longissimus capitis, associated with the head region; the longissimus cervicis, associated with the cervical region; and the longissimus thoracis, associated with the thoracic region. The third group, the spinalis group, comprises the spinalis capitis (head region), the spinalis cervicis (cervical region), and the spinalis thoracis (thoracic region).', '188e589d-3948-4b04-adeb-879af20b57b8': 'The transversospinales muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the semispinalis capitis, the semispinalis cervicis, and the semispinalis thoracis. The multifidus muscle of the lumbar region helps extend and laterally flex the vertebral column.', '151c4b23-ec40-4d3e-bdd2-ec4ef496926f': 'Important in the stabilization of the vertebral column is the segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the scalene muscles work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the anterior scalene muscle (anterior to the middle scalene), the middle scalene muscle (the longest, intermediate between the anterior and posterior scalenes), and the posterior scalene muscle (the smallest, posterior to the middle scalene).', '06219326-3bb3-4ecf-b53e-bff939fe0603': 'Describe the criteria used to name skeletal muscles\n\nExplain how understanding the muscle names helps describe shapes, location, and actions of various muscles', 'f356011f-7111-46ab-be13-b608c5707f5e': 'Taking the time to learn the Latin and Greek roots of the words is crucial to understanding the vocabulary of anatomy and physiology. When you understand the names of muscles it will help you remember where the muscles are located and what they do (Figure 11.3.1, Figure 11.3.2, and Table 11.2).', '8cc6ab97-961f-4588-b921-1abf2bf1d31a': 'Anatomists name the skeletal muscles according to a number of criteria, each of which describes the muscle in some way. These include naming the muscle after its shape, size, fiber direction, location, number of origins or its action.', '274949a6-64d8-4bbf-853f-3a6ccd3f5011': 'Muscle Shape: The names of some muscles reflect their shape. For example, the deltoid is a large, triangular-shaped muscle that covers the shoulder. It is so-named because the Greek letter delta is a triangle.', '654c25bd-7301-4685-a546-4b13216c23da': 'Muscle Location: The skeletal muscle’s anatomical location or its relationship to a particular bone often determines its name. For example, the frontalis muscle is located on top of the frontal bone of the skull. Other examples are muscles of the arm that include the term brachii (of the arm).\n\nSome muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).\nThe location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '7414e005-fceb-433d-be45-8c60543471f4': 'Some muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).', 'c380ee65-0951-499f-95cf-475cdbcc1fc7': 'The location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '0ff4e862-2e02-4d7f-affe-e7c487358ddf': 'Muscle Size: For the buttocks, the size of the muscles influences the names: gluteus maximus (largest), gluteus medius (medium), and the gluteus minimus (smallest). Another example are the pectoral muscles including\xa0major or\xa0minor.\n\nNames are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '3bae7ff4-ecd0-4cb4-b8eb-3ce959545be9': 'Names are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '34e391ca-808e-43a2-ad77-9dca778f2960': 'Muscle Fiber Direction:\xa0The direction of the muscle fibers and fascicles are used to describe muscles. For example, the abdominal muscles all indicate (remove indicated) the direction of the fibers such as the rectus (straight), the\xa0obliques (at an angle) and the transverse (horizontal)\xa0muscles of the abdomen.', 'a2b80e6d-fc80-47ac-91ce-4170ca4cb64b': 'Number of Muscle Origins (or muscles in a group): Some muscle names indicate the number of muscles origins, or number of muscles in a group,\xa0depending upon one’s perspective. For example, when considering the anterior thigh muscle(s), known as the quadriceps, some consider it to be a single muscle with four heads (origins) and others consider the quadriceps to be a group of four muscles. In either case, the prefix quad- refers to four. One example of this is the quadriceps, a group of four muscles located on the anterior (front) thigh.\xa0Other examples include the biceps brachii and the triceps brachii. The prefix bi indicates that the muscle has two origins and tri indicates three origins.', 'b9665524-a30f-4031-8fc5-6dee34f11483': 'The last feature by which to name a muscle is its action. When muscles are named for the movement they produce, one can find action words in their name. Some examples are flexors (decrease the angle at the joint), extensors (increase the angle at the joint), abductors (move the bone away from the midline), or adductors (move the bone toward the midline).'}"
+Figure 11.3.1,Anatomy_And_Physio/images/Figure 11.3.1.jpg,"Figure 11.3.1 – Overview of the Muscular System: On the anterior and posterior views of the muscular system above, superficial muscles (those at the surface) are shown on the right side of the body while deep muscles (those underneath the superficial muscles) are shown on the left half of the body. For the legs, superficial muscles are shown in the anterior view while the posterior view shows both superficial and deep muscles.","Taking the time to learn the Latin and Greek roots of the words is crucial to understanding the vocabulary of anatomy and physiology. When you understand the names of muscles it will help you remember where the muscles are located and what they do (Figure 11.3.1, Figure 11.3.2, and Table 11.2).","{'98a0a71b-b052-46a7-999c-b8e0c73c9629': 'The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.', '6bd8d13c-a71d-4b6f-8d85-d8c7c5cb9c4e': 'The splenius muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the splenius capitis inserts onto the head region, and the splenius cervicis extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 11.4.8).', '091c86eb-35b5-4da1-98a2-18c81b554c26': 'The erector spinae group forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls extension, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.', 'f5e1155a-b3d1-4842-82b3-5f161f9d8ec4': 'The iliocostalis group includes the iliocostalis cervicis, associated with the cervical region; the iliocostalis thoracis, associated with the thoracic region; and the iliocostalis lumborum, associated with the lumbar region. The three muscles of the longissimus group are the longissimus capitis, associated with the head region; the longissimus cervicis, associated with the cervical region; and the longissimus thoracis, associated with the thoracic region. The third group, the spinalis group, comprises the spinalis capitis (head region), the spinalis cervicis (cervical region), and the spinalis thoracis (thoracic region).', '188e589d-3948-4b04-adeb-879af20b57b8': 'The transversospinales muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the semispinalis capitis, the semispinalis cervicis, and the semispinalis thoracis. The multifidus muscle of the lumbar region helps extend and laterally flex the vertebral column.', '151c4b23-ec40-4d3e-bdd2-ec4ef496926f': 'Important in the stabilization of the vertebral column is the segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the scalene muscles work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the anterior scalene muscle (anterior to the middle scalene), the middle scalene muscle (the longest, intermediate between the anterior and posterior scalenes), and the posterior scalene muscle (the smallest, posterior to the middle scalene).', '06219326-3bb3-4ecf-b53e-bff939fe0603': 'Describe the criteria used to name skeletal muscles\n\nExplain how understanding the muscle names helps describe shapes, location, and actions of various muscles', 'f356011f-7111-46ab-be13-b608c5707f5e': 'Taking the time to learn the Latin and Greek roots of the words is crucial to understanding the vocabulary of anatomy and physiology. When you understand the names of muscles it will help you remember where the muscles are located and what they do (Figure 11.3.1, Figure 11.3.2, and Table 11.2).', '8cc6ab97-961f-4588-b921-1abf2bf1d31a': 'Anatomists name the skeletal muscles according to a number of criteria, each of which describes the muscle in some way. These include naming the muscle after its shape, size, fiber direction, location, number of origins or its action.', '274949a6-64d8-4bbf-853f-3a6ccd3f5011': 'Muscle Shape: The names of some muscles reflect their shape. For example, the deltoid is a large, triangular-shaped muscle that covers the shoulder. It is so-named because the Greek letter delta is a triangle.', '654c25bd-7301-4685-a546-4b13216c23da': 'Muscle Location: The skeletal muscle’s anatomical location or its relationship to a particular bone often determines its name. For example, the frontalis muscle is located on top of the frontal bone of the skull. Other examples are muscles of the arm that include the term brachii (of the arm).\n\nSome muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).\nThe location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '7414e005-fceb-433d-be45-8c60543471f4': 'Some muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).', 'c380ee65-0951-499f-95cf-475cdbcc1fc7': 'The location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.', '0ff4e862-2e02-4d7f-affe-e7c487358ddf': 'Muscle Size: For the buttocks, the size of the muscles influences the names: gluteus maximus (largest), gluteus medius (medium), and the gluteus minimus (smallest). Another example are the pectoral muscles including\xa0major or\xa0minor.\n\nNames are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '3bae7ff4-ecd0-4cb4-b8eb-3ce959545be9': 'Names are often used to\xa0indicate length, which is related to muscle size. For example, brevis (short), longus (long).', '34e391ca-808e-43a2-ad77-9dca778f2960': 'Muscle Fiber Direction:\xa0The direction of the muscle fibers and fascicles are used to describe muscles. For example, the abdominal muscles all indicate (remove indicated) the direction of the fibers such as the rectus (straight), the\xa0obliques (at an angle) and the transverse (horizontal)\xa0muscles of the abdomen.', 'a2b80e6d-fc80-47ac-91ce-4170ca4cb64b': 'Number of Muscle Origins (or muscles in a group): Some muscle names indicate the number of muscles origins, or number of muscles in a group,\xa0depending upon one’s perspective. For example, when considering the anterior thigh muscle(s), known as the quadriceps, some consider it to be a single muscle with four heads (origins) and others consider the quadriceps to be a group of four muscles. In either case, the prefix quad- refers to four. One example of this is the quadriceps, a group of four muscles located on the anterior (front) thigh.\xa0Other examples include the biceps brachii and the triceps brachii. The prefix bi indicates that the muscle has two origins and tri indicates three origins.', 'b9665524-a30f-4031-8fc5-6dee34f11483': 'The last feature by which to name a muscle is its action. When muscles are named for the movement they produce, one can find action words in their name. Some examples are flexors (decrease the angle at the joint), extensors (increase the angle at the joint), abductors (move the bone away from the midline), or adductors (move the bone toward the midline).'}"
+Figure 10.2.1,Anatomy_And_Physio/images/Figure 10.2.1.jpg,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium.","Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.","{'93100b76-a6bc-4d13-b5d0-831dbe9d069f': 'Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.', '72a24f4d-c9b4-4af3-b7ee-fbff975786e9': 'Parallel\xa0muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).', '835b0cd7-579c-494f-8471-e43454702b86': 'Circular\xa0muscles are also called sphincters (see\xa0Figure 11.2.1). When they relax, the sphincters’ concentrically arranged bundles of muscle fibers increase the size of the opening, and when they contract, the size of the opening shrinks to the point of closure. The orbicularis oris muscle is a circular muscle that goes around the mouth. When it contracts, the oral opening becomes smaller, as when puckering the lips for whistling. Another example is the orbicularis oculi, one of which surrounds each eye. Consider, for example, the names of the two orbicularis muscles (orbicularis oris and oribicularis oculi), where part of the first name of both muscles is the same. The first part of orbicularis, orb (orb = “circular”), is a reference to a round or circular structure; it may also make one think of orbit, such as the moon’s path around the earth. The word oris (oris = “oral”) refers to the oral cavity, or the mouth. The word oculi (ocular = “eye”) refers to the eye.', '47cd1715-24ac-4184-a95b-73a77cb50730': 'When a muscle has a widespread expansion over a sizable area and the fascicles come to a single, common attachment point, the muscle is called\xa0convergent. The attachment point for a convergent muscle could be a tendon, an aponeurosis (a flat, broad tendon), or a raphe (a very slender tendon). The large muscle on the chest, the pectoralis major, is an example of a convergent muscle because it converges on the intertubercular groove and greater tubercle of the humerus via a tendon (see image 11.3).', '8dcee826-9929-4df5-aa56-f8a9f66ac5af': 'Pennate\xa0muscles (penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle fascicles arranged similar to the feathers. Due to this design, the muscle fibers in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far. However, because a pennate muscle generally can hold more muscle fibers within it, it can produce relatively more tension for its size, compared to non-pennate muscles. There are three subtypes of pennate muscles.', 'c13fc478-b376-4e72-a57a-819f0a5fd2a1': 'In a\xa0unipennate\xa0muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A\xa0bipennate\xa0muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging\xa0on a central point. A common example is the deltoid muscle of the shoulder, which covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus.', 'ffee369e-025d-4ab2-84fb-bf63784c1bc9': 'The number of skeletal muscle fibers in a given muscle is genetically determined and does not change. Muscle strength is directly related to the amount of myofibrils and sarcomeres within each fiber. Factors, such as hormones and stress (and artificial anabolic steroids), acting on the muscle can increase the production of sarcomeres and myofibrils within the muscle fibers, a change called hypertrophy, which results in the increased mass and bulk in a skeletal muscle. Likewise, decreased use of a skeletal muscle results in atrophy, where the number of sarcomeres and myofibrils disappear (but not the number of muscle fibers). It is common for a limb in a cast to show atrophied muscles when the cast is removed, and certain diseases, such as polio, show atrophied muscles.', '50e165f4-aeea-4b4c-adc6-56aee9a55e8b': 'Each skeletal muscle is an organ that consists of various integrated tissues. These tissues include the skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue. Each skeletal muscle has three layers of connective tissue (called mysia) that enclose it, provide structure to the muscle, and compartmentalize the muscle fibers within the muscle (Figure 10.2.1). Each muscle is wrapped in a sheath of dense, irregular connective tissue called the epimysium, which allows a muscle to contract and move powerfully while maintaining its structural integrity. The epimysium also separates muscle from other tissues and organs in the area, allowing the muscle to move independently.', '038727e5-093f-425f-8b8a-c7e7d7f34145': 'Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, surrounded by a middle layer of connective tissue called the perimysium. This fascicular organization is common in muscles of the limbs; it allows the nervous system to trigger a specific movement of a muscle by activating a subset of muscle fibers within a fascicle of the muscle. Inside each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular fibers called the endomysium. The endomysium surrounds the\xa0extracellular matrix of the cells and plays a role in transferring force produced by the muscle fibers to the tendons.', 'e4e68d03-03ba-42b5-8930-1282a8c96792': 'In skeletal muscles that work with tendons to pull on bones, the collagen in the three connective tissue layers intertwines with the collagen of a tendon. At the other end of the tendon, it fuses with the periosteum coating the bone. The tension created by contraction of the muscle fibers is then transferred though the connective tissue layers, to the tendon, and then to the periosteum to pull on the bone for movement of the skeleton. In other places, the mysia may fuse with a broad, tendon-like sheet called an aponeurosis, or to fascia, the connective tissue between skin and bones. The broad sheet of connective tissue in the lower back that the latissimus dorsi muscles (the “lats”) fuse into is an example of an aponeurosis.', '996ede2a-7ae9-450a-a6eb-7bcdec4684f9': 'Every skeletal muscle is also richly supplied by blood vessels for nourishment, oxygen delivery, and waste removal. In addition, every muscle fiber in a skeletal muscle is supplied by the axon branch of a somatic motor neuron, which signals the fiber to contract. Unlike cardiac and smooth muscle, the only way to functionally contract a skeletal muscle is through signaling from the nervous system.'}"
+Figure 11.2.1,Anatomy_And_Physio/images/Figure 11.2.1.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.,Parallel muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).,"{'93100b76-a6bc-4d13-b5d0-831dbe9d069f': 'Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.', '72a24f4d-c9b4-4af3-b7ee-fbff975786e9': 'Parallel\xa0muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).', '835b0cd7-579c-494f-8471-e43454702b86': 'Circular\xa0muscles are also called sphincters (see\xa0Figure 11.2.1). When they relax, the sphincters’ concentrically arranged bundles of muscle fibers increase the size of the opening, and when they contract, the size of the opening shrinks to the point of closure. The orbicularis oris muscle is a circular muscle that goes around the mouth. When it contracts, the oral opening becomes smaller, as when puckering the lips for whistling. Another example is the orbicularis oculi, one of which surrounds each eye. Consider, for example, the names of the two orbicularis muscles (orbicularis oris and oribicularis oculi), where part of the first name of both muscles is the same. The first part of orbicularis, orb (orb = “circular”), is a reference to a round or circular structure; it may also make one think of orbit, such as the moon’s path around the earth. The word oris (oris = “oral”) refers to the oral cavity, or the mouth. The word oculi (ocular = “eye”) refers to the eye.', '47cd1715-24ac-4184-a95b-73a77cb50730': 'When a muscle has a widespread expansion over a sizable area and the fascicles come to a single, common attachment point, the muscle is called\xa0convergent. The attachment point for a convergent muscle could be a tendon, an aponeurosis (a flat, broad tendon), or a raphe (a very slender tendon). The large muscle on the chest, the pectoralis major, is an example of a convergent muscle because it converges on the intertubercular groove and greater tubercle of the humerus via a tendon (see image 11.3).', '8dcee826-9929-4df5-aa56-f8a9f66ac5af': 'Pennate\xa0muscles (penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle fascicles arranged similar to the feathers. Due to this design, the muscle fibers in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far. However, because a pennate muscle generally can hold more muscle fibers within it, it can produce relatively more tension for its size, compared to non-pennate muscles. There are three subtypes of pennate muscles.', 'c13fc478-b376-4e72-a57a-819f0a5fd2a1': 'In a\xa0unipennate\xa0muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A\xa0bipennate\xa0muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging\xa0on a central point. A common example is the deltoid muscle of the shoulder, which covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus.'}"
+Figure 11.2.1,Anatomy_And_Physio/images/Figure 11.2.1.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.,Parallel muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).,"{'93100b76-a6bc-4d13-b5d0-831dbe9d069f': 'Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.', '72a24f4d-c9b4-4af3-b7ee-fbff975786e9': 'Parallel\xa0muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).', '835b0cd7-579c-494f-8471-e43454702b86': 'Circular\xa0muscles are also called sphincters (see\xa0Figure 11.2.1). When they relax, the sphincters’ concentrically arranged bundles of muscle fibers increase the size of the opening, and when they contract, the size of the opening shrinks to the point of closure. The orbicularis oris muscle is a circular muscle that goes around the mouth. When it contracts, the oral opening becomes smaller, as when puckering the lips for whistling. Another example is the orbicularis oculi, one of which surrounds each eye. Consider, for example, the names of the two orbicularis muscles (orbicularis oris and oribicularis oculi), where part of the first name of both muscles is the same. The first part of orbicularis, orb (orb = “circular”), is a reference to a round or circular structure; it may also make one think of orbit, such as the moon’s path around the earth. The word oris (oris = “oral”) refers to the oral cavity, or the mouth. The word oculi (ocular = “eye”) refers to the eye.', '47cd1715-24ac-4184-a95b-73a77cb50730': 'When a muscle has a widespread expansion over a sizable area and the fascicles come to a single, common attachment point, the muscle is called\xa0convergent. The attachment point for a convergent muscle could be a tendon, an aponeurosis (a flat, broad tendon), or a raphe (a very slender tendon). The large muscle on the chest, the pectoralis major, is an example of a convergent muscle because it converges on the intertubercular groove and greater tubercle of the humerus via a tendon (see image 11.3).', '8dcee826-9929-4df5-aa56-f8a9f66ac5af': 'Pennate\xa0muscles (penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle fascicles arranged similar to the feathers. Due to this design, the muscle fibers in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far. However, because a pennate muscle generally can hold more muscle fibers within it, it can produce relatively more tension for its size, compared to non-pennate muscles. There are three subtypes of pennate muscles.', 'c13fc478-b376-4e72-a57a-819f0a5fd2a1': 'In a\xa0unipennate\xa0muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A\xa0bipennate\xa0muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging\xa0on a central point. A common example is the deltoid muscle of the shoulder, which covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus.'}"
+Figure 11.1.1,Anatomy_And_Physio/images/Figure 11.1.1.jpg,"Figure 11.1.1 – Prime Movers and Synergists: The biceps brachii flex the lower arm. The brachoradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion.","Although a number of muscles may be involved in an action, the principal muscle involved is called the prime mover, or agonist. During forearm flexion, for example lifting a cup, a muscle called the biceps brachii is the prime mover. Because it can be assisted by the brachialis, the brachialis is called a synergist in this action (Figure 11.1.1). A synergist can also be a fixator that stabilizes the muscle’s origin.","{'0ede28f4-6dbd-4f91-8ce9-eb6d9d3d54d3': 'The moveable end of the muscle that attaches to the bone being pulled is called the muscle’s insertion, and the end of the muscle attached to a fixed (stabilized) bone is called the origin. Muscle pull rather than push. Upon activation, the muscle pulls the insertion toward the origin.', '53d6e0d9-e525-47a7-bc69-74ed0369b2f6': 'Although a number of muscles may be involved in an action, the principal muscle involved is called the prime mover, or agonist. During forearm flexion, for example\xa0lifting a cup, a muscle called the biceps brachii is the prime mover. Because it can be assisted by the brachialis, the brachialis is called a synergist in this action (Figure 11.1.1). A synergist can also be a fixator that stabilizes the muscle’s origin.', 'bbba3dbd-6c34-4d6e-a158-9d3bb1436fd0': 'A muscle with the opposite action of the prime mover is called an antagonist. Antagonists play two important roles in muscle function: (1) they maintain body or limb position, such as holding the arm out or standing erect; and (2) they control rapid movement, as in shadow boxing without landing a punch or the ability to check the motion of a limb.', '3b512ae6-0304-4d40-8f8f-f63ae9573e58': 'For example, to extend the leg at the knee, a group of four muscles called the quadriceps femoris in the anterior compartment of the thigh are activated (and would be called the agonists of leg extension at the knee). A\xa0set of\xa0antagonists called the hamstrings in the posterior compartment of the thigh are activated to slow or stop the movement.', '6df07e5d-c6a1-47ef-a5f2-6089ce9b4ca9': 'These terms are\xa0reversed for the opposite action, flexion of the leg at the knee. In this case\xa0the hamstrings would be called the agonists and the quadriceps femoris would be called the antagonists.', 'c2b770c3-d2d5-41e9-95ca-f06179607c6c': 'There are also muscles that do not pull against the skeleton for movements such as\xa0the muscles of\xa0facial expressions. The insertions and origins of facial muscles are in the skin, so that certain individual muscles contract to form a smile or frown, form sounds or words, and raise the eyebrows. There also are skeletal muscles in the tongue, and the external urinary and anal sphincters that allow for voluntary regulation of urination and defecation, respectively. There are four helpful rules that can be applied to all major joints except the ankle and knee because the lower extremity is rotated during development. For example, in the case of the knee, muscles of the posterior thigh cause knee flexion and anterior thigh muscles cause knee extension, which is opposite of the rules stated below for most other joints.'}"
+Figure 10.7.2,Anatomy_And_Physio/images/Figure 10.7.2.jpg,"Figure 10.7.2 – Muscle Contraction: The dense bodies and intermediate filaments are networked through the sarcoplasm, which cause the muscle fiber to contract.","When the thin filaments slide past the thick filaments, they pull on the dense bodies, which then pull on the intermediate filaments networks throughout the sarcoplasm. This arrangement causes the entire muscle fiber to contract in a manner whereby the ends are pulled toward the center, causing the midsection to bulge in a corkscrew motion (Figure 10.7.2).","{'c7bd6d53-a2bc-4b91-b273-de0d5d429ec5': 'Identify the skeletal muscles and their actions on the skeleton and soft tissues of the body', '818499bd-df71-49a3-9744-d41aab0ff4dd': 'Identify the origins and insertions of skeletal muscles and the prime movements', '8916e9e8-7bdf-4d4c-82a4-a201ebb7c256': 'Most muscle tissue of the body arises from embryonic mesoderm. Paraxial mesodermal cells adjacent to the neural tube form blocks of cells called somites. Skeletal muscles, excluding those of the head and limbs, develop from mesodermal somites, whereas skeletal muscle in the head and limbs develop from general mesoderm. Somites give rise to myoblasts. A myoblast is a muscle-forming stem cell that migrates to different regions in the body and then fuse(s) to form a syncytium, or myotube. As a myotube is formed from many different myoblast cells, it contains many nuclei, but has a continuous cytoplasm. This is why skeletal muscle cells are multinucleate, as the nucleus of each contributing myoblast remains intact in the mature skeletal muscle cell. However, cardiac and smooth muscle cells are not multinucleate because the myoblasts that form their cells do not fuse.', '3e7cee4b-6793-484b-8fb5-5fedffe21537': 'Gap junctions develop in the cardiac and single-unit smooth muscle in the early stages of development. In skeletal muscles, ACh receptors are initially present along most of the surface of the myoblasts, but spinal nerve innervation causes the release of growth factors that stimulate the formation of motor end-plates and NMJs. As neurons become active, electrical signals that are sent through the muscle influence the distribution of slow and fast fibers in the muscle.', 'd515d5b7-f21a-49c4-a004-b96d505c9fe8': 'Although the number of muscle cells is set during development, satellite cells help to repair skeletal muscle cells. A satellite cell is similar to a myoblast because it is a type of stem cell; however, satellite cells are incorporated into muscle cells and facilitate the protein synthesis required for repair and growth. These cells are located outside the sarcolemma and are stimulated to grow and fuse with muscle cells by growth factors that are released by muscle fibers under certain forms of stress. Satellite cells can regenerate muscle fibers to a very limited extent, but they primarily help to repair damage in living cells. If a cell is damaged to a greater extent than can be repaired by satellite cells, the muscle fibers are replaced by scar tissue in a process called fibrosis. Because scar tissue cannot contract, muscle that has sustained significant damage loses strength and cannot produce the same amount of power or endurance as it could before being damaged.', '87a6600e-a30d-4a65-b805-42e4ee9d46f8': 'Smooth muscle tissue can regenerate from a type of stem cell called a pericyte, which is found in some small blood vessels. Pericytes allow smooth muscle cells to regenerate and repair much more readily than skeletal and cardiac muscle tissue. Similar to skeletal muscle tissue, cardiac muscle does not regenerate to a great extent. Dead cardiac muscle tissue is replaced by scar tissue, which cannot contract. As scar tissue accumulates, the heart loses its ability to pump because of the loss of contractile power. However, some minor regeneration may occur due to stem cells found in the blood that occasionally enter cardiac tissue.', '58c87578-675e-41f2-88fd-05061ee09305': 'As muscle cells die, they are not regenerated but instead are replaced by connective tissue and adipose tissue, which do not possess the contractile abilities of muscle tissue. Muscles atrophy when they are not used, and over time if atrophy is prolonged, muscle cells die. It is therefore important that those who are susceptible to muscle atrophy exercise to maintain muscle function and prevent the complete loss of muscle tissue. In extreme cases, when movement is not possible, electrical stimulation can be introduced to a muscle from an external source. This acts as a substitute for endogenous neural stimulation, stimulating the muscle to contract and preventing the loss of proteins that occurs with a lack of use.', '036fe217-d23a-49a2-b4e8-1c66ccd22211': 'Physiotherapists work with patients to maintain muscles. They are trained to target muscles susceptible to atrophy, and to prescribe and monitor exercises designed to stimulate those muscles. There are various causes of atrophy, including mechanical injury, disease, and age. After breaking a limb or undergoing surgery, muscle use is impaired and can lead to disuse atrophy. If the muscles are not exercised, this atrophy can lead to long-term muscle weakness. A stroke can also cause muscle impairment by interrupting neural stimulation to certain muscles. Without neural inputs, these muscles do not contract and thus begin to lose structural proteins. Exercising these muscles can help to restore muscle function and minimize functional impairments. Age-related muscle loss is also a target of physical therapy, as exercise can reduce the effects of age-related atrophy and improve muscle function.', '1f3dc75f-0460-4c13-8189-0283d393834c': 'The goal of a physiotherapist is to improve physical functioning and reduce functional impairments; this is achieved by understanding the cause of muscle impairment and assessing the capabilities of a patient, after which a program to enhance these capabilities is designed. Some factors that are assessed include strength, balance, and endurance, which are continually monitored as exercises are introduced to track improvements in muscle function. Physiotherapists can also instruct patients on the proper use of equipment, such as crutches, and assess whether someone has sufficient strength to use the equipment and when they can function without it.', '44ea4cc6-d0db-4eb7-895c-652db87ca1c5': 'Smooth muscle, so-named because the cells do not have visible striations, is present in the walls of hollow organs (e.g., urinary bladder),\xa0lining the blood vessels, and in the eye (e.g., iris) and skin (e.g.,\xa0erector pili muscle).\xa0 Smooth muscle displays involuntary control and\xa0can be\xa0triggered\xa0via hormones, neural stimulation by the ANS, and local factors. In certain locations, such as the walls of visceral organs, stretching the muscle can trigger its contraction).', '72b3b0c0-4f33-40c4-8195-a527fea7f636': 'Smooth muscle fibers are spindle-shaped and, unlike skeletal muscle fibers,\xa0have a single nucleus; individual cells range in size from\xa0 30 to 200 μm.\xa0 Smooth muscle fibers are often found forming sheets of tissue and function in a coordinated fashion due to the presence of gap junctions between the cells.\xa0 Termed unitary smooth muscle or visceral muscle, this type of smooth muscle is the most common observed in the human body, forming the walls of\xa0hollow\xa0organs. Single-unit smooth muscle produces slow, steady contractions that allow substances, such as food in the digestive tract, to move through the body.', '682605d9-0a4a-4f70-8e78-f4f874fe2d50': 'Multi-unit smooth muscle, the second type of smooth muscle observed,\xa0are composed of cells that rarely possess gap junctions, and thus are not electrically coupled. As a result, contraction does not spread from one cell to the next, but is instead confined to the cell that was originally stimulated. This type of smooth muscle is observed in the large airways to the lungs, in the large arteries, the arrector pili muscles associated with hair follicles, and the internal eye muscles which regulate light entry and lens shape.', 'fc1257bc-0219-4a61-b996-38dea9a7b143': 'Although smooth muscle cells do not have striations,\xa0smooth muscle fibers do have actin and myosin contractile proteins which interact to generate tension. These fibers are not arranged in orderly sarcomeres (hence, no striations) but instead are anchored to dense bodies which are scattered throughout the cytoplasm and anchored to the sarcolemma.\xa0\xa0 A network of intermediate fibers run between the dense bodies providing an internal framework for contractile proteins to work against.', '1804d239-c25e-4478-8c39-050257ae9d9b': 'A dense body is analogous to the Z-discs of skeletal muscle, anchoring the thin filaments in position. Calcium ions are supplied primarily from the extracellular environment.\xa0 T-tubules are absent but small indentations, called calveoli, in the sarcolemma represent locations where there are a high density of calcium channels present to facilitate calcium entry.\xa0 Sarcoplasmic reticulum is present in the fibers but is\xa0less developed than that observed in skeletal muscle.', 'd0e360db-9852-4c39-8798-988324cbe490': 'Because smooth muscle cells do not contain troponin, cross-bridge formation is not regulated by the troponin-tropomyosin complex but instead by the regulatory protein calmodulin. When a smooth muscle cell is stimulated, external Ca++ ions passing through opened calcium channels in the sarcolemma, with additional Ca++ released by the sarcoplasmic reticulum.\xa0 Calcium binds to calmodulin in the cytoplasm with the Ca++-calmodulin complex then activating an enzyme called myosin (light chain) kinase.\xa0 Myosin light chain kinase in turn, activates the myosin heads by phosphorylating them (converting ATP to ADP and Pi, with the Pi attaching to the head). The heads can then attach to actin-binding sites and pull on the thin filaments.', '63412cdf-0ac8-4b51-83be-9466e230eeab': 'When the thin filaments slide past the thick filaments, they pull on the dense bodies, which then pull on the intermediate filaments networks throughout the sarcoplasm. This arrangement causes the entire muscle fiber to contract in a manner whereby the ends are pulled toward the center, causing the midsection to bulge in a corkscrew motion (Figure 10.7.2).', '6121bc3d-e599-4ba7-a951-2df155a88556': 'Muscle contraction continues until ATP-dependent calcium pumps actively transport Ca++ ions out of the cell or back into the sarcoplasmic reticulum.\xa0 However, a low concentration of calcium remains in the sarcoplasm to maintain muscle tone. This remaining calcium keeps the muscle slightly contracted, which is important in\xa0 certain\xa0functions, such as maintaining pressure in blood vessels.', '9ead590a-c914-49a3-b9d8-0c742eb036d4': 'Because most smooth muscles must function for long periods without rest, their power output is relatively low to minimize energy needs. Some smooth muscle can also maintain contractions even as Ca++ is removed and myosin kinase is inactivated/dephosphorylated. This can happen as a subset of cross-bridges between myosin heads and actin, called latch-bridges, keep the thick and thin filaments linked together for a prolonged period, without the need for ATP. This allows for the maintaining of muscle “tone” in smooth muscle that lines arterioles and other visceral organs with very little energy expenditure.', '7bd4939d-51bd-4e76-9f28-985dbbdb5ff5': 'For smooth muscle stimulated by neurons, the\xa0axons from autonomic\xa0nervous system neurons do not form the highly organized\xa0neuromuscular junctions as observed in skeletal muscle. Instead, there is a series of neurotransmitter-filled bulges, called varicosities, along the axon of the neuron feeding the smooth muscle that release neurotransmitters over a wide\xa0synaptic cleft.\xa0 Also, visceral muscle in the walls of the hollow organs (except the heart) contains pacesetter cells. A pacesetter cell can spontaneously trigger action potentials and contractions in the muscle.'}"
+Figure 10.6.1,Anatomy_And_Physio/images/Figure 10.6.1.jpg,Figure 10.6.1 – Marathoners: Long-distance runners have a large number of slow oxidative fibers and relatively few fast oxidative and fast glycolytic fibers. (credit: “Tseo2”/Wikimedia Commons),"The proportion of slow oxidative muscle fibers in muscle determines the suitability of a muscle for endurance, and may benefit those participating in endurance activities (Figure 10.6.1). Postural muscles have a large number of slow oxidative fibers as they are continually contracting to keep the body erect.  Endurance athletes benefit greatly from having muscles containing a larger proportion of slow oxidative fibers compared to fast oxidative fibers.  Studies suggest that genetics play a critical role in determining the overall fiber proportions of slow oxidative to fast glycolytic fibers in muscles with repetitive training having its greatest influence on the fast oxidative fibers.","{'44272320-3cac-4a56-9c59-0efd983e32b5': 'Slow fibers are predominantly used in endurance exercises that require limited force generation but involve numerous repetitions. The aerobic metabolism used by slow oxidative fibers allows them to maintain contractions over long periods. Endurance training modifies these slow fibers to make them even more efficient by producing more mitochondria and synthesizing more myoglobin, both which lead to an increase in ATP production by increasing the rate of aerobic metabolism.', '85610bdb-1e86-427d-b0f8-27fff81a817f': 'The training can trigger the formation of more extensive capillary networks around the fiber, a process called angiogenesis, to supply oxygen to the fibers and remove metabolic waste. To allow these capillary networks to supply the deep portions of the muscle, muscle mass does not greatly increase in order to maintain a smaller area for the diffusion of nutrients and gases.', 'd7a57ef7-1c78-400f-a9d7-20d08f2acc88': 'The proportion of slow oxidative muscle fibers in muscle determines the suitability of a muscle for endurance, and may benefit those participating in endurance activities (Figure 10.6.1). Postural muscles have a large number of slow oxidative fibers as they are continually contracting to keep the body erect.\xa0 Endurance athletes benefit greatly from having muscles containing a larger proportion of slow oxidative fibers compared to fast oxidative fibers.\xa0 Studies suggest that genetics play a critical role in determining the overall fiber proportions of slow oxidative to fast glycolytic fibers in muscles with repetitive training having its greatest influence on the fast oxidative fibers.'}"
+Figure 10.6.2,Anatomy_And_Physio/images/Figure 10.6.2.jpg,Figure 10.6.2 – Muscle hypertrophy: Body builders work on increasing the size of the fast glycolytic fibers through resistance training. (credit: Lin Mei/flickr),"Resistance exercises, as opposed to endurance exercise, target fast glycolytic fibers by focusing on short, powerful movements that are not repeated over long periods. The high rates of ATP hydrolysis and cross-bridge formation in fast glycolytic fibers is responsible for such powerful muscle contractions. Thus, muscles used for power often have a higher ratio of fast glycolytic fibers compared to slow oxidative fibers. Resistance exercise affects muscles by increasing the formation of myofibrils, thereby increasing the diameter of muscle fibers (Figure 10.6.2). Because this muscular enlargement is achieved by the addition of structural proteins, athletes trying to build muscle mass often ingest large amounts of protein.","{'abb5006c-f485-4f36-9dbc-eacdffcfe848': 'Resistance exercises, as opposed to endurance exercise, target fast glycolytic fibers\xa0by focusing on short, powerful movements that are not repeated over long periods. The high rates of ATP hydrolysis and cross-bridge formation in fast glycolytic\xa0fibers is responsible for such powerful muscle contractions. Thus, muscles used for power often have a higher ratio of fast glycolytic fibers compared to slow oxidative fibers. Resistance exercise affects muscles by increasing the formation of myofibrils, thereby increasing the diameter of muscle fibers (Figure 10.6.2). Because this muscular enlargement is achieved by the addition of structural proteins, athletes trying to build muscle mass often ingest large amounts of protein.', 'ae18ebae-e6eb-4c3e-9b03-cb6ab0a4ad4d': 'In addition to the increase in muscle fiber diameter, resistance training also increases the development of connective tissue,\xa0adding to the overall mass of the muscle.\xa0 Increases in connective tissue\xa0help to contain muscles as they produce increasingly powerful contractions. Tendons also become stronger to prevent tendon damage, as the force produced by muscles is transferred to tendons that attach the muscle to bone.', '919e5c77-f9d4-426c-8163-136b4fc9b01f': 'For effective strength training, the intensity of the exercise must continually be increased. For instance, continued weight lifting without increasing the weight of the load does not increase muscle size. To produce ever-greater results, the weights lifted must become increasingly heavier, making it more difficult for muscles to move the load. The muscle then adapts to this heavier load, and an even heavier load must be used if even greater muscle mass is desired.', '02e38507-e159-4ce0-b528-8ac4bc01422b': 'If done improperly, resistance training can lead to overuse injuries of the muscle, tendon, or bone. These injuries can occur if the load is too heavy, or if the muscles are not given sufficient time between workouts to recover, or if joints are not aligned properly during the exercises. Cellular damage to muscle fibers that occurs after intense exercise includes damage to the sarcolemma and myofibrils. This muscle damage contributes to the feeling of soreness after strenuous exercise, but muscles gain mass as this damage is repaired, and additional structural proteins are added to replace the damaged ones.', 'd2080423-6276-4df8-b956-91987d0134b4': 'Skeletal muscle fibers can be classified based on two criteria:\xa01)\xa0how fast do fibers contract relative to others, and 2) how do fibers regenerate ATP.\xa0 Using these criteria, there are three main types of skeletal muscle fibers recognized (Table 10.5.1). Slow oxidative (also called slow twitch or Type I) fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP. Fast oxidative (also called fast twitch or Type IIa) fibers have relatively fast contractions and primarily use aerobic respiration to generate ATP. Lastly, fast glycolytic (also called fast twitch or Type IIx) fibers have relatively\xa0fast contractions and primarily use anaerobic glycolysis. Most skeletal muscles in a human body\xa0contain all three types, although in varying proportions.', '620d5fa4-24ec-4fb8-a9a6-486a4a83eceb': 'The speed of contraction is dependent on how quickly myosin’s ATPase hydrolyzes ATP to produce cross-bridge action. Fast fibers hydrolyze ATP approximately twice as rapidly as slow fibers, resulting in much quicker cross-bridge cycling (which pulls the thin filaments toward the center of the sarcomeres at a faster rate).', '473c89b6-bfbc-4064-b1ba-c0d1d1f93fa6': 'The primary metabolic pathway used by a muscle fiber determines whether the fiber is classified as oxidative or glycolytic. If a fiber primarily produces ATP through aerobic pathways, then\xa0it is classified as oxidative. More ATP can be produced during each metabolic cycle, making the fiber more resistant to fatigue. Glycolytic fibers primarily create ATP through anaerobic glycolysis, which produces less ATP per cycle. As a result, glycolytic fibers fatigue at a quicker rate.', '0b8050d6-e60b-4fd5-8f44-33c465ec66e3': 'Slow oxidative fibers have structural elements that maximize their ability to generate ATP through aerobic metabolism.\xa0\xa0These fibers contain many more mitochondria than the glycolytic fibers, as aerobic metabolism, which uses oxygen (O2) in the metabolic pathway, occurs in the mitochondria. This allows slow oxidative fibers to contract for longer periods because of the large amount of ATP they can produce, but they have a relatively small diameter and thus do not produce a large amount of tension.', 'd347434e-6216-49d1-afe6-8e088c86b383': 'In addition to increased numbers of mitochondria, slow oxidative\xa0fibers are extensively supplied with blood capillaries to supply O2 from the bloodstream.\xa0 They\xa0also possess myoglobin, an O2-binding molecule similar to hemoglobin in the red blood cells. The myoglobin stores some of the needed O2 within the fibers themselves and is partially responsible for giving oxidative fibers a dark red color.', 'e6d97658-736e-4b79-9584-01911c3ff60b': 'The\xa0ability of slow oxidative\xa0fibers to function for long periods without fatiguing makes them useful in maintaining posture, producing isometric contractions, and\xa0stabilizing bones and joints.\xa0 Because they do not produce high tension, they are not used for powerful, fast movements that require high amounts of energy and rapid cross-bridge cycling.', '778e9d55-3e12-4736-bf3a-917daa1a84cf': 'Fast glycolytic fibers primarily use anaerobic glycolysis as their ATP source.\xa0 They have a large diameter and possess large volumes of glycogen which is used in glycolysis to generate ATP quickly.\xa0 Because of their reliance on anaerobic metabolism, these fibers do not possess substantial numbers of mitochondria, a limited capillary supply,\xa0or significant amounts of myoglobin, resulting in a white coloration for muscles containing large numbers of these fibers.', '8a55c2b4-2636-4b29-a891-22c4e77a479a': 'Fast glycolytic fibers fatigue quickly, permitting them to only be used for short periods.\xa0 However, during these short periods, the fibers are able to produce rapid, forceful contractions associated with quick, powerful movements.', '55222a02-1bde-4d5d-8b3a-8c92451e7963': 'These different fiber types can be easily identified in poultry. Imagine a turkey. The legs and thighs of the turkey are dark meat, due to their slow oxidative fibers and robust supply of blood vessels and myoglobin. Turkeys spend most of their days walking around looking for food, so their legs must be able to work all day without fatiguing. Alternately, turkey breast is white meat, due to its fast glycolytic fibers and relatively insubstantial supply of myoglobin and lesser blood supply. Turkeys do not fly long distances, but only need to get into trees to roost. Their breast tissue produces strong, rapid contractions, but only for very brief flights.', 'b288a8ba-264f-49e6-8551-a9a16b116654': 'Fast oxidative\xa0fibers are sometimes called intermediate fibers because they possess characteristics that are intermediate between slow oxidative fibers and fast glycolytic fibers. These fibers produce ATP relatively quickly,\xa0and thus can produce relatively high amounts of tension, but because they are oxidative, they do not fatigue quickly.\xa0 Fast\xa0oxidative fibers are used primarily for movements, such as walking, that require more energy than postural control but less energy than an explosive movement.', '14b536d7-66be-4cd3-8045-5c72da99c8e5': 'What changes occur at the cellular level in response to endurance training?', '69bc05ee-9056-4b7f-9d5f-362cdf54b568': 'What changes occur at the cellular level in response to resistance training?', 'f39dd778-055f-4169-ba8d-381fc5fe11f0': 'To move an object, referred to as a\xa0load,\xa0the muscle fibers of a skeletal muscle must shorten. The force generated by a contracting muscle is called muscle tension. Muscle tension can also be generated when the muscle is contracting against a load that does not move, resulting in two main types of skeletal muscle contractions: isotonic contractions and isometric contractions (Figure 10.4.1).', '3be094e5-53db-4c8a-bdfa-7740bcee8ac4': 'In isotonic contractions, where the tension in the muscle stays relatively constant, a load is moved as the length of the muscle changes. A concentric contraction involves the muscle producing tension and shortening to move a load. An example of this is the contraction of the biceps brachii muscle when a hand weight is brought upward toward the body. An eccentric contraction occurs when the muscle tension produced is less than the load and a muscle lengthens while under tension. This type of contraction is observed when the same hand weight is lowered in a slow and controlled manner by the biceps brachii. Both concentric and eccentric contractions involve force production by the muscle and crossbridge cycling with the myosin heads pulling toward the M-line. The only difference between the two is whether the muscle length is shortening or elongating during the contraction.', '55b5945f-38e9-4b5c-a2cf-2e8d761c869e': 'An isometric contraction occurs when a muscle produces tension without a change in muscle length. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load. For example, if one attempts to lift a hand weight that is too heavy, there will be sarcomere activation and shortening to a point, and ever-increasing muscle tension, but no change in the position of the hand weight. In everyday living, isometric contractions are active in maintaining posture and maintaining bone and joint stability.', '5e84b3fe-7c3f-4cf1-b9bd-41f97b55ceed': 'Most actions of the body are the result of a combination of isotonic and isometric contractions working together to produce a wide range of outcomes. \xa0These muscle activities are under the control of the nervous system. A crucial aspect of nervous system control of skeletal muscles is the role of motor units.'}"
+Figure 10.4.1,Anatomy_And_Physio/images/Figure 10.4.1.jpg,"Figure 10.4.1- Types of Muscle Contractions: During isotonic contractions (concentric and eccentric contractions), muscle length changes to move a load. During isometric contractions, muscle length does not change because the load equals the tension the muscle generates.","To move an object, referred to as a load, the muscle fibers of a skeletal muscle must shorten. The force generated by a contracting muscle is called muscle tension. Muscle tension can also be generated when the muscle is contracting against a load that does not move, resulting in two main types of skeletal muscle contractions: isotonic contractions and isometric contractions (Figure 10.4.1).","{'abb5006c-f485-4f36-9dbc-eacdffcfe848': 'Resistance exercises, as opposed to endurance exercise, target fast glycolytic fibers\xa0by focusing on short, powerful movements that are not repeated over long periods. The high rates of ATP hydrolysis and cross-bridge formation in fast glycolytic\xa0fibers is responsible for such powerful muscle contractions. Thus, muscles used for power often have a higher ratio of fast glycolytic fibers compared to slow oxidative fibers. Resistance exercise affects muscles by increasing the formation of myofibrils, thereby increasing the diameter of muscle fibers (Figure 10.6.2). Because this muscular enlargement is achieved by the addition of structural proteins, athletes trying to build muscle mass often ingest large amounts of protein.', 'ae18ebae-e6eb-4c3e-9b03-cb6ab0a4ad4d': 'In addition to the increase in muscle fiber diameter, resistance training also increases the development of connective tissue,\xa0adding to the overall mass of the muscle.\xa0 Increases in connective tissue\xa0help to contain muscles as they produce increasingly powerful contractions. Tendons also become stronger to prevent tendon damage, as the force produced by muscles is transferred to tendons that attach the muscle to bone.', '919e5c77-f9d4-426c-8163-136b4fc9b01f': 'For effective strength training, the intensity of the exercise must continually be increased. For instance, continued weight lifting without increasing the weight of the load does not increase muscle size. To produce ever-greater results, the weights lifted must become increasingly heavier, making it more difficult for muscles to move the load. The muscle then adapts to this heavier load, and an even heavier load must be used if even greater muscle mass is desired.', '02e38507-e159-4ce0-b528-8ac4bc01422b': 'If done improperly, resistance training can lead to overuse injuries of the muscle, tendon, or bone. These injuries can occur if the load is too heavy, or if the muscles are not given sufficient time between workouts to recover, or if joints are not aligned properly during the exercises. Cellular damage to muscle fibers that occurs after intense exercise includes damage to the sarcolemma and myofibrils. This muscle damage contributes to the feeling of soreness after strenuous exercise, but muscles gain mass as this damage is repaired, and additional structural proteins are added to replace the damaged ones.', 'd2080423-6276-4df8-b956-91987d0134b4': 'Skeletal muscle fibers can be classified based on two criteria:\xa01)\xa0how fast do fibers contract relative to others, and 2) how do fibers regenerate ATP.\xa0 Using these criteria, there are three main types of skeletal muscle fibers recognized (Table 10.5.1). Slow oxidative (also called slow twitch or Type I) fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP. Fast oxidative (also called fast twitch or Type IIa) fibers have relatively fast contractions and primarily use aerobic respiration to generate ATP. Lastly, fast glycolytic (also called fast twitch or Type IIx) fibers have relatively\xa0fast contractions and primarily use anaerobic glycolysis. Most skeletal muscles in a human body\xa0contain all three types, although in varying proportions.', '620d5fa4-24ec-4fb8-a9a6-486a4a83eceb': 'The speed of contraction is dependent on how quickly myosin’s ATPase hydrolyzes ATP to produce cross-bridge action. Fast fibers hydrolyze ATP approximately twice as rapidly as slow fibers, resulting in much quicker cross-bridge cycling (which pulls the thin filaments toward the center of the sarcomeres at a faster rate).', '473c89b6-bfbc-4064-b1ba-c0d1d1f93fa6': 'The primary metabolic pathway used by a muscle fiber determines whether the fiber is classified as oxidative or glycolytic. If a fiber primarily produces ATP through aerobic pathways, then\xa0it is classified as oxidative. More ATP can be produced during each metabolic cycle, making the fiber more resistant to fatigue. Glycolytic fibers primarily create ATP through anaerobic glycolysis, which produces less ATP per cycle. As a result, glycolytic fibers fatigue at a quicker rate.', '0b8050d6-e60b-4fd5-8f44-33c465ec66e3': 'Slow oxidative fibers have structural elements that maximize their ability to generate ATP through aerobic metabolism.\xa0\xa0These fibers contain many more mitochondria than the glycolytic fibers, as aerobic metabolism, which uses oxygen (O2) in the metabolic pathway, occurs in the mitochondria. This allows slow oxidative fibers to contract for longer periods because of the large amount of ATP they can produce, but they have a relatively small diameter and thus do not produce a large amount of tension.', 'd347434e-6216-49d1-afe6-8e088c86b383': 'In addition to increased numbers of mitochondria, slow oxidative\xa0fibers are extensively supplied with blood capillaries to supply O2 from the bloodstream.\xa0 They\xa0also possess myoglobin, an O2-binding molecule similar to hemoglobin in the red blood cells. The myoglobin stores some of the needed O2 within the fibers themselves and is partially responsible for giving oxidative fibers a dark red color.', 'e6d97658-736e-4b79-9584-01911c3ff60b': 'The\xa0ability of slow oxidative\xa0fibers to function for long periods without fatiguing makes them useful in maintaining posture, producing isometric contractions, and\xa0stabilizing bones and joints.\xa0 Because they do not produce high tension, they are not used for powerful, fast movements that require high amounts of energy and rapid cross-bridge cycling.', '778e9d55-3e12-4736-bf3a-917daa1a84cf': 'Fast glycolytic fibers primarily use anaerobic glycolysis as their ATP source.\xa0 They have a large diameter and possess large volumes of glycogen which is used in glycolysis to generate ATP quickly.\xa0 Because of their reliance on anaerobic metabolism, these fibers do not possess substantial numbers of mitochondria, a limited capillary supply,\xa0or significant amounts of myoglobin, resulting in a white coloration for muscles containing large numbers of these fibers.', '8a55c2b4-2636-4b29-a891-22c4e77a479a': 'Fast glycolytic fibers fatigue quickly, permitting them to only be used for short periods.\xa0 However, during these short periods, the fibers are able to produce rapid, forceful contractions associated with quick, powerful movements.', '55222a02-1bde-4d5d-8b3a-8c92451e7963': 'These different fiber types can be easily identified in poultry. Imagine a turkey. The legs and thighs of the turkey are dark meat, due to their slow oxidative fibers and robust supply of blood vessels and myoglobin. Turkeys spend most of their days walking around looking for food, so their legs must be able to work all day without fatiguing. Alternately, turkey breast is white meat, due to its fast glycolytic fibers and relatively insubstantial supply of myoglobin and lesser blood supply. Turkeys do not fly long distances, but only need to get into trees to roost. Their breast tissue produces strong, rapid contractions, but only for very brief flights.', 'b288a8ba-264f-49e6-8551-a9a16b116654': 'Fast oxidative\xa0fibers are sometimes called intermediate fibers because they possess characteristics that are intermediate between slow oxidative fibers and fast glycolytic fibers. These fibers produce ATP relatively quickly,\xa0and thus can produce relatively high amounts of tension, but because they are oxidative, they do not fatigue quickly.\xa0 Fast\xa0oxidative fibers are used primarily for movements, such as walking, that require more energy than postural control but less energy than an explosive movement.', '14b536d7-66be-4cd3-8045-5c72da99c8e5': 'What changes occur at the cellular level in response to endurance training?', '69bc05ee-9056-4b7f-9d5f-362cdf54b568': 'What changes occur at the cellular level in response to resistance training?', 'f39dd778-055f-4169-ba8d-381fc5fe11f0': 'To move an object, referred to as a\xa0load,\xa0the muscle fibers of a skeletal muscle must shorten. The force generated by a contracting muscle is called muscle tension. Muscle tension can also be generated when the muscle is contracting against a load that does not move, resulting in two main types of skeletal muscle contractions: isotonic contractions and isometric contractions (Figure 10.4.1).', '3be094e5-53db-4c8a-bdfa-7740bcee8ac4': 'In isotonic contractions, where the tension in the muscle stays relatively constant, a load is moved as the length of the muscle changes. A concentric contraction involves the muscle producing tension and shortening to move a load. An example of this is the contraction of the biceps brachii muscle when a hand weight is brought upward toward the body. An eccentric contraction occurs when the muscle tension produced is less than the load and a muscle lengthens while under tension. This type of contraction is observed when the same hand weight is lowered in a slow and controlled manner by the biceps brachii. Both concentric and eccentric contractions involve force production by the muscle and crossbridge cycling with the myosin heads pulling toward the M-line. The only difference between the two is whether the muscle length is shortening or elongating during the contraction.', '55b5945f-38e9-4b5c-a2cf-2e8d761c869e': 'An isometric contraction occurs when a muscle produces tension without a change in muscle length. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load. For example, if one attempts to lift a hand weight that is too heavy, there will be sarcomere activation and shortening to a point, and ever-increasing muscle tension, but no change in the position of the hand weight. In everyday living, isometric contractions are active in maintaining posture and maintaining bone and joint stability.', '5e84b3fe-7c3f-4cf1-b9bd-41f97b55ceed': 'Most actions of the body are the result of a combination of isotonic and isometric contractions working together to produce a wide range of outcomes. \xa0These muscle activities are under the control of the nervous system. A crucial aspect of nervous system control of skeletal muscles is the role of motor units.'}"
+Figure 10.4.2,Anatomy_And_Physio/images/Figure 10.4.2.jpg,Figure 10.4.2 – Skeletal Muscle Contractions,"As previously discussed, the contraction of skeletal muscle fibers is triggered by  signaling from a motor neuron.  Each muscle fiber is innervated by only one motor neuron but a single motor neuron can innervate multiple muscle fibers.  A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).","{'8dd0a52d-7325-4019-a336-2f926d571eba': 'As previously discussed, the contraction of skeletal muscle fibers is triggered by \xa0signaling from a motor neuron.\xa0 Each muscle fiber is innervated by only one motor neuron but a single\xa0motor neuron can innervate multiple muscle fibers.\xa0 A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).', '475209dc-8518-499b-bbee-747b856ccd7f': 'The size of a motor unit dictates its function.\xa0 A small motor unit, composed of a motor neuron and only a few muscle fibers, permits very fine motor control of a muscle. For example, the extraocular eye muscles have thousands of muscle fibers with every 5 – 10 fibers supplied by a single motor neuron; this allows for exquisite control of eye movements so that both eyes can quickly focus on an object. Small motor units are also involved in the many fine movements of the fingers and thumb of the hand for grasping, texting, etc.', 'e55afe46-ab6c-44c5-9bdb-d0da6a457c1e': 'Large motor units have more muscle fibers per neuron than small motor units. Larger motor units are concerned with simple, or “gross,” movements, such as moving parts of the body against gravity. The large motor units of the thigh muscles or back muscles, where a single motor neuron will supply thousands of muscle fibers in a muscle, are representative of this type of activity.', 'a0700068-545a-41bc-b858-93d60c9f7269': 'Most muscles in the human body have a mixture of small and large motor units which gives the nervous system a wide range of control over the muscle. The smaller motor units in a muscle have motor neurons that are more excitable.\xa0 Initial activation of these smaller motor units results in a relatively small degree of tension generated in a muscle. As more strength is needed, larger motor units are enlisted to generate more tension. This\xa0 process of\xa0bringing on additional\xa0motor units to produce\xa0more\xa0tension is\xa0known as recruitment.\xa0 This process allows a muscle such as the biceps brachii to pick up a feather with minimal force generation versus picking up a heavy weight which requires a much greater amount of force generation.', 'c864fea4-d9b4-482d-8410-d2581430b9e1': 'When necessary, the maximal number of motor units in a muscle can be recruited simultaneously, producing the maximum force of contraction for that muscle, but this cannot last for very long because of the energy requirements to sustain the contraction. To prevent complete muscle fatigue, motor units are generally not all simultaneously active, but instead some motor units rest while others are active, which allows for longer muscle contractions. The nervous system thus uses recruitment as a mechanism to efficiently utilize a skeletal muscle.'}"
+Figure 10.4.2,Anatomy_And_Physio/images/Figure 10.4.2.jpg,Figure 10.4.2b,"As previously discussed, the contraction of skeletal muscle fibers is triggered by  signaling from a motor neuron.  Each muscle fiber is innervated by only one motor neuron but a single motor neuron can innervate multiple muscle fibers.  A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).","{'8dd0a52d-7325-4019-a336-2f926d571eba': 'As previously discussed, the contraction of skeletal muscle fibers is triggered by \xa0signaling from a motor neuron.\xa0 Each muscle fiber is innervated by only one motor neuron but a single\xa0motor neuron can innervate multiple muscle fibers.\xa0 A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).', '475209dc-8518-499b-bbee-747b856ccd7f': 'The size of a motor unit dictates its function.\xa0 A small motor unit, composed of a motor neuron and only a few muscle fibers, permits very fine motor control of a muscle. For example, the extraocular eye muscles have thousands of muscle fibers with every 5 – 10 fibers supplied by a single motor neuron; this allows for exquisite control of eye movements so that both eyes can quickly focus on an object. Small motor units are also involved in the many fine movements of the fingers and thumb of the hand for grasping, texting, etc.', 'e55afe46-ab6c-44c5-9bdb-d0da6a457c1e': 'Large motor units have more muscle fibers per neuron than small motor units. Larger motor units are concerned with simple, or “gross,” movements, such as moving parts of the body against gravity. The large motor units of the thigh muscles or back muscles, where a single motor neuron will supply thousands of muscle fibers in a muscle, are representative of this type of activity.', 'a0700068-545a-41bc-b858-93d60c9f7269': 'Most muscles in the human body have a mixture of small and large motor units which gives the nervous system a wide range of control over the muscle. The smaller motor units in a muscle have motor neurons that are more excitable.\xa0 Initial activation of these smaller motor units results in a relatively small degree of tension generated in a muscle. As more strength is needed, larger motor units are enlisted to generate more tension. This\xa0 process of\xa0bringing on additional\xa0motor units to produce\xa0more\xa0tension is\xa0known as recruitment.\xa0 This process allows a muscle such as the biceps brachii to pick up a feather with minimal force generation versus picking up a heavy weight which requires a much greater amount of force generation.', 'c864fea4-d9b4-482d-8410-d2581430b9e1': 'When necessary, the maximal number of motor units in a muscle can be recruited simultaneously, producing the maximum force of contraction for that muscle, but this cannot last for very long because of the energy requirements to sustain the contraction. To prevent complete muscle fatigue, motor units are generally not all simultaneously active, but instead some motor units rest while others are active, which allows for longer muscle contractions. The nervous system thus uses recruitment as a mechanism to efficiently utilize a skeletal muscle.'}"
+Figure 10.4.4,Anatomy_And_Physio/images/Figure 10.4.4.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops.","The ideal length of a sarcomere to produce maximal tension occurs at 80 percent to 120 percent of its resting length, with 100 percent being the state where the medial edges of the thin filaments are just at the most-medial myosin heads of the thick filaments (Figure 10.4.4). This length maximizes the overlap of actin-binding sites and myosin heads.","{'1ff0329a-f95a-4f3e-a05d-841422f84ac3': 'As discussed previously, when a skeletal muscle fiber contracts, myosin heads attach to actin to form cross-bridges followed by the thin filaments sliding over the thick filaments as the heads pull the actin, and this results in sarcomere shortening, creating the tension of the muscle contraction. The cross-bridges can only form where thin and thick filaments overlap; thus,\xa0the length of the sarcomere has a direct influence on the force generated when the sarcomere shortens. This is called the length-tension relationship.', '3dd0506e-3993-44ba-8fa9-916966d660b9': 'The ideal length of a sarcomere to produce maximal tension occurs at 80 percent to 120 percent of its resting length, with 100 percent being the state where the medial edges of the thin filaments are just at the most-medial myosin heads of the thick filaments (Figure 10.4.4). This length maximizes the overlap of actin-binding sites and myosin heads.', '4783fac0-2434-4a51-bbb0-f1209dfa22f9': 'If a sarcomere is stretched past the ideal length (beyond 120 percent), thick and thin filaments do not fully overlap, which results in less tension produced. If the muscle is stretched to the point where the thick and thin filaments do not overlap at all, no cross-bridges can be formed, and no tension is generated.\xa0 This amount of stretching does not usually occur as accessory proteins and connective tissue oppose extreme stretching.', 'd140e82c-8f8c-4b04-96f5-3c0b56c6b8e8': 'If a sarcomere is shortened beyond 80 percent, the zone of overlap is reduced with the thin filaments jutting beyond the last of the myosin heads. Eventually, there is nowhere else for the thin filaments to go and the amount of tension is diminished.', 'd1934205-ce04-47d1-a520-44d14cd93a70': 'A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from\xa0a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).', 'b1d5c6ca-3759-4b71-86ed-6affa921734a': 'Three phases are recognized\xa0for a muscle twitch.\xa0 The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,\xa0 returning the muscle fibers to their resting state.', 'dfb9b009-eeee-4ec6-b40f-4f8fba4116e5': 'Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead,\xa0a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a\xa0graded muscle response.', 'a21696df-dcef-47f5-ba2f-1e5a53024f2a': 'A graded muscle response works as follows:\xa0\xa0if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.', '2e765358-f944-4b5d-b03f-f90a7a1b7602': 'If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).', '6d731dd7-7264-48c5-9aa3-6fe4020511bd': 'During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).'}"
+Figure 10.4.4,Anatomy_And_Physio/images/Figure 10.4.4.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops.","The ideal length of a sarcomere to produce maximal tension occurs at 80 percent to 120 percent of its resting length, with 100 percent being the state where the medial edges of the thin filaments are just at the most-medial myosin heads of the thick filaments (Figure 10.4.4). This length maximizes the overlap of actin-binding sites and myosin heads.","{'1ff0329a-f95a-4f3e-a05d-841422f84ac3': 'As discussed previously, when a skeletal muscle fiber contracts, myosin heads attach to actin to form cross-bridges followed by the thin filaments sliding over the thick filaments as the heads pull the actin, and this results in sarcomere shortening, creating the tension of the muscle contraction. The cross-bridges can only form where thin and thick filaments overlap; thus,\xa0the length of the sarcomere has a direct influence on the force generated when the sarcomere shortens. This is called the length-tension relationship.', '3dd0506e-3993-44ba-8fa9-916966d660b9': 'The ideal length of a sarcomere to produce maximal tension occurs at 80 percent to 120 percent of its resting length, with 100 percent being the state where the medial edges of the thin filaments are just at the most-medial myosin heads of the thick filaments (Figure 10.4.4). This length maximizes the overlap of actin-binding sites and myosin heads.', '4783fac0-2434-4a51-bbb0-f1209dfa22f9': 'If a sarcomere is stretched past the ideal length (beyond 120 percent), thick and thin filaments do not fully overlap, which results in less tension produced. If the muscle is stretched to the point where the thick and thin filaments do not overlap at all, no cross-bridges can be formed, and no tension is generated.\xa0 This amount of stretching does not usually occur as accessory proteins and connective tissue oppose extreme stretching.', 'd140e82c-8f8c-4b04-96f5-3c0b56c6b8e8': 'If a sarcomere is shortened beyond 80 percent, the zone of overlap is reduced with the thin filaments jutting beyond the last of the myosin heads. Eventually, there is nowhere else for the thin filaments to go and the amount of tension is diminished.', 'd1934205-ce04-47d1-a520-44d14cd93a70': 'A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from\xa0a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).', 'b1d5c6ca-3759-4b71-86ed-6affa921734a': 'Three phases are recognized\xa0for a muscle twitch.\xa0 The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,\xa0 returning the muscle fibers to their resting state.', 'dfb9b009-eeee-4ec6-b40f-4f8fba4116e5': 'Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead,\xa0a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a\xa0graded muscle response.', 'a21696df-dcef-47f5-ba2f-1e5a53024f2a': 'A graded muscle response works as follows:\xa0\xa0if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.', '2e765358-f944-4b5d-b03f-f90a7a1b7602': 'If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).', '6d731dd7-7264-48c5-9aa3-6fe4020511bd': 'During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).'}"
+Figure 10.4.5,Anatomy_And_Physio/images/Figure 10.4.5.jpg,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus.","A graded muscle response works as follows:  if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.","{'d1934205-ce04-47d1-a520-44d14cd93a70': 'A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from\xa0a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).', 'b1d5c6ca-3759-4b71-86ed-6affa921734a': 'Three phases are recognized\xa0for a muscle twitch.\xa0 The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,\xa0 returning the muscle fibers to their resting state.', 'dfb9b009-eeee-4ec6-b40f-4f8fba4116e5': 'Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead,\xa0a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a\xa0graded muscle response.', 'a21696df-dcef-47f5-ba2f-1e5a53024f2a': 'A graded muscle response works as follows:\xa0\xa0if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.', '2e765358-f944-4b5d-b03f-f90a7a1b7602': 'If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).', '6d731dd7-7264-48c5-9aa3-6fe4020511bd': 'During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).', '1df7d399-9d74-4003-8dc4-6c9ba4a77897': 'When a skeletal muscle has been dormant for an extended period and then stimulated to contract, with all other things being equal, the initial contractions generate about one-half the force of later contractions. The muscle tension increases in a graded manner that to some looks like a set of stairs. This tension increase is called treppe, a condition where muscle contractions become more efficient. It’s also known as the “staircase effect” (Figure 10.4.5).', 'c6749fa0-4b26-4c3c-9f04-8e6a0bb2cd34': 'It is believed that treppe results from a higher concentration of Ca++ in the sarcoplasm resulting from the steady stream of signals from the motor neuron. It can only be maintained with adequate ATP.'}"
+Figure 10.4.5,Anatomy_And_Physio/images/Figure 10.4.5.jpg,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus.","A graded muscle response works as follows:  if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.","{'d1934205-ce04-47d1-a520-44d14cd93a70': 'A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from\xa0a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).', 'b1d5c6ca-3759-4b71-86ed-6affa921734a': 'Three phases are recognized\xa0for a muscle twitch.\xa0 The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,\xa0 returning the muscle fibers to their resting state.', 'dfb9b009-eeee-4ec6-b40f-4f8fba4116e5': 'Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead,\xa0a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a\xa0graded muscle response.', 'a21696df-dcef-47f5-ba2f-1e5a53024f2a': 'A graded muscle response works as follows:\xa0\xa0if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.', '2e765358-f944-4b5d-b03f-f90a7a1b7602': 'If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).', '6d731dd7-7264-48c5-9aa3-6fe4020511bd': 'During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).', '1df7d399-9d74-4003-8dc4-6c9ba4a77897': 'When a skeletal muscle has been dormant for an extended period and then stimulated to contract, with all other things being equal, the initial contractions generate about one-half the force of later contractions. The muscle tension increases in a graded manner that to some looks like a set of stairs. This tension increase is called treppe, a condition where muscle contractions become more efficient. It’s also known as the “staircase effect” (Figure 10.4.5).', 'c6749fa0-4b26-4c3c-9f04-8e6a0bb2cd34': 'It is believed that treppe results from a higher concentration of Ca++ in the sarcoplasm resulting from the steady stream of signals from the motor neuron. It can only be maintained with adequate ATP.'}"
+Figure 10.4.5,Anatomy_And_Physio/images/Figure 10.4.5.jpg,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus.","A graded muscle response works as follows:  if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.","{'d1934205-ce04-47d1-a520-44d14cd93a70': 'A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from\xa0a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).', 'b1d5c6ca-3759-4b71-86ed-6affa921734a': 'Three phases are recognized\xa0for a muscle twitch.\xa0 The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,\xa0 returning the muscle fibers to their resting state.', 'dfb9b009-eeee-4ec6-b40f-4f8fba4116e5': 'Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead,\xa0a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a\xa0graded muscle response.', 'a21696df-dcef-47f5-ba2f-1e5a53024f2a': 'A graded muscle response works as follows:\xa0\xa0if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.', '2e765358-f944-4b5d-b03f-f90a7a1b7602': 'If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).', '6d731dd7-7264-48c5-9aa3-6fe4020511bd': 'During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).', '1df7d399-9d74-4003-8dc4-6c9ba4a77897': 'When a skeletal muscle has been dormant for an extended period and then stimulated to contract, with all other things being equal, the initial contractions generate about one-half the force of later contractions. The muscle tension increases in a graded manner that to some looks like a set of stairs. This tension increase is called treppe, a condition where muscle contractions become more efficient. It’s also known as the “staircase effect” (Figure 10.4.5).', 'c6749fa0-4b26-4c3c-9f04-8e6a0bb2cd34': 'It is believed that treppe results from a higher concentration of Ca++ in the sarcoplasm resulting from the steady stream of signals from the motor neuron. It can only be maintained with adequate ATP.'}"
+Figure 10.3.1,Anatomy_And_Physio/images/Figure 10.3.1.jpg,"Figure 10.3.1 – Motor End-Plate and Innervation: At the NMJ, the axon terminal releases acetylcholine (ACh). The motor end-plate is the location of the ACh-receptors in the muscle fiber sarcolemma. When ACh molecules are released, they diffuse across a minute space called the synaptic cleft and bind to the receptors.","In skeletal muscle, cross-bridge formation and contraction requires the presence of calcium (Ca++) inside the muscle cell. Excitation signalling of action potentials from the motor neuron are coupled with calcium release. Thus, the excitation-contraction coupling process begins with signaling from the nervous system at the neuromuscular junction (Figure 10.3.1) and ends with calcium release for muscle contraction.","{'f432cee9-eb50-4b89-a54d-ba5e86d142ad': 'All living cells have membrane potentials, or electrical gradients across their membranes based on the distribution of positively and negatively charged ions. The inside of the membrane is usually around -60 to -90 mV, relative to the outside. Neurons and muscle cells can use their membrane potentials to generate and conduct electrical signals by controlling the movement of charged ions across their membranes to create electrical currents. This movement is controlled by selective opening and closing of specialized proteins in the membrane called ion channels. Although the currents generated by ions moving through these channel proteins are very small, they form the basis of both neural signaling and muscle contraction.', '7e390b38-412c-42ff-af16-0a8b1442350d': 'Both neurons and skeletal muscle cells are electrically excitable, meaning that they are able to generate action potentials. An action potential is a special type of electrical signal that can travel along a cell membrane as a wave. This allows a signal to be transmitted quickly over long distances.', '0b758a94-d4f1-4093-b9eb-48d51fc3c0c1': 'In skeletal muscle, cross-bridge formation and contraction requires the presence of calcium (Ca++) inside the muscle cell. Excitation signalling of action potentials from the motor neuron are coupled with calcium release. Thus, the\xa0excitation-contraction coupling process begins with signaling from the nervous system at the neuromuscular junction (Figure 10.3.1) and ends with calcium release for muscle contraction.', 'd8afa98b-d09b-4629-b8ec-99d58877eaeb': 'Most motor neurons that tell the skeletal muscle fibers to contract originate in the spinal cord. A smaller number of motor neurons are located in the brainstem for activation of skeletal muscles of the face, head, and neck. These neurons have long processes, called axons, which are specialized to transmit action potentials long distances— in this case, all the way from the spinal cord to the muscle itself (which may be up to three feet away). The axons of multiple neurons bundle together to form nerves, like wires bundled together in a cable.', '02d019ee-cb60-4598-946e-709c7d68a36b': 'Signaling begins when a neuronal action potential travels along the axon of a motor neuron to the axon terminals at the NMJ. The ACh molecules diffuse across a minute space called the synaptic cleft and bind to ACh receptors on chemically-gated or ligand-gated channels located within the motor end-plate of the sarcolemma on the other side of the synapse. Once ACh binds, the chemically gated channel opens and positively charged ions can pass through into the muscle fiber, causing it to depolarize, meaning that the membrane potential of the muscle fiber becomes less negative (closer to zero.)', 'dffe1aa3-b5eb-4f28-8b73-a7fd7672afe8': 'The membrane depolarization at the synaptic cleft triggers nearby voltage-gated sodium channels to open. Sodium ions enter the muscle fiber further depolarizing the membrane, and an action potential rapidly spreads (or “fires”) along the entire membrane to initiate excitation-contraction coupling.', 'ffef1268-8767-4b01-b11c-68fb999076dd': 'Things happen very quickly in the world of excitable membranes (just think about how quickly you can snap your fingers as soon as you decide to do it). Immediately following depolarization of the membrane, repolarization occurs. Depolarization causes voltage-gated potassium channels open and allow potassium to leave the cell which returns the cell membrane to a negative membrane potential. The concentration gradients of sodium and potassium are then re-established by the sodium-potassium pump. Meanwhile, the ACh in the synaptic cleft is degraded by the enzyme acetylcholinesterase (AChE) so that the ACh cannot rebind to a receptor and reopen its channel, which would cause unwanted extended muscle excitation and contraction.', '83b9d915-7c56-4252-a414-d808d04c6d60': 'Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap. \xa0The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).', '5700d629-407b-4f8a-89bf-5f609525d3b0': 'Voltage-sensitive dihydropyridine receptors (DHPR) on the sarcolemma are mechanically linked to calcium channels in the adjacent SR membrane called ryanadine receptors (RyR). \xa0Through the DHPR, the action potential in the sarcolemma triggers the opening of RyR, allowing Ca++ to diffuse out of the SR and into the sarcoplasm. It is the arrival of Ca++ in the sarcoplasm that allows for the binding of actin and myosin and thus initiates contraction and shortening of sarcomeres.'}"
+Figure 10.3.2,Anatomy_And_Physio/images/Figure 10.3.2.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them.","Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap.  The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).","{'f432cee9-eb50-4b89-a54d-ba5e86d142ad': 'All living cells have membrane potentials, or electrical gradients across their membranes based on the distribution of positively and negatively charged ions. The inside of the membrane is usually around -60 to -90 mV, relative to the outside. Neurons and muscle cells can use their membrane potentials to generate and conduct electrical signals by controlling the movement of charged ions across their membranes to create electrical currents. This movement is controlled by selective opening and closing of specialized proteins in the membrane called ion channels. Although the currents generated by ions moving through these channel proteins are very small, they form the basis of both neural signaling and muscle contraction.', '7e390b38-412c-42ff-af16-0a8b1442350d': 'Both neurons and skeletal muscle cells are electrically excitable, meaning that they are able to generate action potentials. An action potential is a special type of electrical signal that can travel along a cell membrane as a wave. This allows a signal to be transmitted quickly over long distances.', '0b758a94-d4f1-4093-b9eb-48d51fc3c0c1': 'In skeletal muscle, cross-bridge formation and contraction requires the presence of calcium (Ca++) inside the muscle cell. Excitation signalling of action potentials from the motor neuron are coupled with calcium release. Thus, the\xa0excitation-contraction coupling process begins with signaling from the nervous system at the neuromuscular junction (Figure 10.3.1) and ends with calcium release for muscle contraction.', 'd8afa98b-d09b-4629-b8ec-99d58877eaeb': 'Most motor neurons that tell the skeletal muscle fibers to contract originate in the spinal cord. A smaller number of motor neurons are located in the brainstem for activation of skeletal muscles of the face, head, and neck. These neurons have long processes, called axons, which are specialized to transmit action potentials long distances— in this case, all the way from the spinal cord to the muscle itself (which may be up to three feet away). The axons of multiple neurons bundle together to form nerves, like wires bundled together in a cable.', '02d019ee-cb60-4598-946e-709c7d68a36b': 'Signaling begins when a neuronal action potential travels along the axon of a motor neuron to the axon terminals at the NMJ. The ACh molecules diffuse across a minute space called the synaptic cleft and bind to ACh receptors on chemically-gated or ligand-gated channels located within the motor end-plate of the sarcolemma on the other side of the synapse. Once ACh binds, the chemically gated channel opens and positively charged ions can pass through into the muscle fiber, causing it to depolarize, meaning that the membrane potential of the muscle fiber becomes less negative (closer to zero.)', 'dffe1aa3-b5eb-4f28-8b73-a7fd7672afe8': 'The membrane depolarization at the synaptic cleft triggers nearby voltage-gated sodium channels to open. Sodium ions enter the muscle fiber further depolarizing the membrane, and an action potential rapidly spreads (or “fires”) along the entire membrane to initiate excitation-contraction coupling.', 'ffef1268-8767-4b01-b11c-68fb999076dd': 'Things happen very quickly in the world of excitable membranes (just think about how quickly you can snap your fingers as soon as you decide to do it). Immediately following depolarization of the membrane, repolarization occurs. Depolarization causes voltage-gated potassium channels open and allow potassium to leave the cell which returns the cell membrane to a negative membrane potential. The concentration gradients of sodium and potassium are then re-established by the sodium-potassium pump. Meanwhile, the ACh in the synaptic cleft is degraded by the enzyme acetylcholinesterase (AChE) so that the ACh cannot rebind to a receptor and reopen its channel, which would cause unwanted extended muscle excitation and contraction.', '83b9d915-7c56-4252-a414-d808d04c6d60': 'Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap. \xa0The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).', '5700d629-407b-4f8a-89bf-5f609525d3b0': 'Voltage-sensitive dihydropyridine receptors (DHPR) on the sarcolemma are mechanically linked to calcium channels in the adjacent SR membrane called ryanadine receptors (RyR). \xa0Through the DHPR, the action potential in the sarcolemma triggers the opening of RyR, allowing Ca++ to diffuse out of the SR and into the sarcoplasm. It is the arrival of Ca++ in the sarcoplasm that allows for the binding of actin and myosin and thus initiates contraction and shortening of sarcomeres.', '7860dd9c-4646-4865-bd61-ca1422f51115': 'The sequence of events that result in the contraction of an individual muscle fiber begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fiber. The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR). The Ca++ then initiates contraction, which is sustained by ATP (Figure 10.3.5). As long as Ca++ ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites “unshielded,” and as long as ATP is available to drive the cross-bridge cycling and the pulling of actin strands by myosin, the muscle fiber will continue to shorten to an anatomical limit.', '14076bc4-cc3e-4070-9a07-6d1bade5b878': 'Muscle contraction usually stops when signaling from the motor neuron ends, which repolarizes the sarcolemma and T-tubules, and closes the calcium channels in the SR. Ca++ ions are then pumped back into the SR, which causes the tropomyosin to re-cover the binding sites on actin (Figure 10.3.2).'}"
+Figure 10.3.5,Anatomy_And_Physio/images/Figure 10.3.5.jpg,"Figure 10.3.5 – Contraction of a Muscle Fiber: A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten. Relaxation of a Muscle Fiber: Ca++ ions are pumped back into the SR, which causes the tropomyosin to reshield the binding sites on the actin strands. A muscle may also stop contracting when it runs out of ATP and becomes fatigued.","The sequence of events that result in the contraction of an individual muscle fiber begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fiber. The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR). The Ca++ then initiates contraction, which is sustained by ATP (Figure 10.3.5). As long as Ca++ ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites “unshielded,” and as long as ATP is available to drive the cross-bridge cycling and the pulling of actin strands by myosin, the muscle fiber will continue to shorten to an anatomical limit.","{'7860dd9c-4646-4865-bd61-ca1422f51115': 'The sequence of events that result in the contraction of an individual muscle fiber begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fiber. The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR). The Ca++ then initiates contraction, which is sustained by ATP (Figure 10.3.5). As long as Ca++ ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites “unshielded,” and as long as ATP is available to drive the cross-bridge cycling and the pulling of actin strands by myosin, the muscle fiber will continue to shorten to an anatomical limit.', '14076bc4-cc3e-4070-9a07-6d1bade5b878': 'Muscle contraction usually stops when signaling from the motor neuron ends, which repolarizes the sarcolemma and T-tubules, and closes the calcium channels in the SR. Ca++ ions are then pumped back into the SR, which causes the tropomyosin to re-cover the binding sites on actin (Figure 10.3.2).'}"
+Figure 10.3.2,Anatomy_And_Physio/images/Figure 10.3.2.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them.","Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap.  The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).","{'f432cee9-eb50-4b89-a54d-ba5e86d142ad': 'All living cells have membrane potentials, or electrical gradients across their membranes based on the distribution of positively and negatively charged ions. The inside of the membrane is usually around -60 to -90 mV, relative to the outside. Neurons and muscle cells can use their membrane potentials to generate and conduct electrical signals by controlling the movement of charged ions across their membranes to create electrical currents. This movement is controlled by selective opening and closing of specialized proteins in the membrane called ion channels. Although the currents generated by ions moving through these channel proteins are very small, they form the basis of both neural signaling and muscle contraction.', '7e390b38-412c-42ff-af16-0a8b1442350d': 'Both neurons and skeletal muscle cells are electrically excitable, meaning that they are able to generate action potentials. An action potential is a special type of electrical signal that can travel along a cell membrane as a wave. This allows a signal to be transmitted quickly over long distances.', '0b758a94-d4f1-4093-b9eb-48d51fc3c0c1': 'In skeletal muscle, cross-bridge formation and contraction requires the presence of calcium (Ca++) inside the muscle cell. Excitation signalling of action potentials from the motor neuron are coupled with calcium release. Thus, the\xa0excitation-contraction coupling process begins with signaling from the nervous system at the neuromuscular junction (Figure 10.3.1) and ends with calcium release for muscle contraction.', 'd8afa98b-d09b-4629-b8ec-99d58877eaeb': 'Most motor neurons that tell the skeletal muscle fibers to contract originate in the spinal cord. A smaller number of motor neurons are located in the brainstem for activation of skeletal muscles of the face, head, and neck. These neurons have long processes, called axons, which are specialized to transmit action potentials long distances— in this case, all the way from the spinal cord to the muscle itself (which may be up to three feet away). The axons of multiple neurons bundle together to form nerves, like wires bundled together in a cable.', '02d019ee-cb60-4598-946e-709c7d68a36b': 'Signaling begins when a neuronal action potential travels along the axon of a motor neuron to the axon terminals at the NMJ. The ACh molecules diffuse across a minute space called the synaptic cleft and bind to ACh receptors on chemically-gated or ligand-gated channels located within the motor end-plate of the sarcolemma on the other side of the synapse. Once ACh binds, the chemically gated channel opens and positively charged ions can pass through into the muscle fiber, causing it to depolarize, meaning that the membrane potential of the muscle fiber becomes less negative (closer to zero.)', 'dffe1aa3-b5eb-4f28-8b73-a7fd7672afe8': 'The membrane depolarization at the synaptic cleft triggers nearby voltage-gated sodium channels to open. Sodium ions enter the muscle fiber further depolarizing the membrane, and an action potential rapidly spreads (or “fires”) along the entire membrane to initiate excitation-contraction coupling.', 'ffef1268-8767-4b01-b11c-68fb999076dd': 'Things happen very quickly in the world of excitable membranes (just think about how quickly you can snap your fingers as soon as you decide to do it). Immediately following depolarization of the membrane, repolarization occurs. Depolarization causes voltage-gated potassium channels open and allow potassium to leave the cell which returns the cell membrane to a negative membrane potential. The concentration gradients of sodium and potassium are then re-established by the sodium-potassium pump. Meanwhile, the ACh in the synaptic cleft is degraded by the enzyme acetylcholinesterase (AChE) so that the ACh cannot rebind to a receptor and reopen its channel, which would cause unwanted extended muscle excitation and contraction.', '83b9d915-7c56-4252-a414-d808d04c6d60': 'Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap. \xa0The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).', '5700d629-407b-4f8a-89bf-5f609525d3b0': 'Voltage-sensitive dihydropyridine receptors (DHPR) on the sarcolemma are mechanically linked to calcium channels in the adjacent SR membrane called ryanadine receptors (RyR). \xa0Through the DHPR, the action potential in the sarcolemma triggers the opening of RyR, allowing Ca++ to diffuse out of the SR and into the sarcoplasm. It is the arrival of Ca++ in the sarcoplasm that allows for the binding of actin and myosin and thus initiates contraction and shortening of sarcomeres.', '7860dd9c-4646-4865-bd61-ca1422f51115': 'The sequence of events that result in the contraction of an individual muscle fiber begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fiber. The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR). The Ca++ then initiates contraction, which is sustained by ATP (Figure 10.3.5). As long as Ca++ ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites “unshielded,” and as long as ATP is available to drive the cross-bridge cycling and the pulling of actin strands by myosin, the muscle fiber will continue to shorten to an anatomical limit.', '14076bc4-cc3e-4070-9a07-6d1bade5b878': 'Muscle contraction usually stops when signaling from the motor neuron ends, which repolarizes the sarcolemma and T-tubules, and closes the calcium channels in the SR. Ca++ ions are then pumped back into the SR, which causes the tropomyosin to re-cover the binding sites on actin (Figure 10.3.2).'}"
+Figure 10.2.1,Anatomy_And_Physio/images/Figure 10.2.1.jpg,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium.","Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.","{'93100b76-a6bc-4d13-b5d0-831dbe9d069f': 'Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.', '72a24f4d-c9b4-4af3-b7ee-fbff975786e9': 'Parallel\xa0muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).', '835b0cd7-579c-494f-8471-e43454702b86': 'Circular\xa0muscles are also called sphincters (see\xa0Figure 11.2.1). When they relax, the sphincters’ concentrically arranged bundles of muscle fibers increase the size of the opening, and when they contract, the size of the opening shrinks to the point of closure. The orbicularis oris muscle is a circular muscle that goes around the mouth. When it contracts, the oral opening becomes smaller, as when puckering the lips for whistling. Another example is the orbicularis oculi, one of which surrounds each eye. Consider, for example, the names of the two orbicularis muscles (orbicularis oris and oribicularis oculi), where part of the first name of both muscles is the same. The first part of orbicularis, orb (orb = “circular”), is a reference to a round or circular structure; it may also make one think of orbit, such as the moon’s path around the earth. The word oris (oris = “oral”) refers to the oral cavity, or the mouth. The word oculi (ocular = “eye”) refers to the eye.', '47cd1715-24ac-4184-a95b-73a77cb50730': 'When a muscle has a widespread expansion over a sizable area and the fascicles come to a single, common attachment point, the muscle is called\xa0convergent. The attachment point for a convergent muscle could be a tendon, an aponeurosis (a flat, broad tendon), or a raphe (a very slender tendon). The large muscle on the chest, the pectoralis major, is an example of a convergent muscle because it converges on the intertubercular groove and greater tubercle of the humerus via a tendon (see image 11.3).', '8dcee826-9929-4df5-aa56-f8a9f66ac5af': 'Pennate\xa0muscles (penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle fascicles arranged similar to the feathers. Due to this design, the muscle fibers in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far. However, because a pennate muscle generally can hold more muscle fibers within it, it can produce relatively more tension for its size, compared to non-pennate muscles. There are three subtypes of pennate muscles.', 'c13fc478-b376-4e72-a57a-819f0a5fd2a1': 'In a\xa0unipennate\xa0muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A\xa0bipennate\xa0muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging\xa0on a central point. A common example is the deltoid muscle of the shoulder, which covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus.', 'ffee369e-025d-4ab2-84fb-bf63784c1bc9': 'The number of skeletal muscle fibers in a given muscle is genetically determined and does not change. Muscle strength is directly related to the amount of myofibrils and sarcomeres within each fiber. Factors, such as hormones and stress (and artificial anabolic steroids), acting on the muscle can increase the production of sarcomeres and myofibrils within the muscle fibers, a change called hypertrophy, which results in the increased mass and bulk in a skeletal muscle. Likewise, decreased use of a skeletal muscle results in atrophy, where the number of sarcomeres and myofibrils disappear (but not the number of muscle fibers). It is common for a limb in a cast to show atrophied muscles when the cast is removed, and certain diseases, such as polio, show atrophied muscles.', '50e165f4-aeea-4b4c-adc6-56aee9a55e8b': 'Each skeletal muscle is an organ that consists of various integrated tissues. These tissues include the skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue. Each skeletal muscle has three layers of connective tissue (called mysia) that enclose it, provide structure to the muscle, and compartmentalize the muscle fibers within the muscle (Figure 10.2.1). Each muscle is wrapped in a sheath of dense, irregular connective tissue called the epimysium, which allows a muscle to contract and move powerfully while maintaining its structural integrity. The epimysium also separates muscle from other tissues and organs in the area, allowing the muscle to move independently.', '038727e5-093f-425f-8b8a-c7e7d7f34145': 'Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, surrounded by a middle layer of connective tissue called the perimysium. This fascicular organization is common in muscles of the limbs; it allows the nervous system to trigger a specific movement of a muscle by activating a subset of muscle fibers within a fascicle of the muscle. Inside each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular fibers called the endomysium. The endomysium surrounds the\xa0extracellular matrix of the cells and plays a role in transferring force produced by the muscle fibers to the tendons.', 'e4e68d03-03ba-42b5-8930-1282a8c96792': 'In skeletal muscles that work with tendons to pull on bones, the collagen in the three connective tissue layers intertwines with the collagen of a tendon. At the other end of the tendon, it fuses with the periosteum coating the bone. The tension created by contraction of the muscle fibers is then transferred though the connective tissue layers, to the tendon, and then to the periosteum to pull on the bone for movement of the skeleton. In other places, the mysia may fuse with a broad, tendon-like sheet called an aponeurosis, or to fascia, the connective tissue between skin and bones. The broad sheet of connective tissue in the lower back that the latissimus dorsi muscles (the “lats”) fuse into is an example of an aponeurosis.', '996ede2a-7ae9-450a-a6eb-7bcdec4684f9': 'Every skeletal muscle is also richly supplied by blood vessels for nourishment, oxygen delivery, and waste removal. In addition, every muscle fiber in a skeletal muscle is supplied by the axon branch of a somatic motor neuron, which signals the fiber to contract. Unlike cardiac and smooth muscle, the only way to functionally contract a skeletal muscle is through signaling from the nervous system.'}"
+Figure 10.2.2,Anatomy_And_Physio/images/Figure 10.2.2.jpg,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance.","The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm (Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber.  The sarcomere is the smallest functional unit of a skeletal muscle fiber and is a highly organized arrangement of contractile, regulatory, and structural proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).","{'926e255d-353c-4760-aad9-2fd0b112943f': 'Because skeletal muscle cells are long and cylindrical, they are commonly referred to as muscle fibers (or myofibers). Skeletal muscle fibers can be quite large compared to other cells, with diameters up to 100 μm and lengths up to 30 cm (11.8 in) in the Sartorius of the upper leg. Having many nuclei allows for production of the large amounts of proteins and enzymes needed for maintaining normal function of these large protein dense cells. \xa0In addition to nuclei, skeletal muscle fibers also contain cellular organelles found in other cells, such as mitochondria and endoplasmic reticulum. \xa0However, some of these structures are specialized in muscle fibers. \xa0The specialized smooth endoplasmic reticulum, called the sarcoplasmic reticulum (SR), stores, releases, and retrieves calcium ions (Ca++).', '884363d1-4dbf-4215-be36-e931835f641e': 'The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm\xa0(Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber. \xa0The sarcomere is the smallest functional unit of a skeletal muscle fiber and\xa0is\xa0a highly organized arrangement of contractile, regulatory, and structural\xa0proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).', 'c192b758-f9f2-4392-9710-1d83ead9624f': 'A sarcomere is defined as the region of a myofibril contained between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands), and the striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere (Figure 10.2.2). \xa0The dark striated A band\xa0is composed of the thick filaments containing myosin, which span the center of the sarcomere extending toward the Z-dics. \xa0The thick filaments are anchored at the middle of the sarcomere (the M-line) by a protein called myomesin. \xa0The lighter I band regions contain thin actin filaments anchored at the Z-discs by a protein called α-actinin. \xa0The thin filaments extend into the A band toward the M-line and overlap with regions of the thick filament. \xa0The A band is dark because of the thicker myosin filaments as well as overlap with the actin filaments. The H zone in the middle of the A band is a little lighter in color because it only contain the portion of the thick filaments that does not overlap with the thin filaments (i.e. the thin filaments do not extend into the H zone).', '6612eb2b-9404-4925-bb02-ab85c82e4b13': 'Because a sarcomere is defined by Z-discs, a single sarcomere contains one dark A band with half of the lighter I band on each end (Figure 10.2.2). \xa0During contraction the myofilaments themselves do not change length, but actually slide across each other so the distance between the Z-discs shortens resulting in the shortening of the sarcomere. The length of the A band does not change (the thick myosin filament remains a constant length), but the H zone and I band regions shrink. \xa0These regions represent areas where the filaments do not overlap, and as filament overlap increases during contraction these regions of no overlap decrease.', '33f9062e-18a0-4fef-8c24-cc052bab4744': 'The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3). \xa0These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere. \xa0Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin. \xa0The troponin protein complex consists of three polypeptides. \xa0Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions. \xa0Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.', 'f23f1a7f-a7a8-4470-9c68-294886aa6a70': 'Thick myofilaments are composed of myosin protein complexes, which are composed of six proteins: two myosin heavy chains and four light chain molecules. \xa0The heavy chains consist of a tail region, flexible hinge region, and globular head which contains an Actin-binding site and a binding site for the high energy molecule ATP. \xa0The light chains play a regulatory role at the hinge region, but the heavy chain head region interacts with actin and is the most important factor for generating force. \xa0Hundreds of myosin proteins are arranged into each thick filament with tails toward the M-line and heads extending toward the Z-discs.', '793ac47b-20e5-41f1-9342-caba34e94a62': 'Other structural proteins are associated with the sarcomere but do not play a direct role in active force production. \xa0Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere. \xa0Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc. \xa0The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments.'}"
+Figure 10.2.2,Anatomy_And_Physio/images/Figure 10.2.2.jpg,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance.","The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm (Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber.  The sarcomere is the smallest functional unit of a skeletal muscle fiber and is a highly organized arrangement of contractile, regulatory, and structural proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).","{'926e255d-353c-4760-aad9-2fd0b112943f': 'Because skeletal muscle cells are long and cylindrical, they are commonly referred to as muscle fibers (or myofibers). Skeletal muscle fibers can be quite large compared to other cells, with diameters up to 100 μm and lengths up to 30 cm (11.8 in) in the Sartorius of the upper leg. Having many nuclei allows for production of the large amounts of proteins and enzymes needed for maintaining normal function of these large protein dense cells. \xa0In addition to nuclei, skeletal muscle fibers also contain cellular organelles found in other cells, such as mitochondria and endoplasmic reticulum. \xa0However, some of these structures are specialized in muscle fibers. \xa0The specialized smooth endoplasmic reticulum, called the sarcoplasmic reticulum (SR), stores, releases, and retrieves calcium ions (Ca++).', '884363d1-4dbf-4215-be36-e931835f641e': 'The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm\xa0(Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber. \xa0The sarcomere is the smallest functional unit of a skeletal muscle fiber and\xa0is\xa0a highly organized arrangement of contractile, regulatory, and structural\xa0proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).', 'c192b758-f9f2-4392-9710-1d83ead9624f': 'A sarcomere is defined as the region of a myofibril contained between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands), and the striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere (Figure 10.2.2). \xa0The dark striated A band\xa0is composed of the thick filaments containing myosin, which span the center of the sarcomere extending toward the Z-dics. \xa0The thick filaments are anchored at the middle of the sarcomere (the M-line) by a protein called myomesin. \xa0The lighter I band regions contain thin actin filaments anchored at the Z-discs by a protein called α-actinin. \xa0The thin filaments extend into the A band toward the M-line and overlap with regions of the thick filament. \xa0The A band is dark because of the thicker myosin filaments as well as overlap with the actin filaments. The H zone in the middle of the A band is a little lighter in color because it only contain the portion of the thick filaments that does not overlap with the thin filaments (i.e. the thin filaments do not extend into the H zone).', '6612eb2b-9404-4925-bb02-ab85c82e4b13': 'Because a sarcomere is defined by Z-discs, a single sarcomere contains one dark A band with half of the lighter I band on each end (Figure 10.2.2). \xa0During contraction the myofilaments themselves do not change length, but actually slide across each other so the distance between the Z-discs shortens resulting in the shortening of the sarcomere. The length of the A band does not change (the thick myosin filament remains a constant length), but the H zone and I band regions shrink. \xa0These regions represent areas where the filaments do not overlap, and as filament overlap increases during contraction these regions of no overlap decrease.', '33f9062e-18a0-4fef-8c24-cc052bab4744': 'The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3). \xa0These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere. \xa0Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin. \xa0The troponin protein complex consists of three polypeptides. \xa0Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions. \xa0Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.', 'f23f1a7f-a7a8-4470-9c68-294886aa6a70': 'Thick myofilaments are composed of myosin protein complexes, which are composed of six proteins: two myosin heavy chains and four light chain molecules. \xa0The heavy chains consist of a tail region, flexible hinge region, and globular head which contains an Actin-binding site and a binding site for the high energy molecule ATP. \xa0The light chains play a regulatory role at the hinge region, but the heavy chain head region interacts with actin and is the most important factor for generating force. \xa0Hundreds of myosin proteins are arranged into each thick filament with tails toward the M-line and heads extending toward the Z-discs.', '793ac47b-20e5-41f1-9342-caba34e94a62': 'Other structural proteins are associated with the sarcomere but do not play a direct role in active force production. \xa0Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere. \xa0Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc. \xa0The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments.'}"
+Figure 10.2.2,Anatomy_And_Physio/images/Figure 10.2.2.jpg,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance.","The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm (Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber.  The sarcomere is the smallest functional unit of a skeletal muscle fiber and is a highly organized arrangement of contractile, regulatory, and structural proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).","{'926e255d-353c-4760-aad9-2fd0b112943f': 'Because skeletal muscle cells are long and cylindrical, they are commonly referred to as muscle fibers (or myofibers). Skeletal muscle fibers can be quite large compared to other cells, with diameters up to 100 μm and lengths up to 30 cm (11.8 in) in the Sartorius of the upper leg. Having many nuclei allows for production of the large amounts of proteins and enzymes needed for maintaining normal function of these large protein dense cells. \xa0In addition to nuclei, skeletal muscle fibers also contain cellular organelles found in other cells, such as mitochondria and endoplasmic reticulum. \xa0However, some of these structures are specialized in muscle fibers. \xa0The specialized smooth endoplasmic reticulum, called the sarcoplasmic reticulum (SR), stores, releases, and retrieves calcium ions (Ca++).', '884363d1-4dbf-4215-be36-e931835f641e': 'The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm\xa0(Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber. \xa0The sarcomere is the smallest functional unit of a skeletal muscle fiber and\xa0is\xa0a highly organized arrangement of contractile, regulatory, and structural\xa0proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).', 'c192b758-f9f2-4392-9710-1d83ead9624f': 'A sarcomere is defined as the region of a myofibril contained between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands), and the striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere (Figure 10.2.2). \xa0The dark striated A band\xa0is composed of the thick filaments containing myosin, which span the center of the sarcomere extending toward the Z-dics. \xa0The thick filaments are anchored at the middle of the sarcomere (the M-line) by a protein called myomesin. \xa0The lighter I band regions contain thin actin filaments anchored at the Z-discs by a protein called α-actinin. \xa0The thin filaments extend into the A band toward the M-line and overlap with regions of the thick filament. \xa0The A band is dark because of the thicker myosin filaments as well as overlap with the actin filaments. The H zone in the middle of the A band is a little lighter in color because it only contain the portion of the thick filaments that does not overlap with the thin filaments (i.e. the thin filaments do not extend into the H zone).', '6612eb2b-9404-4925-bb02-ab85c82e4b13': 'Because a sarcomere is defined by Z-discs, a single sarcomere contains one dark A band with half of the lighter I band on each end (Figure 10.2.2). \xa0During contraction the myofilaments themselves do not change length, but actually slide across each other so the distance between the Z-discs shortens resulting in the shortening of the sarcomere. The length of the A band does not change (the thick myosin filament remains a constant length), but the H zone and I band regions shrink. \xa0These regions represent areas where the filaments do not overlap, and as filament overlap increases during contraction these regions of no overlap decrease.', '33f9062e-18a0-4fef-8c24-cc052bab4744': 'The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3). \xa0These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere. \xa0Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin. \xa0The troponin protein complex consists of three polypeptides. \xa0Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions. \xa0Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.', 'f23f1a7f-a7a8-4470-9c68-294886aa6a70': 'Thick myofilaments are composed of myosin protein complexes, which are composed of six proteins: two myosin heavy chains and four light chain molecules. \xa0The heavy chains consist of a tail region, flexible hinge region, and globular head which contains an Actin-binding site and a binding site for the high energy molecule ATP. \xa0The light chains play a regulatory role at the hinge region, but the heavy chain head region interacts with actin and is the most important factor for generating force. \xa0Hundreds of myosin proteins are arranged into each thick filament with tails toward the M-line and heads extending toward the Z-discs.', '793ac47b-20e5-41f1-9342-caba34e94a62': 'Other structural proteins are associated with the sarcomere but do not play a direct role in active force production. \xa0Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere. \xa0Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc. \xa0The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments.'}"
+Figure 10.2.3,Anatomy_And_Physio/images/Figure 10.2.3.jpg,"Figure 10.2.3 – The Sarcomere: The sarcomere, the region from one Z-disc to the next Z-disc, is the functional unit of a skeletal muscle fiber.","The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3).  These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere.  Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin.  The troponin protein complex consists of three polypeptides.  Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions.  Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.","{'c192b758-f9f2-4392-9710-1d83ead9624f': 'A sarcomere is defined as the region of a myofibril contained between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands), and the striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere (Figure 10.2.2). \xa0The dark striated A band\xa0is composed of the thick filaments containing myosin, which span the center of the sarcomere extending toward the Z-dics. \xa0The thick filaments are anchored at the middle of the sarcomere (the M-line) by a protein called myomesin. \xa0The lighter I band regions contain thin actin filaments anchored at the Z-discs by a protein called α-actinin. \xa0The thin filaments extend into the A band toward the M-line and overlap with regions of the thick filament. \xa0The A band is dark because of the thicker myosin filaments as well as overlap with the actin filaments. The H zone in the middle of the A band is a little lighter in color because it only contain the portion of the thick filaments that does not overlap with the thin filaments (i.e. the thin filaments do not extend into the H zone).', '6612eb2b-9404-4925-bb02-ab85c82e4b13': 'Because a sarcomere is defined by Z-discs, a single sarcomere contains one dark A band with half of the lighter I band on each end (Figure 10.2.2). \xa0During contraction the myofilaments themselves do not change length, but actually slide across each other so the distance between the Z-discs shortens resulting in the shortening of the sarcomere. The length of the A band does not change (the thick myosin filament remains a constant length), but the H zone and I band regions shrink. \xa0These regions represent areas where the filaments do not overlap, and as filament overlap increases during contraction these regions of no overlap decrease.', '33f9062e-18a0-4fef-8c24-cc052bab4744': 'The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3). \xa0These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere. \xa0Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin. \xa0The troponin protein complex consists of three polypeptides. \xa0Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions. \xa0Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.', 'f23f1a7f-a7a8-4470-9c68-294886aa6a70': 'Thick myofilaments are composed of myosin protein complexes, which are composed of six proteins: two myosin heavy chains and four light chain molecules. \xa0The heavy chains consist of a tail region, flexible hinge region, and globular head which contains an Actin-binding site and a binding site for the high energy molecule ATP. \xa0The light chains play a regulatory role at the hinge region, but the heavy chain head region interacts with actin and is the most important factor for generating force. \xa0Hundreds of myosin proteins are arranged into each thick filament with tails toward the M-line and heads extending toward the Z-discs.', '793ac47b-20e5-41f1-9342-caba34e94a62': 'Other structural proteins are associated with the sarcomere but do not play a direct role in active force production. \xa0Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere. \xa0Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc. \xa0The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments.'}"
+Figure 10.2.4,Anatomy_And_Physio/images/Figure 10.2.4.jpg,"Figure 10.2.4 – The Sliding Filament Model of Muscle Contraction: When a sarcomere shortens, the Z-discs move closer together, and the I band becomes smaller. The A band stays the same width. At full contraction, the thin and thick filaments have the most amount of overlap.","The arrangement and interactions between thin and thick filaments allows for the sarcomeres to generates force. When signaled by a motor neuron, a skeletal muscle fiber is activated. Cross bridges form between the thick and thin filaments and the thin filaments are pulled which slide past the thick filaments within the fiber’s sarcomeres. It is important to note that while the sarcomere shortens, the individual proteins and filaments do not change length but simply slide next to each other. This process is known as the sliding filament model of muscle contraction (Figure 10.2.4).","{'38c4b674-1ccc-46f6-9f4b-60306ffc4833': 'The arrangement and interactions between thin and thick filaments allows for the sarcomeres to generates force. When signaled by a motor neuron, a skeletal muscle fiber is activated. Cross bridges form between the thick and thin filaments and the thin filaments are pulled which slide past the thick filaments within the fiber’s sarcomeres. It is important to note that while the sarcomere shortens, the individual proteins and filaments do not change length but simply slide next to each other. This process is known as the sliding filament model of muscle contraction (Figure 10.2.4).', '39d0edf5-da75-447c-badc-dc438a044fca': 'The filament sliding process of contraction can only occur when myosin-binding sites on the actin filaments are exposed by a series of steps that begins with Ca++ entry into the sarcoplasm. \xa0Tropomyosin winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The troponin-tropomyosin complex uses calcium ion binding to TnC to regulate when the myosin heads form cross-bridges to the actin filaments. \xa0Cross-bridge formation and filament sliding will occur when calcium is present, and the signaling process leading to calcium release and muscle contraction is known as Excitation-Contraction Coupling.'}"
+Figure 10.1.1,Anatomy_And_Physio/images/Figure 10.1.1.jpg,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.","{'2432fb10-8781-4f42-a4c6-1c77afe51533': 'The major hormones influencing total body water are ADH, aldosterone, and ANH. Circumstances that lead to fluid depletion in the body include blood loss and dehydration. Homeostasis requires that volume and osmolarity be preserved. Blood volume is important in maintaining sufficient blood pressure, and there are nonrenal mechanisms involved in its preservation, including vasoconstriction, which can act within seconds of a drop in pressure. Thirst mechanisms are also activated to promote the consumption of water lost through respiration, evaporation, or urination. Hormonal mechanisms are activated to recover volume while maintaining a normal osmotic environment. These mechanisms act principally on the kidney.', '1a7bcd02-09d3-4f84-be6d-e2a31ad33e26': 'With up to 180 liters per day passing through the nephrons of the kidney, it is quite obvious that most of that fluid and its contents must be reabsorbed. Recall that substances that need to be removd from the body but were not yet filtered, can be secreted. This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5.1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes. While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT. About 10 percent (about 18 L) reaches the collecting ducts. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them, in cases of dehydration, or almost none of the water, in cases of over-hydration.', '610adc61-f5b4-49b5-b918-93c994a25eb3': 'Having reviewed the anatomy and microanatomy of the urinary system, now is the time to focus on the physiology. Recall that the glomerulus produce a simple filtrate of the blood and the remainder of the nephron works to modify the filtrate into urine. You will discover that different parts of the nephron utilize three specific processes to produce urine: filtration, reabsorption, and secretion. You will learn how each of these processes works and where they occur along the nephron and collecting ducts. The physiologic goal is to modify the composition of the plasma and, in doing so, produce the waste product urine.', '0e9dafa2-edd5-4690-8747-5eaabe461aaf': 'Glomerular filtration occurs as blood passes into the glomerulus producing a plasma-like filtrate (minus proteins) that gets captured by the Bowman’s (glomerular) capsule and funneled into the renal tubule. This filtrate produced then becomes highly modified along its route through the nephron by the following processes, finally producing urine at the end of the collecting duct.', '88198aff-edd3-4544-9455-a2de3d3d35ca': 'As the filtrate travels along the length of the nephron, the cells lining the tubule selectively, and often actively, take substances from the filtrate and move them out of the tubule into the blood. Recall that the glomerulus is simply a filter and anything suspended in the plasma that can fit through the holes in the filtration membrane can end up in the filtrate. This includes very physiologically important molecules such as water, sodium, chloride, and bicarbonate (along with many others) as well as molecules that the digestive system used a lot of energy to absorb, such as glucose and amino acids. These molecules would be lost in the urine if not reclaimed by the tubule cells. These cells are so efficient that they can reclaim all of the glucose and amino acids and up to 99% of the water and important ions lost due to glomerular filtration. The filtrate that is not reasbsorbed becomes urine at the base of the collecting duct.', '066b23c9-a978-4fbf-b10b-493ea6dd7838': 'Nephrons are the “functional units” of the kidney; they cleanse the blood of toxins and balance the constituents of the circulation to homeostatic set points through the processes of filtration, reabsorption, and secretion. The nephrons also function to control blood pressure (via production of renin), red blood cell production (via the hormone erythropoetin), and calcium absorption (via conversion of calcidiol into calcitriol, the active form of vitamin D).', '14552618-fe9e-43db-9389-3e93f577e75c': 'This section is about how the immune system goes wrong. When it goes haywire, and becomes too weak or too strong, it leads to a state of disease. The factors that maintain immunological homeostasis are complex and incompletely understood.', '498f8f2a-b050-4166-abb5-9d065a244fdd': 'The immune system is the complex collection of cells and organs that destroys or neutralizes pathogens that would otherwise cause disease or death. The lymphatic system, for most people, is associated with the immune system to such a degree that the two systems are virtually indistinguishable. The lymphatic system is the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood. The swelling of lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels are but two examples of the many connections between these critical organ systems.', '535b8abb-5a6e-4c96-a28d-2f4f781a63c4': 'Describe structural and functional differences of skeletal, cardiac, and smooth muscle tissue', '1b4d95d8-5492-46db-aad8-a65c586e4233': 'Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.', '069a73e3-7426-4a39-9941-c2f6e90737f2': 'A unique property common to all three types of muscle is\xa0contractility,\xa0which is the ability of the cells to shorten and generate force. \xa0While muscle tissue can shorten with contractions, it also displays\xa0extensibility\xa0or the ability to stretch and extend beyond the resting length of the cells. \xa0After being stretched, the elasticity\xa0of muscle allows it to recoil back to its original length.', '74637967-9cc6-445c-b01c-1083803def1b': 'The muscles all begin the mechanical process of contracting (shortening) when a protein called actin is pulled by a protein called myosin, and differences in the microscopic organization of these contractile proteins exist among the three muscle types.\xa0 In both skeletal and cardiac muscle, the actin and myosin proteins are arranged very regularly in the cytoplasm of individual muscle cells, which creates an alternating light and dark striped pattern called striations. The striations are visible with a light microscope under high magnification (see Figure 10.1.1). \xa0Smooth muscle (named for it’s lack of striations), does not produce this striped pattern because the contractile proteins are not arranged in such regular fashion.', '4eaded9d-9d7d-4c33-b204-2507c8b91b08': 'Skeletal muscle\xa0cells (also called muscle fibers)\xa0are unique in that they are multinucleated with the nuclei located on the periphery of the cell under the cell plasma membrane (also called sarcolemma in muscle).\xa0 During early development, embryonic myoblasts, each with its own nucleus, fuse with hundreds of other myoblasts to form long multinucleated skeletal muscle fibers.\xa0Cardiac muscle\xa0cells each generally have one nucleus centrally located in the cell, but the cells are physically and electrically connected to each other so that the contraction signals spread through cells and the entire heart contracts as one unit. \xa0Smooth muscle cells contain a single nucleus and can exist in electrically linked units contracting together as a single-unit or as multi-unit smooth muscle where cells are not electrically linked.', '83607dca-c2a9-41f7-bd6e-f99a9c2c0954': 'The best-known feature of skeletal muscle is its ability to contract and cause movement. Skeletal muscles act not only to produce movement but also to stop movement, such as resisting gravity to maintain posture. Small, constant adjustments of the skeletal muscles are needed to hold a body upright or balanced in any position. Muscles also prevent excess movement of the bones and joints, maintaining skeletal stability and preventing skeletal structure damage or deformation.\xa0\xa0Skeletal muscles are located throughout the body at the openings of internal tracts to control the movement of various substances. These muscles allow functions, such as swallowing, urination, and defecation, to be under voluntary control. Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external barrier or shield to external trauma and by supporting the weight of the organs.', 'b8d405e5-666f-400c-b736-9f516acb3e36': 'Skeletal muscles contribute to the maintenance of homeostasis in the body by generating heat. Muscle contraction requires energy, and when ATP is broken down, heat is produced. This heat is very noticeable during exercise, when sustained muscle movement causes body temperature to rise, and in cases of extreme cold, when shivering produces random skeletal muscle contractions to generate heat.', '981a9036-67c6-4a72-a4c0-44e6778734ed': 'Cardiac muscle is only found in the heart and functions to generate force and build pressure gradients to drive blood flow throughout the body. Smooth muscle in the walls of arteries is a critical component that regulates blood pressure and blood flow through the circulatory system. \xa0Smooth muscle in the skin, visceral organs, and internal passageways is also essential for moving materials through the body. Neither cardiac nor smooth muscle connect to bone and therefore they cannot produce the gross movements we associate with skeletal muscle.', 'd86919ae-8f74-4ed3-98ed-fdfe9173e989': 'When most people think of muscles, they think of the muscles that are visible just under the skin, particularly of the limbs. These are skeletal muscles, so-named because most of them move the skeleton. But there are two other types of muscle in the body, with distinctly different jobs. Cardiac muscle, found in the heart, is concerned with pumping blood through the circulatory system. Smooth muscle is concerned with various involuntary movements, such as having one’s hair stand on end when cold or frightened, or moving food through the digestive system. This chapter will examine the structure and function of these three types of muscles.'}"
+Figure 10.1.1,Anatomy_And_Physio/images/Figure 10.1.1.jpg,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.","{'2432fb10-8781-4f42-a4c6-1c77afe51533': 'The major hormones influencing total body water are ADH, aldosterone, and ANH. Circumstances that lead to fluid depletion in the body include blood loss and dehydration. Homeostasis requires that volume and osmolarity be preserved. Blood volume is important in maintaining sufficient blood pressure, and there are nonrenal mechanisms involved in its preservation, including vasoconstriction, which can act within seconds of a drop in pressure. Thirst mechanisms are also activated to promote the consumption of water lost through respiration, evaporation, or urination. Hormonal mechanisms are activated to recover volume while maintaining a normal osmotic environment. These mechanisms act principally on the kidney.', '1a7bcd02-09d3-4f84-be6d-e2a31ad33e26': 'With up to 180 liters per day passing through the nephrons of the kidney, it is quite obvious that most of that fluid and its contents must be reabsorbed. Recall that substances that need to be removd from the body but were not yet filtered, can be secreted. This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5.1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes. While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT. About 10 percent (about 18 L) reaches the collecting ducts. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them, in cases of dehydration, or almost none of the water, in cases of over-hydration.', '610adc61-f5b4-49b5-b918-93c994a25eb3': 'Having reviewed the anatomy and microanatomy of the urinary system, now is the time to focus on the physiology. Recall that the glomerulus produce a simple filtrate of the blood and the remainder of the nephron works to modify the filtrate into urine. You will discover that different parts of the nephron utilize three specific processes to produce urine: filtration, reabsorption, and secretion. You will learn how each of these processes works and where they occur along the nephron and collecting ducts. The physiologic goal is to modify the composition of the plasma and, in doing so, produce the waste product urine.', '0e9dafa2-edd5-4690-8747-5eaabe461aaf': 'Glomerular filtration occurs as blood passes into the glomerulus producing a plasma-like filtrate (minus proteins) that gets captured by the Bowman’s (glomerular) capsule and funneled into the renal tubule. This filtrate produced then becomes highly modified along its route through the nephron by the following processes, finally producing urine at the end of the collecting duct.', '88198aff-edd3-4544-9455-a2de3d3d35ca': 'As the filtrate travels along the length of the nephron, the cells lining the tubule selectively, and often actively, take substances from the filtrate and move them out of the tubule into the blood. Recall that the glomerulus is simply a filter and anything suspended in the plasma that can fit through the holes in the filtration membrane can end up in the filtrate. This includes very physiologically important molecules such as water, sodium, chloride, and bicarbonate (along with many others) as well as molecules that the digestive system used a lot of energy to absorb, such as glucose and amino acids. These molecules would be lost in the urine if not reclaimed by the tubule cells. These cells are so efficient that they can reclaim all of the glucose and amino acids and up to 99% of the water and important ions lost due to glomerular filtration. The filtrate that is not reasbsorbed becomes urine at the base of the collecting duct.', '066b23c9-a978-4fbf-b10b-493ea6dd7838': 'Nephrons are the “functional units” of the kidney; they cleanse the blood of toxins and balance the constituents of the circulation to homeostatic set points through the processes of filtration, reabsorption, and secretion. The nephrons also function to control blood pressure (via production of renin), red blood cell production (via the hormone erythropoetin), and calcium absorption (via conversion of calcidiol into calcitriol, the active form of vitamin D).', '14552618-fe9e-43db-9389-3e93f577e75c': 'This section is about how the immune system goes wrong. When it goes haywire, and becomes too weak or too strong, it leads to a state of disease. The factors that maintain immunological homeostasis are complex and incompletely understood.', '498f8f2a-b050-4166-abb5-9d065a244fdd': 'The immune system is the complex collection of cells and organs that destroys or neutralizes pathogens that would otherwise cause disease or death. The lymphatic system, for most people, is associated with the immune system to such a degree that the two systems are virtually indistinguishable. The lymphatic system is the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood. The swelling of lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels are but two examples of the many connections between these critical organ systems.', '535b8abb-5a6e-4c96-a28d-2f4f781a63c4': 'Describe structural and functional differences of skeletal, cardiac, and smooth muscle tissue', '1b4d95d8-5492-46db-aad8-a65c586e4233': 'Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.', '069a73e3-7426-4a39-9941-c2f6e90737f2': 'A unique property common to all three types of muscle is\xa0contractility,\xa0which is the ability of the cells to shorten and generate force. \xa0While muscle tissue can shorten with contractions, it also displays\xa0extensibility\xa0or the ability to stretch and extend beyond the resting length of the cells. \xa0After being stretched, the elasticity\xa0of muscle allows it to recoil back to its original length.', '74637967-9cc6-445c-b01c-1083803def1b': 'The muscles all begin the mechanical process of contracting (shortening) when a protein called actin is pulled by a protein called myosin, and differences in the microscopic organization of these contractile proteins exist among the three muscle types.\xa0 In both skeletal and cardiac muscle, the actin and myosin proteins are arranged very regularly in the cytoplasm of individual muscle cells, which creates an alternating light and dark striped pattern called striations. The striations are visible with a light microscope under high magnification (see Figure 10.1.1). \xa0Smooth muscle (named for it’s lack of striations), does not produce this striped pattern because the contractile proteins are not arranged in such regular fashion.', '4eaded9d-9d7d-4c33-b204-2507c8b91b08': 'Skeletal muscle\xa0cells (also called muscle fibers)\xa0are unique in that they are multinucleated with the nuclei located on the periphery of the cell under the cell plasma membrane (also called sarcolemma in muscle).\xa0 During early development, embryonic myoblasts, each with its own nucleus, fuse with hundreds of other myoblasts to form long multinucleated skeletal muscle fibers.\xa0Cardiac muscle\xa0cells each generally have one nucleus centrally located in the cell, but the cells are physically and electrically connected to each other so that the contraction signals spread through cells and the entire heart contracts as one unit. \xa0Smooth muscle cells contain a single nucleus and can exist in electrically linked units contracting together as a single-unit or as multi-unit smooth muscle where cells are not electrically linked.', '83607dca-c2a9-41f7-bd6e-f99a9c2c0954': 'The best-known feature of skeletal muscle is its ability to contract and cause movement. Skeletal muscles act not only to produce movement but also to stop movement, such as resisting gravity to maintain posture. Small, constant adjustments of the skeletal muscles are needed to hold a body upright or balanced in any position. Muscles also prevent excess movement of the bones and joints, maintaining skeletal stability and preventing skeletal structure damage or deformation.\xa0\xa0Skeletal muscles are located throughout the body at the openings of internal tracts to control the movement of various substances. These muscles allow functions, such as swallowing, urination, and defecation, to be under voluntary control. Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external barrier or shield to external trauma and by supporting the weight of the organs.', 'b8d405e5-666f-400c-b736-9f516acb3e36': 'Skeletal muscles contribute to the maintenance of homeostasis in the body by generating heat. Muscle contraction requires energy, and when ATP is broken down, heat is produced. This heat is very noticeable during exercise, when sustained muscle movement causes body temperature to rise, and in cases of extreme cold, when shivering produces random skeletal muscle contractions to generate heat.', '981a9036-67c6-4a72-a4c0-44e6778734ed': 'Cardiac muscle is only found in the heart and functions to generate force and build pressure gradients to drive blood flow throughout the body. Smooth muscle in the walls of arteries is a critical component that regulates blood pressure and blood flow through the circulatory system. \xa0Smooth muscle in the skin, visceral organs, and internal passageways is also essential for moving materials through the body. Neither cardiac nor smooth muscle connect to bone and therefore they cannot produce the gross movements we associate with skeletal muscle.', 'd86919ae-8f74-4ed3-98ed-fdfe9173e989': 'When most people think of muscles, they think of the muscles that are visible just under the skin, particularly of the limbs. These are skeletal muscles, so-named because most of them move the skeleton. But there are two other types of muscle in the body, with distinctly different jobs. Cardiac muscle, found in the heart, is concerned with pumping blood through the circulatory system. Smooth muscle is concerned with various involuntary movements, such as having one’s hair stand on end when cold or frightened, or moving food through the digestive system. This chapter will examine the structure and function of these three types of muscles.'}"
+Figure 9.1.2,Anatomy_And_Physio/images/Figure 9.1.2.jpg,Figure 9.1.2 – Intervertebral Disc: An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint.,"In addition to being held together by symphyses at the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called zygapophysial joints (facet joints) (see Chapter 9.1 Figure 9.1.2). These are plane joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the range of motion available in each vertebral region; the cervical and lumbar regions have the greatest ranges of motions.","{'c1454f9a-293a-4f2d-9ca6-8899b939ad27': 'In addition to being held together by symphyses at the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called zygapophysial joints (facet joints) (see Chapter 9.1 Figure 9.1.2). These are plane\xa0joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the range\xa0of motion available in each vertebral region; the cervical and lumbar regions have the greatest ranges of motions.', '30debed4-82d2-48c0-9b93-c5b4fe9ff8d2': 'In the neck, the articular processes of cervical vertebrae are flattened and generally face upward or downward. This orientation provides the cervical vertebral column with extensive ranges of motion for flexion, extension, lateral flexion, and rotation. In the thoracic region, the downward projecting and overlapping spinous processes, along with the attached thoracic cage, greatly limit flexion, extension, and lateral flexion. However, the flattened and vertically positioned thoracic articular processes allow for the greatest range of rotation within the vertebral column. The lumbar region allows for considerable extension, flexion, and lateral flexion, but the orientation of the articular processes largely prohibits rotation.', 'e34a6d4e-263b-452f-910b-970956f8a5ba': 'The articulations formed between the skull, the atlas (C1 vertebra), and the axis (C2 vertebra) differ from the articulations in other vertebral areas and play important roles in movement of the head. The atlanto-occipital joint is formed by the articulations between the superior articular processes of the atlas and the occipital condyles on the base of the skull. This articulation has a pronounced U-shaped curvature, oriented along the anterior-posterior axis. This allows the skull to rock forward and backward, producing flexion and extension of the head. This moves the head up and down, as when shaking your head “yes.”', 'e5c8bf6d-2d1a-4e09-9ad0-4c46b539ff61': 'The atlantoaxial joint, between the atlas and axis, consists of three articulations. The paired superior articular processes of the axis articulate with the inferior articular processes of the atlas. These articulating surfaces are relatively flat and oriented horizontally. The third articulation is the pivot joint formed between the dens, which projects upward from the body of the axis, and the inner aspect of the anterior arch of the atlas (Figure 9.6.1). A strong ligament passes posterior to the dens to hold it in position against the anterior arch. These articulations allow the atlas to rotate on top of the axis, moving the head toward the right or left, as when shaking your head “no.”'}"
+Figure 9.6.1,Anatomy_And_Physio/images/Figure 9.6.1.jpg,"Figure 9.6.1 – Atlantoaxial Joint: The atlantoaxial joint is a pivot type of joint between the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament.","The atlantoaxial joint, between the atlas and axis, consists of three articulations. The paired superior articular processes of the axis articulate with the inferior articular processes of the atlas. These articulating surfaces are relatively flat and oriented horizontally. The third articulation is the pivot joint formed between the dens, which projects upward from the body of the axis, and the inner aspect of the anterior arch of the atlas (Figure 9.6.1). A strong ligament passes posterior to the dens to hold it in position against the anterior arch. These articulations allow the atlas to rotate on top of the axis, moving the head toward the right or left, as when shaking your head “no.”","{'c1454f9a-293a-4f2d-9ca6-8899b939ad27': 'In addition to being held together by symphyses at the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called zygapophysial joints (facet joints) (see Chapter 9.1 Figure 9.1.2). These are plane\xa0joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the range\xa0of motion available in each vertebral region; the cervical and lumbar regions have the greatest ranges of motions.', '30debed4-82d2-48c0-9b93-c5b4fe9ff8d2': 'In the neck, the articular processes of cervical vertebrae are flattened and generally face upward or downward. This orientation provides the cervical vertebral column with extensive ranges of motion for flexion, extension, lateral flexion, and rotation. In the thoracic region, the downward projecting and overlapping spinous processes, along with the attached thoracic cage, greatly limit flexion, extension, and lateral flexion. However, the flattened and vertically positioned thoracic articular processes allow for the greatest range of rotation within the vertebral column. The lumbar region allows for considerable extension, flexion, and lateral flexion, but the orientation of the articular processes largely prohibits rotation.', 'e34a6d4e-263b-452f-910b-970956f8a5ba': 'The articulations formed between the skull, the atlas (C1 vertebra), and the axis (C2 vertebra) differ from the articulations in other vertebral areas and play important roles in movement of the head. The atlanto-occipital joint is formed by the articulations between the superior articular processes of the atlas and the occipital condyles on the base of the skull. This articulation has a pronounced U-shaped curvature, oriented along the anterior-posterior axis. This allows the skull to rock forward and backward, producing flexion and extension of the head. This moves the head up and down, as when shaking your head “yes.”', 'e5c8bf6d-2d1a-4e09-9ad0-4c46b539ff61': 'The atlantoaxial joint, between the atlas and axis, consists of three articulations. The paired superior articular processes of the axis articulate with the inferior articular processes of the atlas. These articulating surfaces are relatively flat and oriented horizontally. The third articulation is the pivot joint formed between the dens, which projects upward from the body of the axis, and the inner aspect of the anterior arch of the atlas (Figure 9.6.1). A strong ligament passes posterior to the dens to hold it in position against the anterior arch. These articulations allow the atlas to rotate on top of the axis, moving the head toward the right or left, as when shaking your head “no.”'}"
+Figure 9.6.2,Anatomy_And_Physio/images/Figure 9.6.2.jpg,"Figure 9.6.2 – Temporomandibular Joint: The temporomandibular joint is the articulation between the temporal bone of the skull and the condyle of the mandible, with an articular disc located between these bones. During depression of the mandible (opening of the mouth), the mandibular condyle moves both forward and hinges downward as it travels from the mandibular fossa onto the articular tubercle.","The temporomandibular joint (TMJ) is the modified hinge joint that allows for mandibular depression and elevation, as well as excursion, and protraction/retraction of the lower jaw. This joint involves the articulation between the mandibular fossa and articular tubercle of the temporal bone, with the condyle (head) of the mandible. Located between these bony structures, filling the gap between the skull and mandible, is a flexible articular disc (Figure 9.6.2). This disc serves to smooth the movements between the temporal bone and mandibular condyle.","{'ff16de58-6fc1-4688-bd50-9a8b7e23aeaa': 'The temporomandibular joint (TMJ) is the modified hinge joint that allows for mandibular depression\xa0and elevation, as well as excursion, and protraction/retraction of the lower jaw. This joint involves the articulation between the mandibular fossa and articular tubercle of the temporal bone, with the condyle (head) of the mandible. Located between these bony structures, filling the gap between the skull and mandible, is a flexible articular disc (Figure 9.6.2). This disc serves to smooth the movements between the temporal bone and mandibular condyle.', '8fbdf673-f4ca-4104-8438-b2c34eed900d': 'Movement at the TMJ during opening and closing of the mouth involves both gliding and hinge motions of the mandible. With the mouth closed, the mandibular condyle and articular disc are located within the mandibular fossa of the temporal bone. During opening of the mouth, the mandible hinges downward and at the same time is pulled anteriorly, causing both the condyle and the articular disc to glide forward from the mandibular fossa onto the downward projecting articular tubercle. The net result is a forward and downward motion of the condyle and mandibular depression. The temporomandibular joint is supported by an extrinsic ligament that anchors the mandible to the skull.', '152005ef-d95c-4819-92c5-f017e07cbe7f': 'Dislocation of the TMJ may occur when opening the mouth too wide (such as when taking a large bite) or following a blow to the jaw, resulting in the mandibular condyle moving beyond (anterior to) the articular tubercle. In this case, the individual would not be able to close his or her mouth. Temporomandibular joint disorder is a painful condition that may arise due to arthritis, wearing of the articular cartilage covering the bony surfaces of the joint, muscle fatigue from overuse or grinding of the teeth, damage to the articular disc within the joint, or jaw injury. Temporomandibular joint disorders can also cause headache, difficulty chewing, or even the inability to move the jaw (lock jaw). Pharmacologic agents for pain or other therapies, including bite guards, are used as treatments.'}"
+Figure 9.6.3,Anatomy_And_Physio/images/Figure 9.6.3.jpg,Figure 9.6.3 – Glenohumeral Joint: The glenohumeral (shoulder) joint is a ball-and-socket joint that provides the widest range of motions. It has a loose articular capsule and is supported by ligaments and the rotator cuff muscles.,"The shoulder joint is called the glenohumeral joint. This is a ball-and-socket joint formed by the articulation between the head of the humerus and the glenoid cavity of the scapula (Figure 9.6.3). This joint has the largest range of motion of any joint in the body. However, this freedom of movement is due to the minimal structural support and thus the enhanced mobility is offset by a loss of stability.","{'031a95c0-d797-4849-8ddf-463c4af73eae': 'The shoulder joint is called the glenohumeral joint. This is a ball-and-socket joint formed by the articulation between the head of the humerus and the glenoid cavity of the scapula (Figure 9.6.3). This joint has the largest range of motion of any joint in the body. However, this freedom of movement is due to the minimal structural support and thus the enhanced mobility is offset by a loss of stability.', '228256f0-1da1-4e85-9dda-1b88453ae0b0': 'The large range of motions at the shoulder joint is provided by the articulation of the large, rounded humeral head with the small and shallow glenoid cavity, which is only about one third of the size of the humeral head. The socket formed by the glenoid cavity is deepened slightly by a small lip of fibrocartilage called the glenoid labrum, which extends around the outer margin of the cavity. The articular capsule that surrounds the glenohumeral joint is relatively thin and loose to allow for large motions of the upper limb. Some structural support for the joint is provided by thickenings of the articular capsule wall that form weak intrinsic ligaments. These include the coracohumeral ligament, running from the coracoid process of the scapula to the anterior humerus, and three ligaments, each called a glenohumeral ligament, located on the anterior side of the articular capsule. These ligaments help to strengthen the superior and anterior capsule walls.', '779d48b6-8099-4811-92b2-577750548f40': 'However, the primary support for the shoulder joint is provided by muscles crossing the joint, particularly the four rotator cuff muscles. These muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) arise from the scapula and attach to the greater or lesser tubercles of the humerus. As these muscles cross the shoulder joint, their tendons encircle the head of the humerus and become fused to the anterior, superior, and posterior walls of the articular capsule. The thickening of the capsule formed by the fusion of these four muscle tendons is called the rotator cuff. Two bursae, the subacromial bursa and the subscapular bursa, help to prevent friction between the rotator cuff muscle tendons and the scapula as these tendons cross the glenohumeral joint. In addition to their individual actions of moving the upper limb, the rotator cuff muscles also serve to hold the head of the humerus in position within the glenoid cavity. By constantly adjusting their strength of contraction to resist forces acting on the shoulder, these muscles serve as “dynamic ligaments” and thus provide the primary structural support for the glenohumeral joint.', '5815042a-a163-4e85-aa1f-69a2d799b8a0': 'Injuries to the shoulder joint are common. Repetitive use of the upper limb, particularly in abduction such as during throwing, swimming, or racquet sports, may lead to acute or chronic inflammation of the bursa or muscle tendons, a tear of the glenoid labrum, or degeneration or tears of the rotator cuff. Because the humeral head is strongly supported by the biceps brachii anteriorly, the acromion process of the scapula superiorly, and other tendons and ligaments on the anterior, superior and posterior aspects, most dislocations of the humerus occur in an inferior direction. This can occur when force is applied to the humerus when the upper limb is fully abducted, as when diving to catch a baseball and landing on your hand or elbow. Inflammatory responses to any shoulder injury can lead to the formation of scar tissue between the articular capsule and surrounding structures, thus reducing shoulder mobility, a condition called adhesive capsulitis (“frozen shoulder”).'}"
+Figure 9.6.4,Anatomy_And_Physio/images/Figure 9.6.4.jpg,"Figure 9.6.4 – Elbow Joint: (a) The elbow is a hinge joint that allows only for flexion and extension of the forearm. (b) It is supported by the ulnar and radial collateral ligaments. (c) The annular ligament supports the head of the radius at the proximal radioulnar joint, the pivot joint that allows for rotation of the radius","The elbow joint is a uniaxial hinge joint formed by the humeroulnar joint, the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Also associated with the elbow are the humeroradial joint and the proximal radioulnar joint. All three of these joints are enclosed within a single articular capsule (Figure 9.6.4).","{'108a8810-0466-4ab8-8b30-15b0beb83b11': 'The elbow joint is a uniaxial hinge joint formed by the humeroulnar joint, the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Also associated with the elbow are the humeroradial joint and the proximal radioulnar joint. All three of these joints are enclosed within a single articular capsule (Figure 9.6.4).', '45228966-9c9f-4a82-bd0a-fbbc27f4c568': 'The articular capsule of the elbow is thin on its anterior and posterior aspects, but is thickened along its outside margins by strong intrinsic ligaments. These ligaments prevent side-to-side movements and hyperextension. On the medial side is the triangular ulnar collateral ligament. This arises from the medial epicondyle of the humerus and attaches to the medial side of the proximal ulna. The strongest part of this ligament is the anterior portion, which resists hyperextension of the elbow. The ulnar collateral ligament may be injured by frequent, forceful extensions of the forearm, as is seen in baseball pitchers. Reconstructive surgical repair of this ligament is referred to as Tommy John surgery, named for the former major league pitcher who was the first person to have this treatment.', 'c112b3c8-7730-4646-878d-79c894ebc164': 'The lateral side of the elbow is supported by the radial collateral ligament. This arises from the lateral epicondyle of the humerus and then blends into the lateral side of the annular ligament. The annular ligament encircles the head of the radius. This ligament supports the head of the radius as it articulates with the radial notch of the ulna at the proximal radioulnar joint. This is a pivot joint that allows for rotation of the radius during supination and pronation of the forearm.'}"
+Figure 9.6.5,Anatomy_And_Physio/images/Figure 9.6.5.jpg,"Figure 9.6.5 – Hip Joint: (a) The ball-and-socket joint of the hip is a multiaxial joint that provides both stability and a wide range of motion. (b–c) When standing, the supporting ligaments are tight, pulling the head of the femur into the acetabulum.","The hip joint is a multiaxial ball-and-socket joint between the head of the femur and the acetabulum of the hip bone (Figure 9.6.5). The hip carries the weight of the body and thus requires strength and stability during standing and walking. For these reasons, its range of motion is more limited than at the shoulder joint, though it is capable of  the same actions as the shoulder.","{'87fcdc42-017f-4ed5-b196-ba5a153f5836': 'The hip joint is a multiaxial ball-and-socket joint between the head of the femur and the acetabulum of the hip bone (Figure 9.6.5). The hip carries the weight of the body and thus requires strength and stability during standing and walking. For these reasons, its range of motion is more limited than at the shoulder joint, though it is capable of \xa0the same actions as the shoulder.', 'c731536f-1719-4793-ac06-757a0bea57c1': 'The acetabulum is the socket portion of the hip joint. This space is deep and has a large articulation area for the femoral head, thus giving stability and weight bearing ability to the joint. The acetabulum is further deepened by the acetabular labrum, a fibrocartilage lip attached to the outer margin of the acetabulum. The surrounding articular capsule is strong, with several thickened areas forming intrinsic ligaments. These ligaments arise from the hip bone, at the margins of the acetabulum, and attach to the femur at the base of the neck. The ligaments are the iliofemoral ligament, pubofemoral ligament, and ischiofemoral ligament, all of which spiral around the head and neck of the femur. The ligaments are tightened by extension at the hip, thus pulling the head of the femur tightly into the acetabulum when in the upright, standing position. Very little additional extension of the thigh is permitted beyond this vertical position. These ligaments thus stabilize the hip joint and allow you to maintain an upright standing position with only minimal muscle contraction. Inside of the articular capsule, the ligament of the head of the femur (ligamentum teres) spans between the acetabulum and femoral head. This intracapsular ligament is normally slack and does not provide any significant joint support, but it does provide a pathway for an important artery that supplies the head of the femur.', '3102c917-130f-41ce-b657-2d3b147297b6': 'The hip is prone to osteoarthritis, and thus was the first joint for which a replacement prosthesis was developed. A common injury in elderly individuals, particularly those with weakened bones due to osteoporosis, is a “broken hip,” which is actually a fracture of the femoral neck. This may result from a fall, or it may cause the fall. This can happen as one lower limb is taking a step and all of the body weight is placed on the other limb, causing the femoral neck to break and producing a fall. Any accompanying disruption of the blood supply to the femoral neck or head can lead to necrosis of these areas, resulting in bone and cartilage death. Femoral fractures usually require surgical treatment, after which the patient will need mobility assistance for a prolonged period. Consequentially, the associated health care costs of “broken hips” are substantial. In addition, hip fractures are associated with increased rates of morbidity (incidences of disease) and mortality (death). Surgery for a hip fracture followed by prolonged bed rest may lead to life-threatening complications, including pneumonia, infection of pressure ulcers (bedsores), and thrombophlebitis (deep vein thrombosis; blood clot formation) that can result in a pulmonary embolism (blood clot within the lung).'}"
+Figure 9.6.6,Anatomy_And_Physio/images/Figure 9.6.6.jpg,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles.","The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.","{'82ebe0b0-2067-4983-8f7e-502809d9c0a2': 'The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.', 'eeeb86bf-3572-47f7-965c-dbe33871bc0c': 'At the femoropatellar joint, the patella slides vertically within a groove on the distal femur. The patella is a sesamoid bone incorporated into the tendon of the quadriceps femoris group, which are four\xa0large muscles of the anterior thigh. The patella serves to protect the quadriceps tendon from friction against the distal femur. Continuing from the patella to the anterior tibia just below the knee is the patellar ligament. Acting via the patella and patellar ligament, the quadriceps are\xa0powerful muscles that act to extend the leg at the knee. It\xa0also serves as a “dynamic ligament” to provide very important support and stabilization for the knee joint.', 'd5dff95f-97aa-49a3-b31b-c8d21f50715c': 'The medial and lateral tibiofemoral joints are the articulations between the rounded condyles of the femur and the relatively flat condyles of the tibia. During flexion and extension motions, the condyles of the femur both roll and glide over the surfaces of the tibia. The rolling action produces flexion or extension, while the gliding action serves to maintain the femoral condyles centered over the tibial condyles, thus ensuring maximal bony, weight-bearing support for the femur in all knee positions. As the knee comes into full extension, the femur undergoes a slight medial rotation in relation to tibia. The rotation results because the lateral condyle of the femur is slightly smaller than the medial condyle. Thus, the lateral condyle finishes its rolling motion first, followed by the medial condyle. The resulting small medial rotation of the femur serves to “lock” the knee into its fully extended and most stable position. Flexion of the knee is initiated by a slight lateral rotation of the femur on the tibia, which “unlocks” the knee. This lateral rotation motion is produced by the popliteus muscle of the posterior leg. This slight rotation of the knee is why it is referred to as a modified hinge, as opposed to a true hinge which is only capable of flexion and extension.', '19dde259-82a2-4351-9254-51fdb43d000b': 'Located between the articulating surfaces of the femur and tibia are two articular discs, the medial meniscus and lateral meniscus (see Figure 9.6.6b). Each is a C-shaped fibrocartilage structure that is thin along its inside margin and thick along the outer margin. They are attached to their tibial condyles, but do not attach to the femur. The menisci provide padding between the bones and help to fill the gap between the round femoral condyles and flattened tibial condyles. Some areas of each meniscus lack an arterial blood supply and thus these areas heal poorly if damaged.', 'c8f5d53f-4fb4-4cd5-9bc3-537b22fe6e29': 'The knee joint has multiple ligaments that provide support, particularly in the extended position (see Figure 9.6.6c). Outside of the articular capsule, located at the sides of the knee, are two extrinsic ligaments. The fibular collateral ligament (lateral collateral ligament) is on the lateral side and spans from the lateral epicondyle of the femur to the head of the fibula. The tibial collateral ligament (medial collateral ligament) of the medial knee runs from the medial epicondyle of the femur to the medial tibia. As it crosses the knee, the tibial collateral ligament is firmly attached on its internal\xa0surface\xa0to the articular capsule and to the medial meniscus, an important factor when considering knee injuries. In the fully extended knee position, both collateral ligaments are taut (tight), thus serving to stabilize and support the extended knee and preventing side-to-side or rotational motions between the femur and tibia.', 'a3deb882-2b07-4873-96c2-155be31635dc': 'The articular capsule of the posterior knee is thickened by intrinsic ligaments that help to resist knee hyperextension. Inside the knee are two intracapsular ligaments, the anterior cruciate ligament and posterior cruciate ligament. These ligaments are anchored inferiorly to the tibia at the intercondylar eminence, the roughened area between the tibial condyles. The cruciate ligaments are named for whether they are attached anteriorly or posteriorly to this tibial region. Each ligament runs diagonally upward to attach to the inner aspect of a femoral condyle. The cruciate ligaments are named for the X-shape formed as they pass each other (cruciate means “cross”). The posterior cruciate ligament is the stronger ligament. It serves to support the knee when it is flexed and weight bearing, as when walking downhill. In this position, the posterior cruciate ligament prevents the femur from sliding anteriorly off the top of the tibia. The anterior cruciate ligament becomes tight when the knee is extended, and thus resists hyperextension.'}"
+Figure 9.6.6,Anatomy_And_Physio/images/Figure 9.6.6.jpg,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles.","The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.","{'82ebe0b0-2067-4983-8f7e-502809d9c0a2': 'The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.', 'eeeb86bf-3572-47f7-965c-dbe33871bc0c': 'At the femoropatellar joint, the patella slides vertically within a groove on the distal femur. The patella is a sesamoid bone incorporated into the tendon of the quadriceps femoris group, which are four\xa0large muscles of the anterior thigh. The patella serves to protect the quadriceps tendon from friction against the distal femur. Continuing from the patella to the anterior tibia just below the knee is the patellar ligament. Acting via the patella and patellar ligament, the quadriceps are\xa0powerful muscles that act to extend the leg at the knee. It\xa0also serves as a “dynamic ligament” to provide very important support and stabilization for the knee joint.', 'd5dff95f-97aa-49a3-b31b-c8d21f50715c': 'The medial and lateral tibiofemoral joints are the articulations between the rounded condyles of the femur and the relatively flat condyles of the tibia. During flexion and extension motions, the condyles of the femur both roll and glide over the surfaces of the tibia. The rolling action produces flexion or extension, while the gliding action serves to maintain the femoral condyles centered over the tibial condyles, thus ensuring maximal bony, weight-bearing support for the femur in all knee positions. As the knee comes into full extension, the femur undergoes a slight medial rotation in relation to tibia. The rotation results because the lateral condyle of the femur is slightly smaller than the medial condyle. Thus, the lateral condyle finishes its rolling motion first, followed by the medial condyle. The resulting small medial rotation of the femur serves to “lock” the knee into its fully extended and most stable position. Flexion of the knee is initiated by a slight lateral rotation of the femur on the tibia, which “unlocks” the knee. This lateral rotation motion is produced by the popliteus muscle of the posterior leg. This slight rotation of the knee is why it is referred to as a modified hinge, as opposed to a true hinge which is only capable of flexion and extension.', '19dde259-82a2-4351-9254-51fdb43d000b': 'Located between the articulating surfaces of the femur and tibia are two articular discs, the medial meniscus and lateral meniscus (see Figure 9.6.6b). Each is a C-shaped fibrocartilage structure that is thin along its inside margin and thick along the outer margin. They are attached to their tibial condyles, but do not attach to the femur. The menisci provide padding between the bones and help to fill the gap between the round femoral condyles and flattened tibial condyles. Some areas of each meniscus lack an arterial blood supply and thus these areas heal poorly if damaged.', 'c8f5d53f-4fb4-4cd5-9bc3-537b22fe6e29': 'The knee joint has multiple ligaments that provide support, particularly in the extended position (see Figure 9.6.6c). Outside of the articular capsule, located at the sides of the knee, are two extrinsic ligaments. The fibular collateral ligament (lateral collateral ligament) is on the lateral side and spans from the lateral epicondyle of the femur to the head of the fibula. The tibial collateral ligament (medial collateral ligament) of the medial knee runs from the medial epicondyle of the femur to the medial tibia. As it crosses the knee, the tibial collateral ligament is firmly attached on its internal\xa0surface\xa0to the articular capsule and to the medial meniscus, an important factor when considering knee injuries. In the fully extended knee position, both collateral ligaments are taut (tight), thus serving to stabilize and support the extended knee and preventing side-to-side or rotational motions between the femur and tibia.', 'a3deb882-2b07-4873-96c2-155be31635dc': 'The articular capsule of the posterior knee is thickened by intrinsic ligaments that help to resist knee hyperextension. Inside the knee are two intracapsular ligaments, the anterior cruciate ligament and posterior cruciate ligament. These ligaments are anchored inferiorly to the tibia at the intercondylar eminence, the roughened area between the tibial condyles. The cruciate ligaments are named for whether they are attached anteriorly or posteriorly to this tibial region. Each ligament runs diagonally upward to attach to the inner aspect of a femoral condyle. The cruciate ligaments are named for the X-shape formed as they pass each other (cruciate means “cross”). The posterior cruciate ligament is the stronger ligament. It serves to support the knee when it is flexed and weight bearing, as when walking downhill. In this position, the posterior cruciate ligament prevents the femur from sliding anteriorly off the top of the tibia. The anterior cruciate ligament becomes tight when the knee is extended, and thus resists hyperextension.'}"
+Figure 9.6.6,Anatomy_And_Physio/images/Figure 9.6.6.jpg,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles.","The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.","{'82ebe0b0-2067-4983-8f7e-502809d9c0a2': 'The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.', 'eeeb86bf-3572-47f7-965c-dbe33871bc0c': 'At the femoropatellar joint, the patella slides vertically within a groove on the distal femur. The patella is a sesamoid bone incorporated into the tendon of the quadriceps femoris group, which are four\xa0large muscles of the anterior thigh. The patella serves to protect the quadriceps tendon from friction against the distal femur. Continuing from the patella to the anterior tibia just below the knee is the patellar ligament. Acting via the patella and patellar ligament, the quadriceps are\xa0powerful muscles that act to extend the leg at the knee. It\xa0also serves as a “dynamic ligament” to provide very important support and stabilization for the knee joint.', 'd5dff95f-97aa-49a3-b31b-c8d21f50715c': 'The medial and lateral tibiofemoral joints are the articulations between the rounded condyles of the femur and the relatively flat condyles of the tibia. During flexion and extension motions, the condyles of the femur both roll and glide over the surfaces of the tibia. The rolling action produces flexion or extension, while the gliding action serves to maintain the femoral condyles centered over the tibial condyles, thus ensuring maximal bony, weight-bearing support for the femur in all knee positions. As the knee comes into full extension, the femur undergoes a slight medial rotation in relation to tibia. The rotation results because the lateral condyle of the femur is slightly smaller than the medial condyle. Thus, the lateral condyle finishes its rolling motion first, followed by the medial condyle. The resulting small medial rotation of the femur serves to “lock” the knee into its fully extended and most stable position. Flexion of the knee is initiated by a slight lateral rotation of the femur on the tibia, which “unlocks” the knee. This lateral rotation motion is produced by the popliteus muscle of the posterior leg. This slight rotation of the knee is why it is referred to as a modified hinge, as opposed to a true hinge which is only capable of flexion and extension.', '19dde259-82a2-4351-9254-51fdb43d000b': 'Located between the articulating surfaces of the femur and tibia are two articular discs, the medial meniscus and lateral meniscus (see Figure 9.6.6b). Each is a C-shaped fibrocartilage structure that is thin along its inside margin and thick along the outer margin. They are attached to their tibial condyles, but do not attach to the femur. The menisci provide padding between the bones and help to fill the gap between the round femoral condyles and flattened tibial condyles. Some areas of each meniscus lack an arterial blood supply and thus these areas heal poorly if damaged.', 'c8f5d53f-4fb4-4cd5-9bc3-537b22fe6e29': 'The knee joint has multiple ligaments that provide support, particularly in the extended position (see Figure 9.6.6c). Outside of the articular capsule, located at the sides of the knee, are two extrinsic ligaments. The fibular collateral ligament (lateral collateral ligament) is on the lateral side and spans from the lateral epicondyle of the femur to the head of the fibula. The tibial collateral ligament (medial collateral ligament) of the medial knee runs from the medial epicondyle of the femur to the medial tibia. As it crosses the knee, the tibial collateral ligament is firmly attached on its internal\xa0surface\xa0to the articular capsule and to the medial meniscus, an important factor when considering knee injuries. In the fully extended knee position, both collateral ligaments are taut (tight), thus serving to stabilize and support the extended knee and preventing side-to-side or rotational motions between the femur and tibia.', 'a3deb882-2b07-4873-96c2-155be31635dc': 'The articular capsule of the posterior knee is thickened by intrinsic ligaments that help to resist knee hyperextension. Inside the knee are two intracapsular ligaments, the anterior cruciate ligament and posterior cruciate ligament. These ligaments are anchored inferiorly to the tibia at the intercondylar eminence, the roughened area between the tibial condyles. The cruciate ligaments are named for whether they are attached anteriorly or posteriorly to this tibial region. Each ligament runs diagonally upward to attach to the inner aspect of a femoral condyle. The cruciate ligaments are named for the X-shape formed as they pass each other (cruciate means “cross”). The posterior cruciate ligament is the stronger ligament. It serves to support the knee when it is flexed and weight bearing, as when walking downhill. In this position, the posterior cruciate ligament prevents the femur from sliding anteriorly off the top of the tibia. The anterior cruciate ligament becomes tight when the knee is extended, and thus resists hyperextension.'}"
+Figure 9.6.8,Anatomy_And_Physio/images/Figure 9.6.8.jpg,"Figure 9.6.8 – Ankle Joint: The talocrural (ankle) joint is a uniaxial hinge joint that only allows for dorsiflexion or plantar flexion of the foot. Movements at the subtalar joint, between the talus and calcaneus bones, combined with motions at other intertarsal joints, enables eversion/inversion movements of the foot. Ligaments that unite the medial or lateral malleolus with the talus and calcaneus bones serve to support the talocrural joint and to resist excess eversion or inversion of the foot.","The ankle is formed by the talocrural joint (Figure 9.6.8). It consists of the articulations between the talus bone of the foot and the distal ends of the tibia and fibula of the leg (crural = “leg”). The superior aspect of the talus bone is square-shaped and has three areas of articulation. The top of the talus articulates with the inferior tibia. This is the portion of the ankle joint that carries the body weight between the leg and foot. The sides of the talus are firmly held in position by the articulations with the medial malleolus of the tibia and the lateral malleolus of the fibula, which prevent any side-to-side motion of the talus. The ankle is a true hinge joint that allows only for dorsiflexion and plantar flexion of the foot.","{'0f0aeda9-8d5e-4887-8692-79fd4a6b9ba5': 'The ankle is formed by the talocrural joint (Figure 9.6.8). It consists of the articulations between the talus bone of the foot and the distal ends of the tibia and fibula of the leg (crural = “leg”). The superior aspect of the talus bone is square-shaped and has three areas of articulation. The top of the talus articulates with the inferior tibia. This is the portion of the ankle joint that carries the body weight between the leg and foot. The sides of the talus are firmly held in position by the articulations with the medial malleolus of the tibia and the lateral malleolus of the fibula, which prevent any side-to-side motion of the talus. The ankle is a true\xa0hinge joint that allows only for dorsiflexion and plantar flexion of the foot.', '4768773d-8999-4d44-a654-246d6abb14e7': 'Additional joints between the tarsal bones of the posterior foot allow for the movements of foot inversion and eversion. Most important for these movements is the subtalar joint, located between the talus and calcaneus bones. The joints between the talus and navicular bones and the calcaneus and cuboid bones are also important contributors to these movements. All of the joints between tarsal bones are plane joints. Together, the small motions that take place at these joints all contribute to the production of inversion and eversion foot motions.', 'acd5ee06-1222-4b2e-a58f-08da1d1461c7': 'Like the hinge joints of the elbow and knee, the talocrural joint of the ankle is supported by several strong ligaments located on the sides of the joint. These ligaments extend from the medial malleolus of the tibia or lateral malleolus of the fibula and anchor to the talus and calcaneus bones. Since they are located on the sides of the ankle joint, they allow for dorsiflexion and plantar flexion of the foot. They also prevent abnormal side-to-side and twisting movements of the talus and calcaneus bones during eversion and inversion of the foot. On the medial side is the broad deltoid ligament. The deltoid ligament supports the ankle joint and also resists excessive eversion of the foot. The lateral side of the ankle has several smaller ligaments. These include the anterior talofibular ligament and the posterior talofibular ligament, both of which span between the talus bone and the lateral malleolus of the fibula, and the calcaneofibular ligament, located between the calcaneus bone and fibula. These ligaments support the ankle and also resist excess inversion of the foot.'}"
+Figure 9.5.1,Anatomy_And_Physio/images/Figure 9.5.1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).","Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.","{'b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9': 'Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.', '09f72c4e-4abd-4867-95a7-468b082a41b6': 'Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.', 'e034a39b-764c-42b5-86a0-205d9dd1885c': 'In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).', 'abeb041e-ac9e-4fd5-b475-995a6c8b2433': 'Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.', '0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc': 'Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).', '8e3ea142-ccbb-41e5-badf-a36dc5d2e607': 'Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).', '8a75dbcb-42e3-4233-8a2d-18dd756aa6ed': 'Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.', '061c3599-4a25-4c5a-a2d6-bb222b4b15ee': 'Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.'}"
+Figure 9.5.1,Anatomy_And_Physio/images/Figure 9.5.1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).","Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.","{'b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9': 'Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.', '09f72c4e-4abd-4867-95a7-468b082a41b6': 'Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.', 'e034a39b-764c-42b5-86a0-205d9dd1885c': 'In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).', 'abeb041e-ac9e-4fd5-b475-995a6c8b2433': 'Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.', '0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc': 'Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).', '8e3ea142-ccbb-41e5-badf-a36dc5d2e607': 'Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).', '8a75dbcb-42e3-4233-8a2d-18dd756aa6ed': 'Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.', '061c3599-4a25-4c5a-a2d6-bb222b4b15ee': 'Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.'}"
+Figure 9.5.1,Anatomy_And_Physio/images/Figure 9.5.1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).","Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.","{'b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9': 'Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.', '09f72c4e-4abd-4867-95a7-468b082a41b6': 'Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.', 'e034a39b-764c-42b5-86a0-205d9dd1885c': 'In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).', 'abeb041e-ac9e-4fd5-b475-995a6c8b2433': 'Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.', '0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc': 'Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).', '8e3ea142-ccbb-41e5-badf-a36dc5d2e607': 'Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).', '8a75dbcb-42e3-4233-8a2d-18dd756aa6ed': 'Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.', '061c3599-4a25-4c5a-a2d6-bb222b4b15ee': 'Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.'}"
+Figure 9.5.1,Anatomy_And_Physio/images/Figure 9.5.1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).","Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.","{'b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9': 'Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.', '09f72c4e-4abd-4867-95a7-468b082a41b6': 'Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.', 'e034a39b-764c-42b5-86a0-205d9dd1885c': 'In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).', 'abeb041e-ac9e-4fd5-b475-995a6c8b2433': 'Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.', '0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc': 'Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).', '8e3ea142-ccbb-41e5-badf-a36dc5d2e607': 'Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).', '8a75dbcb-42e3-4233-8a2d-18dd756aa6ed': 'Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.', '061c3599-4a25-4c5a-a2d6-bb222b4b15ee': 'Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.'}"
+Figure 9.5.1,Anatomy_And_Physio/images/Figure 9.5.1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).","Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.","{'b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9': 'Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.', '09f72c4e-4abd-4867-95a7-468b082a41b6': 'Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.', 'e034a39b-764c-42b5-86a0-205d9dd1885c': 'In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).', 'abeb041e-ac9e-4fd5-b475-995a6c8b2433': 'Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.', '0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc': 'Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).', '8e3ea142-ccbb-41e5-badf-a36dc5d2e607': 'Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).', '8a75dbcb-42e3-4233-8a2d-18dd756aa6ed': 'Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.', '061c3599-4a25-4c5a-a2d6-bb222b4b15ee': 'Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.5.2,Anatomy_And_Physio/images/Figure 9.5.2.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.","Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).","{'193115a3-0d0a-4750-8e2d-0a3d449bf4dd': 'Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.', '8b655d5d-9a06-4b66-8f51-bb253dd6f6dd': 'Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).', 'c9169291-eb22-4ef7-acb0-4b5194f55f41': 'Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).', 'edd85379-1849-47b4-bcfc-adba48a8ab39': 'Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).', '13d7460e-3500-4848-a40c-592817813782': 'Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)', 'f24d0f73-cf47-494d-beaa-61168957a776': 'Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).', 'ffe49292-19b2-488b-a4e4-61de84b163e5': 'Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).'}"
+Figure 9.4.1,Anatomy_And_Physio/images/Figure 9.4.1.jpg,Figure 9.4.1 – Synovial Joints: Synovial joints allow for smooth movements between the adjacent bones. The joint is surrounded by an articular capsule that defines a joint cavity filled with synovial fluid. The articulating surfaces of the bones are covered by a thin layer of articular cartilage. Ligaments support the joint by holding the bones together and resisting excess or abnormal joint motions.,"Synovial joints are the most common type of joint in the body (Figure 9.4.1). A key structural characteristic for a synovial joint that is not seen at fibrous or cartilaginous joints is the presence of a joint cavity. This fluid-filled space is the site at which the articulating surfaces of the bones contact each other. At synovial joints, the articular surfaces of bones are covered with smooth articular cartilage. This gives the bones of a synovial joint the ability to move smoothly against each other, allowing for increased joint mobility.","{'606c70ef-ae85-4f12-b4cc-66ba16f1431f': 'Synovial joints are the most common type of joint in the body (Figure 9.4.1). A key structural characteristic for a synovial joint that is not seen at fibrous or cartilaginous joints is the presence of a joint cavity. This fluid-filled space is the site at which the articulating surfaces of the bones contact each other. At synovial joints, the articular surfaces of bones are covered with smooth articular cartilage. This gives the bones of a synovial joint the ability to move smoothly against each other, allowing for increased joint mobility.'}"
+Figure 9.4.2,Anatomy_And_Physio/images/Figure 9.4.2.jpg,"Figure 9.4.2 – Bursae: Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg","Additional structures located outside of a synovial joint serve to prevent friction between the bones of the joint and the overlying muscle tendons or skin. A bursa (plural = bursae) is a thin connective tissue sac filled with lubricating liquid. They are located in regions where skin, ligaments, muscles, or muscle tendons can rub against each other, usually near a body joint (Figure 9.4.2). Bursae reduce friction by separating the adjacent structures, preventing them from rubbing directly against each other. Bursae are classified by their location. A subcutaneous bursa is located between the skin and an underlying bone. It allows skin to move smoothly over the bone. Examples include the prepatellar bursa located over the kneecap and the olecranon bursa at the tip of the elbow. A submuscular bursa is found between a muscle and an underlying bone, or between adjacent muscles. These prevent rubbing of the muscle during movements. A large submuscular bursa, the trochanteric bursa, is found at the lateral hip, between the greater trochanter of the femur and the overlying gluteus maximus muscle. A subtendinous bursa is found between a tendon and a bone. Examples include the subacromial bursa that protects the tendon of shoulder muscle as it passes under the acromion of the scapula, and the suprapatellar bursa that separates the tendon of the large anterior thigh muscle from the distal femur just above the knee.","{'b9583703-1799-4f7c-bb62-dd073f65f1d0': 'A few synovial joints of the body have a fibrocartilage structure located between the articulating bones. This is called an articular disc, which is generally small and oval-shaped, or a meniscus, which is larger and C-shaped. These structures can serve several functions, depending on the specific joint. In some places, an articular disc may act to strongly unite the bones of the joint to each other. Examples of this include the articular discs found at the sternoclavicular joint or between the distal ends of the radius and ulna bones. At other synovial joints, the disc can provide shock absorption and cushioning between the bones, which is the function of each meniscus within the knee joint. Finally, an articular disc can serve to smooth the movements between the articulating bones, as seen at the temporomandibular joint. Some synovial joints also have a fat pad, which can serve as a cushion between the bones.', 'ec912e68-0731-498b-8b49-a24cd76a3ae0': 'Additional structures located outside of a synovial joint serve to prevent friction between the bones of the joint and the overlying muscle tendons or skin. A bursa (plural = bursae) is a thin connective tissue sac filled with lubricating liquid. They are located in regions where skin, ligaments, muscles, or muscle tendons can rub against each other, usually near a body joint (Figure 9.4.2). Bursae reduce friction by separating the adjacent structures, preventing them from rubbing directly against each other. Bursae are classified by their location. A subcutaneous bursa is located between the skin and an underlying bone. It allows skin to move smoothly over the bone. Examples include the prepatellar bursa located over the kneecap and the olecranon bursa at the tip of the elbow. A submuscular bursa is found between a muscle and an underlying bone, or between adjacent muscles. These prevent rubbing of the muscle during movements. A large submuscular bursa, the trochanteric bursa, is found at the lateral hip, between the greater trochanter of the femur and the overlying gluteus maximus muscle. A subtendinous bursa is found between a tendon and a bone. Examples include the subacromial bursa that protects the tendon of shoulder muscle as it passes under the acromion of the scapula, and the suprapatellar bursa that separates the tendon of the large anterior thigh muscle from the distal femur just above the knee.', 'b24d79b4-0302-41ad-87f1-e40677ab4ed0': 'A tendon sheath is similar in structure to a bursa, but smaller. It is a connective tissue sac that surrounds a muscle tendon at places where the tendon crosses a joint. It contains a lubricating fluid that allows for smooth motions of the tendon during muscle contraction and joint movements.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.4.3,Anatomy_And_Physio/images/Figure 9.4.3.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.","Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).","{'c5caa4d6-97f5-4287-8934-f2cd47a2b040': 'Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).', 'c12df6db-a815-47d7-9dc8-380de6510172': 'At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.', '866a2109-44e1-4c1d-88b4-603dac876cd9': 'In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.', 'e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64': 'At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.', 'e0c0b690-db27-4122-bc0c-e126f425860d': 'At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.', '87587173-a70e-4e0e-af94-033ed46fe4d6': 'At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation\xa0and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).', '5567414a-7be0-4af0-9683-75b85b809a76': 'The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.', '263409d4-f18d-4419-b36a-85941b614055': 'Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.'}"
+Figure 9.3.1,Anatomy_And_Physio/images/Figure 9.3.1.jpg,"Figure 9.3.1 – Cartiliginous Joints: At cartilaginous joints, bones are united by hyaline cartilage to form a synchondrosis or by fibrocartilage to form a symphysis. (a) The hyaline cartilage of the epiphyseal plate (growth plate) forms a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length. (b) The pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage, forming the pubic symphysis.","As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.","{'f52703d1-68c3-408b-a57a-61bd4693ffa6': 'As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.', '38521220-23b7-4852-acf0-423e4ba5f27a': 'At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.'}"
+Figure 9.2.1,Anatomy_And_Physio/images/Figure 9.2.1.jpg,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.,"At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.","{'f52703d1-68c3-408b-a57a-61bd4693ffa6': 'As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.', '38521220-23b7-4852-acf0-423e4ba5f27a': 'At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.', 'c29499c4-0b81-4c39-a64e-6460ca6700d0': 'All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate\xa0closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.', '53b7e019-aac7-4381-b0a5-5f755d007dc6': 'In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.', '5be9873d-3348-4a7d-aec6-3b9c30fc52bd': 'A syndesmosis (“fastened with a band”, plural = syndesmoses) is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane.', 'e8e24c7f-64ef-4677-a687-d66d7556f935': 'In the forearm, the wide gap between the shaft portions of the radius and ulna bones are strongly united by an interosseous membrane (see Figure 9.2.1b). Similarly, in the leg, the shafts of the tibia and fibula are also united by an interosseous membrane. In addition, at the distal tibiofibular joint, the narrow gap between the bones is anchored by fibrous connective tissue and ligaments on both the anterior and posterior aspects of the joint. Together, the interosseous membrane and these ligaments form the tibiofibular syndesmosis.', '6e73008b-458c-4075-ad3f-5de29eebe1cf': 'The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation. However, a syndesmosis does not prevent all movement between the bones, and thus this type of fibrous joint is functionally classified as an amphiarthrosis. In the leg, the syndesmosis between the tibia and fibula strongly unites the bones, allows for little movement, and firmly locks the talus bone in place between the tibia and fibula at the ankle joint. This provides strength and stability to the leg and ankle, which are important during weight bearing. In the forearm, the interosseous membrane is flexible enough to allow for rotation of the radius bone during forearm movements. Thus in contrast to the stability provided by the tibiofibular syndesmosis, the flexibility of the antebrachial (forearm) interosseous membrane allows for the much greater mobility of the forearm.', '2b408eb3-4c1c-4abd-96d1-f4042be434d8': 'The interosseous membranes of the leg and forearm also provide areas for muscle attachment. Damage to a syndesmotic joint, which usually results from a fracture of the bone with an accompanying tear of the interosseous membrane, will produce pain, loss of stability of the bones, and may damage the muscles attached to the interosseous membrane. If the fracture site is not properly immobilized with a cast or splint, contractile activity by these muscles can cause improper alignment of the broken bones during healing.', '516f84ae-b08e-47f9-be84-a79cee61df73': 'A gomphosis (“fastened with bolts”, plural = gomphoses) is the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull. A gomphosis is also known as a peg-and-socket joint and is considered a joint even though teeth are not bones. Spanning between the bony walls of the socket and the root of the tooth are numerous short bands of dense connective tissue, each of which is called a periodontal ligament (see Figure 9.2.1c). Due to the immobility of a gomphosis, this type of joint is functionally classified as a synarthrosis.'}"
+Figure 9.2.1,Anatomy_And_Physio/images/Figure 9.2.1.jpg,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.,"At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.","{'f52703d1-68c3-408b-a57a-61bd4693ffa6': 'As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.', '38521220-23b7-4852-acf0-423e4ba5f27a': 'At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.', 'c29499c4-0b81-4c39-a64e-6460ca6700d0': 'All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate\xa0closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.', '53b7e019-aac7-4381-b0a5-5f755d007dc6': 'In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.', '5be9873d-3348-4a7d-aec6-3b9c30fc52bd': 'A syndesmosis (“fastened with a band”, plural = syndesmoses) is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane.', 'e8e24c7f-64ef-4677-a687-d66d7556f935': 'In the forearm, the wide gap between the shaft portions of the radius and ulna bones are strongly united by an interosseous membrane (see Figure 9.2.1b). Similarly, in the leg, the shafts of the tibia and fibula are also united by an interosseous membrane. In addition, at the distal tibiofibular joint, the narrow gap between the bones is anchored by fibrous connective tissue and ligaments on both the anterior and posterior aspects of the joint. Together, the interosseous membrane and these ligaments form the tibiofibular syndesmosis.', '6e73008b-458c-4075-ad3f-5de29eebe1cf': 'The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation. However, a syndesmosis does not prevent all movement between the bones, and thus this type of fibrous joint is functionally classified as an amphiarthrosis. In the leg, the syndesmosis between the tibia and fibula strongly unites the bones, allows for little movement, and firmly locks the talus bone in place between the tibia and fibula at the ankle joint. This provides strength and stability to the leg and ankle, which are important during weight bearing. In the forearm, the interosseous membrane is flexible enough to allow for rotation of the radius bone during forearm movements. Thus in contrast to the stability provided by the tibiofibular syndesmosis, the flexibility of the antebrachial (forearm) interosseous membrane allows for the much greater mobility of the forearm.', '2b408eb3-4c1c-4abd-96d1-f4042be434d8': 'The interosseous membranes of the leg and forearm also provide areas for muscle attachment. Damage to a syndesmotic joint, which usually results from a fracture of the bone with an accompanying tear of the interosseous membrane, will produce pain, loss of stability of the bones, and may damage the muscles attached to the interosseous membrane. If the fracture site is not properly immobilized with a cast or splint, contractile activity by these muscles can cause improper alignment of the broken bones during healing.', '516f84ae-b08e-47f9-be84-a79cee61df73': 'A gomphosis (“fastened with bolts”, plural = gomphoses) is the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull. A gomphosis is also known as a peg-and-socket joint and is considered a joint even though teeth are not bones. Spanning between the bony walls of the socket and the root of the tooth are numerous short bands of dense connective tissue, each of which is called a periodontal ligament (see Figure 9.2.1c). Due to the immobility of a gomphosis, this type of joint is functionally classified as a synarthrosis.'}"
+Figure 9.2.2,Anatomy_And_Physio/images/Figure 9.2.2.jpg,Figure 9.2.2 – The Newborn Skull: The fontanelles of a newborn’s skull are broad areas of fibrous connective tissue that form fibrous joints between the bones of the skull.,"In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.","{'c29499c4-0b81-4c39-a64e-6460ca6700d0': 'All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate\xa0closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.', '53b7e019-aac7-4381-b0a5-5f755d007dc6': 'In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.'}"
+Figure 9.2.1,Anatomy_And_Physio/images/Figure 9.2.1.jpg,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.,"At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.","{'f52703d1-68c3-408b-a57a-61bd4693ffa6': 'As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.', '38521220-23b7-4852-acf0-423e4ba5f27a': 'At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.', 'c29499c4-0b81-4c39-a64e-6460ca6700d0': 'All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate\xa0closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.', '53b7e019-aac7-4381-b0a5-5f755d007dc6': 'In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.', '5be9873d-3348-4a7d-aec6-3b9c30fc52bd': 'A syndesmosis (“fastened with a band”, plural = syndesmoses) is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane.', 'e8e24c7f-64ef-4677-a687-d66d7556f935': 'In the forearm, the wide gap between the shaft portions of the radius and ulna bones are strongly united by an interosseous membrane (see Figure 9.2.1b). Similarly, in the leg, the shafts of the tibia and fibula are also united by an interosseous membrane. In addition, at the distal tibiofibular joint, the narrow gap between the bones is anchored by fibrous connective tissue and ligaments on both the anterior and posterior aspects of the joint. Together, the interosseous membrane and these ligaments form the tibiofibular syndesmosis.', '6e73008b-458c-4075-ad3f-5de29eebe1cf': 'The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation. However, a syndesmosis does not prevent all movement between the bones, and thus this type of fibrous joint is functionally classified as an amphiarthrosis. In the leg, the syndesmosis between the tibia and fibula strongly unites the bones, allows for little movement, and firmly locks the talus bone in place between the tibia and fibula at the ankle joint. This provides strength and stability to the leg and ankle, which are important during weight bearing. In the forearm, the interosseous membrane is flexible enough to allow for rotation of the radius bone during forearm movements. Thus in contrast to the stability provided by the tibiofibular syndesmosis, the flexibility of the antebrachial (forearm) interosseous membrane allows for the much greater mobility of the forearm.', '2b408eb3-4c1c-4abd-96d1-f4042be434d8': 'The interosseous membranes of the leg and forearm also provide areas for muscle attachment. Damage to a syndesmotic joint, which usually results from a fracture of the bone with an accompanying tear of the interosseous membrane, will produce pain, loss of stability of the bones, and may damage the muscles attached to the interosseous membrane. If the fracture site is not properly immobilized with a cast or splint, contractile activity by these muscles can cause improper alignment of the broken bones during healing.', '516f84ae-b08e-47f9-be84-a79cee61df73': 'A gomphosis (“fastened with bolts”, plural = gomphoses) is the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull. A gomphosis is also known as a peg-and-socket joint and is considered a joint even though teeth are not bones. Spanning between the bony walls of the socket and the root of the tooth are numerous short bands of dense connective tissue, each of which is called a periodontal ligament (see Figure 9.2.1c). Due to the immobility of a gomphosis, this type of joint is functionally classified as a synarthrosis.'}"
+Figure 9.2.1,Anatomy_And_Physio/images/Figure 9.2.1.jpg,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.,"At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.","{'f52703d1-68c3-408b-a57a-61bd4693ffa6': 'As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.', '38521220-23b7-4852-acf0-423e4ba5f27a': 'At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.', 'c29499c4-0b81-4c39-a64e-6460ca6700d0': 'All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate\xa0closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.', '53b7e019-aac7-4381-b0a5-5f755d007dc6': 'In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.', '5be9873d-3348-4a7d-aec6-3b9c30fc52bd': 'A syndesmosis (“fastened with a band”, plural = syndesmoses) is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane.', 'e8e24c7f-64ef-4677-a687-d66d7556f935': 'In the forearm, the wide gap between the shaft portions of the radius and ulna bones are strongly united by an interosseous membrane (see Figure 9.2.1b). Similarly, in the leg, the shafts of the tibia and fibula are also united by an interosseous membrane. In addition, at the distal tibiofibular joint, the narrow gap between the bones is anchored by fibrous connective tissue and ligaments on both the anterior and posterior aspects of the joint. Together, the interosseous membrane and these ligaments form the tibiofibular syndesmosis.', '6e73008b-458c-4075-ad3f-5de29eebe1cf': 'The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation. However, a syndesmosis does not prevent all movement between the bones, and thus this type of fibrous joint is functionally classified as an amphiarthrosis. In the leg, the syndesmosis between the tibia and fibula strongly unites the bones, allows for little movement, and firmly locks the talus bone in place between the tibia and fibula at the ankle joint. This provides strength and stability to the leg and ankle, which are important during weight bearing. In the forearm, the interosseous membrane is flexible enough to allow for rotation of the radius bone during forearm movements. Thus in contrast to the stability provided by the tibiofibular syndesmosis, the flexibility of the antebrachial (forearm) interosseous membrane allows for the much greater mobility of the forearm.', '2b408eb3-4c1c-4abd-96d1-f4042be434d8': 'The interosseous membranes of the leg and forearm also provide areas for muscle attachment. Damage to a syndesmotic joint, which usually results from a fracture of the bone with an accompanying tear of the interosseous membrane, will produce pain, loss of stability of the bones, and may damage the muscles attached to the interosseous membrane. If the fracture site is not properly immobilized with a cast or splint, contractile activity by these muscles can cause improper alignment of the broken bones during healing.', '516f84ae-b08e-47f9-be84-a79cee61df73': 'A gomphosis (“fastened with bolts”, plural = gomphoses) is the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull. A gomphosis is also known as a peg-and-socket joint and is considered a joint even though teeth are not bones. Spanning between the bony walls of the socket and the root of the tooth are numerous short bands of dense connective tissue, each of which is called a periodontal ligament (see Figure 9.2.1c). Due to the immobility of a gomphosis, this type of joint is functionally classified as a synarthrosis.'}"
+Figure 8.5.1,Anatomy_And_Physio/images/Figure 8.5.1.jpg,Figure 8.5.1 – Embryo at Seven Weeks: Limb buds are visible in an embryo at the end of the seventh week of development (embryo derived from an ectopic pregnancy). (credit: Ed Uthman/flickr),"Each upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after (Figure 8.5.1).","{'23913e26-751a-47a3-8ecf-43e26b1852e4': 'Each upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after (Figure 8.5.1).', 'ac0fe9c2-c689-4e30-9676-0dbf36333883': 'Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying mesenchyme to rapidly proliferate, producing the outgrowth of the developing limb. As the limb bud elongates, cells located farther from the apical ectodermal ridge slow their rates of cell division and begin to differentiate. In this way, the limb develops along a proximal-to-distal axis.', '484c3b7f-c31a-445f-bfbb-ec248066f9f2': 'During the sixth week of development, the distal ends of the upper and lower limb buds expand and flatten into a paddle shape. This region will become the hand or foot. The wrist or ankle areas then appear as a constriction that develops at the base of the paddle. Shortly after this, a second constriction on the limb bud appears at the future site of the elbow or knee. Within the paddle, areas of tissue undergo cell death, producing separations between the growing fingers and toes. Also during the sixth week of development, mesenchyme within the limb buds begins to differentiate into hyaline cartilage that will form models of the future limb bones.', '7066bdce-ff65-4864-8e12-986217047423': 'The early outgrowth of the upper and lower limb buds initially has the limbs positioned so that the regions that will become the palm of the hand or the bottom of the foot are facing medially toward the body, with the future thumb or big toe both oriented toward the head. During the seventh week of development, the upper limb rotates laterally by 90 degrees, so that the palm of the hand faces anteriorly and the thumb points laterally. In contrast, the lower limb undergoes a 90-degree medial rotation, thus bringing the big toe to the medial side of the foot.'}"
+Figure 8.4.1,Anatomy_And_Physio/images/Figure 8.4.1.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur.","The femur, or thigh bone, is the single bone of the thigh region (Figure 8.4.1). It is the longest and strongest bone of the body, and accounts for approximately one-quarter of a person’s total height. The rounded, proximal end is the head of the femur, which articulates with the acetabulum of the hip bone to form the hip joint. The fovea capitis is a minor indentation on the medial side of the femoral head that serves as the site of attachment for the ligament of the head of the femur. This ligament spans the femur and acetabulum, but is weak and provides little support for the hip joint. It does, however, carry an important artery that supplies the head of the femur.","{'43a01d40-92d6-4d5b-a408-c1959be58531': 'The femur, or thigh bone, is the single bone of the thigh region (Figure 8.4.1). It is the longest and strongest bone of the body, and accounts for approximately one-quarter of a person’s total height. The rounded, proximal end is the head of the femur, which articulates with the acetabulum of the hip bone to form the hip joint. The fovea capitis is a minor indentation on the medial side of the femoral head that serves as the site of attachment for the ligament of the head of the femur. This ligament spans the femur and acetabulum, but is weak and provides little support for the hip joint. It does, however, carry an important artery that supplies the head of the femur.', '0f85e347-9e42-4411-a965-07a16ca307f5': 'The patella (kneecap) is largest sesamoid bone of the body (see Figure 8.4.1). A sesamoid bone is a bone that is incorporated into the tendon of a muscle where that tendon crosses a joint. The sesamoid bone articulates with the underlying bones to prevent damage to the muscle tendon due to rubbing against the bones during movements of the joint. The patella is found in the tendon of the quadriceps femoris muscle, the large muscle of the anterior thigh that passes across the anterior knee to attach to the tibia. The patella articulates with the patellar surface of the femur and thus prevents rubbing of the muscle tendon against the distal femur. The patella also lifts the tendon away from the knee joint, which increases the leverage power of the quadriceps femoris muscle as it acts across the knee. The patella does not articulate with the tibia.'}"
+Figure 8.4.1,Anatomy_And_Physio/images/Figure 8.4.1.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur.","The femur, or thigh bone, is the single bone of the thigh region (Figure 8.4.1). It is the longest and strongest bone of the body, and accounts for approximately one-quarter of a person’s total height. The rounded, proximal end is the head of the femur, which articulates with the acetabulum of the hip bone to form the hip joint. The fovea capitis is a minor indentation on the medial side of the femoral head that serves as the site of attachment for the ligament of the head of the femur. This ligament spans the femur and acetabulum, but is weak and provides little support for the hip joint. It does, however, carry an important artery that supplies the head of the femur.","{'43a01d40-92d6-4d5b-a408-c1959be58531': 'The femur, or thigh bone, is the single bone of the thigh region (Figure 8.4.1). It is the longest and strongest bone of the body, and accounts for approximately one-quarter of a person’s total height. The rounded, proximal end is the head of the femur, which articulates with the acetabulum of the hip bone to form the hip joint. The fovea capitis is a minor indentation on the medial side of the femoral head that serves as the site of attachment for the ligament of the head of the femur. This ligament spans the femur and acetabulum, but is weak and provides little support for the hip joint. It does, however, carry an important artery that supplies the head of the femur.', '0f85e347-9e42-4411-a965-07a16ca307f5': 'The patella (kneecap) is largest sesamoid bone of the body (see Figure 8.4.1). A sesamoid bone is a bone that is incorporated into the tendon of a muscle where that tendon crosses a joint. The sesamoid bone articulates with the underlying bones to prevent damage to the muscle tendon due to rubbing against the bones during movements of the joint. The patella is found in the tendon of the quadriceps femoris muscle, the large muscle of the anterior thigh that passes across the anterior knee to attach to the tibia. The patella articulates with the patellar surface of the femur and thus prevents rubbing of the muscle tendon against the distal femur. The patella also lifts the tendon away from the knee joint, which increases the leverage power of the quadriceps femoris muscle as it acts across the knee. The patella does not articulate with the tibia.'}"
+Figure 8.4.3,Anatomy_And_Physio/images/Figure 8.4.3.jpg,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight.","The tibia (shin bone) is the medial bone of the leg and is larger than the fibula, with which it is paired (Figure 8.4.3). The tibia is the main weight-bearing bone of the leg and the second longest bone of the body, after the femur. The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg.","{'ba9834ae-f20d-4a61-9b9e-fbeaa39d754a': 'The tibia (shin bone) is the medial bone of the leg and is larger than the fibula, with which it is paired (Figure 8.4.3). The tibia is the main weight-bearing bone of the leg and the second longest bone of the body, after the femur. The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg.', '37a12053-f824-4c26-b466-2e833309c9b3': 'The proximal end of the tibia is greatly expanded. The two sides of this expansion form the medial and lateral condyles of the tibia. The tibia does not have epicondyles. The top surface of each condyle is smooth and flattened. These areas articulate with the medial and lateral condyles of the femur to form the knee joint. Between the articulating surfaces of the tibial condyles is the intercondylar eminence, an irregular, elevated area that serves as the inferior attachment point for two supporting ligaments of the knee.', 'de31ef6c-a36a-41e8-8583-30fd2958c03b': 'The tibial tuberosity is an elevated area on the anterior side of the tibia, near its proximal end. It is the final site of attachment for the muscle tendon associated with the patella. More inferiorly, the shaft of the tibia becomes triangular in shape. The anterior apex of this triangle forms the anterior border of the tibia, which begins at the tibial tuberosity and runs inferiorly along the length of the tibia. Both the anterior border and the medial side of the triangular shaft are located immediately under the skin and can be easily palpated along the entire length of the tibia. A small ridge running down the lateral side of the tibial shaft is the interosseous border of the tibia (not shown). This is for the attachment of the interosseous membrane of the leg, the sheet of dense connective tissue that unites the tibia and fibula bones. Located on the posterior side of the tibia is the soleal line, a diagonally running, roughened ridge that begins below the base of the lateral condyle, and runs down and medially across the proximal third of the posterior tibia. Muscles of the posterior leg attach to this line.', '6431780f-2c0b-40e0-99da-29da3d2e70f6': 'The large expansion found on the medial side of the distal tibia is the medial malleolus (“little hammer”). This forms the large bony bump found on the medial side of the ankle region. Both the smooth surface on the inside of the medial malleolus and the smooth area at the distal end of the tibia articulate with the talus bone of the foot as part of the ankle joint. On the lateral side of the distal tibia is a wide groove called the fibular notch (not shown). This area articulates with the distal end of the fibula, forming the distal tibiofibular joint.', '8aa3b945-0708-4c6a-a40b-e9f9aa9b469a': 'The fibula is the slender bone located on the lateral side of the leg (see Figure 8.4.3). The fibula does not bear weight. It serves primarily for muscle attachments and thus is largely surrounded by muscles. Only the proximal and distal ends of the fibula can be easily palpated.', 'f5fa3ca5-16ad-4217-a418-33ae8924d76c': 'The head of the fibula is the small, knob-like, proximal end of the fibula. It articulates with the inferior aspect of the lateral tibial condyle, forming the proximal tibiofibular joint. The thin shaft of the fibula has the interosseous border of the fibula (not shown), a narrow ridge running down its medial side for the attachment of the interosseous membrane that spans the fibula and tibia. The distal end of the fibula forms the lateral malleolus, which forms the easily palpated bony bump on the lateral side of the ankle. The deep (medial) side of the lateral malleolus articulates with the talus bone of the foot as part of the ankle joint. The distal fibula also articulates with the fibular notch of the tibia.'}"
+Figure 8.4.3,Anatomy_And_Physio/images/Figure 8.4.3.jpg,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight.","The tibia (shin bone) is the medial bone of the leg and is larger than the fibula, with which it is paired (Figure 8.4.3). The tibia is the main weight-bearing bone of the leg and the second longest bone of the body, after the femur. The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg.","{'ba9834ae-f20d-4a61-9b9e-fbeaa39d754a': 'The tibia (shin bone) is the medial bone of the leg and is larger than the fibula, with which it is paired (Figure 8.4.3). The tibia is the main weight-bearing bone of the leg and the second longest bone of the body, after the femur. The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg.', '37a12053-f824-4c26-b466-2e833309c9b3': 'The proximal end of the tibia is greatly expanded. The two sides of this expansion form the medial and lateral condyles of the tibia. The tibia does not have epicondyles. The top surface of each condyle is smooth and flattened. These areas articulate with the medial and lateral condyles of the femur to form the knee joint. Between the articulating surfaces of the tibial condyles is the intercondylar eminence, an irregular, elevated area that serves as the inferior attachment point for two supporting ligaments of the knee.', 'de31ef6c-a36a-41e8-8583-30fd2958c03b': 'The tibial tuberosity is an elevated area on the anterior side of the tibia, near its proximal end. It is the final site of attachment for the muscle tendon associated with the patella. More inferiorly, the shaft of the tibia becomes triangular in shape. The anterior apex of this triangle forms the anterior border of the tibia, which begins at the tibial tuberosity and runs inferiorly along the length of the tibia. Both the anterior border and the medial side of the triangular shaft are located immediately under the skin and can be easily palpated along the entire length of the tibia. A small ridge running down the lateral side of the tibial shaft is the interosseous border of the tibia (not shown). This is for the attachment of the interosseous membrane of the leg, the sheet of dense connective tissue that unites the tibia and fibula bones. Located on the posterior side of the tibia is the soleal line, a diagonally running, roughened ridge that begins below the base of the lateral condyle, and runs down and medially across the proximal third of the posterior tibia. Muscles of the posterior leg attach to this line.', '6431780f-2c0b-40e0-99da-29da3d2e70f6': 'The large expansion found on the medial side of the distal tibia is the medial malleolus (“little hammer”). This forms the large bony bump found on the medial side of the ankle region. Both the smooth surface on the inside of the medial malleolus and the smooth area at the distal end of the tibia articulate with the talus bone of the foot as part of the ankle joint. On the lateral side of the distal tibia is a wide groove called the fibular notch (not shown). This area articulates with the distal end of the fibula, forming the distal tibiofibular joint.', '8aa3b945-0708-4c6a-a40b-e9f9aa9b469a': 'The fibula is the slender bone located on the lateral side of the leg (see Figure 8.4.3). The fibula does not bear weight. It serves primarily for muscle attachments and thus is largely surrounded by muscles. Only the proximal and distal ends of the fibula can be easily palpated.', 'f5fa3ca5-16ad-4217-a418-33ae8924d76c': 'The head of the fibula is the small, knob-like, proximal end of the fibula. It articulates with the inferior aspect of the lateral tibial condyle, forming the proximal tibiofibular joint. The thin shaft of the fibula has the interosseous border of the fibula (not shown), a narrow ridge running down its medial side for the attachment of the interosseous membrane that spans the fibula and tibia. The distal end of the fibula forms the lateral malleolus, which forms the easily palpated bony bump on the lateral side of the ankle. The deep (medial) side of the lateral malleolus articulates with the talus bone of the foot as part of the ankle joint. The distal fibula also articulates with the fibular notch of the tibia.'}"
+Figure 8.4.4,Anatomy_And_Physio/images/Figure 8.4.4.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.,"The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.","{'9d3193b8-63ad-41b0-8219-934f02d696d5': 'The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.', 'cb1b6411-91ce-44a7-9b17-c3210388eef6': 'The cuboid bone articulates with the anterior end of the calcaneus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (medial-lateral) curvature of the foot. The navicular and lateral cuneiform bones also articulate with the medial side of the cuboid bone.', 'b60cb96a-5070-4500-8890-ba12b2525540': 'The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.4.4). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot.', 'dc469763-113a-45e5-a355-35c9f373fb06': 'The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8.4.4). The toes are numbered 1–5, starting with the big toe (hallux). The big toe has two phalanx bones, the proximal and distal phalanges. The remaining toes all have proximal, middle, and distal phalanges. A joint between adjacent phalanx bones is called an interphalangeal joint.', '034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.'}"
+Figure 8.4.4,Anatomy_And_Physio/images/Figure 8.4.4.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.,"The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.","{'9d3193b8-63ad-41b0-8219-934f02d696d5': 'The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.', 'cb1b6411-91ce-44a7-9b17-c3210388eef6': 'The cuboid bone articulates with the anterior end of the calcaneus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (medial-lateral) curvature of the foot. The navicular and lateral cuneiform bones also articulate with the medial side of the cuboid bone.', 'b60cb96a-5070-4500-8890-ba12b2525540': 'The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.4.4). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot.', 'dc469763-113a-45e5-a355-35c9f373fb06': 'The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8.4.4). The toes are numbered 1–5, starting with the big toe (hallux). The big toe has two phalanx bones, the proximal and distal phalanges. The remaining toes all have proximal, middle, and distal phalanges. A joint between adjacent phalanx bones is called an interphalangeal joint.', '034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.'}"
+Figure 8.4.4,Anatomy_And_Physio/images/Figure 8.4.4.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.,"The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.","{'9d3193b8-63ad-41b0-8219-934f02d696d5': 'The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.', 'cb1b6411-91ce-44a7-9b17-c3210388eef6': 'The cuboid bone articulates with the anterior end of the calcaneus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (medial-lateral) curvature of the foot. The navicular and lateral cuneiform bones also articulate with the medial side of the cuboid bone.', 'b60cb96a-5070-4500-8890-ba12b2525540': 'The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.4.4). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot.', 'dc469763-113a-45e5-a355-35c9f373fb06': 'The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8.4.4). The toes are numbered 1–5, starting with the big toe (hallux). The big toe has two phalanx bones, the proximal and distal phalanges. The remaining toes all have proximal, middle, and distal phalanges. A joint between adjacent phalanx bones is called an interphalangeal joint.', '034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.'}"
+Figure 8.4.4,Anatomy_And_Physio/images/Figure 8.4.4.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.,"The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.","{'9d3193b8-63ad-41b0-8219-934f02d696d5': 'The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.', 'cb1b6411-91ce-44a7-9b17-c3210388eef6': 'The cuboid bone articulates with the anterior end of the calcaneus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (medial-lateral) curvature of the foot. The navicular and lateral cuneiform bones also articulate with the medial side of the cuboid bone.', 'b60cb96a-5070-4500-8890-ba12b2525540': 'The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.4.4). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot.', 'dc469763-113a-45e5-a355-35c9f373fb06': 'The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8.4.4). The toes are numbered 1–5, starting with the big toe (hallux). The big toe has two phalanx bones, the proximal and distal phalanges. The remaining toes all have proximal, middle, and distal phalanges. A joint between adjacent phalanx bones is called an interphalangeal joint.', '034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.'}"
+Figure 8.3.1,Anatomy_And_Physio/images/Figure 8.3.1.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis.","The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).","{'034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.', '7ada0d60-838b-4419-9631-688f40d9b7d0': 'The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.', 'bdde0a6e-f55e-4b3e-896a-1b4105c2edc2': 'The ilium is the fan-like, superior region that forms the largest part of the hip bone. It is firmly united to the sacrum at the largely immobile sacroiliac joint (see Figure 8.3.1). The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.', '8037649d-4111-4eaa-9e47-e988546e7873': 'The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.', '1880ed16-c491-471c-abd7-97bb9e34bf15': 'The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.', '246376b0-4722-4cb4-8b32-b8b63d3098f6': 'Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.', 'f938e00a-6ccc-47da-b478-b68e20d825c2': 'The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.', '185368d9-42a5-4d20-96c8-246a19fe8185': 'The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.', '461941b4-9d91-4bf7-9555-fa565640831a': 'A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.', '35c3d1bf-6b05-41c5-b005-43d6f762d64e': 'While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.', '9b497150-91cd-407f-8372-871f72331c36': 'Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.', 'e1856c95-7ce7-4d41-8379-7fe4a63e8f20': 'Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand', 'c9667f1a-5582-4b8f-9c72-de35ce8b82a3': 'The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.'}"
+Figure 8.3.2,Anatomy_And_Physio/images/Figure 8.3.2.jpg,"Figure 8.3.2 – The Hip Bone: Each adult hip bone consists of three regions. The ilium forms the large, fan-shaped superior portion, the ischium forms the posteroinferior portion, and the pubis forms the anteromedial portion.","The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.","{'7ada0d60-838b-4419-9631-688f40d9b7d0': 'The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.', 'bdde0a6e-f55e-4b3e-896a-1b4105c2edc2': 'The ilium is the fan-like, superior region that forms the largest part of the hip bone. It is firmly united to the sacrum at the largely immobile sacroiliac joint (see Figure 8.3.1). The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.'}"
+Figure 8.3.1,Anatomy_And_Physio/images/Figure 8.3.1.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis.","The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).","{'034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.', '7ada0d60-838b-4419-9631-688f40d9b7d0': 'The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.', 'bdde0a6e-f55e-4b3e-896a-1b4105c2edc2': 'The ilium is the fan-like, superior region that forms the largest part of the hip bone. It is firmly united to the sacrum at the largely immobile sacroiliac joint (see Figure 8.3.1). The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.', '8037649d-4111-4eaa-9e47-e988546e7873': 'The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.', '1880ed16-c491-471c-abd7-97bb9e34bf15': 'The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.', '246376b0-4722-4cb4-8b32-b8b63d3098f6': 'Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.', 'f938e00a-6ccc-47da-b478-b68e20d825c2': 'The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.', '185368d9-42a5-4d20-96c8-246a19fe8185': 'The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.', '461941b4-9d91-4bf7-9555-fa565640831a': 'A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.', '35c3d1bf-6b05-41c5-b005-43d6f762d64e': 'While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.', '9b497150-91cd-407f-8372-871f72331c36': 'Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.', 'e1856c95-7ce7-4d41-8379-7fe4a63e8f20': 'Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand', 'c9667f1a-5582-4b8f-9c72-de35ce8b82a3': 'The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.'}"
+Figure 8.3.1,Anatomy_And_Physio/images/Figure 8.3.1.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis.","The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).","{'034279ea-b9d6-4e05-a940-e7d23637d82c': 'When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.', '185a649a-fe1d-4541-82e3-efd358327066': 'The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.', 'c460ae07-4ba6-401b-aeb1-f215f7c337ee': 'The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.', '1fc2d251-ab8a-4c8b-8a13-706ce8140c37': 'Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).', '26899a0f-b044-41c5-bddc-5079ebb42ae4': 'Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.', 'a63fa321-7f25-4643-9b9e-60aa88fedd4d': 'The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).', 'ef05eed8-6350-4f4c-bc92-87e0b7d12502': 'Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.', '7ada0d60-838b-4419-9631-688f40d9b7d0': 'The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.', 'bdde0a6e-f55e-4b3e-896a-1b4105c2edc2': 'The ilium is the fan-like, superior region that forms the largest part of the hip bone. It is firmly united to the sacrum at the largely immobile sacroiliac joint (see Figure 8.3.1). The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.', '8037649d-4111-4eaa-9e47-e988546e7873': 'The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.', '1880ed16-c491-471c-abd7-97bb9e34bf15': 'The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.', '246376b0-4722-4cb4-8b32-b8b63d3098f6': 'Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.', 'f938e00a-6ccc-47da-b478-b68e20d825c2': 'The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.', '185368d9-42a5-4d20-96c8-246a19fe8185': 'The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.', '461941b4-9d91-4bf7-9555-fa565640831a': 'A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.', '35c3d1bf-6b05-41c5-b005-43d6f762d64e': 'While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.', '9b497150-91cd-407f-8372-871f72331c36': 'Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.', 'e1856c95-7ce7-4d41-8379-7fe4a63e8f20': 'Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand', 'c9667f1a-5582-4b8f-9c72-de35ce8b82a3': 'The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.'}"
+Figure 8.3.3,Anatomy_And_Physio/images/Figure 8.3.3.jpg,"Figure 8.3.3 – Ligaments of the Pelvis: The posterior sacroiliac ligament supports the sacroiliac joint. The sacrospinous ligament spans the sacrum to the ischial spine, and the sacrotuberous ligament spans the sacrum to the ischial tuberosity. The sacrospinous and sacrotuberous ligaments contribute to the formation of the greater and lesser sciatic foramens.","Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.","{'8037649d-4111-4eaa-9e47-e988546e7873': 'The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.', '1880ed16-c491-471c-abd7-97bb9e34bf15': 'The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.', '246376b0-4722-4cb4-8b32-b8b63d3098f6': 'Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.', 'f938e00a-6ccc-47da-b478-b68e20d825c2': 'The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.', '185368d9-42a5-4d20-96c8-246a19fe8185': 'The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.', '461941b4-9d91-4bf7-9555-fa565640831a': 'A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.', '35c3d1bf-6b05-41c5-b005-43d6f762d64e': 'While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.', '9b497150-91cd-407f-8372-871f72331c36': 'Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.', 'e1856c95-7ce7-4d41-8379-7fe4a63e8f20': 'Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand', 'c9667f1a-5582-4b8f-9c72-de35ce8b82a3': 'The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.'}"
+Figure 8.3.4,Anatomy_And_Physio/images/Figure 8.3.4.jpg,"Figure 8.3.4 – Male and Female Pelvis: The female pelvis is adapted for childbirth and is broader, with a larger subpubic angle, a rounder pelvic brim, and a wider and more shallow lesser pelvic cavity than the male pelvis.","The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.","{'8037649d-4111-4eaa-9e47-e988546e7873': 'The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.', '1880ed16-c491-471c-abd7-97bb9e34bf15': 'The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.', '246376b0-4722-4cb4-8b32-b8b63d3098f6': 'Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.', 'f938e00a-6ccc-47da-b478-b68e20d825c2': 'The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.', '185368d9-42a5-4d20-96c8-246a19fe8185': 'The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.', '461941b4-9d91-4bf7-9555-fa565640831a': 'A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.', '35c3d1bf-6b05-41c5-b005-43d6f762d64e': 'While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.', '9b497150-91cd-407f-8372-871f72331c36': 'Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.', 'e1856c95-7ce7-4d41-8379-7fe4a63e8f20': 'Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand', 'c9667f1a-5582-4b8f-9c72-de35ce8b82a3': 'The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.'}"
+Figure 8.2.1,Anatomy_And_Physio/images/Figure 8.2.1.jpg,Figure 8.2.1 – Humerus and Elbow Joint: The humerus is the single bone of the arm region. It articulates with the radius and ulna bones of the forearm to form the elbow joint.,"The humerus is the single bone of the arm region (Figure 8.2.1). At its proximal end is the head of the humerus. This is the large, round, smooth region that faces medially. The head articulates with the glenoid cavity of the scapula to form the glenohumeral (shoulder) joint (see Chapter 9). The margin of the smooth area of the head is the anatomical neck of the humerus. Located on the lateral side of the proximal humerus is an expanded bony area called the greater tubercle. The smaller lesser tubercle of the humerus is found on the anterior aspect of the humerus. Both the greater and lesser tubercles serve as attachment sites for muscles that act across the shoulder joint (see Chapter 11). Passing between the greater and lesser tubercles is the narrow intertubercular groove (sulcus), which is also known as the bicipital groove because it provides passage for a tendon of the biceps brachii muscle. The surgical neck is located where the proximal end of the humerus joins the narrow shaft of the humerus, and is a common site of arm fractures. The deltoid tuberosity is a roughened, V-shaped region located on the lateral side in the middle of the humerus shaft. As its name indicates, it is the site of attachment for the deltoid muscle.","{'3b92b8a2-36fc-4e90-a611-fac73f4276fd': 'The humerus is the single bone of the arm region (Figure 8.2.1). At its proximal end is the head of the humerus. This is the large, round, smooth region that faces medially. The head articulates with the glenoid cavity of the scapula to form the glenohumeral (shoulder) joint (see Chapter 9). The margin of the smooth area of the head is the anatomical neck of the humerus. Located on the lateral side of the proximal humerus is an expanded bony area called the greater tubercle. The smaller lesser tubercle of the humerus is found on the anterior aspect of the humerus. Both the greater and lesser tubercles serve as attachment sites for muscles that act across the shoulder joint (see Chapter 11). Passing between the greater and lesser tubercles is the narrow intertubercular groove (sulcus), which is also known as the bicipital groove because it provides passage for a tendon of the biceps brachii muscle. The surgical neck is located where the proximal end of the humerus joins the narrow shaft of the humerus, and is a common site of arm fractures. The deltoid tuberosity is a roughened, V-shaped region located on the lateral side in the middle of the humerus shaft. As its name indicates, it is the site of attachment for the deltoid muscle.', '3842fba8-afce-41a2-8127-64e15fa97c61': 'Distally, the humerus becomes flattened. The prominent bony projection on the medial side is the medial epicondyle of the humerus. The much smaller lateral epicondyle of the humerus is found on the lateral side of the distal humerus. The roughened ridge of bone above the lateral epicondyle is the lateral supracondylar ridge. All of these areas are attachment points for muscles that act on the forearm, wrist, and hand. The powerful grasping muscles of the anterior forearm arise from the medial epicondyle, which is thus larger and more robust than the lateral epicondyle that gives rise to the weaker posterior forearm muscles (see Chapter 11).', 'dc97b34c-1fdb-4ae8-bdf7-315010b00aa8': 'The distal end of the humerus has two articulation areas, which join the ulna and radius bones of the forearm to form the elbow joint. The more medial of these areas is the trochlea, a spindle- or pulley-shaped region (trochlea = “pulley”), which articulates with the ulna bone. Immediately lateral to the trochlea is the capitulum (“small head”), a knob-like structure located on the anterior surface of the distal humerus. The capitulum articulates with the radius bone of the forearm. Just above these bony areas are two small depressions. These spaces accommodate the forearm bones when the elbow is fully bent (flexed). Superior to the trochlea is the coronoid fossa, which receives the coronoid process of the ulna, and superior to the capitulum is the radial fossa, which receives the head of the radius when the elbow is flexed. Similarly, the posterior humerus has the olecranon fossa, a larger depression that receives the olecranon process of the ulna when the forearm is fully extended.'}"
+Figure 8.2.2,Anatomy_And_Physio/images/Figure 8.2.2.jpg,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane.","The ulna is the medial bone of the forearm. It runs parallel to the radius, which is the lateral bone of the forearm (Figure 8.2.2). The proximal end of the ulna resembles a crescent wrench with its large, C-shaped, trochlear notch. This region articulates with the trochlea of the humerus as part of the elbow joint. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. Just below this on the anterior ulna is a roughened area called the ulnar tuberosity. To the lateral side and slightly inferior to the trochlear notch is a small, smooth area called the radial notch of the ulna. This area is the site of articulation between the proximal ends of the radius and ulna, forming the proximal radioulnar joint. The posterior and superior portions of the proximal ulna make up the olecranon process, which forms the bony tip of the elbow.","{'af8da4b3-0c57-4a6f-8b7d-b6b8a033d313': 'The ulna is the medial bone of the forearm. It runs parallel to the radius, which is the lateral bone of the forearm (Figure 8.2.2). The proximal end of the ulna resembles a crescent wrench with its large, C-shaped, trochlear notch. This region articulates with the trochlea of the humerus as part of the elbow joint. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. Just below this on the anterior ulna is a roughened area called the ulnar tuberosity. To the lateral side and slightly inferior to the trochlear notch is a small, smooth area called the radial notch of the ulna. This area is the site of articulation between the proximal ends of the radius and ulna, forming the proximal radioulnar joint. The posterior and superior portions of the proximal ulna make up the olecranon process, which forms the bony tip of the elbow.', 'e0b1e2cb-cbba-4024-a6a3-5395a15ae6e1': 'More distal is the shaft of the ulna. The lateral side of the shaft forms a ridge called the interosseous border of the ulna. This is the line of attachment for the interosseous membrane of the forearm, a sheet of dense connective tissue that unites the ulna and radius bones. The small, rounded area that forms the distal end is the head of the ulna. Projecting from the posterior side of the ulnar head is the styloid process of the ulna, a short bony projection. This serves as an attachment point for connective tissues that unite the distal end of the ulna with the carpal bones of the wrist joint.', 'a2b8ab75-d5fc-4009-9eb0-a4a27626a956': 'In the anatomical position, with the elbow fully extended and the palms facing forward, the arm and forearm do not form a straight line. Instead, the forearm deviates laterally by 5–15 degrees from the line of the arm. This deviation is called the carrying angle. It allows the forearm and hand to swing freely or to carry an object without hitting the hip. The carrying angle is larger in females.', '13601fee-40c1-4a86-a154-5ea4a5e97be1': 'The radius runs parallel to the ulna, on the lateral (thumb) side of the forearm (see Figure 8.2.2). The head of the radius is a disc-shaped structure that forms the proximal end. The small depression on the surface of the head articulates with the capitulum of the humerus as part of the elbow joint, whereas the smooth, outer margin of the head articulates with the radial notch of the ulna at the proximal radioulnar joint. The neck of the radius is the narrowed region immediately below the expanded head. Inferior to this point on the medial side is the radial tuberosity, an oval-shaped, bony protuberance that serves as a muscle attachment point. The shaft of the radius is slightly curved and has a small ridge along its medial side. This ridge forms the interosseous border of the radius, which, like the similar border of the ulna, is the line of attachment for the interosseous membrane that unites the two forearm bones. The distal end of the radius has a smooth surface for articulation with two carpal bones to form the radiocarpal joint or wrist joint (Figure 8.2.3 and Figure 8.2.4). On the medial side of the distal radius is the ulnar notch of the radius. This shallow depression articulates with the head of the ulna, which together form the distal radioulnar joint. The lateral end of the radius has a pointed projection called the styloid process of the radius. This provides attachment for ligaments that support the lateral side of the wrist joint. Compared to the styloid process of the ulna, the styloid process of the radius projects more distally, thereby limiting the range of movement for lateral deviations of the hand at the wrist joint.'}"
+Figure 8.2.2,Anatomy_And_Physio/images/Figure 8.2.2.jpg,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane.","The ulna is the medial bone of the forearm. It runs parallel to the radius, which is the lateral bone of the forearm (Figure 8.2.2). The proximal end of the ulna resembles a crescent wrench with its large, C-shaped, trochlear notch. This region articulates with the trochlea of the humerus as part of the elbow joint. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. Just below this on the anterior ulna is a roughened area called the ulnar tuberosity. To the lateral side and slightly inferior to the trochlear notch is a small, smooth area called the radial notch of the ulna. This area is the site of articulation between the proximal ends of the radius and ulna, forming the proximal radioulnar joint. The posterior and superior portions of the proximal ulna make up the olecranon process, which forms the bony tip of the elbow.","{'af8da4b3-0c57-4a6f-8b7d-b6b8a033d313': 'The ulna is the medial bone of the forearm. It runs parallel to the radius, which is the lateral bone of the forearm (Figure 8.2.2). The proximal end of the ulna resembles a crescent wrench with its large, C-shaped, trochlear notch. This region articulates with the trochlea of the humerus as part of the elbow joint. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. Just below this on the anterior ulna is a roughened area called the ulnar tuberosity. To the lateral side and slightly inferior to the trochlear notch is a small, smooth area called the radial notch of the ulna. This area is the site of articulation between the proximal ends of the radius and ulna, forming the proximal radioulnar joint. The posterior and superior portions of the proximal ulna make up the olecranon process, which forms the bony tip of the elbow.', 'e0b1e2cb-cbba-4024-a6a3-5395a15ae6e1': 'More distal is the shaft of the ulna. The lateral side of the shaft forms a ridge called the interosseous border of the ulna. This is the line of attachment for the interosseous membrane of the forearm, a sheet of dense connective tissue that unites the ulna and radius bones. The small, rounded area that forms the distal end is the head of the ulna. Projecting from the posterior side of the ulnar head is the styloid process of the ulna, a short bony projection. This serves as an attachment point for connective tissues that unite the distal end of the ulna with the carpal bones of the wrist joint.', 'a2b8ab75-d5fc-4009-9eb0-a4a27626a956': 'In the anatomical position, with the elbow fully extended and the palms facing forward, the arm and forearm do not form a straight line. Instead, the forearm deviates laterally by 5–15 degrees from the line of the arm. This deviation is called the carrying angle. It allows the forearm and hand to swing freely or to carry an object without hitting the hip. The carrying angle is larger in females.', '13601fee-40c1-4a86-a154-5ea4a5e97be1': 'The radius runs parallel to the ulna, on the lateral (thumb) side of the forearm (see Figure 8.2.2). The head of the radius is a disc-shaped structure that forms the proximal end. The small depression on the surface of the head articulates with the capitulum of the humerus as part of the elbow joint, whereas the smooth, outer margin of the head articulates with the radial notch of the ulna at the proximal radioulnar joint. The neck of the radius is the narrowed region immediately below the expanded head. Inferior to this point on the medial side is the radial tuberosity, an oval-shaped, bony protuberance that serves as a muscle attachment point. The shaft of the radius is slightly curved and has a small ridge along its medial side. This ridge forms the interosseous border of the radius, which, like the similar border of the ulna, is the line of attachment for the interosseous membrane that unites the two forearm bones. The distal end of the radius has a smooth surface for articulation with two carpal bones to form the radiocarpal joint or wrist joint (Figure 8.2.3 and Figure 8.2.4). On the medial side of the distal radius is the ulnar notch of the radius. This shallow depression articulates with the head of the ulna, which together form the distal radioulnar joint. The lateral end of the radius has a pointed projection called the styloid process of the radius. This provides attachment for ligaments that support the lateral side of the wrist joint. Compared to the styloid process of the ulna, the styloid process of the radius projects more distally, thereby limiting the range of movement for lateral deviations of the hand at the wrist joint.'}"
+Figure 8.2.3,Anatomy_And_Physio/images/Figure 8.2.3.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.,"The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.', '358b0607-30f9-4d2d-a5bb-f31caac8c56f': 'The palm of the hand contains five elongated metacarpal bones. These bones lie between the carpal bones of the wrist and the bones of the fingers and thumb (see Figure 8.2.3). The proximal end of each metacarpal bone articulates with one of the distal carpal bones. Each of these articulations is a carpometacarpal joint (see Figure 8.2.4). The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers. The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1–5, beginning at the thumb.', 'ef0565af-aaf6-4061-b8f1-d847ccd45dcc': 'The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.', 'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.'}"
+Figure 8.2.4,Anatomy_And_Physio/images/Figure 8.2.4.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek,"The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.'}"
+Figure 8.2.4,Anatomy_And_Physio/images/Figure 8.2.4.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek,"The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.'}"
+Figure 8.2.5,Anatomy_And_Physio/images/Figure 8.2.5.jpg,"Figure 8.2.5 – Carpal Tunnel: The carpal tunnel is the passageway by which nine muscle tendons and the median nerve enter the hand from the anterior forearm. The walls and floor of the carpal tunnel are formed by the U-shaped grouping of the carpal bones, and the roof is formed by the flexor retinaculum, a strong ligament that anteriorly unites the bones.","In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.'}"
+Figure 8.2.3,Anatomy_And_Physio/images/Figure 8.2.3.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.,"The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.', '358b0607-30f9-4d2d-a5bb-f31caac8c56f': 'The palm of the hand contains five elongated metacarpal bones. These bones lie between the carpal bones of the wrist and the bones of the fingers and thumb (see Figure 8.2.3). The proximal end of each metacarpal bone articulates with one of the distal carpal bones. Each of these articulations is a carpometacarpal joint (see Figure 8.2.4). The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers. The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1–5, beginning at the thumb.', 'ef0565af-aaf6-4061-b8f1-d847ccd45dcc': 'The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.', 'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.'}"
+Figure 8.2.6,Anatomy_And_Physio/images/Figure 8.2.6.jpg,"Figure 8.2.6 – Hand During Gripping: During tight gripping—compare (b) to (a)—the fourth and, particularly, the fifth metatarsal bones are pulled anteriorly. This increases the contact between the object and the medial side of the hand, thus improving the firmness of the grip.","The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.","{'358b0607-30f9-4d2d-a5bb-f31caac8c56f': 'The palm of the hand contains five elongated metacarpal bones. These bones lie between the carpal bones of the wrist and the bones of the fingers and thumb (see Figure 8.2.3). The proximal end of each metacarpal bone articulates with one of the distal carpal bones. Each of these articulations is a carpometacarpal joint (see Figure 8.2.4). The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers. The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1–5, beginning at the thumb.', 'ef0565af-aaf6-4061-b8f1-d847ccd45dcc': 'The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.'}"
+Figure 8.2.3,Anatomy_And_Physio/images/Figure 8.2.3.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.,"The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.","{'f67e6e5a-4baf-4f4d-be01-85183966bffd': 'The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.', '4e97e85d-db81-4a3e-9fa9-32aad8a86011': 'A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.', '8df2c9d2-f811-4a02-b7b9-e49543990009': 'The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.', '24904c00-574e-4139-bdc7-cd5961cffe25': 'The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.', 'e898b77a-7031-453a-a72b-3eedabc9531f': 'In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.', '358b0607-30f9-4d2d-a5bb-f31caac8c56f': 'The palm of the hand contains five elongated metacarpal bones. These bones lie between the carpal bones of the wrist and the bones of the fingers and thumb (see Figure 8.2.3). The proximal end of each metacarpal bone articulates with one of the distal carpal bones. Each of these articulations is a carpometacarpal joint (see Figure 8.2.4). The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers. The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1–5, beginning at the thumb.', 'ef0565af-aaf6-4061-b8f1-d847ccd45dcc': 'The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.', 'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.'}"
+Figure 8.1.1,Anatomy_And_Physio/images/Figure 8.1.1.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton.","The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.","{'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.', '5111dc21-8b2f-42df-9789-3863ce7c9e65': 'The clavicle is the only long bone that lies in a horizontal position in the body (see Figure 8.1.1). The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb. The clavicle also transmits forces acting on the upper limb to the sternum and axial skeleton. Finally, it serves to protect the underlying nerves and blood vessels as they pass between the trunk of the body and the upper limb.', '2106c9f8-d0f7-4913-9f92-9ef114193a7c': 'The clavicle has three regions: the medial end, the lateral end, and the shaft. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. This forms the sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. This joint allows considerable mobility, enabling the clavicle and scapula to move in upward/downward and anterior/posterior directions during shoulder movements. The sternoclavicular joint is indirectly supported by the costoclavicular ligament (costo- = “rib”), which spans the sternal end of the clavicle and the underlying first rib. The lateral or acromial end of the clavicle articulates with the acromion of the scapula, the portion of the scapula that forms the bony tip of the shoulder. There are some sex differences in the morphology of the clavicle. In women, the clavicle tends to be shorter, thinner, and less curved. In men, the clavicle is heavier and longer, and has a greater curvature and rougher surfaces where muscles attach.', 'd53d5a6b-e213-48b5-9485-e11c3bdabf8e': 'The clavicle is the most commonly fractured bone in the body. Such breaks often occur because of the force exerted on the clavicle when a person falls onto his or her outstretched arm, or when the lateral shoulder receives a strong blow. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. If the fracture is complete, the shoulder and lateral clavicle fragment will drop due to the weight of the upper limb, causing the person to support the sagging limb with their other hand. Muscles acting across the shoulder will also pull the shoulder and lateral clavicle anteriorly and medially, causing the clavicle fragments to overlap. The clavicle overlies many important blood vessels and nerves for the upper limb, but fortunately, due to the anterior displacement of a broken clavicle, these structures are rarely affected when the clavicle is fractured.', '2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 8.1.1,Anatomy_And_Physio/images/Figure 8.1.1.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton.","The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.","{'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.', '5111dc21-8b2f-42df-9789-3863ce7c9e65': 'The clavicle is the only long bone that lies in a horizontal position in the body (see Figure 8.1.1). The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb. The clavicle also transmits forces acting on the upper limb to the sternum and axial skeleton. Finally, it serves to protect the underlying nerves and blood vessels as they pass between the trunk of the body and the upper limb.', '2106c9f8-d0f7-4913-9f92-9ef114193a7c': 'The clavicle has three regions: the medial end, the lateral end, and the shaft. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. This forms the sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. This joint allows considerable mobility, enabling the clavicle and scapula to move in upward/downward and anterior/posterior directions during shoulder movements. The sternoclavicular joint is indirectly supported by the costoclavicular ligament (costo- = “rib”), which spans the sternal end of the clavicle and the underlying first rib. The lateral or acromial end of the clavicle articulates with the acromion of the scapula, the portion of the scapula that forms the bony tip of the shoulder. There are some sex differences in the morphology of the clavicle. In women, the clavicle tends to be shorter, thinner, and less curved. In men, the clavicle is heavier and longer, and has a greater curvature and rougher surfaces where muscles attach.', 'd53d5a6b-e213-48b5-9485-e11c3bdabf8e': 'The clavicle is the most commonly fractured bone in the body. Such breaks often occur because of the force exerted on the clavicle when a person falls onto his or her outstretched arm, or when the lateral shoulder receives a strong blow. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. If the fracture is complete, the shoulder and lateral clavicle fragment will drop due to the weight of the upper limb, causing the person to support the sagging limb with their other hand. Muscles acting across the shoulder will also pull the shoulder and lateral clavicle anteriorly and medially, causing the clavicle fragments to overlap. The clavicle overlies many important blood vessels and nerves for the upper limb, but fortunately, due to the anterior displacement of a broken clavicle, these structures are rarely affected when the clavicle is fractured.', '2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 8.1.2,Anatomy_And_Physio/images/Figure 8.1.2.jpg,"Figure 8.1.2 – Scapula: The isolated scapula is shown here from its anterior (deep) side, lateral side and its posterior (superficial) side.","The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.","{'2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 8.1.1,Anatomy_And_Physio/images/Figure 8.1.1.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton.","The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.","{'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.', '5111dc21-8b2f-42df-9789-3863ce7c9e65': 'The clavicle is the only long bone that lies in a horizontal position in the body (see Figure 8.1.1). The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb. The clavicle also transmits forces acting on the upper limb to the sternum and axial skeleton. Finally, it serves to protect the underlying nerves and blood vessels as they pass between the trunk of the body and the upper limb.', '2106c9f8-d0f7-4913-9f92-9ef114193a7c': 'The clavicle has three regions: the medial end, the lateral end, and the shaft. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. This forms the sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. This joint allows considerable mobility, enabling the clavicle and scapula to move in upward/downward and anterior/posterior directions during shoulder movements. The sternoclavicular joint is indirectly supported by the costoclavicular ligament (costo- = “rib”), which spans the sternal end of the clavicle and the underlying first rib. The lateral or acromial end of the clavicle articulates with the acromion of the scapula, the portion of the scapula that forms the bony tip of the shoulder. There are some sex differences in the morphology of the clavicle. In women, the clavicle tends to be shorter, thinner, and less curved. In men, the clavicle is heavier and longer, and has a greater curvature and rougher surfaces where muscles attach.', 'd53d5a6b-e213-48b5-9485-e11c3bdabf8e': 'The clavicle is the most commonly fractured bone in the body. Such breaks often occur because of the force exerted on the clavicle when a person falls onto his or her outstretched arm, or when the lateral shoulder receives a strong blow. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. If the fracture is complete, the shoulder and lateral clavicle fragment will drop due to the weight of the upper limb, causing the person to support the sagging limb with their other hand. Muscles acting across the shoulder will also pull the shoulder and lateral clavicle anteriorly and medially, causing the clavicle fragments to overlap. The clavicle overlies many important blood vessels and nerves for the upper limb, but fortunately, due to the anterior displacement of a broken clavicle, these structures are rarely affected when the clavicle is fractured.', '2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 8.1.1,Anatomy_And_Physio/images/Figure 8.1.1.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton.","The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.","{'ef2ce10d-3190-4d8c-bffc-6ae415faab04': 'The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).', '7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0': 'Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton', '17d87bb1-51f4-46c7-a66d-2008b267e2ea': 'The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.', '762f8479-d10a-4a62-a91b-59efc231f5a6': 'The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.', 'a3c5b6fb-f052-49fe-a185-ddc0a198d444': 'The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.', '5111dc21-8b2f-42df-9789-3863ce7c9e65': 'The clavicle is the only long bone that lies in a horizontal position in the body (see Figure 8.1.1). The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb. The clavicle also transmits forces acting on the upper limb to the sternum and axial skeleton. Finally, it serves to protect the underlying nerves and blood vessels as they pass between the trunk of the body and the upper limb.', '2106c9f8-d0f7-4913-9f92-9ef114193a7c': 'The clavicle has three regions: the medial end, the lateral end, and the shaft. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. This forms the sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. This joint allows considerable mobility, enabling the clavicle and scapula to move in upward/downward and anterior/posterior directions during shoulder movements. The sternoclavicular joint is indirectly supported by the costoclavicular ligament (costo- = “rib”), which spans the sternal end of the clavicle and the underlying first rib. The lateral or acromial end of the clavicle articulates with the acromion of the scapula, the portion of the scapula that forms the bony tip of the shoulder. There are some sex differences in the morphology of the clavicle. In women, the clavicle tends to be shorter, thinner, and less curved. In men, the clavicle is heavier and longer, and has a greater curvature and rougher surfaces where muscles attach.', 'd53d5a6b-e213-48b5-9485-e11c3bdabf8e': 'The clavicle is the most commonly fractured bone in the body. Such breaks often occur because of the force exerted on the clavicle when a person falls onto his or her outstretched arm, or when the lateral shoulder receives a strong blow. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. If the fracture is complete, the shoulder and lateral clavicle fragment will drop due to the weight of the upper limb, causing the person to support the sagging limb with their other hand. Muscles acting across the shoulder will also pull the shoulder and lateral clavicle anteriorly and medially, causing the clavicle fragments to overlap. The clavicle overlies many important blood vessels and nerves for the upper limb, but fortunately, due to the anterior displacement of a broken clavicle, these structures are rarely affected when the clavicle is fractured.', '2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 8.0.2,Anatomy_And_Physio/images/Figure 8.0.2.jpg,"Figure 8.0.2 – Axial and Appendicular Skeletons: The axial skeleton forms the central axis of the body and consists of the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of the pectoral and pelvic girdles, the limb bones, and the bones of the hands and feet.","Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.","{'2ee245a4-d917-428b-b484-5db504719766': 'The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.', 'ab46ea20-07c0-4f82-97e0-a9cc5fddc31c': 'The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.', '037776e6-f1cf-4f56-96a6-0978898704e0': 'The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.', 'c31379f0-7935-45a7-a13f-b76fc203dbc6': 'The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.', '7683f56e-7a54-4597-8ae1-52c348a71da9': 'The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.', 'da493b69-07e0-47f7-9b0c-239033f6343b': 'Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.', 'a9e366bc-4332-4501-90ad-1b584289bb1b': 'Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.'}"
+Figure 7.6.1,Anatomy_And_Physio/images/Figure 7.6.1.jpg,"Figure 7.6.1 – Newborn Skull: The bones of the newborn skull are not fully ossified and are separated by large areas called fontanelles, which are filled with fibrous connective tissue. The fontanelles allow for continued growth of the brain and skull after birth. At the time of birth, the facial bones are small and underdeveloped, and the mastoid process has not yet formed.","The bones of the skull arise from mesenchyme during embryonic development in two different ways. The first mechanism produces the bones that form the top and sides of the brain case. This involves the local accumulation of mesenchymal cells at the site of the future bone. These cells then differentiate directly into bone producing cells, which form the skull bones through the process of intramembranous ossification. As the cranial bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle (Figure 7.6.1). The fontanelles are the soft spots on an infant’s head. They are important during birth because these areas allow the skull to change shape as it squeezes through the birth canal. As part of the newborn exam, fontanelles are palpated for bulging which indicates increased intracranial pressure often associated with hydrocephalus. After birth, the fontanelles allow for continued growth and expansion of the skull as the brain enlarges. The largest fontanelle is located on the anterior head, at the junction of the frontal and parietal bones. The fontanelles decrease in size and disappear by age 2. However, the skull bones remained separated from each other at the sutures, which contain dense fibrous connective tissue that unites the adjacent bones. The connective tissue of the sutures allows for continued growth of the skull bones as the brain enlarges during childhood growth.","{'e50e70fc-9467-4831-b74a-7713ace13a25': 'During the third week of embryonic development, a rod-like structure called the notochord develops dorsally along the length of the embryo. The tissue overlying the notochord enlarges and forms the neural tube, which will give rise to the brain and spinal cord. By the fourth week, mesoderm tissue located on either side of the notochord thickens and separates into a repeating series of block-like tissue structures, each of which is called a somite. As the somites enlarge, each one will split into several parts. The most medial of these parts is called a sclerotome. The sclerotomes consist of an embryonic tissue called mesenchyme, which will give rise to the fibrous connective tissues, cartilages, and bones of the body.', 'cd62ae65-0027-4d22-8a22-0115b9fde011': 'The bones of the skull arise from mesenchyme during embryonic development in two different ways. The first mechanism produces the bones that form the top and sides of the brain case. This involves the local accumulation of mesenchymal cells at the site of the future bone. These cells then differentiate directly into bone producing cells, which form the skull bones through the process of intramembranous ossification. As the cranial\xa0bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle (Figure 7.6.1). The fontanelles are the soft spots on an infant’s head. They are important during birth because these areas allow the skull to change shape as it squeezes through the birth canal. As part of the newborn exam, fontanelles are palpated for bulging which indicates increased intracranial pressure often associated with\xa0hydrocephalus. After birth, the fontanelles allow for continued growth and expansion of the skull as the brain enlarges. The largest fontanelle is located on the anterior head, at the junction of the frontal and parietal bones. The fontanelles decrease in size and disappear by age 2. However, the skull bones remained separated from each other at the sutures, which contain dense fibrous connective tissue that unites the adjacent bones. The connective tissue of the sutures allows for continued growth of the skull bones as the brain enlarges during childhood growth.', '02ce616a-c52a-4bf3-b366-3200c826b8fa': 'The second mechanism for bone development in the skull produces the facial bones and floor of the brain case. This also begins with the localized accumulation of mesenchymal cells. However, these cells differentiate into cartilage cells, which produce a hyaline cartilage model of the future bone. As this cartilage model grows, it is gradually converted into bone through the process of endochondral ossification. This is a slow process and the cartilage is not completely converted to bone until the skull achieves its full adult size.', '154455e9-3ac9-4ceb-85e7-471e2e5c408e': 'At birth, the brain case and orbits of the skull are disproportionally large compared to the bones of the jaws and lower face. This reflects the relative underdevelopment of the maxilla and mandible, which lack teeth, and the small sizes of the paranasal sinuses and nasal cavity. During early childhood, the mastoid process enlarges, the two halves of the mandible and frontal bone fuse together to form single bones, and the paranasal sinuses enlarge. The jaws also expand as the teeth begin to appear. These changes all contribute to the rapid growth and enlargement of the face during childhood.'}"
+Figure 7.5.1,Anatomy_And_Physio/images/Figure 7.5.1.jpg,"Figure 7.5.1 – Thoracic Cage: The thoracic cage is formed by the (a) sternum and (b) 12 pairs of ribs with their costal cartilages. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The ribs are classified as true ribs (1–7) and false ribs (8–12). The last two pairs of false ribs are also known as floating ribs (11–12).",The thoracic cage (rib cage) forms the thorax (chest) portion of the body. It consists of the 12 pairs of ribs with their costal cartilages and the sternum (Figure 7.5.1). The ribs are anchored posteriorly to the 12 thoracic vertebrae (T1–T12). The thoracic cage protects the heart and lungs.,{'fdf3a0b3-e9f4-4b80-98f2-6b33db56a689': 'The thoracic cage (rib cage) forms the thorax (chest) portion of the body. It consists of the 12 pairs of ribs with their costal cartilages and the sternum (Figure 7.5.1). The ribs are anchored posteriorly to the 12 thoracic vertebrae (T1–T12). The thoracic cage protects the heart and lungs.'}
+Figure 7.4.1,Anatomy_And_Physio/images/Figure 7.4.1.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves).","The vertebral column is also known as the spinal column (Figure 7.4.1). It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by a cartilaginous intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes through openings in the vertebrae.","{'e00387ea-a967-4201-b242-1030d418a6b7': 'Each rib is a curved, flattened bone that contributes to the wall of the thorax. The ribs articulate posteriorly with the T1–T12 thoracic vertebrae, and most attach anteriorly via their costal cartilages to the sternum. There are 12 pairs of ribs. The ribs are numbered 1–12 in accordance with the thoracic vertebrae.', '7f9a7599-81cb-446e-bbf6-4026a5e51ef9': 'Discuss the vertebral column and regional variations in its bony components and curvatures', 'c3292362-673c-4105-a01b-4237b1463b69': 'The vertebral column is also known as the spinal column (Figure 7.4.1). It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by a cartilaginous\xa0intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes through openings in the vertebrae.', 'f6cd8fc5-07dc-487e-b51c-9826d94cbb04': 'The adult vertebral column does not form a straight line, but instead has four curvatures along its length (see Figure 7.4.1). These curves increase the vertebral column’s strength, flexibility, and ability to absorb shock. When the load on the spine is increased, by carrying a heavy backpack for example, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spring back when the weight is removed. The four adult curvatures are classified as either primary or secondary curvatures. Primary curvatures are retained from the original fetal curvature, while secondary curvatures develop after birth.', 'f21d27c0-d54f-4499-9d8b-6e6a0cfd5b24': 'During fetal development, the body is flexed anteriorly into the fetal position, giving the entire vertebral column a single curvature that is concave anteriorly. In the adult, this primary\xa0curvature is retained in two regions of the vertebral column as the thoracic curve, which involves the thoracic vertebrae, and the sacrococcygeal curve, formed by the sacrum and coccyx.', 'ec24854a-92e4-4611-bc1c-8838397a4c89': 'A secondary curve develops gradually after birth as the child learns to sit upright, stand, and walk. Secondary curves are concave posteriorly, opposite in direction to the original fetal curvature. The cervical curve of the neck region develops as the infant begins to hold their head upright when sitting. Later, as the child begins to stand and then to walk, the lumbar curve of the lower back develops. In adults, the lumbar curve is generally deeper in females.', '9d736e9d-3dd4-467d-beb2-73dd2ff7558a': 'Disorders associated with the curvature of the spine include kyphosis (an excessive posterior curvature of the thoracic region), lordosis (an excessive anterior curvature of the lumbar region), and scoliosis (an abnormal, lateral curvature, accompanied by twisting of the vertebral column).'}"
+Figure 7.4.1,Anatomy_And_Physio/images/Figure 7.4.1.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves).","The vertebral column is also known as the spinal column (Figure 7.4.1). It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by a cartilaginous intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes through openings in the vertebrae.","{'e00387ea-a967-4201-b242-1030d418a6b7': 'Each rib is a curved, flattened bone that contributes to the wall of the thorax. The ribs articulate posteriorly with the T1–T12 thoracic vertebrae, and most attach anteriorly via their costal cartilages to the sternum. There are 12 pairs of ribs. The ribs are numbered 1–12 in accordance with the thoracic vertebrae.', '7f9a7599-81cb-446e-bbf6-4026a5e51ef9': 'Discuss the vertebral column and regional variations in its bony components and curvatures', 'c3292362-673c-4105-a01b-4237b1463b69': 'The vertebral column is also known as the spinal column (Figure 7.4.1). It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by a cartilaginous\xa0intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes through openings in the vertebrae.', 'f6cd8fc5-07dc-487e-b51c-9826d94cbb04': 'The adult vertebral column does not form a straight line, but instead has four curvatures along its length (see Figure 7.4.1). These curves increase the vertebral column’s strength, flexibility, and ability to absorb shock. When the load on the spine is increased, by carrying a heavy backpack for example, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spring back when the weight is removed. The four adult curvatures are classified as either primary or secondary curvatures. Primary curvatures are retained from the original fetal curvature, while secondary curvatures develop after birth.', 'f21d27c0-d54f-4499-9d8b-6e6a0cfd5b24': 'During fetal development, the body is flexed anteriorly into the fetal position, giving the entire vertebral column a single curvature that is concave anteriorly. In the adult, this primary\xa0curvature is retained in two regions of the vertebral column as the thoracic curve, which involves the thoracic vertebrae, and the sacrococcygeal curve, formed by the sacrum and coccyx.', 'ec24854a-92e4-4611-bc1c-8838397a4c89': 'A secondary curve develops gradually after birth as the child learns to sit upright, stand, and walk. Secondary curves are concave posteriorly, opposite in direction to the original fetal curvature. The cervical curve of the neck region develops as the infant begins to hold their head upright when sitting. Later, as the child begins to stand and then to walk, the lumbar curve of the lower back develops. In adults, the lumbar curve is generally deeper in females.', '9d736e9d-3dd4-467d-beb2-73dd2ff7558a': 'Disorders associated with the curvature of the spine include kyphosis (an excessive posterior curvature of the thoracic region), lordosis (an excessive anterior curvature of the lumbar region), and scoliosis (an abnormal, lateral curvature, accompanied by twisting of the vertebral column).'}"
+Figure 7.4.4,Anatomy_And_Physio/images/Figure 7.4.4.jpg,"Figure 7.4.4 – Parts of a Typical Vertebra: A typical vertebra consists of a body and a vertebral arch. The arch is formed by the paired pedicles and paired laminae. Arising from the vertebral arch are the transverse, spinous, superior articular, and inferior articular processes. The vertebral foramen provides for passage of the spinal cord. Each spinal nerve exits through an intervertebral foramen, located between adjacent vertebrae. Intervertebral discs unite the bodies of adjacent vertebrae.","Within the different regions of the vertebral column, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral arch, and seven processes (Figure 7.4.4).","{'576b209b-80f7-46d2-9917-24e66d6053d7': 'Within the different regions of the vertebral column, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral arch, and seven processes (Figure 7.4.4).', '320b9033-4dca-420f-87b9-9cd5f6eddfaa': 'The body is the anterior portion of each vertebra and is the part that supports the body weight. Because of this, the vertebral bodies progressively increase in size and thickness going down the vertebral column. The bodies of adjacent vertebrae are separated and strongly united by an intervertebral disc.', '671c508c-25df-4a21-a4ca-98c94d5041c6': 'The vertebral arch forms the posterior portion of each vertebra. It consists of four parts, the right and left pedicles and the right and left laminae. Each pedicle forms one of the lateral sides of the vertebral arch. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms part of the posterior roof of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen, which contains the spinal cord. In the intact vertebral column, the vertebral foramina of all of the vertebrae align to form the vertebral (spinal) canal, which serves as the bony protection and passageway for the spinal cord down the back. When the vertebrae are aligned together in the vertebral column, notches in the margins of the pedicles of adjacent vertebrae together form an intervertebral foramen, the opening through which a spinal nerve exits from the vertebral column (Figure 7.4.5).', 'aead9cd7-7ad7-43ae-b7e4-185092e24129': 'Seven processes arise from the vertebral arch. Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina. The single spinous process (vertebral spine) projects posteriorly at the midline of the back. The vertebral spines can easily be felt as a series of bumps just under the skin down the middle of the back. The transverse and spinous processes serve as important muscle attachment sites. A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of a vertebrae. Facets of the paired superior articular processes of one vertebra articulate\xa0with corresponding facets of the paired inferior articular processes from the next higher vertebra. These junctions form slightly moveable joints between the adjacent vertebrae. The shape and orientation of the articular processes vary in different regions of the vertebral column and play a major role in determining the type and range of motion available in each region.'}"
+Figure 7.4.5,Anatomy_And_Physio/images/Figure 7.4.5.jpg,"Figure 7.4.5 – Intervertebral Disc: The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The intervertebral foramen is the opening formed between adjacent vertebrae for the exit of a spinal nerve.","The vertebral arch forms the posterior portion of each vertebra. It consists of four parts, the right and left pedicles and the right and left laminae. Each pedicle forms one of the lateral sides of the vertebral arch. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms part of the posterior roof of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen, which contains the spinal cord. In the intact vertebral column, the vertebral foramina of all of the vertebrae align to form the vertebral (spinal) canal, which serves as the bony protection and passageway for the spinal cord down the back. When the vertebrae are aligned together in the vertebral column, notches in the margins of the pedicles of adjacent vertebrae together form an intervertebral foramen, the opening through which a spinal nerve exits from the vertebral column (Figure 7.4.5).","{'576b209b-80f7-46d2-9917-24e66d6053d7': 'Within the different regions of the vertebral column, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral arch, and seven processes (Figure 7.4.4).', '320b9033-4dca-420f-87b9-9cd5f6eddfaa': 'The body is the anterior portion of each vertebra and is the part that supports the body weight. Because of this, the vertebral bodies progressively increase in size and thickness going down the vertebral column. The bodies of adjacent vertebrae are separated and strongly united by an intervertebral disc.', '671c508c-25df-4a21-a4ca-98c94d5041c6': 'The vertebral arch forms the posterior portion of each vertebra. It consists of four parts, the right and left pedicles and the right and left laminae. Each pedicle forms one of the lateral sides of the vertebral arch. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms part of the posterior roof of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen, which contains the spinal cord. In the intact vertebral column, the vertebral foramina of all of the vertebrae align to form the vertebral (spinal) canal, which serves as the bony protection and passageway for the spinal cord down the back. When the vertebrae are aligned together in the vertebral column, notches in the margins of the pedicles of adjacent vertebrae together form an intervertebral foramen, the opening through which a spinal nerve exits from the vertebral column (Figure 7.4.5).', 'aead9cd7-7ad7-43ae-b7e4-185092e24129': 'Seven processes arise from the vertebral arch. Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina. The single spinous process (vertebral spine) projects posteriorly at the midline of the back. The vertebral spines can easily be felt as a series of bumps just under the skin down the middle of the back. The transverse and spinous processes serve as important muscle attachment sites. A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of a vertebrae. Facets of the paired superior articular processes of one vertebra articulate\xa0with corresponding facets of the paired inferior articular processes from the next higher vertebra. These junctions form slightly moveable joints between the adjacent vertebrae. The shape and orientation of the articular processes vary in different regions of the vertebral column and play a major role in determining the type and range of motion available in each region.'}"
+Figure 7.3.1,Anatomy_And_Physio/images/Figure 7.3.1.jpg,"Figure 7.3.1 – Parts of the Skull: The skull consists of the rounded cranium that houses the brain and the facial bones that form the upper and lower jaws, nose, orbits, and other facial structures.","The skull is the skeletal structure of the head that supports the face and protects the brain. It is subdivided into the facial bones and the cranium, or cranial vault (Figure 7.3.1). The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. The rounded cranium surrounds and protects the brain and houses the middle and inner ear structures.","{'58f3d82c-8e19-41a5-98cf-624a62fddcd8': 'The bodies of adjacent vertebrae are strongly anchored to each other by an intervertebral disc. This structure provides padding between the bones during weight bearing, and because it can change shape, also allows for movement between the vertebrae. Although the total amount of movement available between any two adjacent vertebrae is small, when these movements are summed together along the entire length of the vertebral column, large body movements can be produced. Ligaments that extend along the length of the vertebral column also contribute to its overall support and stability.', '978ef113-66ff-451e-af44-1bd6d0b703e9': 'Chiropractors are health professionals who use nonsurgical techniques to help patients with musculoskeletal system problems that involve the bones, muscles, ligaments, tendons, or nervous system. They treat problems such as neck pain, back pain, joint pain, or headaches. Chiropractors focus on the patient’s overall health and can also provide counseling related to lifestyle issues, such as diet, exercise, or sleep problems. If needed, they will refer the patient to other medical specialists.', 'bc3951e7-2ad3-4dcd-8f22-204c45f33fc4': 'Chiropractors use a drug-free, hands-on approach for patient diagnosis and treatment. They will perform a physical exam, assess the patient’s posture and spine, and may perform additional diagnostic tests, including taking X-ray images. They primarily use manual techniques, such as spinal manipulation, to adjust the patient’s spine or other joints. They can recommend therapeutic or rehabilitative exercises, and some also include acupuncture, massage therapy, or ultrasound as part of the treatment program. In addition to those in general practice, some chiropractors specialize in sport injuries, neurology, orthopaedics, pediatrics, nutrition, internal disorders, or diagnostic imaging.', '5a5e5d8d-8436-4808-b962-87931a0e70f8': 'To become a chiropractor, students must have 3–4 years of undergraduate education, attend an accredited, four-year Doctor of Chiropractic (D.C.) degree program, and pass a licensure examination to be licensed for practice in their state. With the aging of the baby-boom generation, employment for chiropractors is expected to increase.', '25672b6c-44f3-4424-a9b7-ff193aebfb04': 'The skull is the skeletal structure of the head that supports the face and protects the brain. It is subdivided into the facial bones and the cranium, or cranial vault (Figure 7.3.1). The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. The rounded cranium surrounds and protects the brain and houses the middle and inner ear structures.', '8117acc1-39bd-4345-a318-a207fccfa77d': 'In the adult, the skull consists of 22 individual bones, 21 of which are immobile and united into a single unit. The 22nd bone is the mandible (lower jaw), which is the only moveable bone of the skull.'}"
+Figure 7.3.2,Anatomy_And_Physio/images/Figure 7.3.2.jpg,"Figure 7.3.2 – Anterior View of Skull: An anterior view of the skull shows the bones that form the forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws.","The anterior skull consists of the facial bones and provides the bony support for the eyes, teeth and structures of the face and provides openings for eating and breathing. This view of the skull is dominated by the openings of the orbits and the nasal cavity. Also seen are the upper and lower jaws, with their respective teeth (Figure 7.3.2).","{'beaf244e-0b36-4bfc-9056-880d85529297': 'The anterior skull consists of the facial bones and provides the bony support for the eyes, teeth and structures of the face and provides openings for eating and breathing. This view of the skull is dominated by the openings of the orbits and the nasal cavity. Also seen are the upper and lower jaws, with their respective teeth (Figure 7.3.2).', '3beb88f5-aba6-4804-9e87-c66bb03cbb80': 'The orbit is the bony socket that houses the eyeball and muscles that move the eyeball or open the upper eyelid. The upper margin of the anterior orbit is the supraorbital margin. Located near the midpoint of the supraorbital margin is a small opening called the supraorbital foramen. This provides for passage of a sensory nerve to the skin of the forehead. Below the orbit is the infraorbital foramen, which is the point of emergence for a sensory nerve that supplies the anterior face below the orbit.', '43dc065c-9a33-4c25-9ecc-2ca4cc496962': 'Inside the nasal area of the skull, the nasal cavity is divided into halves by the nasal septum. The upper portion of the nasal septum is formed by the perpendicular plate of the ethmoid bone and the lower portion is the vomer bone. When looking into the nasal cavity from the front of the skull, two bony plates are seen projecting from each lateral wall. The larger of these is the inferior nasal concha, an independent bone of the skull. Located just above the inferior concha is the middle nasal concha, which is part of the ethmoid bone. A third bony plate, also part of the ethmoid bone, is the superior nasal concha. It is much smaller and out of sight, above the middle concha. The superior nasal concha is located just lateral to the perpendicular plate, in the upper nasal cavity.'}"
+Figure 7.3.3,Anatomy_And_Physio/images/Figure 7.3.3.jpg,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum.","A view of the lateral skull is dominated by the large, rounded cranium above and the upper and lower jaws with their teeth below (Figure 7.3.3). Separating these areas is the bridge of bone called the zygomatic arch. The zygomatic arch (cheekbone) is the bony arch on the side of skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes: a short anterior component, the temporal process of the zygomatic bone and a longer posterior portion, the zygomatic process of the temporal bone, extending forward from the temporal bone. Thus the temporal process (anteriorly) and the zygomatic process (posteriorly) join together, like the two ends of a drawbridge, to form the zygomatic arch. One of the major muscles that pulls the mandible upward during biting and chewing, the masseter, arises from the zygomatic arch.","{'57df196b-b112-4539-a5ab-16728fc92241': 'A view of the lateral skull is dominated by the large, rounded cranium above and the upper and lower jaws with their teeth below (Figure 7.3.3). Separating these areas is the bridge of bone called the zygomatic arch. The zygomatic arch\xa0(cheekbone) is the bony arch on the side of skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes: a short anterior component, the temporal process of the zygomatic bone\xa0and a longer posterior portion, the zygomatic process of the temporal bone, extending forward from the temporal bone. Thus the temporal process (anteriorly) and the zygomatic process (posteriorly) join together, like the two ends of a drawbridge, to form the zygomatic arch. One of the major muscles that pulls the mandible upward during biting and chewing, the masseter, arises from the zygomatic arch.', '066b7070-59c3-4f32-acf4-298959fca1a9': 'On the lateral side of the cranium, above the level of the zygomatic arch, is a shallow space called the temporal fossa. Arising from the temporal fossa and passing deep to the zygomatic arch is another muscle that acts on the mandible during chewing, the temporalis.', 'f5e8911a-336c-44ab-b73f-2e022c78fcd1': 'A suture is an immobile joint between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the bones of the cranium\xa0are not straight, but instead follow irregular, tightly twisting paths. These twisting lines serve to tightly interlock the adjacent bones, thus adding strength to the skull to protect the brain.', 'c2f6d7ea-8d0f-4cb9-8524-03ba511164d4': 'The two suture lines seen on the top of the skull are the coronal and sagittal sutures. The coronal suture runs from side to side across the skull, within the coronal plane of section (see Figure 7.3.3). It joins the frontal bone to the right and left parietal bones. The sagittal suture extends posteriorly from the coronal suture at the intersection called\xa0bregma, running along the midline at the top of the skull in the sagittal plane of section (see Figure 7.3.8). It unites the right and left parietal bones. On the posterior skull, the sagittal suture terminates by joining the lambdoid suture at the intersection called lambda. The lambdoid suture extends downward and laterally to either side away from its junction with the sagittal suture. The lambdoid suture joins the occipital bone to the right and left parietal and temporal bones. This suture is named for its upside-down “V” shape, which resembles the capital letter version of the Greek letter lambda (Λ). The squamous suture is located on the lateral skull. It unites the squamous portion of the temporal bone with the parietal bone (see Figure 7.3.3). At the intersection of the frontal bone, parietal bone, squamous portion of the temporal bone, and greater wing of the sphenoid bone is the pterion, a small, capital-H-shaped suture line that unites the region. It is the weakest part of the skull. The pterion is located approximately two finger widths above the zygomatic arch and a thumb’s width posterior to the upward portion of the zygomatic bone.'}"
+Figure 7.3.4,Anatomy_And_Physio/images/Figure 7.3.4.jpg,"Figure 7.3.4 – Cranial Fossae: The bones of the brain case surround and protect the brain, which occupies the cranial cavity. The base of the brain case, which forms the floor of cranial cavity, is subdivided into the shallow anterior cranial fossa, the middle cranial fossa, and the deep posterior cranial fossa.","The floor of the brain case is referred to as the base of the skull or cranial floor. This is a complex area that varies in depth and has numerous openings for the passage of cranial nerves, blood vessels, and the spinal cord. Inside the skull, the base is subdivided into three large spaces, called the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa (fossa = “trench or ditch”) (Figure 7.3.4). From anterior to posterior, the fossae increase in depth. The shape and depth of each fossa correspond to the shape and size of the brain region that each houses.","{'684e7888-0257-4221-ad0a-dee2929a565a': 'The cranium contains and protects the brain. The interior space that is almost completely occupied by the brain is called the cranial cavity. This cavity is bounded superiorly by the rounded top of the skull, which is called the calvaria (skullcap), and the lateral and posterior sides of the skull. The bones that form the top and sides of the cranium are usually referred to as the “flat” bones of the skull.', '95bcc992-26c0-4f08-85ba-d673e07ed01e': 'The floor of the brain case is referred to as the base of the skull or cranial floor. This is a complex area that varies in depth and has numerous openings for the passage of cranial nerves, blood vessels, and the spinal cord. Inside the skull, the base is subdivided into three large spaces, called the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa (fossa = “trench or ditch”) (Figure 7.3.4). From anterior to posterior, the fossae increase in depth. The shape and depth of each fossa correspond to the shape and size of the brain region that each houses.', 'cb0602db-a65f-4a2c-8438-021b7f9a6ca3': 'The cranium consists of eight bones. These include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones.'}"
+Figure 7.3.3,Anatomy_And_Physio/images/Figure 7.3.3.jpg,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum.","A view of the lateral skull is dominated by the large, rounded cranium above and the upper and lower jaws with their teeth below (Figure 7.3.3). Separating these areas is the bridge of bone called the zygomatic arch. The zygomatic arch (cheekbone) is the bony arch on the side of skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes: a short anterior component, the temporal process of the zygomatic bone and a longer posterior portion, the zygomatic process of the temporal bone, extending forward from the temporal bone. Thus the temporal process (anteriorly) and the zygomatic process (posteriorly) join together, like the two ends of a drawbridge, to form the zygomatic arch. One of the major muscles that pulls the mandible upward during biting and chewing, the masseter, arises from the zygomatic arch.","{'57df196b-b112-4539-a5ab-16728fc92241': 'A view of the lateral skull is dominated by the large, rounded cranium above and the upper and lower jaws with their teeth below (Figure 7.3.3). Separating these areas is the bridge of bone called the zygomatic arch. The zygomatic arch\xa0(cheekbone) is the bony arch on the side of skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes: a short anterior component, the temporal process of the zygomatic bone\xa0and a longer posterior portion, the zygomatic process of the temporal bone, extending forward from the temporal bone. Thus the temporal process (anteriorly) and the zygomatic process (posteriorly) join together, like the two ends of a drawbridge, to form the zygomatic arch. One of the major muscles that pulls the mandible upward during biting and chewing, the masseter, arises from the zygomatic arch.', '066b7070-59c3-4f32-acf4-298959fca1a9': 'On the lateral side of the cranium, above the level of the zygomatic arch, is a shallow space called the temporal fossa. Arising from the temporal fossa and passing deep to the zygomatic arch is another muscle that acts on the mandible during chewing, the temporalis.', 'f5e8911a-336c-44ab-b73f-2e022c78fcd1': 'A suture is an immobile joint between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the bones of the cranium\xa0are not straight, but instead follow irregular, tightly twisting paths. These twisting lines serve to tightly interlock the adjacent bones, thus adding strength to the skull to protect the brain.', 'c2f6d7ea-8d0f-4cb9-8524-03ba511164d4': 'The two suture lines seen on the top of the skull are the coronal and sagittal sutures. The coronal suture runs from side to side across the skull, within the coronal plane of section (see Figure 7.3.3). It joins the frontal bone to the right and left parietal bones. The sagittal suture extends posteriorly from the coronal suture at the intersection called\xa0bregma, running along the midline at the top of the skull in the sagittal plane of section (see Figure 7.3.8). It unites the right and left parietal bones. On the posterior skull, the sagittal suture terminates by joining the lambdoid suture at the intersection called lambda. The lambdoid suture extends downward and laterally to either side away from its junction with the sagittal suture. The lambdoid suture joins the occipital bone to the right and left parietal and temporal bones. This suture is named for its upside-down “V” shape, which resembles the capital letter version of the Greek letter lambda (Λ). The squamous suture is located on the lateral skull. It unites the squamous portion of the temporal bone with the parietal bone (see Figure 7.3.3). At the intersection of the frontal bone, parietal bone, squamous portion of the temporal bone, and greater wing of the sphenoid bone is the pterion, a small, capital-H-shaped suture line that unites the region. It is the weakest part of the skull. The pterion is located approximately two finger widths above the zygomatic arch and a thumb’s width posterior to the upward portion of the zygomatic bone.'}"
+Figure 7.3.15,Anatomy_And_Physio/images/Figure 7.3.15.jpg,Figure 7.3.15 – Bones of the Orbit: Seven skull bones contribute to the walls of the orbit. Opening into the posterior orbit from the cranial cavity are the optic canal and superior orbital fissure.,"The walls of each orbit include contributions from seven skull bones (Figure 7.3.15). The frontal bone forms the roof and the zygomatic bone forms the lateral wall and lateral floor. The medial floor is primarily formed by the maxilla, with a small contribution from the palatine bone. The ethmoid bone and lacrimal bone make up much of the medial wall and the sphenoid bone forms the posterior orbit.","{'fda04f14-e033-4126-890c-00b93b5994bb': 'The orbit is the bony socket that houses the eyeball and contains the muscles that move the eyeball or open the upper eyelid. Each orbit is cone-shaped, with a narrow posterior region that widens toward the large anterior opening. To help protect the eye, the bony margins of the anterior opening are thickened and somewhat constricted. The medial walls of the two orbits are parallel to each other but each lateral wall diverges away from the midline at a 45° angle. This divergence provides greater lateral peripheral vision.', '0983328f-2bfe-4baa-8d08-4f964943c2ab': 'The walls of each orbit include contributions from seven skull bones (Figure 7.3.15). The frontal bone forms the roof and the zygomatic bone forms the lateral wall and lateral floor. The medial floor is primarily formed by the maxilla, with a small contribution from the palatine bone. The ethmoid bone and lacrimal bone make up much of the medial wall and the sphenoid bone forms the posterior orbit.', '2e2ab4d1-0be4-498b-9b86-7bab936251d6': 'At the posterior apex of the orbit is the opening of the optic canal, which allows for passage of the optic nerve from the retina to the brain. Lateral to this is the elongated and irregularly shaped superior orbital fissure, which provides passage for the artery that supplies the eyeball, sensory nerves, and the nerves that supply the muscles involved in eye movements.'}"
+Figure 7.3.16,Anatomy_And_Physio/images/Figure 7.3.16.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.,"The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.","{'504d8ad9-9a5d-4f62-9ae4-d6e5ae3b0daa': 'The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.', '4cb7f1cd-f3a0-4fe1-ab0c-4cd013d5f196': 'Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.3.12). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae are the inferior nasal conchae, which is an independent bone of the skull. The middle conchae and the superior conchae, which are\xa0the smallest, are all\xa0formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal conchae are well hidden above and behind the middle conchae.', 'eb0a973e-f4d4-401b-8e4b-aa3201de1395': 'The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.3.17). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion which causes\xa0swelling of the mucosa and excess mucus production, obstructing the narrow passageways between the sinuses and the nasal cavity and causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort.', '04fe0a3b-6222-4b0c-b584-99e0e6163eb9': 'The paranasal sinuses are named for the skull bone that each occupies. The frontal sinus is located just above the eyebrows, within the frontal bone (see Figure 7.3.16). This irregular space may be divided at the midline into bilateral spaces, or these may be fused into a single sinus space. The frontal sinus is the most anterior of the paranasal sinuses. The largest sinus is the maxillary sinus. These are paired and located within the right and left maxillary bones, where they occupy the area just below the orbits. The maxillary sinuses are most commonly involved during sinus infections. Because their connection to the nasal cavity is located high on their medial wall, they are difficult to drain. The sphenoid sinus is a single, midline sinus. It is located within the body of the sphenoid bone, just anterior and inferior to the sella turcica, thus making it the most posterior of the paranasal sinuses. The lateral aspects of the ethmoid bone contain multiple small spaces separated by very thin bony walls. Each of these spaces is called an ethmoid air cell. These are located on both sides of the ethmoid bone, between the upper nasal cavity and medial orbit, just behind the superior nasal conchae.'}"
+Figure 7.3.12,Anatomy_And_Physio/images/Figure 7.3.12.jpg,Figure 7.3.12 Sutures of the skull,"Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.3.12). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae are the inferior nasal conchae, which is an independent bone of the skull. The middle conchae and the superior conchae, which are the smallest, are all formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal conchae are well hidden above and behind the middle conchae.","{'504d8ad9-9a5d-4f62-9ae4-d6e5ae3b0daa': 'The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.', '4cb7f1cd-f3a0-4fe1-ab0c-4cd013d5f196': 'Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.3.12). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae are the inferior nasal conchae, which is an independent bone of the skull. The middle conchae and the superior conchae, which are\xa0the smallest, are all\xa0formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal conchae are well hidden above and behind the middle conchae.'}"
+Figure 7.3.17,Anatomy_And_Physio/images/Figure 7.3.17.jpg,"Figure 7.3.17 – Paranasal Sinuses: The air-filled paranasal sinuses, each named for the bone in which it is found, drain into the nasal cavity.","The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.3.17). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion which causes swelling of the mucosa and excess mucus production, obstructing the narrow passageways between the sinuses and the nasal cavity and causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort.","{'eb0a973e-f4d4-401b-8e4b-aa3201de1395': 'The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.3.17). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion which causes\xa0swelling of the mucosa and excess mucus production, obstructing the narrow passageways between the sinuses and the nasal cavity and causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort.', '04fe0a3b-6222-4b0c-b584-99e0e6163eb9': 'The paranasal sinuses are named for the skull bone that each occupies. The frontal sinus is located just above the eyebrows, within the frontal bone (see Figure 7.3.16). This irregular space may be divided at the midline into bilateral spaces, or these may be fused into a single sinus space. The frontal sinus is the most anterior of the paranasal sinuses. The largest sinus is the maxillary sinus. These are paired and located within the right and left maxillary bones, where they occupy the area just below the orbits. The maxillary sinuses are most commonly involved during sinus infections. Because their connection to the nasal cavity is located high on their medial wall, they are difficult to drain. The sphenoid sinus is a single, midline sinus. It is located within the body of the sphenoid bone, just anterior and inferior to the sella turcica, thus making it the most posterior of the paranasal sinuses. The lateral aspects of the ethmoid bone contain multiple small spaces separated by very thin bony walls. Each of these spaces is called an ethmoid air cell. These are located on both sides of the ethmoid bone, between the upper nasal cavity and medial orbit, just behind the superior nasal conchae.'}"
+Figure 7.3.16,Anatomy_And_Physio/images/Figure 7.3.16.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.,"The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.","{'504d8ad9-9a5d-4f62-9ae4-d6e5ae3b0daa': 'The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.', '4cb7f1cd-f3a0-4fe1-ab0c-4cd013d5f196': 'Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.3.12). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae are the inferior nasal conchae, which is an independent bone of the skull. The middle conchae and the superior conchae, which are\xa0the smallest, are all\xa0formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal conchae are well hidden above and behind the middle conchae.', 'eb0a973e-f4d4-401b-8e4b-aa3201de1395': 'The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.3.17). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion which causes\xa0swelling of the mucosa and excess mucus production, obstructing the narrow passageways between the sinuses and the nasal cavity and causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort.', '04fe0a3b-6222-4b0c-b584-99e0e6163eb9': 'The paranasal sinuses are named for the skull bone that each occupies. The frontal sinus is located just above the eyebrows, within the frontal bone (see Figure 7.3.16). This irregular space may be divided at the midline into bilateral spaces, or these may be fused into a single sinus space. The frontal sinus is the most anterior of the paranasal sinuses. The largest sinus is the maxillary sinus. These are paired and located within the right and left maxillary bones, where they occupy the area just below the orbits. The maxillary sinuses are most commonly involved during sinus infections. Because their connection to the nasal cavity is located high on their medial wall, they are difficult to drain. The sphenoid sinus is a single, midline sinus. It is located within the body of the sphenoid bone, just anterior and inferior to the sella turcica, thus making it the most posterior of the paranasal sinuses. The lateral aspects of the ethmoid bone contain multiple small spaces separated by very thin bony walls. Each of these spaces is called an ethmoid air cell. These are located on both sides of the ethmoid bone, between the upper nasal cavity and medial orbit, just behind the superior nasal conchae.'}"
+Figure 7.3.18,Anatomy_And_Physio/images/Figure 7.3.18.jpg,"Figure 7.3.18 – Hyoid Bone: The hyoid bone is located in the upper neck and does not join with any other bone. It provides attachments for muscles that act on the tongue, larynx, and pharynx.","The hyoid bone is an independent bone that does not contact any other bone and thus is not part of the skull (Figure 7.3.18). It is a small U-shaped bone located in the upper neck near the level of the inferior mandible, with the tips of the “U” pointing posteriorly. The hyoid serves as the base for the tongue above, and is attached to the larynx below and the pharynx posteriorly. The hyoid is held in position by a series of small muscles that attach to it either from above or below. These muscles act to move the hyoid up/down or forward/back. Movements of the hyoid are coordinated with movements of the tongue, larynx, and pharynx during swallowing and speaking.","{'b51f023f-2f2b-4700-8bd6-4375ee78edc8': 'The hyoid bone is an independent bone that does not contact any other bone and thus is not part of the skull (Figure 7.3.18). It is a small U-shaped bone located in the upper neck near the level of the inferior mandible, with the tips of the “U” pointing posteriorly. The hyoid serves as the base for the tongue above, and is attached to the larynx below and the pharynx posteriorly. The hyoid is held in position by a series of small muscles that attach to it either from above or below. These muscles act to move the hyoid up/down or forward/back. Movements of the hyoid are coordinated with movements of the tongue, larynx, and pharynx during swallowing and speaking.'}"
+Figure 7.2.1,Anatomy_And_Physio/images/Figure 7.2.1.jpg,"Figure 7.2.1 – Bone Features: The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves.","The surface features of bones vary considerably, depending on the function and location in the body. Table 7.2 describes the bone markings, which are illustrated in (Figure 7.2.1). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.","{'cb93fb2d-92bd-417e-96bf-bd8ac084bcec': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 7.2 describes the bone markings, which are illustrated in (Figure 7.2.1). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.', 'b449bdd4-d7ec-410c-821f-f1ad424e3b77': 'Describe the functions of the skeletal system and define its two major subdivisions', '36e81620-6109-46a0-a7e8-4d9c42b8bb2e': 'The skeletal system includes all of the bones, cartilages, and ligaments of the body that support and give shape to the body and body structures, whereas the skeleton consists of the bones of the body. For adults, there are 206 named bones in the skeleton. Younger individuals have higher numbers of bones because some bones fuse together during childhood and adolescence. The primary functions of the skeleton are to provide a rigid, internal structure that protects internal organs and supports the weight of the body, and to provide a structure upon which muscles can act to produce movements of the body. The bones of the skeleton also serve as the primary storage site for important minerals such as calcium and phosphate. The bone marrow found within bones stores fat and houses the blood-cell producing tissue of the body.', 'cd30f384-7a01-44ce-bf00-a2ec6348a1be': 'The skeleton is subdivided into two major divisions—the axial and appendicular.'}"
+Figure 7.1.1,Anatomy_And_Physio/images/Figure 7.1.1.jpg,"Figure 7.1.1 – Axial and Appendicular Skeleton: The axial skeleton supports the head, neck, back, and chest and thus forms the vertical axis of the body. It consists of the skull, vertebral column (including the sacrum and coccyx), and the thoracic cage, formed by the ribs and sternum. The appendicular skeleton is made up of all bones of the upper and lower limbs and the girdles which attach them to the axial skeleton.","The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 7.1.1). It serves to protect the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip joints to move their corresponding limbs.","{'726e8299-716f-4746-ad85-e18770c8b6c3': 'The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 7.1.1). It serves to protect the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip joints to move their corresponding limbs.', 'dc9a6048-5100-4a12-8bc3-07b8b8887949': 'The axial skeleton of the adult consists of 80 bones, comprising the skull, the vertebral column, and the thoracic cage. The skull is formed by 22 bones. Also associated with the head are an additional seven bones, including the hyoid bone\xa0(found in the upper neck) and the ear ossicles (three small bones found in each middle ear). The vertebral column consists of 24 bones, each called a vertebra, plus the fused vertebrae of the\xa0sacrum and coccyx. The thoracic cage includes 12 pairs of ribs, and the sternum, the flattened bone of the anterior chest.'}"
+Figure 6.7.1,Anatomy_And_Physio/images/Figure 6.7.1.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.,"Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).","{'6725184c-c21c-4436-b42c-6a18f648e8f7': 'The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones of the pectoral and pelvic girdles that attach each limb to the axial skeleton. There are 126 bones in the appendicular skeleton of an adult. The lower portion of the appendicular skeleton is specialized for stability during walking or running. In contrast, the upper portion of the appendicular skeleton has greater mobility and ranges of motion, features that allow you to lift and carry objects. The bones of the appendicular skeleton are covered in a separate chapter.', '0f9b3f56-507b-4732-ae15-a5e08f4ec836': 'The skeletal system forms the rigid internal framework of the body. It consists of the bones, cartilages, and ligaments. Bones support the weight of the body, allow for body movements, and protect internal organs. Cartilage provides flexible strength and support for body structures such as the thoracic cage, the external ear, and the trachea and larynx. At joints of the body, cartilage can also unite adjacent bones or provide cushioning between them. Ligaments are the strong connective tissue bands that hold the bones together at a moveable joint and serve to prevent excessive movements of the joint that would result in injury. Providing force to create movement of the skeleton are the skeletal muscles of the body, which are firmly attached to the skeleton via connective tissue structures called tendons. As muscles contract, they pull on the bones to produce movements of the body. Thus, without a skeleton, you would not be able to stand, run, or even feed yourself!', 'd9c3412c-ce33-4a96-90f2-86a4ac54dda9': 'Each bone of the body serves a particular function, and therefore bones vary in size, shape, and strength based on these functions. For example, the bones of the lower back and lower limb are thick and strong to support your body weight. Similarly, the size of a bony landmark that serves as a muscle attachment site on an individual bone is related to the strength of this muscle. Muscles can apply very strong pulling forces to the bones of the skeleton. Due to these forces, bones develop enlarged bony landmarks at sites where powerful muscles attach. This means that not only the size of a bone, but also its shape, is related to its function. For this reason, the identification of bony landmarks is important during your study of the skeletal system.', 'e8054b46-6bb8-4a69-a37b-84cdc67fdfcf': 'Bones are dynamic organs that can modify their density and thickness in response to application of forces and changes in body chemistry. Thus, muscle attachment sites on bones will thicken if you begin a workout program that increases muscle strength. Similarly, the walls of weight-bearing bones will thicken if you gain body weight or begin pounding the pavement as part of a new running regimen. In contrast, a reduction in muscle strength or body weight will cause bones to become thinner. This may happen during a prolonged hospital stay, following limb immobilization in a cast, or going into the weightlessness of outer space. Even a change in diet, such as eating only soft food due to the loss of teeth, will result in a noticeable decrease in the size and thickness of the jaw bones.\xa0Changes in hormones such as estrogen and testosterone also cause changes to bone mass as a normal part of development and aging.', '4c5f8dbb-93c1-4447-8485-11fce6ea3a52': 'Calcium is not only the most abundant mineral in bone, it is also the most abundant mineral in the human body. Calcium ions are needed not only for bone mineralization but for tooth health, regulation of the heart rate and strength of contraction, blood coagulation, contraction of smooth and skeletal muscle cells, and regulation of nerve impulse conduction. The normal level of calcium in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo- or hypercalcemia.', '66dcdb56-03e5-4e7a-a9cb-1d62bc62b017': 'Hypocalcemia, a condition characterized by abnormally low levels of calcium, can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone. Without adequate calcium, blood has difficulty coagulating, the heart may skip beats or stop beating altogether, muscles may have difficulty contracting, nerves may have difficulty functioning, and bones may become brittle. The causes of hypocalcemia can range from hormonal imbalances to an improper diet. Treatments vary according to the cause, but prognoses are generally good.', 'fd330610-64bc-48df-9d64-8b3f2e6e22d0': 'Conversely, in hypercalcemia, a condition characterized by abnormally high levels of calcium, the nervous system is underactive, which results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.', '471e5fb3-24c1-4fc7-b236-ab3394085747': 'Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).', '439df380-b08f-4acb-819e-24bbd60551dc': 'Calcium is a chemical element that cannot be produced by any biological processes. The only way it can enter the body is through the diet. The bones act as a storage site for calcium: The body deposits calcium in the bones when blood levels get too high, and it releases calcium when blood levels drop too low. This process is regulated by PTH, vitamin D, and calcitonin.', '9efdab46-6bc1-47b6-afab-64ca7ad57d21': 'Cells of the parathyroid gland have plasma membrane receptors for calcium. When calcium is not binding to these receptors, the cells release PTH, which stimulates osteoclast proliferation and resorption of bone by osteoclasts. This demineralization process releases calcium into the blood. PTH promotes reabsorption of calcium from the urine by the kidneys, so that the calcium returns to the blood. Finally, PTH stimulates the synthesis of vitamin D, which in turn, stimulates calcium absorption from any digested food in the small intestine.', '552b1283-90a2-4952-9068-75b6aaeaea2a': 'When all these processes return blood calcium levels to normal, there is enough calcium to bind with the receptors on the surface of the cells of the parathyroid glands, and this cycle of events is turned off (Figure 6.7.1).', '28cc553c-c581-4d81-a9aa-38792722a0ff': 'When blood levels of calcium get too high, the thyroid gland is stimulated to release calcitonin (Figure 6.7.1), which inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys. All of these actions lower blood levels of calcium. When blood calcium levels return to normal, the thyroid gland stops secreting calcitonin.', 'ce760f78-4898-47e8-a4ea-eca0b9db4155': 'All of the organ systems of your body are interdependent, and the skeletal system is no exception. The food you take in via your digestive system and the hormones secreted by your endocrine system affect your bones. Even using your muscles to engage in exercise has an impact on your bones.'}"
+Figure 6.7.1,Anatomy_And_Physio/images/Figure 6.7.1.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.,"Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).","{'6725184c-c21c-4436-b42c-6a18f648e8f7': 'The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones of the pectoral and pelvic girdles that attach each limb to the axial skeleton. There are 126 bones in the appendicular skeleton of an adult. The lower portion of the appendicular skeleton is specialized for stability during walking or running. In contrast, the upper portion of the appendicular skeleton has greater mobility and ranges of motion, features that allow you to lift and carry objects. The bones of the appendicular skeleton are covered in a separate chapter.', '0f9b3f56-507b-4732-ae15-a5e08f4ec836': 'The skeletal system forms the rigid internal framework of the body. It consists of the bones, cartilages, and ligaments. Bones support the weight of the body, allow for body movements, and protect internal organs. Cartilage provides flexible strength and support for body structures such as the thoracic cage, the external ear, and the trachea and larynx. At joints of the body, cartilage can also unite adjacent bones or provide cushioning between them. Ligaments are the strong connective tissue bands that hold the bones together at a moveable joint and serve to prevent excessive movements of the joint that would result in injury. Providing force to create movement of the skeleton are the skeletal muscles of the body, which are firmly attached to the skeleton via connective tissue structures called tendons. As muscles contract, they pull on the bones to produce movements of the body. Thus, without a skeleton, you would not be able to stand, run, or even feed yourself!', 'd9c3412c-ce33-4a96-90f2-86a4ac54dda9': 'Each bone of the body serves a particular function, and therefore bones vary in size, shape, and strength based on these functions. For example, the bones of the lower back and lower limb are thick and strong to support your body weight. Similarly, the size of a bony landmark that serves as a muscle attachment site on an individual bone is related to the strength of this muscle. Muscles can apply very strong pulling forces to the bones of the skeleton. Due to these forces, bones develop enlarged bony landmarks at sites where powerful muscles attach. This means that not only the size of a bone, but also its shape, is related to its function. For this reason, the identification of bony landmarks is important during your study of the skeletal system.', 'e8054b46-6bb8-4a69-a37b-84cdc67fdfcf': 'Bones are dynamic organs that can modify their density and thickness in response to application of forces and changes in body chemistry. Thus, muscle attachment sites on bones will thicken if you begin a workout program that increases muscle strength. Similarly, the walls of weight-bearing bones will thicken if you gain body weight or begin pounding the pavement as part of a new running regimen. In contrast, a reduction in muscle strength or body weight will cause bones to become thinner. This may happen during a prolonged hospital stay, following limb immobilization in a cast, or going into the weightlessness of outer space. Even a change in diet, such as eating only soft food due to the loss of teeth, will result in a noticeable decrease in the size and thickness of the jaw bones.\xa0Changes in hormones such as estrogen and testosterone also cause changes to bone mass as a normal part of development and aging.', '4c5f8dbb-93c1-4447-8485-11fce6ea3a52': 'Calcium is not only the most abundant mineral in bone, it is also the most abundant mineral in the human body. Calcium ions are needed not only for bone mineralization but for tooth health, regulation of the heart rate and strength of contraction, blood coagulation, contraction of smooth and skeletal muscle cells, and regulation of nerve impulse conduction. The normal level of calcium in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo- or hypercalcemia.', '66dcdb56-03e5-4e7a-a9cb-1d62bc62b017': 'Hypocalcemia, a condition characterized by abnormally low levels of calcium, can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone. Without adequate calcium, blood has difficulty coagulating, the heart may skip beats or stop beating altogether, muscles may have difficulty contracting, nerves may have difficulty functioning, and bones may become brittle. The causes of hypocalcemia can range from hormonal imbalances to an improper diet. Treatments vary according to the cause, but prognoses are generally good.', 'fd330610-64bc-48df-9d64-8b3f2e6e22d0': 'Conversely, in hypercalcemia, a condition characterized by abnormally high levels of calcium, the nervous system is underactive, which results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.', '471e5fb3-24c1-4fc7-b236-ab3394085747': 'Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).', '439df380-b08f-4acb-819e-24bbd60551dc': 'Calcium is a chemical element that cannot be produced by any biological processes. The only way it can enter the body is through the diet. The bones act as a storage site for calcium: The body deposits calcium in the bones when blood levels get too high, and it releases calcium when blood levels drop too low. This process is regulated by PTH, vitamin D, and calcitonin.', '9efdab46-6bc1-47b6-afab-64ca7ad57d21': 'Cells of the parathyroid gland have plasma membrane receptors for calcium. When calcium is not binding to these receptors, the cells release PTH, which stimulates osteoclast proliferation and resorption of bone by osteoclasts. This demineralization process releases calcium into the blood. PTH promotes reabsorption of calcium from the urine by the kidneys, so that the calcium returns to the blood. Finally, PTH stimulates the synthesis of vitamin D, which in turn, stimulates calcium absorption from any digested food in the small intestine.', '552b1283-90a2-4952-9068-75b6aaeaea2a': 'When all these processes return blood calcium levels to normal, there is enough calcium to bind with the receptors on the surface of the cells of the parathyroid glands, and this cycle of events is turned off (Figure 6.7.1).', '28cc553c-c581-4d81-a9aa-38792722a0ff': 'When blood levels of calcium get too high, the thyroid gland is stimulated to release calcitonin (Figure 6.7.1), which inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys. All of these actions lower blood levels of calcium. When blood calcium levels return to normal, the thyroid gland stops secreting calcitonin.', 'ce760f78-4898-47e8-a4ea-eca0b9db4155': 'All of the organ systems of your body are interdependent, and the skeletal system is no exception. The food you take in via your digestive system and the hormones secreted by your endocrine system affect your bones. Even using your muscles to engage in exercise has an impact on your bones.'}"
+Figure 6.7.1,Anatomy_And_Physio/images/Figure 6.7.1.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.,"Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).","{'6725184c-c21c-4436-b42c-6a18f648e8f7': 'The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones of the pectoral and pelvic girdles that attach each limb to the axial skeleton. There are 126 bones in the appendicular skeleton of an adult. The lower portion of the appendicular skeleton is specialized for stability during walking or running. In contrast, the upper portion of the appendicular skeleton has greater mobility and ranges of motion, features that allow you to lift and carry objects. The bones of the appendicular skeleton are covered in a separate chapter.', '0f9b3f56-507b-4732-ae15-a5e08f4ec836': 'The skeletal system forms the rigid internal framework of the body. It consists of the bones, cartilages, and ligaments. Bones support the weight of the body, allow for body movements, and protect internal organs. Cartilage provides flexible strength and support for body structures such as the thoracic cage, the external ear, and the trachea and larynx. At joints of the body, cartilage can also unite adjacent bones or provide cushioning between them. Ligaments are the strong connective tissue bands that hold the bones together at a moveable joint and serve to prevent excessive movements of the joint that would result in injury. Providing force to create movement of the skeleton are the skeletal muscles of the body, which are firmly attached to the skeleton via connective tissue structures called tendons. As muscles contract, they pull on the bones to produce movements of the body. Thus, without a skeleton, you would not be able to stand, run, or even feed yourself!', 'd9c3412c-ce33-4a96-90f2-86a4ac54dda9': 'Each bone of the body serves a particular function, and therefore bones vary in size, shape, and strength based on these functions. For example, the bones of the lower back and lower limb are thick and strong to support your body weight. Similarly, the size of a bony landmark that serves as a muscle attachment site on an individual bone is related to the strength of this muscle. Muscles can apply very strong pulling forces to the bones of the skeleton. Due to these forces, bones develop enlarged bony landmarks at sites where powerful muscles attach. This means that not only the size of a bone, but also its shape, is related to its function. For this reason, the identification of bony landmarks is important during your study of the skeletal system.', 'e8054b46-6bb8-4a69-a37b-84cdc67fdfcf': 'Bones are dynamic organs that can modify their density and thickness in response to application of forces and changes in body chemistry. Thus, muscle attachment sites on bones will thicken if you begin a workout program that increases muscle strength. Similarly, the walls of weight-bearing bones will thicken if you gain body weight or begin pounding the pavement as part of a new running regimen. In contrast, a reduction in muscle strength or body weight will cause bones to become thinner. This may happen during a prolonged hospital stay, following limb immobilization in a cast, or going into the weightlessness of outer space. Even a change in diet, such as eating only soft food due to the loss of teeth, will result in a noticeable decrease in the size and thickness of the jaw bones.\xa0Changes in hormones such as estrogen and testosterone also cause changes to bone mass as a normal part of development and aging.', '4c5f8dbb-93c1-4447-8485-11fce6ea3a52': 'Calcium is not only the most abundant mineral in bone, it is also the most abundant mineral in the human body. Calcium ions are needed not only for bone mineralization but for tooth health, regulation of the heart rate and strength of contraction, blood coagulation, contraction of smooth and skeletal muscle cells, and regulation of nerve impulse conduction. The normal level of calcium in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo- or hypercalcemia.', '66dcdb56-03e5-4e7a-a9cb-1d62bc62b017': 'Hypocalcemia, a condition characterized by abnormally low levels of calcium, can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone. Without adequate calcium, blood has difficulty coagulating, the heart may skip beats or stop beating altogether, muscles may have difficulty contracting, nerves may have difficulty functioning, and bones may become brittle. The causes of hypocalcemia can range from hormonal imbalances to an improper diet. Treatments vary according to the cause, but prognoses are generally good.', 'fd330610-64bc-48df-9d64-8b3f2e6e22d0': 'Conversely, in hypercalcemia, a condition characterized by abnormally high levels of calcium, the nervous system is underactive, which results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.', '471e5fb3-24c1-4fc7-b236-ab3394085747': 'Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).', '439df380-b08f-4acb-819e-24bbd60551dc': 'Calcium is a chemical element that cannot be produced by any biological processes. The only way it can enter the body is through the diet. The bones act as a storage site for calcium: The body deposits calcium in the bones when blood levels get too high, and it releases calcium when blood levels drop too low. This process is regulated by PTH, vitamin D, and calcitonin.', '9efdab46-6bc1-47b6-afab-64ca7ad57d21': 'Cells of the parathyroid gland have plasma membrane receptors for calcium. When calcium is not binding to these receptors, the cells release PTH, which stimulates osteoclast proliferation and resorption of bone by osteoclasts. This demineralization process releases calcium into the blood. PTH promotes reabsorption of calcium from the urine by the kidneys, so that the calcium returns to the blood. Finally, PTH stimulates the synthesis of vitamin D, which in turn, stimulates calcium absorption from any digested food in the small intestine.', '552b1283-90a2-4952-9068-75b6aaeaea2a': 'When all these processes return blood calcium levels to normal, there is enough calcium to bind with the receptors on the surface of the cells of the parathyroid glands, and this cycle of events is turned off (Figure 6.7.1).', '28cc553c-c581-4d81-a9aa-38792722a0ff': 'When blood levels of calcium get too high, the thyroid gland is stimulated to release calcitonin (Figure 6.7.1), which inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys. All of these actions lower blood levels of calcium. When blood calcium levels return to normal, the thyroid gland stops secreting calcitonin.', 'ce760f78-4898-47e8-a4ea-eca0b9db4155': 'All of the organ systems of your body are interdependent, and the skeletal system is no exception. The food you take in via your digestive system and the hormones secreted by your endocrine system affect your bones. Even using your muscles to engage in exercise has an impact on your bones.'}"
+Figure 6.6.1,Anatomy_And_Physio/images/Figure 6.6.1.jpg,Figure 6.6.1 – Synthesis of Vitamin D: Sunlight is one source of vitamin D.,"Except for fatty fish like salmon and tuna, or fortified milk or cereal, vitamin D is not found naturally in many foods. The action of sunlight on the skin triggers the body to produce its own vitamin D (Figure 6.6.1), but many people, especially those of darker complexion and those living in northern latitudes where the sun’s rays are not as strong, are deficient in vitamin D. In cases of deficiency, a doctor can prescribe a vitamin D supplement.","{'18f82ee0-afd3-48d5-904e-8c9066e30110': 'You already know that calcium is a critical component of bone, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without vitamin D. Therefore, intake of vitamin D is also critical to bone health. In addition to vitamin D’s role in calcium absorption, it also plays a role, though not as clearly understood, in bone remodeling.', 'b1e68691-dc32-403e-b0c2-812f5324d819': 'Milk and other dairy foods are not the only sources of calcium. This important nutrient is also found in green leafy vegetables, broccoli, and intact salmon and canned sardines with their soft bones. Nuts, beans, seeds, and shellfish provide calcium in smaller quantities.', '021df50c-fb0a-4b73-813e-8ac34a5f2dc3': 'Except for fatty fish like salmon and tuna, or fortified milk or cereal, vitamin D is not found naturally in many foods. The action of sunlight on the skin triggers the body to produce its own vitamin D (Figure 6.6.1), but many people, especially those of darker complexion and those living in northern latitudes where the sun’s rays are not as strong, are deficient in vitamin D. In cases of deficiency, a doctor can prescribe a vitamin D supplement.'}"
+Figure 6.5.1,Anatomy_And_Physio/images/Figure 6.5.1.jpg,"Figure 6.5.1 – Types of Fractures: Compare healthy bone with different types of fractures: (a) open fracture, (b) closed fracture, (c) oblique fracture, (d) comminuted fracture, (e) spiral fracture , (f) impacted fracture, (g) greenstick fracture, and (h) transverse fracture.","Fractures are classified by their complexity, location, and other features (Figure 6.5.1). Table 6.4 outlines common types of fractures. Some fractures may be described using more than one term because it may have the features of more than one type (e.g., an open transverse fracture).","{'cdae035d-ec70-499f-8dd7-dd8f838b43b9': 'Fractures are classified by their complexity, location, and other features (Figure 6.5.1). Table 6.4 outlines common types of fractures. Some fractures may be described using more than one term because it may have the features of more than one type (e.g., an open transverse fracture).'}"
+Figure 6.5.2,Anatomy_And_Physio/images/Figure 6.5.2.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone.","Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.","{'fda9b11f-ed73-4b7a-af3a-6a4e177c3776': 'Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation\xa0in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.', 'b19ec1a3-552c-4d81-9b64-8ae2c0eaedff': 'Within about 48 hours after the fracture, stem cells from the endosteum of the bone differentiate into chondrocytes which then\xa0secrete a fibrocartilaginous matrix between the two ends of the broken bone; gradually over several days to weeks, this matrix unites the opposite ends of the fracture into an internal callus (plural = calli or calluses). Additionally, the periosteal chondrocytes form and working with osteoblasts, create an external callus of cartilage and bone, respectively, around the outside of the break (Figure 6.5.2b). Together, these temporary soft calluses stabilize the fracture.', 'ea802e5a-79ce-4875-bd09-f77b51f6d876': 'Over the next several weeks, osteoclasts resorb the dead bone while osteogenic cells become active, divide, and differentiate into more osteoblasts. The cartilage in the calluses is replaced by trabecular bone via endochondral ossification (destruction of cartilage and replacement by bone) (Figure 6.5.2c). This new bony callus is also called the hard callus.', 'c88bcd92-f146-41e6-8fa8-04c6716bd5d9': 'Over several more weeks or months, compact bone replaces spongy bone at the outer margins of the fracture and the bone is remodeled in response to strain (Figure 6.5.2d). Once healing and remodeling are\xa0complete a slight swelling may remain on the outer surface of the bone, but quite often, no external evidence of the fracture remains. This is why bone is said to be a regenerative tissue that can completely replace itself without scars.', '8b836a71-48d6-41b5-9edf-bf632e8c1950': 'In the early stages of embryonic development, the embryo’s skeleton consists of fibrous membranes and hyaline cartilage. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but in the end, mature bone is the same regardless of the pathway that produces it.'}"
+Figure 6.5.2,Anatomy_And_Physio/images/Figure 6.5.2.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone.","Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.","{'fda9b11f-ed73-4b7a-af3a-6a4e177c3776': 'Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation\xa0in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.', 'b19ec1a3-552c-4d81-9b64-8ae2c0eaedff': 'Within about 48 hours after the fracture, stem cells from the endosteum of the bone differentiate into chondrocytes which then\xa0secrete a fibrocartilaginous matrix between the two ends of the broken bone; gradually over several days to weeks, this matrix unites the opposite ends of the fracture into an internal callus (plural = calli or calluses). Additionally, the periosteal chondrocytes form and working with osteoblasts, create an external callus of cartilage and bone, respectively, around the outside of the break (Figure 6.5.2b). Together, these temporary soft calluses stabilize the fracture.', 'ea802e5a-79ce-4875-bd09-f77b51f6d876': 'Over the next several weeks, osteoclasts resorb the dead bone while osteogenic cells become active, divide, and differentiate into more osteoblasts. The cartilage in the calluses is replaced by trabecular bone via endochondral ossification (destruction of cartilage and replacement by bone) (Figure 6.5.2c). This new bony callus is also called the hard callus.', 'c88bcd92-f146-41e6-8fa8-04c6716bd5d9': 'Over several more weeks or months, compact bone replaces spongy bone at the outer margins of the fracture and the bone is remodeled in response to strain (Figure 6.5.2d). Once healing and remodeling are\xa0complete a slight swelling may remain on the outer surface of the bone, but quite often, no external evidence of the fracture remains. This is why bone is said to be a regenerative tissue that can completely replace itself without scars.', '8b836a71-48d6-41b5-9edf-bf632e8c1950': 'In the early stages of embryonic development, the embryo’s skeleton consists of fibrous membranes and hyaline cartilage. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but in the end, mature bone is the same regardless of the pathway that produces it.'}"
+Figure 6.5.2,Anatomy_And_Physio/images/Figure 6.5.2.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone.","Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.","{'fda9b11f-ed73-4b7a-af3a-6a4e177c3776': 'Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation\xa0in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.', 'b19ec1a3-552c-4d81-9b64-8ae2c0eaedff': 'Within about 48 hours after the fracture, stem cells from the endosteum of the bone differentiate into chondrocytes which then\xa0secrete a fibrocartilaginous matrix between the two ends of the broken bone; gradually over several days to weeks, this matrix unites the opposite ends of the fracture into an internal callus (plural = calli or calluses). Additionally, the periosteal chondrocytes form and working with osteoblasts, create an external callus of cartilage and bone, respectively, around the outside of the break (Figure 6.5.2b). Together, these temporary soft calluses stabilize the fracture.', 'ea802e5a-79ce-4875-bd09-f77b51f6d876': 'Over the next several weeks, osteoclasts resorb the dead bone while osteogenic cells become active, divide, and differentiate into more osteoblasts. The cartilage in the calluses is replaced by trabecular bone via endochondral ossification (destruction of cartilage and replacement by bone) (Figure 6.5.2c). This new bony callus is also called the hard callus.', 'c88bcd92-f146-41e6-8fa8-04c6716bd5d9': 'Over several more weeks or months, compact bone replaces spongy bone at the outer margins of the fracture and the bone is remodeled in response to strain (Figure 6.5.2d). Once healing and remodeling are\xa0complete a slight swelling may remain on the outer surface of the bone, but quite often, no external evidence of the fracture remains. This is why bone is said to be a regenerative tissue that can completely replace itself without scars.', '8b836a71-48d6-41b5-9edf-bf632e8c1950': 'In the early stages of embryonic development, the embryo’s skeleton consists of fibrous membranes and hyaline cartilage. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but in the end, mature bone is the same regardless of the pathway that produces it.'}"
+Figure 6.5.2,Anatomy_And_Physio/images/Figure 6.5.2.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone.","Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.","{'fda9b11f-ed73-4b7a-af3a-6a4e177c3776': 'Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation\xa0in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.', 'b19ec1a3-552c-4d81-9b64-8ae2c0eaedff': 'Within about 48 hours after the fracture, stem cells from the endosteum of the bone differentiate into chondrocytes which then\xa0secrete a fibrocartilaginous matrix between the two ends of the broken bone; gradually over several days to weeks, this matrix unites the opposite ends of the fracture into an internal callus (plural = calli or calluses). Additionally, the periosteal chondrocytes form and working with osteoblasts, create an external callus of cartilage and bone, respectively, around the outside of the break (Figure 6.5.2b). Together, these temporary soft calluses stabilize the fracture.', 'ea802e5a-79ce-4875-bd09-f77b51f6d876': 'Over the next several weeks, osteoclasts resorb the dead bone while osteogenic cells become active, divide, and differentiate into more osteoblasts. The cartilage in the calluses is replaced by trabecular bone via endochondral ossification (destruction of cartilage and replacement by bone) (Figure 6.5.2c). This new bony callus is also called the hard callus.', 'c88bcd92-f146-41e6-8fa8-04c6716bd5d9': 'Over several more weeks or months, compact bone replaces spongy bone at the outer margins of the fracture and the bone is remodeled in response to strain (Figure 6.5.2d). Once healing and remodeling are\xa0complete a slight swelling may remain on the outer surface of the bone, but quite often, no external evidence of the fracture remains. This is why bone is said to be a regenerative tissue that can completely replace itself without scars.', '8b836a71-48d6-41b5-9edf-bf632e8c1950': 'In the early stages of embryonic development, the embryo’s skeleton consists of fibrous membranes and hyaline cartilage. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but in the end, mature bone is the same regardless of the pathway that produces it.'}"
+Figure 6.4.1,Anatomy_And_Physio/images/Figure 6.4.1.jpg,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow.","The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.","{'84e22a55-ff8a-49bb-be5d-ad3b98cf930f': 'During intramembranous ossification, compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue. The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via intramembranous ossification.', '6ef298f9-656f-40d5-8bad-a7e0006bf27d': 'The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.', 'af933738-c0c6-42f0-b49d-17dc87c6da53': 'The osteoblasts secrete osteoid, uncalcified matrix consisting of collagen precursors and other organic proteins, which calcifies (hardens) within a few days as mineral salts are deposited on it, thereby entrapping the osteoblasts within. Once entrapped, the osteoblasts become osteocytes (Figure 6.4.1b). As osteoblasts transform into osteocytes, osteogenic cells in the surrounding connective tissue differentiate into new osteoblasts at the edges of the growing bone.', '6b1ba284-802a-4b2d-884d-ccafb1c84dbc': 'Several clusters of osteoid unite around the capillaries to form a trabecular matrix, while osteoblasts on the surface of the newly formed spongy bone become the cellular layer of the periosteum (Figure 6.4.1c). The periosteum then secretes compact bone superficial to the spongy bone. The spongy bone crowds nearby blood vessels, which eventually condense into red bone marrow (Figure 6.4.1d). The new bone is constantly also remodeling under the action of osteoclasts (not shown).'}"
+Figure 6.4.1,Anatomy_And_Physio/images/Figure 6.4.1.jpg,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow.","The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.","{'84e22a55-ff8a-49bb-be5d-ad3b98cf930f': 'During intramembranous ossification, compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue. The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via intramembranous ossification.', '6ef298f9-656f-40d5-8bad-a7e0006bf27d': 'The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.', 'af933738-c0c6-42f0-b49d-17dc87c6da53': 'The osteoblasts secrete osteoid, uncalcified matrix consisting of collagen precursors and other organic proteins, which calcifies (hardens) within a few days as mineral salts are deposited on it, thereby entrapping the osteoblasts within. Once entrapped, the osteoblasts become osteocytes (Figure 6.4.1b). As osteoblasts transform into osteocytes, osteogenic cells in the surrounding connective tissue differentiate into new osteoblasts at the edges of the growing bone.', '6b1ba284-802a-4b2d-884d-ccafb1c84dbc': 'Several clusters of osteoid unite around the capillaries to form a trabecular matrix, while osteoblasts on the surface of the newly formed spongy bone become the cellular layer of the periosteum (Figure 6.4.1c). The periosteum then secretes compact bone superficial to the spongy bone. The spongy bone crowds nearby blood vessels, which eventually condense into red bone marrow (Figure 6.4.1d). The new bone is constantly also remodeling under the action of osteoclasts (not shown).'}"
+Figure 6.4.1,Anatomy_And_Physio/images/Figure 6.4.1.jpg,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow.","The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.","{'84e22a55-ff8a-49bb-be5d-ad3b98cf930f': 'During intramembranous ossification, compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue. The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via intramembranous ossification.', '6ef298f9-656f-40d5-8bad-a7e0006bf27d': 'The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.', 'af933738-c0c6-42f0-b49d-17dc87c6da53': 'The osteoblasts secrete osteoid, uncalcified matrix consisting of collagen precursors and other organic proteins, which calcifies (hardens) within a few days as mineral salts are deposited on it, thereby entrapping the osteoblasts within. Once entrapped, the osteoblasts become osteocytes (Figure 6.4.1b). As osteoblasts transform into osteocytes, osteogenic cells in the surrounding connective tissue differentiate into new osteoblasts at the edges of the growing bone.', '6b1ba284-802a-4b2d-884d-ccafb1c84dbc': 'Several clusters of osteoid unite around the capillaries to form a trabecular matrix, while osteoblasts on the surface of the newly formed spongy bone become the cellular layer of the periosteum (Figure 6.4.1c). The periosteum then secretes compact bone superficial to the spongy bone. The spongy bone crowds nearby blood vessels, which eventually condense into red bone marrow (Figure 6.4.1d). The new bone is constantly also remodeling under the action of osteoclasts (not shown).'}"
+Figure 6.4.2,Anatomy_And_Physio/images/Figure 6.4.2.jpg,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.","In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding perichondrium, a membrane that covers the cartilage,a).","{'faebcdfd-e341-4a75-a0b3-07f359d072b6': 'In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification.\xa0Bones at the base of the skull and long bones form via endochondral ossification.', '7438c93e-650d-4099-b375-bcabc46093b6': 'In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding\xa0perichondrium, a membrane that covers the cartilage,a).', '5aef1f80-ad33-48d9-928c-427dd8d51ebf': 'As more and more matrix is produced, the cartilaginous model grow in size. Blood vessels in the perichondrium bring osteoblasts to the edges of the structure and these arriving osteoblasts deposit bone in a ring around the diaphysis – this is called a bone collar (Figure 6.4.2b). The bony edges of the developing structure prevent nutrients from diffusing into the center of the hyaline cartilage. This results in chondrocyte death and disintegration in the center of the structure. Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting spaces, not only enlarging the cavities but also carrying osteogenic cells with them, many of which will become osteoblasts. These enlarging spaces eventually combine to become the medullary cavity. Bone is now deposited within the structure creating the primary ossification center\xa0(Figure 6.4.2c).', 'bb307add-9d86-4898-b1ae-f0e6fbb9ffae': 'While these deep changes are occurring, chondrocytes and cartilage continue to grow at the ends of the structure (the future epiphyses), which increases the structure’s length at the same time bone is replacing cartilage in the diaphyses. This continued growth is accompanied by remodeling inside the medullary cavity (osteoclasts were also brought with invading blood vessels) and overall lengthening of the structure (Figure 6.4.2d). By the time the fetal skeleton is fully formed, cartilage remains at the epiphyses and at the joint surface as articular cartilage.', '675ff3f9-0cae-46ac-9d44-e1ae58f359e4': 'After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a secondary ossification center (Figure 6.4.2e). Throughout childhood and adolescence, there remains a thin plate of hyaline cartilage between the diaphysis and epiphysis known as the growth or epiphyseal plate\xa0(Figure 6.4.2f). Eventually, this hyaline cartilage will be removed and replaced by bone to become the epiphyseal line.'}"
+Figure 6.4.2,Anatomy_And_Physio/images/Figure 6.4.2.jpg,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.","In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding perichondrium, a membrane that covers the cartilage,a).","{'faebcdfd-e341-4a75-a0b3-07f359d072b6': 'In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification.\xa0Bones at the base of the skull and long bones form via endochondral ossification.', '7438c93e-650d-4099-b375-bcabc46093b6': 'In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding\xa0perichondrium, a membrane that covers the cartilage,a).', '5aef1f80-ad33-48d9-928c-427dd8d51ebf': 'As more and more matrix is produced, the cartilaginous model grow in size. Blood vessels in the perichondrium bring osteoblasts to the edges of the structure and these arriving osteoblasts deposit bone in a ring around the diaphysis – this is called a bone collar (Figure 6.4.2b). The bony edges of the developing structure prevent nutrients from diffusing into the center of the hyaline cartilage. This results in chondrocyte death and disintegration in the center of the structure. Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting spaces, not only enlarging the cavities but also carrying osteogenic cells with them, many of which will become osteoblasts. These enlarging spaces eventually combine to become the medullary cavity. Bone is now deposited within the structure creating the primary ossification center\xa0(Figure 6.4.2c).', 'bb307add-9d86-4898-b1ae-f0e6fbb9ffae': 'While these deep changes are occurring, chondrocytes and cartilage continue to grow at the ends of the structure (the future epiphyses), which increases the structure’s length at the same time bone is replacing cartilage in the diaphyses. This continued growth is accompanied by remodeling inside the medullary cavity (osteoclasts were also brought with invading blood vessels) and overall lengthening of the structure (Figure 6.4.2d). By the time the fetal skeleton is fully formed, cartilage remains at the epiphyses and at the joint surface as articular cartilage.', '675ff3f9-0cae-46ac-9d44-e1ae58f359e4': 'After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a secondary ossification center (Figure 6.4.2e). Throughout childhood and adolescence, there remains a thin plate of hyaline cartilage between the diaphysis and epiphysis known as the growth or epiphyseal plate\xa0(Figure 6.4.2f). Eventually, this hyaline cartilage will be removed and replaced by bone to become the epiphyseal line.'}"
+Figure 6.4.2,Anatomy_And_Physio/images/Figure 6.4.2.jpg,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.","In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding perichondrium, a membrane that covers the cartilage,a).","{'faebcdfd-e341-4a75-a0b3-07f359d072b6': 'In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification.\xa0Bones at the base of the skull and long bones form via endochondral ossification.', '7438c93e-650d-4099-b375-bcabc46093b6': 'In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding\xa0perichondrium, a membrane that covers the cartilage,a).', '5aef1f80-ad33-48d9-928c-427dd8d51ebf': 'As more and more matrix is produced, the cartilaginous model grow in size. Blood vessels in the perichondrium bring osteoblasts to the edges of the structure and these arriving osteoblasts deposit bone in a ring around the diaphysis – this is called a bone collar (Figure 6.4.2b). The bony edges of the developing structure prevent nutrients from diffusing into the center of the hyaline cartilage. This results in chondrocyte death and disintegration in the center of the structure. Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting spaces, not only enlarging the cavities but also carrying osteogenic cells with them, many of which will become osteoblasts. These enlarging spaces eventually combine to become the medullary cavity. Bone is now deposited within the structure creating the primary ossification center\xa0(Figure 6.4.2c).', 'bb307add-9d86-4898-b1ae-f0e6fbb9ffae': 'While these deep changes are occurring, chondrocytes and cartilage continue to grow at the ends of the structure (the future epiphyses), which increases the structure’s length at the same time bone is replacing cartilage in the diaphyses. This continued growth is accompanied by remodeling inside the medullary cavity (osteoclasts were also brought with invading blood vessels) and overall lengthening of the structure (Figure 6.4.2d). By the time the fetal skeleton is fully formed, cartilage remains at the epiphyses and at the joint surface as articular cartilage.', '675ff3f9-0cae-46ac-9d44-e1ae58f359e4': 'After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a secondary ossification center (Figure 6.4.2e). Throughout childhood and adolescence, there remains a thin plate of hyaline cartilage between the diaphysis and epiphysis known as the growth or epiphyseal plate\xa0(Figure 6.4.2f). Eventually, this hyaline cartilage will be removed and replaced by bone to become the epiphyseal line.'}"
+Figure 6.4.2,Anatomy_And_Physio/images/Figure 6.4.2.jpg,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.","In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding perichondrium, a membrane that covers the cartilage,a).","{'faebcdfd-e341-4a75-a0b3-07f359d072b6': 'In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification.\xa0Bones at the base of the skull and long bones form via endochondral ossification.', '7438c93e-650d-4099-b375-bcabc46093b6': 'In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding\xa0perichondrium, a membrane that covers the cartilage,a).', '5aef1f80-ad33-48d9-928c-427dd8d51ebf': 'As more and more matrix is produced, the cartilaginous model grow in size. Blood vessels in the perichondrium bring osteoblasts to the edges of the structure and these arriving osteoblasts deposit bone in a ring around the diaphysis – this is called a bone collar (Figure 6.4.2b). The bony edges of the developing structure prevent nutrients from diffusing into the center of the hyaline cartilage. This results in chondrocyte death and disintegration in the center of the structure. Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting spaces, not only enlarging the cavities but also carrying osteogenic cells with them, many of which will become osteoblasts. These enlarging spaces eventually combine to become the medullary cavity. Bone is now deposited within the structure creating the primary ossification center\xa0(Figure 6.4.2c).', 'bb307add-9d86-4898-b1ae-f0e6fbb9ffae': 'While these deep changes are occurring, chondrocytes and cartilage continue to grow at the ends of the structure (the future epiphyses), which increases the structure’s length at the same time bone is replacing cartilage in the diaphyses. This continued growth is accompanied by remodeling inside the medullary cavity (osteoclasts were also brought with invading blood vessels) and overall lengthening of the structure (Figure 6.4.2d). By the time the fetal skeleton is fully formed, cartilage remains at the epiphyses and at the joint surface as articular cartilage.', '675ff3f9-0cae-46ac-9d44-e1ae58f359e4': 'After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a secondary ossification center (Figure 6.4.2e). Throughout childhood and adolescence, there remains a thin plate of hyaline cartilage between the diaphysis and epiphysis known as the growth or epiphyseal plate\xa0(Figure 6.4.2f). Eventually, this hyaline cartilage will be removed and replaced by bone to become the epiphyseal line.'}"
+Figure 6.4.3,Anatomy_And_Physio/images/Figure 6.4.3.jpg,Figure 6.4.3 – Longitudinal Bone Growth: The epiphyseal plate is responsible for longitudinal bone growth.,The epiphyseal plate is composed of five zones of cells and activity (Figure 6.4.3). The reserve zone is the region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix. These chondrocytes do not participate in bone growth but secure the epiphyseal plate to the overlying osseous tissue of the epiphysis.,"{'40f3d5fb-b666-464d-94c3-122470ca2e7c': 'The epiphyseal plate is the area of elongation in a long bone. It includes a layer of hyaline cartilage where ossification can continue to occur in immature bones. We can divide the epiphyseal plate into a diaphyseal side (closer to the diaphysis) and an epiphyseal side (closer to the epiphysis). On the epiphyseal side of the epiphyseal plate, hyaline cartilage cells are active and are dividing and producing hyaline cartilage matrix. (figure 6.43, reserve and proliferative zones). On the diaphyseal side of the growth plate, cartilage calcifies and dies, then is replaced by bone (figure 6.43, zones of hypertrophy and maturation, calcification and ossification). As cartilage grows, the entire structure grows in length and then is turned into bone. Once cartilage cannot grow further, the structure cannot elongate more.', '8623c072-03cd-4303-b016-0360a99552b0': 'The epiphyseal plate is composed of five zones of cells and activity (Figure 6.4.3). The reserve zone is the region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix. These chondrocytes do not participate in bone growth but secure the epiphyseal plate to the overlying osseous tissue of the epiphysis.', 'e2020a6f-5a68-4a43-8cd7-054461ba815c': 'The proliferative zone is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes. It makes new chondrocytes (via mitosis) to replace those that die at the diaphyseal end of the plate. Chondrocytes in the next layer, the zone of maturation and hypertrophy, are older and larger than those in the proliferative zone. The more mature cells are situated closer to the diaphyseal end of the plate. The longitudinal growth of bone is a result of cellular division in the proliferative zone and the maturation of cells in the zone of maturation and hypertrophy. This growth within a tissue is called\xa0interstitial growth.', 'e04e1e95-f2c6-4d33-99ae-9daa3279ecd0': 'Most of the chondrocytes in the zone of calcified matrix, the zone closest to the diaphysis, are dead because the matrix around them has calcified, restricting nutrient diffusion. Capillaries and osteoblasts from the diaphysis penetrate this zone, and the osteoblasts secrete bone tissue on the remaining calcified cartilage. Thus, the zone of calcified matrix connects the epiphyseal plate to the diaphysis. A bone grows in length when osseous tissue is added to the diaphysis.', '76575189-ddc5-4df9-8420-66b242842f8a': 'Bones continue to grow in length until early adulthood. The rate of growth is controlled by hormones, which will be discussed later. When the chondrocytes in the epiphyseal plate cease their proliferation and bone replaces all the cartilage, longitudinal growth stops. All that remains of the epiphyseal plate is the ossified\xa0epiphyseal line (Figure 6.4.4).'}"
+Figure 6.4.4,Anatomy_And_Physio/images/Figure 6.4.4.jpg,"Figure 6.4.4 – Progression from Epiphyseal Plate to Epiphyseal Line: As a bone matures, the epiphyseal plate progresses to an epiphyseal line. (a) Epiphyseal plates are visible in a growing bone. (b) Epiphyseal lines are the remnants of epiphyseal plates in a mature bone.","Bones continue to grow in length until early adulthood. The rate of growth is controlled by hormones, which will be discussed later. When the chondrocytes in the epiphyseal plate cease their proliferation and bone replaces all the cartilage, longitudinal growth stops. All that remains of the epiphyseal plate is the ossified epiphyseal line (Figure 6.4.4).","{'40f3d5fb-b666-464d-94c3-122470ca2e7c': 'The epiphyseal plate is the area of elongation in a long bone. It includes a layer of hyaline cartilage where ossification can continue to occur in immature bones. We can divide the epiphyseal plate into a diaphyseal side (closer to the diaphysis) and an epiphyseal side (closer to the epiphysis). On the epiphyseal side of the epiphyseal plate, hyaline cartilage cells are active and are dividing and producing hyaline cartilage matrix. (figure 6.43, reserve and proliferative zones). On the diaphyseal side of the growth plate, cartilage calcifies and dies, then is replaced by bone (figure 6.43, zones of hypertrophy and maturation, calcification and ossification). As cartilage grows, the entire structure grows in length and then is turned into bone. Once cartilage cannot grow further, the structure cannot elongate more.', '8623c072-03cd-4303-b016-0360a99552b0': 'The epiphyseal plate is composed of five zones of cells and activity (Figure 6.4.3). The reserve zone is the region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix. These chondrocytes do not participate in bone growth but secure the epiphyseal plate to the overlying osseous tissue of the epiphysis.', 'e2020a6f-5a68-4a43-8cd7-054461ba815c': 'The proliferative zone is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes. It makes new chondrocytes (via mitosis) to replace those that die at the diaphyseal end of the plate. Chondrocytes in the next layer, the zone of maturation and hypertrophy, are older and larger than those in the proliferative zone. The more mature cells are situated closer to the diaphyseal end of the plate. The longitudinal growth of bone is a result of cellular division in the proliferative zone and the maturation of cells in the zone of maturation and hypertrophy. This growth within a tissue is called\xa0interstitial growth.', 'e04e1e95-f2c6-4d33-99ae-9daa3279ecd0': 'Most of the chondrocytes in the zone of calcified matrix, the zone closest to the diaphysis, are dead because the matrix around them has calcified, restricting nutrient diffusion. Capillaries and osteoblasts from the diaphysis penetrate this zone, and the osteoblasts secrete bone tissue on the remaining calcified cartilage. Thus, the zone of calcified matrix connects the epiphyseal plate to the diaphysis. A bone grows in length when osseous tissue is added to the diaphysis.', '76575189-ddc5-4df9-8420-66b242842f8a': 'Bones continue to grow in length until early adulthood. The rate of growth is controlled by hormones, which will be discussed later. When the chondrocytes in the epiphyseal plate cease their proliferation and bone replaces all the cartilage, longitudinal growth stops. All that remains of the epiphyseal plate is the ossified\xa0epiphyseal line (Figure 6.4.4).'}"
+Figure 6.3.1,Anatomy_And_Physio/images/Figure 6.3.1.jpg,Figure 6.3.1 – Anatomy of a Long Bone: A typical long bone showing gross anatomical features.,"A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone) are composed of dense and hard compact bone, a form of osseous tissue.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves.","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.3.3,Anatomy_And_Physio/images/Figure 6.3.3.jpg,Figure 6.3.3 – Anatomy of a Flat Bone: This cross-section of a flat bone shows the spongy bone (diploë) covered on either side by a layer of compact bone.,"Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.'}"
+Figure 6.3.5,Anatomy_And_Physio/images/Figure 6.3.5.jpg,"Figure 6.3.5 – Bone Cells: Four types of cells are found within bone tissue. Osteogenic cells are undifferentiated and develop into osteoblasts. Osteoblasts deposit bone matrix. When osteoblasts get trapped within the calcified matrix, they become osteocytes. Osteoclasts develop from a different cell lineage and act to resorb bone.","Although bone cells compose less than 2% of the bone mass, they are crucial to the function of bones. Four types of cells are found within bone tissue: osteoblasts, osteocytes, osteogenic cells, and osteoclasts (Figure 6.3.5).","{'945543bf-ea6f-469b-b2d4-8bc07029f7f0': 'Although bone cells compose less than 2%\xa0of the bone mass, they are crucial to the function of bones. Four types of cells are found within bone tissue: osteoblasts, osteocytes, osteogenic cells, and osteoclasts (Figure 6.3.5).', 'cafd3e67-d88d-48ce-beb3-4aa683f95b46': 'The osteoblast is the bone cell responsible for forming new bone and is found in the growing portions of bone, including the\xa0endosteum and the cellular layer of the periosteum. Osteoblasts, which do not divide, synthesize and secrete the collagen matrix and other proteins. As the secreted matrix surrounding the osteoblast calcifies, the osteoblast become trapped within it; as a result, it changes in structure and becomes an osteocyte, the primary cell of mature bone and the most common type of bone cell. Each osteocyte is located in a small cavity in the bone tissue called a lacuna (lacunae for plural).\xa0Osteocytes maintain the mineral concentration of the matrix via the secretion of enzymes. Like osteoblasts, osteocytes lack mitotic activity. They can communicate with each other and receive nutrients via long cytoplasmic processes that extend through canaliculi (singular = canaliculus), channels within the bone matrix. Osteocytes are connected to one another within the canaliculi via gap junctions.', '43607270-699a-492d-bbb6-a234a6e156c0': 'If osteoblasts and osteocytes are incapable of mitosis, then how are they replenished when old ones die? The answer lies in the properties of a third category of bone cells—the osteogenic (osteoprogenitor) cell. These osteogenic cells are undifferentiated with high mitotic activity and they are the only bone cells that divide. Immature osteogenic cells are found in the cellular\xa0layer of the periosteum and the endosteum. They differentiate and develop into osteoblasts.', 'f9918e7e-05dc-4b2e-9250-b1ad68df3773': 'The dynamic nature of bone means that new tissue is constantly formed, and old, injured, or unnecessary bone is dissolved for repair or for calcium release. The cells responsible for bone resorption, or breakdown, are the osteoclasts. These multinucleated cells originate from monocytes and macrophages, two types of white blood cells, not from osteogenic cells. Osteoclasts are continually breaking down old bone while osteoblasts are continually forming new bone. The ongoing balance between osteoblasts and osteoclasts is responsible for the constant but subtle reshaping of bone. Table 6.3 reviews the bone cells, their functions, and locations.'}"
+Figure 6.3.6,Anatomy_And_Physio/images/Figure 6.3.6.jpg,"Figure 6.3.6 – Diagram of Compact Bone: (a) This cross-sectional view of compact bone shows several osteons, the basic structural unit of compact bone. (b) In this micrograph of the osteon, you can see the concentric lamellae around the central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Compact bone is the denser, stronger of the two types of osseous tissue (Figure 6.3.6). It makes up the outer cortex of all bones and is in immediate contact with the periosteum. In long bones, as you move from the outer cortical compact bone to the inner medullary cavity, the bone transitions to spongy bone.","{'50c565a1-13f7-4ed4-9c33-831d1d6df411': 'Compact bone is the denser, stronger of the two types of osseous tissue (Figure 6.3.6). It makes up the outer cortex of all bones and is in immediate contact with the periosteum. In long bones, as you move from the outer cortical compact bone to the inner medullary cavity, the bone transitions to spongy bone.', 'e8d51f73-f6b5-4145-808f-9c2d124af481': 'If you look at compact bone under the microscope, you will observe a highly organized arrangement of concentric circles that look like tree trunks. Each group of concentric circles (each “tree”) makes up the microscopic structural unit of compact bone called an osteon (this is also called a\xa0Haversian system). Each ring of the osteon is made of collagen and calcified matrix and is called a lamella (plural = lamellae). The collagen fibers of adjacent lamallae run at perpendicular angles to each other, allowing osteons to resist twisting forces in multiple directions (see figure 6.34a). Running down the center of each osteon is the central canal, or Haversian canal, which contains blood vessels, nerves, and lymphatic vessels. These vessels and nerves branch off at right angles through a perforating canal, also known as Volkmann’s canals, to extend to the periosteum and endosteum. The endosteum also lines each central canal, allowing osteons to be removed, remodeled and rebuilt over time.', '6d08d74a-71ea-4602-b1fb-53e28f1589ed': 'The osteocytes are trapped within their lacuane, found at the borders of adjacent lamellae. As described earlier, canaliculi connect with the canaliculi of other lacunae and eventually with the central canal. This system allows nutrients to be transported to the osteocytes and wastes to be removed from them despite the impervious calcified matrix.'}"
+Figure 6.3.8,Anatomy_And_Physio/images/Figure 6.3.8.jpg,Figure 6.3.8 – Diagram of Spongy Bone: Spongy bone is composed of trabeculae that contain the osteocytes. Red marrow fills the spaces in some bones.,"Like compact bone, spongy bone, also known as cancellous bone, contains osteocytes housed in lacunae, but they are not arranged in concentric circles. Instead, the lacunae and osteocytes are found in a lattice-like network of matrix spikes called trabeculae (singular = trabecula) (Figure 6.3.8). The trabeculae are covered by the endosteum, which can readily remodel them. The trabeculae may appear to be a random network, but each trabecula forms along lines of stress to direct forces out to the more solid compact bone providing strength to the bone. Spongy bone provides balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. In addition, the spaces in some spongy bones contain red bone marrow, protected by the trabeculae, where hematopoiesis occurs.","{'10b59662-6640-4bab-a6f2-2ace0f0ed345': 'Like compact bone, spongy bone, also known as cancellous bone, contains osteocytes housed in lacunae, but they are not arranged in concentric circles. Instead, the lacunae and osteocytes are found in a lattice-like network of matrix spikes called trabeculae (singular = trabecula) (Figure 6.3.8). The trabeculae are covered by the endosteum, which can readily remodel them. The trabeculae may appear to be a random network, but each trabecula forms along lines of stress to direct forces out to the more solid compact bone providing\xa0strength to the bone. Spongy bone provides balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. In addition, the spaces in some spongy bones contain red bone marrow, protected by the trabeculae, where hematopoiesis occurs.'}"
+Figure 6.3.10,Anatomy_And_Physio/images/Figure 6.3.10.jpg,Figure 6.3.10 – Diagram of Blood and Nerve Supply to Bone: Blood vessels and nerves enter the bone through the nutrient foramen.,"The spongy bone and medullary cavity receive nourishment from arteries that pass through the compact bone. The arteries enter through the nutrient foramen (plural = foramina), small openings in the diaphysis (Figure 6.3.10). The osteocytes in spongy bone are nourished by blood vessels of the periosteum that penetrate spongy bone and blood that circulates in the marrow cavities. As the blood passes through the marrow cavities, it is collected by veins, which then pass out of the bone through the foramina.","{'46c764b4-9e7c-4578-85af-ec43076e0f3d': 'The spongy bone and medullary cavity receive nourishment from arteries that pass through the compact bone. The arteries enter through the nutrient foramen (plural = foramina), small openings in the diaphysis (Figure 6.3.10). The osteocytes in spongy bone are nourished by blood vessels of the periosteum that penetrate spongy bone and blood that circulates in the marrow cavities. As the blood passes through the marrow cavities, it is collected by veins, which then pass out of the bone through the foramina.', '1c0befdc-9038-40bb-8125-ba17521b2cc8': 'In addition to the blood vessels, nerves follow the same paths into the bone where they tend to concentrate in the more metabolically active regions of the bone. The nerves sense pain, and it appears the nerves also play roles in regulating blood supplies and in bone growth, hence their concentrations in metabolically active sites of the bone.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.3.4,Anatomy_And_Physio/images/Figure 6.3.4.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves.","Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.","{'dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b': 'A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone)\xa0are composed of dense and hard compact bone, a form of osseous tissue.', '2f96fa58-7911-4287-ac93-5faa704dce3e': 'The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis.\xa0During growth, the metaphysis contains the epiphyseal plate, the\xa0site of long bone elongation described later in the chapter.\xa0When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.', '970c5164-30e0-4ed5-9026-e3f7c2d46532': 'Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.', '00c2867c-b69b-4354-993c-665d678ce72f': 'Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.', 'd2e0f48c-3e6e-42ba-bb20-73d99a1723e2': 'The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.'}"
+Figure 6.2.1,Anatomy_And_Physio/images/Figure 6.2.1.jpg,Figure 6.2.1 – Classifications of Bones: Bones are classified according to their shape.,"The 206 bones that compose the adult skeleton are divided into five categories based on their shapes (Figure 6.2.1). Like other structure/function relationships in the body, their shapes and their functions are related such that each categorical shape of bone has a distinct function.","{'c9e61b83-6a9a-4fd7-b511-f1f1e4c7127e': 'The 206 bones that compose the adult skeleton are divided into five categories based on their shapes (Figure 6.2.1). Like other structure/function relationships in the body, their shapes and their functions are related such that each categorical shape of bone has a distinct function.'}"
+Figure 6.1.1,Anatomy_And_Physio/images/Figure 6.1.1.jpg,Figure 6.1.1 Functions of the skeletal system.,"Some functions of the skeletal system are more readily observable than others. When you move you can feel how your bones support you, facilitate your movement, and protect the soft organs of your body. Just as the steel beams of a building provide a scaffold to support its weight, the bones and cartilages of your skeletal system compose the scaffold that supports the rest of your body. Without the skeletal system, you would be a limp mass of organs, muscle, and skin. Bones facilitate movement by serving as points of attachment for your muscles. Bones also protect internal organs from injury by covering or surrounding them. For example, your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain (see Figure 6.1.1).","{'e441ea0d-9739-4f7e-b39c-fd4bad8f6cbf': 'Some functions of the skeletal system are more readily observable than others. When you move you can feel how your bones support you, facilitate your movement, and protect the soft organs of your body. Just as the steel beams of a building provide a scaffold to support its weight, the bones and cartilages of your skeletal system compose the scaffold that supports the rest of your body. Without the skeletal system, you would be a limp mass of organs, muscle, and skin. Bones facilitate movement by serving as points of attachment for your muscles. Bones also protect internal organs from injury by covering or surrounding them. For example, your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain (see Figure 6.1.1).'}"
+Figure 6.1.2,Anatomy_And_Physio/images/Figure 6.1.2.jpg,Figure 6.1.2 – Bone Marrow: Bones contain variable amounts of yellow and/or red bone marrow. Yellow bone marrow stores fat and red bone marrow is responsible for producing blood cells (hematopoiesis).,"Bones also serve as a site for fat storage and blood cell production. The unique connective tissue that fills the interior of most bones is referred to as bone marrow. There are two types of bone marrow: yellow bone marrow and red bone marrow. Yellow bone marrow contains adipose tissue, and the triglycerides stored in the adipocytes of this tissue can be released to serve as a source of energy for other tissues of the body. Red bone marrow is where the production of blood cells (named hematopoiesis, hemato- = “blood”, -poiesis = “to make”) takes place. Red blood cells, white blood cells, and platelets are all produced in the red bone marrow. As we age, the distribution of red and yellow bone marrow changes as seen in the figure (Figure 6.1.2).","{'9f1122a9-1f6e-468a-9d5a-0b79f351555b': 'On a metabolic level, bone tissue performs several critical functions. For one, the bone tissue acts as a reservoir for a number of minerals important to the functioning of the body, especially calcium, and phosphorus. These minerals, incorporated into bone tissue, can be released back into the bloodstream to maintain levels needed to support physiological processes. Calcium ions, for example, are essential for muscle contractions and are\xa0involved in the transmission of nerve impulses.', '4f63ce15-8166-4151-9f92-a497ff516ceb': 'Bones also serve as a site for fat storage and blood cell production. The unique connective tissue that fills the interior of most bones is referred to as bone marrow. There are two types of bone marrow: yellow bone marrow and red bone marrow. Yellow bone marrow contains adipose tissue, and the triglycerides stored in the adipocytes of this tissue can be released to serve as a source of energy for other tissues of the body. Red bone marrow is where the production of blood cells (named hematopoiesis, hemato- = “blood”, -poiesis = “to make”) takes place. Red blood cells, white blood cells, and platelets are all produced in the red bone marrow. As we age, the distribution of red and yellow bone marrow changes as seen in the figure (Figure 6.1.2).'}"
+Figure 6.1.3,Anatomy_And_Physio/images/Figure 6.1.3.jpg,Figure 6.1.3 – Arm Brace: An orthopedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support. (credit: Juhan Sonin),"An orthopedist is a doctor who specializes in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery (Figure 6.1.3).","{'887638da-1622-4ea2-a5c1-78f40434863d': 'An orthopedist is a doctor who specializes in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery (Figure 6.1.3).', '01ce62ff-c6e9-4d15-ae2f-a3e310ebdb62': 'While the origin of the word “orthopedics” (ortho- = “straight”; paed- = “child”), literally means “straightening of the child,” orthopedists can have patients who range from pediatric to geriatric. In recent years, orthopedists have even performed prenatal surgery to correct spina bifida, a congenital defect in which the neural canal in the spine of the fetus fails to close completely during embryologic development.', '816004ba-87f8-4c10-a859-75dda27704fa': 'Orthopedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine. Lateral curvatures (scoliosis) can be severe enough to slip under the shoulder blade (scapula) forcing it up as a hump. Spinal curvatures can also be excessive dorsoventrally (kyphosis) causing a hunch back and thoracic compression. These curvatures often appear in preteens as the result of poor posture, abnormal growth, or indeterminate causes. Mostly, they are readily treated by orthopedists. As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly.', '3fffdb02-6e41-4842-9bd6-b06f439d0179': 'Some orthopedists sub-specialize in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder. Treatment can range from exercise to surgery.', '74cb52e5-5e2a-43b2-b594-1274bce8c073': 'Bones make good fossils. While the soft tissue of a once living organism will decay and fall away over time, bone tissue will, under the right conditions, undergo a process of mineralization, effectively turning the bone to stone. A well-preserved fossil skeleton can give us a good sense of the size and shape of an organism, just as your skeleton helps to define your size and shape. Unlike a fossil skeleton, however, your skeleton is a structure of living tissue that grows, repairs, and renews itself. The bones within it are dynamic and complex organs that serve a number of important functions, including some necessary to maintain homeostasis.', '201b310c-1f39-438b-b473-a5675f682ada': 'The integumentary system is susceptible to a variety of diseases, disorders, and injuries. These range from annoying but relatively benign bacterial or fungal infections that are categorized as disorders, to skin cancer and severe burns, which can be fatal. In this section, you will learn several of the most common skin conditions.'}"
+Figure 5.3.1,Anatomy_And_Physio/images/Figure 5.3.1.jpg,"Figure 5.3.1 – Light Micrograph of a Meissner Corpuscle: In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM × 100. (credit: “Wbensmith”/Wikimedia Commons)","The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the Meissner corpuscle (tactile corpuscle) (Figure 5.3.1), which responds to light touch, and the Pacinian corpuscle (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also touch receptors. In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our environment and react accordingly.","{'aef7ba32-37c9-4fce-9613-92f4eb2269f2': 'The fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment. The hair root plexus surrounding the base of the hair follicle senses a disturbance, and then transmits the information to the central nervous system (brain and spinal cord), which can then respond by activating the skeletal muscles of your eyes to see the ant and the skeletal muscles of the body to act against the ant.', '26b0e0d0-3e94-45fe-8bac-468eee92bb6b': 'The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the Meissner corpuscle (tactile corpuscle) (Figure 5.3.1), which responds to light touch, and the Pacinian corpuscle (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also touch receptors. In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our environment and react accordingly.'}"
+Figure 5.3.2,Anatomy_And_Physio/images/Figure 5.3.2.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)","The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.","{'61d4d139-47c1-44e8-a554-46b0ebc50b88': 'The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.', '4cf3291f-ace1-4544-b439-89857d72f795': 'In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (Figure 5.3.2b). This accounts for the skin redness that many lighter skinned people experience when exercising.', 'b4bfce5e-97c1-4b24-b636-8f278df5f4e3': 'When body temperatures drop, the arterioles serving the superficial dermis constrict to minimize heat loss, particularly in the ends of the digits and tip of the nose. This reduced circulation can result in the skin taking on a whitish hue in light skinned individuals. Although the temperature of the skin drops as a result, passive heat loss is prevented, and internal organs and structures remain warm due to the warm blood remaining closer to the core. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of body core heat can result in the skin actually freezing, a condition called frostbite. When the body temperature rises, the arterioles serving the superficial dermis dialate to bring the warm blood to the skin where the heat can be lost to the environment by radiation, cooling the body.', 'e793178b-2df3-4b72-808f-9078ffb7accc': 'All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 5.3.3). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.', '50f6c8aa-e7b9-4e5e-ae92-0a642dfc4393': 'The accessory structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating ability can cause some elderly to be intolerant to extreme heat. Other cells in the skin, such as melanocytes and dendritic cells, also become less active, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakdown of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the skin, and the inability of the skin to retain adequate moisture.', '577f7abf-9666-46cc-834e-44a9e257cadd': 'Many anti-aging products can be found in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate skin growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling.'}"
+Figure 5.3.2,Anatomy_And_Physio/images/Figure 5.3.2.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)","The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.","{'61d4d139-47c1-44e8-a554-46b0ebc50b88': 'The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.', '4cf3291f-ace1-4544-b439-89857d72f795': 'In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (Figure 5.3.2b). This accounts for the skin redness that many lighter skinned people experience when exercising.', 'b4bfce5e-97c1-4b24-b636-8f278df5f4e3': 'When body temperatures drop, the arterioles serving the superficial dermis constrict to minimize heat loss, particularly in the ends of the digits and tip of the nose. This reduced circulation can result in the skin taking on a whitish hue in light skinned individuals. Although the temperature of the skin drops as a result, passive heat loss is prevented, and internal organs and structures remain warm due to the warm blood remaining closer to the core. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of body core heat can result in the skin actually freezing, a condition called frostbite. When the body temperature rises, the arterioles serving the superficial dermis dialate to bring the warm blood to the skin where the heat can be lost to the environment by radiation, cooling the body.', 'e793178b-2df3-4b72-808f-9078ffb7accc': 'All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 5.3.3). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.', '50f6c8aa-e7b9-4e5e-ae92-0a642dfc4393': 'The accessory structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating ability can cause some elderly to be intolerant to extreme heat. Other cells in the skin, such as melanocytes and dendritic cells, also become less active, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakdown of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the skin, and the inability of the skin to retain adequate moisture.', '577f7abf-9666-46cc-834e-44a9e257cadd': 'Many anti-aging products can be found in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate skin growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling.'}"
+Figure 5.3.3,Anatomy_And_Physio/images/Figure 5.3.3.jpg,"Figure 5.3.3 – Aging: Generally, skin, especially on the face and hands, starts to display the first noticeable signs of aging, as it loses its elasticity over time. (credit: Janet Ramsden)","All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 5.3.3). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.","{'61d4d139-47c1-44e8-a554-46b0ebc50b88': 'The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.', '4cf3291f-ace1-4544-b439-89857d72f795': 'In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (Figure 5.3.2b). This accounts for the skin redness that many lighter skinned people experience when exercising.', 'b4bfce5e-97c1-4b24-b636-8f278df5f4e3': 'When body temperatures drop, the arterioles serving the superficial dermis constrict to minimize heat loss, particularly in the ends of the digits and tip of the nose. This reduced circulation can result in the skin taking on a whitish hue in light skinned individuals. Although the temperature of the skin drops as a result, passive heat loss is prevented, and internal organs and structures remain warm due to the warm blood remaining closer to the core. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of body core heat can result in the skin actually freezing, a condition called frostbite. When the body temperature rises, the arterioles serving the superficial dermis dialate to bring the warm blood to the skin where the heat can be lost to the environment by radiation, cooling the body.', 'e793178b-2df3-4b72-808f-9078ffb7accc': 'All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 5.3.3). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.', '50f6c8aa-e7b9-4e5e-ae92-0a642dfc4393': 'The accessory structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating ability can cause some elderly to be intolerant to extreme heat. Other cells in the skin, such as melanocytes and dendritic cells, also become less active, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakdown of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the skin, and the inability of the skin to retain adequate moisture.', '577f7abf-9666-46cc-834e-44a9e257cadd': 'Many anti-aging products can be found in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate skin growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling.'}"
+Figure 5.2.1,Anatomy_And_Physio/images/Figure 5.2.1.jpg,Figure 5.2.1 – Hair: Hair follicles originate in the epidermis and have many different parts.,"Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Strands of hair originate in an epidermal penetration of the dermis called the hair follicle. The hair shaft is the part of the hair not anchored to the follicle, and much of this can be exposed at the skin’s surface. The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root. The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix. The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis (Figure 5.2.1).","{'4cc6eabc-0d99-472c-a306-cc25d69ae217': 'Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Strands of hair originate in an epidermal penetration of the dermis called the hair follicle. The hair shaft is the part of the hair not anchored to the follicle, and much of this can be exposed at the skin’s surface. The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root. The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix. The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis (Figure 5.2.1).', '11e0181b-8a0a-4339-a6da-fd0c682a7767': 'Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows. The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle. These layers are depicted in a longitudinal cross-section of the hair follicle (Figure 5.2.2), although not all hair has a medullary layer. Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla. The shape and structure of these layers are, in turn, determined by the shape of the hair follicle. Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface. Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible. The external hair is completely dead and composed entirely of keratin. For this reason, our hair does not have sensation. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and plucking both attempt to destroy the hair bulb so hair cannot grow.', '720253ea-7382-4bfd-ab8d-9026b856fc30': 'The wall of the hair follicle is made of three concentric layers of cells. The cells of the internal root sheath surround the root of the growing hair and extend just up to the hair shaft. They are derived from the basal cells of the hair matrix. The external root sheath, which is an extension of the epidermis, encloses the hair root. It is made of basal cells at the base of the hair root and tends to be more keratinous in the upper regions. The glassy membrane is a thick, clear connective tissue sheath covering the hair root, connecting it to the tissue of the dermis.', 'd490756d-8482-4908-9615-20fe783e895b': 'Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. For example, hair on the head protects the skull from the sun. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface. This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface. Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps and even more obvious in animals, such as when a frightened cat raises its fur. Of course, this is much more obvious in organisms with a heavier coat than most humans, such as dogs and cats.'}"
+Figure 5.2.2,Anatomy_And_Physio/images/Figure 5.2.2.jpg,Figure 5.2.2 – Hair Follicle: The slide shows a cross-section of a hair follicle. Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath. Basal cells at the base of the hair root form the outer root sheath. LM × 4. (credit: modification of work by “kilbad”/Wikimedia Commons),"Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows. The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle. These layers are depicted in a longitudinal cross-section of the hair follicle (Figure 5.2.2), although not all hair has a medullary layer. Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla. The shape and structure of these layers are, in turn, determined by the shape of the hair follicle. Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface. Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible. The external hair is completely dead and composed entirely of keratin. For this reason, our hair does not have sensation. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and plucking both attempt to destroy the hair bulb so hair cannot grow.","{'4cc6eabc-0d99-472c-a306-cc25d69ae217': 'Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Strands of hair originate in an epidermal penetration of the dermis called the hair follicle. The hair shaft is the part of the hair not anchored to the follicle, and much of this can be exposed at the skin’s surface. The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root. The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix. The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis (Figure 5.2.1).', '11e0181b-8a0a-4339-a6da-fd0c682a7767': 'Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows. The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle. These layers are depicted in a longitudinal cross-section of the hair follicle (Figure 5.2.2), although not all hair has a medullary layer. Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla. The shape and structure of these layers are, in turn, determined by the shape of the hair follicle. Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface. Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible. The external hair is completely dead and composed entirely of keratin. For this reason, our hair does not have sensation. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and plucking both attempt to destroy the hair bulb so hair cannot grow.', '720253ea-7382-4bfd-ab8d-9026b856fc30': 'The wall of the hair follicle is made of three concentric layers of cells. The cells of the internal root sheath surround the root of the growing hair and extend just up to the hair shaft. They are derived from the basal cells of the hair matrix. The external root sheath, which is an extension of the epidermis, encloses the hair root. It is made of basal cells at the base of the hair root and tends to be more keratinous in the upper regions. The glassy membrane is a thick, clear connective tissue sheath covering the hair root, connecting it to the tissue of the dermis.', 'd490756d-8482-4908-9615-20fe783e895b': 'Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. For example, hair on the head protects the skull from the sun. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface. This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface. Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps and even more obvious in animals, such as when a frightened cat raises its fur. Of course, this is much more obvious in organisms with a heavier coat than most humans, such as dogs and cats.'}"
+Figure 5.2.3,Anatomy_And_Physio/images/Figure 5.2.3.jpg,Figure 5.2.3 – Nails: The nail is an accessory structure of the integumentary system.,"The nail bed is a specialized structure of the epidermis that is found at the tips of our fingers and toes. The nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress (Figure 5.2.3). In addition, the nail body forms a back-support for picking up small objects with the fingers. The nail body is composed of densely packed dead keratinocytes. The epidermis in this part of the body has evolved a specialized structure upon which nails can form. The nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously. The lateral nail fold overlaps the nail on the sides, helping to anchor the nail body. The nail fold that meets the proximal end of the nail body forms the nail cuticle, also called the eponychium. The nail bed is rich in blood vessels, making it appear pink, except at the base, where a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the lunula (the “little moon”). The area beneath the free edge of the nail, furthest from the cuticle, is called the hyponychium. It consists of a thickened layer of stratum corneum.","{'cf3ccf42-e034-4559-afb3-a969137bb457': 'The nail bed is a specialized structure of the epidermis that is found at the tips of our fingers and toes. The nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress (Figure 5.2.3). In addition, the nail body forms a back-support for picking up small objects with the fingers. The nail body is composed of densely packed dead keratinocytes. The epidermis in this part of the body has evolved a specialized structure upon which nails can form. The nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously. The lateral nail fold overlaps the nail on the sides, helping to anchor the nail body. The nail fold that meets the proximal end of the nail body forms the nail cuticle, also called the eponychium. The nail bed is rich in blood vessels, making it appear pink, except at the base, where a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the lunula (the “little moon”). The area beneath the free edge of the nail, furthest from the cuticle, is called the hyponychium. It consists of a thickened layer of stratum corneum.'}"
+Figure 5.2.4,Anatomy_And_Physio/images/Figure 5.2.4.jpg,Figure 5.2.4 – Eccrine Gland: Eccrine glands are coiled glands in the dermis that release sweat that is mostly water.,"An eccrine sweat gland is type of gland that produces a hypotonic sweat for thermoregulation. These glands are found all over the skin’s surface, but are especially abundant on the palms of the hand, the soles of the feet, and the forehead (Figure 5.2.4). They are coiled glands lying deep in the dermis, with the duct rising up to a pore on the skin surface, where the sweat is released. This type of sweat, released by exocytosis, is hypotonic and composed mostly of water, with some salt, antibodies, traces of metabolic waste, and dermicidin, an antimicrobial peptide. Eccrine glands are a primary component of thermoregulation in humans and thus help to maintain homeostasis by producing sweat that evaporates and cools the body.","{'b0a85d53-52c7-43e8-b4d9-87a063fa6198': 'When the body becomes warm, sudoriferous glands\xa0 (sweat glands) produce sweat to cool the body. Sweat glands develop from epidermal projections into the dermis and are classified as merocrine glands; that is, the secretions are excreted by exocytosis through a duct without affecting the cells of the gland. There are two types of sweat glands, each secreting slightly different products.', 'eacb1fb3-1e23-4736-96f9-80f21e150758': 'An eccrine sweat gland is type of gland that produces a hypotonic sweat for thermoregulation. These glands are found all over the skin’s surface, but are especially abundant on the palms of the hand, the soles of the feet, and the forehead (Figure 5.2.4). They are coiled glands lying deep in the dermis, with the duct rising up to a pore on the skin surface, where the sweat is released. This type of sweat, released by exocytosis, is hypotonic and composed mostly of water, with some salt, antibodies, traces of metabolic waste, and dermicidin, an antimicrobial peptide. Eccrine glands are a primary component of thermoregulation in humans and thus help to maintain homeostasis by producing sweat that evaporates and cools the body.', '2bc7e110-5b63-4193-8735-71f65144c45f': 'An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control, and plays a role in the poorly understood human pheromone response. Most commercial antiperspirants use an aluminum-based compound as their primary active ingredient to stop sweat. When the antiperspirant enters the sweat gland duct, the aluminum-based compounds precipitate due to a change in pH and form a physical block in the duct, which prevents sweat from coming out of the pore.'}"
+Figure 5.1.1,Anatomy_And_Physio/images/Figure 5.1.1.jpg,"Figure 5.1.1 – Layers of Skin: The skin is composed of two main layers: the epidermis, made of closely packed epithelial cells, and the dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures. Beneath the dermis lies the hypodermis, which is composed mainly of loose connective and fatty tissues.","Although you may not typically think of the skin as an organ, it is in fact made of tissues that work together as a single structure to perform unique and critical functions. The skin and its accessory structures make up the integumentary system, which provides the body with overall protection. The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue (Figure 5.1.1). The most superficial layer of the skin is the epidermis which is attached to the deeper dermis. Accessory structures, hair, glands, and nails, are found associated with the skin. The deeper layer of skin is well vascularized (has numerous blood vessels) and is superficial to the hypodermics. It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain.","{'f8d748a3-8eb8-4eef-acd5-4714adb665f6': 'A sebaceous gland is a type of oil gland that is found all over the body and helps to lubricate and waterproof the skin and hair. Most sebaceous glands are associated with hair follicles. They generate and excrete sebum, a mixture of lipids, onto the skin surface, thereby naturally lubricating the dry and dead layer of keratinized cells of the stratum corneum, keeping it pliable. The fatty acids of sebum also have antibacterial properties, and prevent water loss from the skin in low-humidity environments. The secretion of sebum is stimulated by hormones, many of which do not become active until puberty. Thus, sebaceous glands are relatively inactive during childhood.', '3bc4be9d-ba9d-4544-bbe9-967327b9cd08': 'Although you may not typically think of the skin as an organ, it is in fact made of tissues that work together as a single structure to perform unique and critical functions. The skin and its accessory structures make up the integumentary system, which provides the body with overall protection. The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue (Figure 5.1.1). The most superficial layer of the skin is the epidermis which is attached to the deeper dermis. Accessory structures, hair, glands, and nails, are found associated with the skin. The deeper layer of skin is well vascularized (has numerous blood vessels) and is superficial to the hypodermics. It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain.'}"
+Figure 5.1.2,Anatomy_And_Physio/images/Figure 5.1.2.jpg,"Figure 5.1.2 – Thin Skin versus Thick Skin: These slides show cross-sections of the epidermis and dermis of (a) thin and (b) thick skin. Note the significant difference in the thickness of the epithelial layer of the thick skin. From top, LM × 40, LM × 40. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it (i.e., it is avascular). Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum (Figure 5.1.2).","{'40da5b91-04c2-4b69-a8a3-100614b2113f': 'The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it (i.e., it is avascular). Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum (Figure 5.1.2).', 'e8021626-5ca1-4aa1-a51e-b5a770c52f11': 'The cells in all of the layers except the stratum basale are called keratinocytes, which make up about 95% of all epidermal cells. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers (Figure 5.1.3).'}"
+Figure 5.1.3,Anatomy_And_Physio/images/Figure 5.1.3.jpg,"Figure 5.1.3 – Epidermis: The epidermis is epithelium composed of multiple layers of cells. The basal layer consists of cuboidal cells, whereas the outer layers are squamous, keratinized cells, so the whole epithelium is often described as being keratinized stratified squamous epithelium. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","The cells in all of the layers except the stratum basale are called keratinocytes, which make up about 95% of all epidermal cells. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers (Figure 5.1.3).","{'40da5b91-04c2-4b69-a8a3-100614b2113f': 'The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it (i.e., it is avascular). Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum (Figure 5.1.2).', 'e8021626-5ca1-4aa1-a51e-b5a770c52f11': 'The cells in all of the layers except the stratum basale are called keratinocytes, which make up about 95% of all epidermal cells. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers (Figure 5.1.3).'}"
+Figure 5.1.6,Anatomy_And_Physio/images/Figure 5.1.6.jpg,"Figure 5.1.6 – Layers of the Dermis: This stained slide shows the two components of the dermis—the papillary layer and the reticular layer. Both are made of connective tissue with fibers of collagen extending from one to the other, making the border between the two somewhat indistinct. The dermal papillae extending into the epidermis belong to the papillary layer, whereas the dense collagen fiber bundles below belong to the reticular layer. LM × 10. (credit: modification of work by “kilbad”/Wikimedia Commons)","The dermis might be considered the “core” of the integumentary system (derma- = “skin”), as distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The epidermis is avascular and cells of this layer must get their oxygen and nutrients from capillaries in the dermis. The dermis is made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts (Figure 5.1.6). The more superficial papillary layer serves as an anchor point for the epidermis above and is intimately connected to the deeper reticular layer.","{'06b00cb2-67a9-483d-827f-e8d8d406b436': 'The dermis might be considered the “core” of the integumentary system (derma- = “skin”), as distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The epidermis is avascular and cells of this layer must get their oxygen and nutrients from capillaries in the dermis. The dermis is made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts (Figure 5.1.6). The more superficial papillary layer serves as an anchor point for the epidermis above and is intimately connected to the deeper reticular layer.'}"
+Figure 5.1.7,Anatomy_And_Physio/images/Figure 5.1.7.jpg,Figure 5.1.7 – Skin Pigmentation: The relative coloration of the skin depends of the amount of melanin produced by melanocytes in the stratum basale and taken up by keratinocytes.,"The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome (Figure 5.1.7).","{'0a8ab4f3-5371-49f4-821e-d507151e3c67': 'The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome (Figure 5.1.7).', 'c73e765d-36c0-49a8-a755-d191e4447e42': 'Melanin occurs in two primary forms. Eumelanin exists as black and brown, whereas pheomelanin provides a red color. Dark-skinned individuals produce more melanin than those with pale skin. Exposure to the UV rays of the sun or a tanning salon causes melanin to be manufactured and built up in keratinocytes, as sun exposure stimulates keratinocytes to secrete chemicals that stimulate melanocytes. The accumulation of melanin in keratinocytes results in the darkening of the skin, or a tan. This increased melanin accumulation protects the DNA of epidermal cells from UV ray damage and the breakdown of folic acid, a nutrient necessary for our health and well-being. In contrast, too much melanin can interfere with the production of vitamin D, an important nutrient involved in calcium absorption. There is a dynamic interplay between the amount of protection from UV radiation that melanin provides and the amount of vitamin D produced. The amount of melanin produced, and therefore UV protection, is directly correlated with the amount of sunlight exposure. The more sunlight, the more UV protection, but the compromise is that with increased melanin there is a decrease in vitamin D produced.', '9826c79a-7717-4fb7-a26c-b8dde688d582': 'It requires about 10 days after initial sun exposure for melanin synthesis to peak, which is why pale-skinned individuals tend to suffer sunburns of the epidermis initially. Dark-skinned individuals can also get sunburns, but are more protected than are pale-skinned individuals. Melanosomes are temporary structures that are eventually destroyed by fusion with lysosomes; this fact, along with melanin-filled keratinocytes in the stratum corneum sloughing off, makes tanning impermanent.', '5d657cec-dfb4-41a3-a772-8a431f7da5f6': 'Too much sun exposure can eventually lead to wrinkling due to the destruction of the cellular structure of the skin, and in severe cases, can cause sufficient DNA damage to result in skin cancer. When there is an irregular accumulation of melanocytes in the skin, freckles appear. Moles are larger masses of melanocytes, and although most are benign, they should be monitored for changes that might indicate the presence of cancer (Figure 5.1.8). A total lack of melanin is caused by the genetic disorder called albinism (See Disorders of the…Integumentary System below)'}"
+Figure 4.6.1,Anatomy_And_Physio/images/Figure 4.6.1.jpg,"Figure 4.6.1 – Tissue Healing: During wound repair, collagen fibers are laid down randomly by fibroblasts that move into repair the area.","After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.6.1 – Tissue Healing).","{'57287f1e-0718-478c-8894-7e774f11017c': 'Inflammation is the standard, initial response of the body to injury. Whether biological, chemical, physical, or radiation burns, all injuries lead to the same sequence of physiological events. Inflammation limits the extent of injury, partially or fully eliminates the cause of injury, and initiates repair and regeneration of damaged tissue. Necrosis, or accidental cell death, causes inflammation. Apoptosis is programmed cell death, a normal step-by-step process that destroys cells no longer needed by the body. By mechanisms still under investigation, apoptosis does not initiate the inflammatory response. Acute inflammation resolves over time by the healing of tissue. If inflammation persists, it becomes chronic and leads to diseased conditions. Arthritis and tuberculosis are examples of chronic inflammation. The suffix “-itis” denotes inflammation of a specific organ or type. For example, peritonitis is the inflammation of the peritoneum, and meningitis refers to the inflammation of the meninges, the tough membranes that surround the central nervous system.', '1dbff0a6-f283-43a8-b797-7d166053fad4': 'The four cardinal signs of inflammation—redness (at least for people with light colored skin), swelling, pain, and local heat—were first recorded in antiquity. Cornelius Celsus is credited with documenting these signs during the days of the Roman Empire, as early as the first century AD. A fifth sign, loss of function, may also accompany inflammation.', '8eab2ce9-a651-4a0d-9b95-54dfd0fc2701': 'Upon tissue injury, damaged cells release inflammatory chemical signals that evoke local vasodilation, the widening of the blood vessels. Increased blood flow can\xa0change the color of the integument\xa0and result in a localized temperature increase. In response to injury, mast cells present in tissue degranulate, releasing the potent vasodilator histamine. Increased blood flow and inflammatory mediators recruit white blood cells to the site of inflammation. The endothelium lining the local blood vessel becomes “leaky” under the influence of histamine and other inflammatory mediators allowing neutrophils, macrophages, and fluid to move from the blood into the interstitial tissue spaces. The excess liquid in tissue causes swelling, properly called edema. The swollen tissues stimulate mechanical receptors, which can cause the perception\xa0of pain. Prostaglandins released from injured cells also activate pain pathways. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce perceived pain because they inhibit the synthesis of prostaglandins. High levels of NSAIDs reduce inflammation. Antihistamines decrease allergies by blocking histamine receptors and as a result, the histamine response.', '8bede91b-18d9-466e-8e7e-23a95a27e7e2': 'After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.6.1 – Tissue Healing).'}"
+Figure 4.6.2,Anatomy_And_Physio/images/Figure 4.6.2.jpg,"Figure 4.6.2 – Development of Cancer: Note the change in cell size, nucleus size, and organization in the tissue.","A mutation is defined as a permanent change in the DNA of a cell. Epigenetic modifications, changes that do not affect the code of the DNA but alter how the DNA is decoded, are also known to generate abnormal cells. Alterations in the genetic material may be caused by environmental agents, infectious agents, or errors in the replication of DNA that accumulate with age. Many mutations do not cause any noticeable change in the functions of a cell, however, if the modification affects key proteins that have an impact on the cell’s ability to proliferate in an orderly fashion, the cell starts to divide abnormally. As changes in cells accumulate, they lose their ability to form regular tissues. A tumor, a mass of cells displaying abnormal architecture, forms in the tissue. Many tumors are benign, meaning they do not metastasize nor cause disease. A tumor becomes malignant, or cancerous, when it breaches the confines of its tissue, promotes angiogenesis, attracts the growth of capillaries, and metastasizes to other organs (Figure 4.6.2 Development of Cancer). The specific names of cancers reflect the tissue of origin. Cancers derived from epithelial cells are referred to as carcinomas. Cancer in myeloid tissue or blood cells form myelomas. Leukemias are cancers of white blood cells, whereas sarcomas derive from connective tissue. Cells in tumors differ both in structure and function. Some cells, called cancer stem cells, appear to be a subtype of cell responsible for uncontrolled growth. Recent research shows that contrary to what was previously assumed, tumors are not disorganized masses of cells, but have their own structures.","{'bf3de8ec-7e4b-46ce-bd9d-8ccae5e8af39': 'Cancer is a generic term for many diseases in which cells escape regulatory signals. Uncontrolled growth, invasion into adjacent tissues, and colonization of other organs, if not treated early enough, are its hallmarks. Health suffers when tumors “rob” blood supply from the “normal” organs.', '4c727b42-0f4a-456c-b048-d0f6e1b51647': 'A mutation is defined as a permanent change in the DNA of a cell. Epigenetic modifications, changes that do not affect the code of the DNA but alter how the DNA is decoded, are also known to generate abnormal cells. Alterations in the genetic material may be caused by environmental agents, infectious agents, or errors in the replication of DNA that accumulate with age. Many mutations do not cause any noticeable change in the functions of a cell, however, if the modification affects key proteins that have an impact on the cell’s ability to proliferate in an orderly fashion, the cell starts to divide abnormally. As changes in cells accumulate, they lose their ability to form regular tissues. A tumor, a mass of cells displaying abnormal architecture, forms in the tissue. Many tumors are benign, meaning they do not metastasize nor cause disease. A tumor becomes malignant, or cancerous, when it breaches the confines of its tissue, promotes angiogenesis, attracts the growth of capillaries, and metastasizes to other organs (Figure 4.6.2 Development of Cancer). The specific names of cancers reflect the tissue of origin. Cancers derived from epithelial cells are referred to as carcinomas. Cancer in myeloid tissue or blood cells form myelomas. Leukemias are cancers of white blood cells, whereas sarcomas derive from connective tissue. Cells in tumors differ both in structure and function. Some cells, called cancer stem cells, appear to be a subtype of cell responsible for uncontrolled growth. Recent research shows that contrary to what was previously assumed, tumors are not disorganized masses of cells, but have their own structures.', '3160d86b-ac63-4c82-b0e8-5b8132ebf42a': 'Cancer treatments vary depending on the disease’s type and stage. Traditional approaches, including surgery, radiation, chemotherapy, and hormonal therapy. The aim is to remove or kill rapidly dividing cancer cells, but these strategies have their limitations. Depending on a tumor’s location, for example, cancer surgeons may be unable to remove it. Radiation and chemotherapy are difficult, and it is often impossible to target only the cancer cells. The treatments inevitably destroy healthy tissue as well. To address this, researchers are working on pharmaceuticals that can target specific proteins implicated in cancer-associated molecular pathways.'}"
+Figure 4.5.1,Anatomy_And_Physio/images/Figure 4.5.1.jpg,"Figure 4.5.1 – The Neuron: The cell body of a neuron, also called the soma, contains the nucleus and mitochondria. The dendrites transfer the nerve impulse to the soma. The axon carries the action potential away to another excitable cell (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Nervous tissue is characterized as being excitable and capable of sending and receiving electrochemical signals that provide the body with information. Two main classes of cells make up nervous tissue: the neuron and neuroglia (Figure 4.5.1 The Neuron). Neurons propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals. Neuroglia play an essential role in supporting neurons.","{'a742e792-bc69-497f-ad54-11a26d6b7ad6': 'Emerson, RW. Old age. Atlantic. 1862 [cited 2012 Dec 4]; 9(51):134–140.', '60edbc8a-829b-4b70-bc21-5bd5fa8a6ab4': 'Nervous tissue is characterized as being excitable and capable of sending and receiving electrochemical signals that provide the body with information. Two main classes of cells make up nervous tissue: the neuron and neuroglia (Figure 4.5.1 The Neuron). Neurons propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals. Neuroglia play an essential role in supporting neurons.', '4ac76e66-d898-4a8b-9642-a749d3794274': 'Neurons display distinctive morphology, well suited to their role as conducting cells, with three main parts. The cell body includes most of the cytoplasm, organelles, and nucleus. Dendrites, which receive input from other neurons, branch off the cell body and appear as thin extensions. A long axon extends from the cell\xa0body and may\xa0be wrapped in an insulating layer known as myelin, which is formed by accessory cells. Axons transmit\xa0electrical signals traveling away from the cell body. The synapse is the gap between nerve cells, or between a nerve cell and its target. The signal is transmitted across the synapse by chemical compounds known as neurotransmitters. Neurons categorized as multipolar neurons have several dendrites and a single prominent axon. Bipolar neurons possess a single dendrite and axon with the cell body, while unipolar neurons have only a single process extending out from the cell body, which divides into a functional dendrite and into a functional axon. When a neuron is sufficiently stimulated, it generates an action potential that propagates down the axon towards the synapse. If enough neurotransmitters are released at the synapse to stimulate the next neuron (or muscle, or gland), a response is generated.', '5e50790b-1e83-4fe6-8394-0c39f16dea3e': 'The second class of neural cells are\xa0the neuroglia or glial cells, which have been characterized as having a simple support role. The word “glia” comes from the Greek word for glue. Recent research is shedding light on the more complex role of neuroglia in the function of the brain and nervous system. Astrocyte cells, named for their distinctive star shape, are abundant in the central nervous system. The astrocytes have many functions, including regulation of ion concentration in the intercellular space, uptake and/or breakdown of some neurotransmitters, and formation of the blood-brain barrier, the membrane that separates the circulatory system from the brain. Microglia protect the nervous system against infection and are related to macrophages. Oligodendrocyte cells produce myelin in the central nervous system (brain and spinal cord) while the Schwann cell produces myelin in the peripheral nervous system\xa0(Figure 4.5.2 Nervous Tissue).', 'f888f32b-6be2-4777-a79f-bca258803f33': 'Stern, P. Focus issue: getting excited about glia. Science [Internet]. 2010 [cited 2012 Dec 4]; 3(147):330-773. Available from:', '96c9ad69-da48-4b48-927f-e6907236016c': 'http://stke.sciencemag.org/cgi/content/abstract/sigtrans;3/147/eg11', '53a06bb0-8ab1-4329-a7ed-ef3c62bd066d': 'Ming GL, Song H. Adult neurogenesis in the mammalian central nervous system. Annu. Rev. Neurosci. 2005 [cited 2012 Dec 4]; 28:223–250.', 'a15fe260-92a4-4156-bf31-8de9b1583de0': 'Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth (Table 4.2).', '5ff6a553-bd17-4c8d-9622-caa0b23f7ec2': 'Skeletal muscle is attached to bones and its contraction makes possible locomotion, facial expressions, posture, and other voluntary movements of the body. Forty percent of your body mass is made up of skeletal muscle. Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis. Shivering is an involuntary contraction of skeletal muscles in response to lower than normal body temperature. The muscle cell, or myocyte, develops from myoblasts derived from the mesoderm. Myocytes and their numbers remain relatively constant throughout life. Skeletal muscle tissue is arranged in bundles surrounded by connective tissue. Under the light microscope, muscle cells appear striated with many nuclei squeezed along the membranes. The striation is due to the regular alternation of the contractile proteins actin and myosin, along with the structural proteins that couple the contractile proteins to connective tissues. The cells are multinucleated as a result of the fusion of the many myoblasts that fuse to form each long muscle fiber.', '1173c4e0-9506-47d4-90cc-89eb7351f3e7': 'Cardiac muscle forms the contractile walls of the heart. The cells of cardiac muscle, known as cardiomyocytes, also appear striated under the microscope. Unlike skeletal muscle fibers, cardiomyocytes are single cells with a single centrally located nucleus. A principal characteristic of cardiomyocytes is that they contract on their own intrinsic rhythm without external stimulation. Cardiomyocytes attach to one another with specialized cell junctions called intercalated discs. Intercalated discs have both anchoring junctions and gap junctions. Attached cells form long, branching cardiac muscle fibers that act as a\xa0syncytium, allowing the cells to synchronize their actions. The cardiac muscle pumps blood through the body and is under involuntary control.', 'f720e6c6-8d42-4921-a6cf-91363d7a7736': 'Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and blood vessels. Each cell is spindle shaped with a single nucleus and no visible striations (Figure 4.4.1 – Muscle Tissue).', '2191ee67-abf3-48af-97b2-5cfed3d6c5cd': 'Kolata, G. Severe diet doesn’t prolong life, at least in monkeys. New York Times [Internet]. 2012 Aug. 29 [cited 2013 Jan 21]; Available from:', 'a747531b-0994-43f2-96a7-7de020a1fc6f': 'http://www.nytimes.com/2012/08/30/science/low-calorie-diet-doesnt-prolong-life-study-of-monkeys-finds.html?_r=2&ref=caloricrestriction&', '178444bb-ff18-4f94-9d69-2cc777985045': 'Despite differences in structure and function, all living cells in multicellular organisms have a surrounding cell membrane. Just as the outer layer of your skin separates your body from its environment, the cell membrane (also known as the plasma membrane) separates the inner contents of a cell from its exterior environment. This cell membrane provides a protective barrier around the cell and regulates which materials can pass in or out.'}"
+Figure 4.5.2,Anatomy_And_Physio/images/Figure 4.5.2.jpg,Figure 4.5.2 – Nervous Tissue: Nervous tissue is made up of neurons and neuroglia. The cells of nervous tissue are specialized to transmit and receive impulses (LM × 872). (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"The second class of neural cells are the neuroglia or glial cells, which have been characterized as having a simple support role. The word “glia” comes from the Greek word for glue. Recent research is shedding light on the more complex role of neuroglia in the function of the brain and nervous system. Astrocyte cells, named for their distinctive star shape, are abundant in the central nervous system. The astrocytes have many functions, including regulation of ion concentration in the intercellular space, uptake and/or breakdown of some neurotransmitters, and formation of the blood-brain barrier, the membrane that separates the circulatory system from the brain. Microglia protect the nervous system against infection and are related to macrophages. Oligodendrocyte cells produce myelin in the central nervous system (brain and spinal cord) while the Schwann cell produces myelin in the peripheral nervous system (Figure 4.5.2 Nervous Tissue).","{'a742e792-bc69-497f-ad54-11a26d6b7ad6': 'Emerson, RW. Old age. Atlantic. 1862 [cited 2012 Dec 4]; 9(51):134–140.', '60edbc8a-829b-4b70-bc21-5bd5fa8a6ab4': 'Nervous tissue is characterized as being excitable and capable of sending and receiving electrochemical signals that provide the body with information. Two main classes of cells make up nervous tissue: the neuron and neuroglia (Figure 4.5.1 The Neuron). Neurons propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals. Neuroglia play an essential role in supporting neurons.', '4ac76e66-d898-4a8b-9642-a749d3794274': 'Neurons display distinctive morphology, well suited to their role as conducting cells, with three main parts. The cell body includes most of the cytoplasm, organelles, and nucleus. Dendrites, which receive input from other neurons, branch off the cell body and appear as thin extensions. A long axon extends from the cell\xa0body and may\xa0be wrapped in an insulating layer known as myelin, which is formed by accessory cells. Axons transmit\xa0electrical signals traveling away from the cell body. The synapse is the gap between nerve cells, or between a nerve cell and its target. The signal is transmitted across the synapse by chemical compounds known as neurotransmitters. Neurons categorized as multipolar neurons have several dendrites and a single prominent axon. Bipolar neurons possess a single dendrite and axon with the cell body, while unipolar neurons have only a single process extending out from the cell body, which divides into a functional dendrite and into a functional axon. When a neuron is sufficiently stimulated, it generates an action potential that propagates down the axon towards the synapse. If enough neurotransmitters are released at the synapse to stimulate the next neuron (or muscle, or gland), a response is generated.', '5e50790b-1e83-4fe6-8394-0c39f16dea3e': 'The second class of neural cells are\xa0the neuroglia or glial cells, which have been characterized as having a simple support role. The word “glia” comes from the Greek word for glue. Recent research is shedding light on the more complex role of neuroglia in the function of the brain and nervous system. Astrocyte cells, named for their distinctive star shape, are abundant in the central nervous system. The astrocytes have many functions, including regulation of ion concentration in the intercellular space, uptake and/or breakdown of some neurotransmitters, and formation of the blood-brain barrier, the membrane that separates the circulatory system from the brain. Microglia protect the nervous system against infection and are related to macrophages. Oligodendrocyte cells produce myelin in the central nervous system (brain and spinal cord) while the Schwann cell produces myelin in the peripheral nervous system\xa0(Figure 4.5.2 Nervous Tissue).', 'f888f32b-6be2-4777-a79f-bca258803f33': 'Stern, P. Focus issue: getting excited about glia. Science [Internet]. 2010 [cited 2012 Dec 4]; 3(147):330-773. Available from:', '96c9ad69-da48-4b48-927f-e6907236016c': 'http://stke.sciencemag.org/cgi/content/abstract/sigtrans;3/147/eg11', '53a06bb0-8ab1-4329-a7ed-ef3c62bd066d': 'Ming GL, Song H. Adult neurogenesis in the mammalian central nervous system. Annu. Rev. Neurosci. 2005 [cited 2012 Dec 4]; 28:223–250.', 'a15fe260-92a4-4156-bf31-8de9b1583de0': 'Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth (Table 4.2).', '5ff6a553-bd17-4c8d-9622-caa0b23f7ec2': 'Skeletal muscle is attached to bones and its contraction makes possible locomotion, facial expressions, posture, and other voluntary movements of the body. Forty percent of your body mass is made up of skeletal muscle. Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis. Shivering is an involuntary contraction of skeletal muscles in response to lower than normal body temperature. The muscle cell, or myocyte, develops from myoblasts derived from the mesoderm. Myocytes and their numbers remain relatively constant throughout life. Skeletal muscle tissue is arranged in bundles surrounded by connective tissue. Under the light microscope, muscle cells appear striated with many nuclei squeezed along the membranes. The striation is due to the regular alternation of the contractile proteins actin and myosin, along with the structural proteins that couple the contractile proteins to connective tissues. The cells are multinucleated as a result of the fusion of the many myoblasts that fuse to form each long muscle fiber.', '1173c4e0-9506-47d4-90cc-89eb7351f3e7': 'Cardiac muscle forms the contractile walls of the heart. The cells of cardiac muscle, known as cardiomyocytes, also appear striated under the microscope. Unlike skeletal muscle fibers, cardiomyocytes are single cells with a single centrally located nucleus. A principal characteristic of cardiomyocytes is that they contract on their own intrinsic rhythm without external stimulation. Cardiomyocytes attach to one another with specialized cell junctions called intercalated discs. Intercalated discs have both anchoring junctions and gap junctions. Attached cells form long, branching cardiac muscle fibers that act as a\xa0syncytium, allowing the cells to synchronize their actions. The cardiac muscle pumps blood through the body and is under involuntary control.', 'f720e6c6-8d42-4921-a6cf-91363d7a7736': 'Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and blood vessels. Each cell is spindle shaped with a single nucleus and no visible striations (Figure 4.4.1 – Muscle Tissue).', '2191ee67-abf3-48af-97b2-5cfed3d6c5cd': 'Kolata, G. Severe diet doesn’t prolong life, at least in monkeys. New York Times [Internet]. 2012 Aug. 29 [cited 2013 Jan 21]; Available from:', 'a747531b-0994-43f2-96a7-7de020a1fc6f': 'http://www.nytimes.com/2012/08/30/science/low-calorie-diet-doesnt-prolong-life-study-of-monkeys-finds.html?_r=2&ref=caloricrestriction&', '178444bb-ff18-4f94-9d69-2cc777985045': 'Despite differences in structure and function, all living cells in multicellular organisms have a surrounding cell membrane. Just as the outer layer of your skin separates your body from its environment, the cell membrane (also known as the plasma membrane) separates the inner contents of a cell from its exterior environment. This cell membrane provides a protective barrier around the cell and regulates which materials can pass in or out.'}"
+Figure 4.4.1,Anatomy_And_Physio/images/Figure 4.4.1.jpg,"Figure 4.4.1 – Muscle Tissue: (a) Skeletal muscle cells have prominent striation and nuclei on their periphery. (b) Smooth muscle cells have a single nucleus and no visible striations. (c) Cardiac muscle cells appear striated and have a single nucleus. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and blood vessels. Each cell is spindle shaped with a single nucleus and no visible striations (Figure 4.4.1 – Muscle Tissue).","{'a742e792-bc69-497f-ad54-11a26d6b7ad6': 'Emerson, RW. Old age. Atlantic. 1862 [cited 2012 Dec 4]; 9(51):134–140.', '60edbc8a-829b-4b70-bc21-5bd5fa8a6ab4': 'Nervous tissue is characterized as being excitable and capable of sending and receiving electrochemical signals that provide the body with information. Two main classes of cells make up nervous tissue: the neuron and neuroglia (Figure 4.5.1 The Neuron). Neurons propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals. Neuroglia play an essential role in supporting neurons.', '4ac76e66-d898-4a8b-9642-a749d3794274': 'Neurons display distinctive morphology, well suited to their role as conducting cells, with three main parts. The cell body includes most of the cytoplasm, organelles, and nucleus. Dendrites, which receive input from other neurons, branch off the cell body and appear as thin extensions. A long axon extends from the cell\xa0body and may\xa0be wrapped in an insulating layer known as myelin, which is formed by accessory cells. Axons transmit\xa0electrical signals traveling away from the cell body. The synapse is the gap between nerve cells, or between a nerve cell and its target. The signal is transmitted across the synapse by chemical compounds known as neurotransmitters. Neurons categorized as multipolar neurons have several dendrites and a single prominent axon. Bipolar neurons possess a single dendrite and axon with the cell body, while unipolar neurons have only a single process extending out from the cell body, which divides into a functional dendrite and into a functional axon. When a neuron is sufficiently stimulated, it generates an action potential that propagates down the axon towards the synapse. If enough neurotransmitters are released at the synapse to stimulate the next neuron (or muscle, or gland), a response is generated.', '5e50790b-1e83-4fe6-8394-0c39f16dea3e': 'The second class of neural cells are\xa0the neuroglia or glial cells, which have been characterized as having a simple support role. The word “glia” comes from the Greek word for glue. Recent research is shedding light on the more complex role of neuroglia in the function of the brain and nervous system. Astrocyte cells, named for their distinctive star shape, are abundant in the central nervous system. The astrocytes have many functions, including regulation of ion concentration in the intercellular space, uptake and/or breakdown of some neurotransmitters, and formation of the blood-brain barrier, the membrane that separates the circulatory system from the brain. Microglia protect the nervous system against infection and are related to macrophages. Oligodendrocyte cells produce myelin in the central nervous system (brain and spinal cord) while the Schwann cell produces myelin in the peripheral nervous system\xa0(Figure 4.5.2 Nervous Tissue).', 'f888f32b-6be2-4777-a79f-bca258803f33': 'Stern, P. Focus issue: getting excited about glia. Science [Internet]. 2010 [cited 2012 Dec 4]; 3(147):330-773. Available from:', '96c9ad69-da48-4b48-927f-e6907236016c': 'http://stke.sciencemag.org/cgi/content/abstract/sigtrans;3/147/eg11', '53a06bb0-8ab1-4329-a7ed-ef3c62bd066d': 'Ming GL, Song H. Adult neurogenesis in the mammalian central nervous system. Annu. Rev. Neurosci. 2005 [cited 2012 Dec 4]; 28:223–250.', 'a15fe260-92a4-4156-bf31-8de9b1583de0': 'Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth (Table 4.2).', '5ff6a553-bd17-4c8d-9622-caa0b23f7ec2': 'Skeletal muscle is attached to bones and its contraction makes possible locomotion, facial expressions, posture, and other voluntary movements of the body. Forty percent of your body mass is made up of skeletal muscle. Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis. Shivering is an involuntary contraction of skeletal muscles in response to lower than normal body temperature. The muscle cell, or myocyte, develops from myoblasts derived from the mesoderm. Myocytes and their numbers remain relatively constant throughout life. Skeletal muscle tissue is arranged in bundles surrounded by connective tissue. Under the light microscope, muscle cells appear striated with many nuclei squeezed along the membranes. The striation is due to the regular alternation of the contractile proteins actin and myosin, along with the structural proteins that couple the contractile proteins to connective tissues. The cells are multinucleated as a result of the fusion of the many myoblasts that fuse to form each long muscle fiber.', '1173c4e0-9506-47d4-90cc-89eb7351f3e7': 'Cardiac muscle forms the contractile walls of the heart. The cells of cardiac muscle, known as cardiomyocytes, also appear striated under the microscope. Unlike skeletal muscle fibers, cardiomyocytes are single cells with a single centrally located nucleus. A principal characteristic of cardiomyocytes is that they contract on their own intrinsic rhythm without external stimulation. Cardiomyocytes attach to one another with specialized cell junctions called intercalated discs. Intercalated discs have both anchoring junctions and gap junctions. Attached cells form long, branching cardiac muscle fibers that act as a\xa0syncytium, allowing the cells to synchronize their actions. The cardiac muscle pumps blood through the body and is under involuntary control.', 'f720e6c6-8d42-4921-a6cf-91363d7a7736': 'Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and blood vessels. Each cell is spindle shaped with a single nucleus and no visible striations (Figure 4.4.1 – Muscle Tissue).', '2191ee67-abf3-48af-97b2-5cfed3d6c5cd': 'Kolata, G. Severe diet doesn’t prolong life, at least in monkeys. New York Times [Internet]. 2012 Aug. 29 [cited 2013 Jan 21]; Available from:', 'a747531b-0994-43f2-96a7-7de020a1fc6f': 'http://www.nytimes.com/2012/08/30/science/low-calorie-diet-doesnt-prolong-life-study-of-monkeys-finds.html?_r=2&ref=caloricrestriction&', '178444bb-ff18-4f94-9d69-2cc777985045': 'Despite differences in structure and function, all living cells in multicellular organisms have a surrounding cell membrane. Just as the outer layer of your skin separates your body from its environment, the cell membrane (also known as the plasma membrane) separates the inner contents of a cell from its exterior environment. This cell membrane provides a protective barrier around the cell and regulates which materials can pass in or out.'}"
+Figure 4.2.2,Anatomy_And_Physio/images/Figure 4.2.2.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.,"All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.","{'b36e9a62-990a-4410-a36e-af0c88a9fc90': 'All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.', '702d5ace-849a-4199-835d-d0809b936b9e': 'Epithelial tissues are classified according to the shape of the cells composing the tissue and by the number of cell layers present in the tissue.(Figure 4.2.2) Cell shapes are classified as being either squamous (flattened and thin), cuboidal (boxy, as wide as it is tall), or columnar (rectangular, taller than it is wide). Similarly, cells in the tissue can be arranged in a single layer, which is called simple epithelium, or more than one layer, which is called stratified epithelium.\xa0 Pseudostratified (pseudo- = “false”) describes an epithelial tissue with a single layer of irregularly shaped cells that give the appearance of more than one layer.\xa0 Transitional describes a form of specialized stratified epithelium in which the shape of the cells, and the number of layers present, can vary depending on the degree of stretch within a tissue.', '1f16231d-0eaa-402b-8d1c-569b6618dd66': 'Epithelial tissue is classified based on the shape of the cells present and the number of cell layers present.\xa0 Figure 4.2.2 summarizes the different categories of epithelial cell tissue cells.'}"
+Figure 4.3.1,Anatomy_And_Physio/images/Figure 4.3.1.jpg,"Figure 4.3.1 – Connective Tissue Proper: Fibroblasts produce this fibrous tissue. Connective tissue proper includes the fixed cells fibrocytes, adipocytes, and mesenchymal cells (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Fibroblasts are present in all connective tissue proper (Figure 4.3.1). Fibrocytes, adipocytes, and mesenchymal cells are fixed cells, which means they remain within the connective tissue. Other cells move in and out of the connective tissue in response to chemical signals. Macrophages, mast cells, lymphocytes, plasma cells, and phagocytic cells are found in connective tissue proper but are actually part of the immune system protecting the body.","{'694637b6-5279-40b1-9e16-2f0db8d65a0f': 'Fibroblasts are present in all connective tissue proper (Figure 4.3.1). Fibrocytes, adipocytes, and mesenchymal cells are fixed cells, which means they remain within the connective tissue. Other cells move in and out of the connective tissue in response to chemical signals. Macrophages, mast cells, lymphocytes, plasma cells, and phagocytic cells are found in connective tissue proper but are actually part of the immune system protecting the body.'}"
+Figure 4.3.2,Anatomy_And_Physio/images/Figure 4.3.2.jpg,Figure 4.3.2 – Adipose Tissue: This is a loose connective tissue that consists of fat cells with little extracellular matrix. It stores fat for energy and provides insulation (LM × 800). (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.","{'e94eacbe-2278-4670-a0b2-97f6d6cff70d': 'Loose connective tissue is found between many organs where it acts both to absorb shock and bind tissues together. It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues.', '505305bd-d7e8-4761-9131-6a0afe3e95f5': 'Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.', '7ea231cc-b0c7-442d-8395-fbedbee2542f': 'Areolar tissue shows relatively little specialization and is the most widely distributed connective tissue in the body. It contains all the cell types and fibers previously described and is structured\xa0in an apparently random, web-like fashion. It fills the spaces between muscle fibers, surrounds blood and lymph vessels, and supports organs in the abdominal cavity. Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes.', 'd526c639-7d91-46b7-ad84-28c30c5820a6': 'Reticular tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver (Figure 4.3.3). The reticular fibers form the network onto which other cells attach. It derives its name from the Latin reticulus, which means “little net.”'}"
+Figure 4.3.2,Anatomy_And_Physio/images/Figure 4.3.2.jpg,Figure 4.3.2a – Areolar tissue,"Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.","{'e94eacbe-2278-4670-a0b2-97f6d6cff70d': 'Loose connective tissue is found between many organs where it acts both to absorb shock and bind tissues together. It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues.', '505305bd-d7e8-4761-9131-6a0afe3e95f5': 'Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.', '7ea231cc-b0c7-442d-8395-fbedbee2542f': 'Areolar tissue shows relatively little specialization and is the most widely distributed connective tissue in the body. It contains all the cell types and fibers previously described and is structured\xa0in an apparently random, web-like fashion. It fills the spaces between muscle fibers, surrounds blood and lymph vessels, and supports organs in the abdominal cavity. Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes.', 'd526c639-7d91-46b7-ad84-28c30c5820a6': 'Reticular tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver (Figure 4.3.3). The reticular fibers form the network onto which other cells attach. It derives its name from the Latin reticulus, which means “little net.”'}"
+Figure 4.3.5,Anatomy_And_Physio/images/Figure 4.3.5.jpg,"Figure 4.3.5 – Types of Cartilage: Cartilage is a connective tissue consisting of collagenous fibers embedded in a firm matrix of chondroitin sulfates. (a) Hyaline cartilage provides support with some flexibility. The example is from dog tissue. (b) Fibrocartilage provides some compressibility and can absorb pressure. (c) Elastic cartilage provides firm but elastic support. From top, LM × 300, LM × 1200, LM × 1016. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage (Figure 4.3.5 – Types of Cartilage). Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It forms the template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. The intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue provides support as well as elasticity. Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage.","{'d6fa6f6b-3b4f-4801-8bd6-a2a541914481': 'The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans. Embedded within the cartilage matrix are chondrocytes, or cartilage cells, and the space they occupy are called lacunae (singular = lacuna). A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus, all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues.', 'f04f72be-bf23-4562-9f67-51d17f804504': 'The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage (Figure 4.3.5 – Types of Cartilage). Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It forms\xa0the\xa0template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. The intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue provides\xa0support as well as elasticity. Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage.'}"
+Figure 4.3.6,Anatomy_And_Physio/images/Figure 4.3.6.jpg,Figure 4.3.6 – Blood: A Fluid Connective Tissue: Blood is a fluid connective tissue containing erythrocytes and various types of leukocytes that circulate in a liquid extracellular matrix (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix. The formed elements circulating in blood are all derived from hematopoietic stem cells located in bone marrow (Figure 4.3.6 – Blood: A Fluid Connective Tissue). Erythrocytes, red blood cells, transport oxygen and carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body.","{'e77a378b-02d2-41cc-9247-c2f6905f2b5a': 'Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix. The formed elements circulating in blood are all derived from hematopoietic stem cells located in bone marrow (Figure 4.3.6 – Blood: A Fluid Connective Tissue). Erythrocytes, red blood cells, transport oxygen and carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body.', '3785c2ce-b352-4e33-83ce-6e4454de1e6f': 'Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are highly\xa0permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels. Lymph vessels return\xa0molecules and fluid to the venous blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood.', 'c1768d56-8c3b-442f-8f81-224bd2092402': 'Epithelial tissue primarily appears as large sheets of cells covering all surfaces of the body exposed to the external environment and lining internal body cavities.\xa0 In addition, epithelial tissue is responsible for forming a majority of glandular tissue found in the human body.', 'ff1d00ec-18f1-4ed7-bbbd-00163244c4e8': 'Epithelial tissue is derived from all three major embryonic layers. The epithelial tissue composing cutaneous membranes develops from the ectoderm.\xa0 Epithelial tissue composing a majority of the mucous membranes originate in the endoderm.\xa0 Epithelial tissue that lines vessels and open spaces within the body are derived from mesoderm.\xa0 Of particular note, epithelial tissue that lines vessels in the lymphatic and cardiovascular systems is called endothelium whereas epithelial tissue that forms the serous membranes lining the true cavities is called mesothelium.', 'c0edc612-7a4e-43da-b532-28ce9475dd5e': 'Regardless of its location and function, all epithelial tissue shares important structural features. First, epithelial tissue is highly cellular, with little or no extracellular material present between cells. Second, adjoining cells form specialized intercellular connections called cell junctions. Third, epithelial cells exhibit polarity with differences in structure and function between the exposed, or apical, facing cell surface and the basal surface closest to the underlying tissue.\xa0 Fourth, epithelial tissues are avascular;\xa0 nutrients must enter the tissue by diffusion or absorption from underlying tissues or the surface.\xa0 Last,\xa0 epithelial tissue is capable of rapidly replacing damaged and dead cells, necessary with respect to the harsh environment this tissue encounters.'}"
+Figure 4.2.1,Anatomy_And_Physio/images/Figure 4.2.1.jpg,"Figure 4.2.1 – Types of Cell Junctions: The three basic types of cell-to-cell junctions are tight junctions, gap junctions, and anchoring junctions.","Cells of epithelia are closely connected with limited extracellular material present. Three basic types of connections may be present: tight junctions, anchoring junctions, and gap junctions (Figure 4.2.1).","{'275dc159-b867-4f12-8acb-4e29a25444ce': 'Epithelial cells are typically characterized by unequal distribution of organelles and membrane-bound proteins between their apical and basal surfaces.\xa0 Structures found on some epithelial cells are an adaptation to specific functions.\xa0 For example, cilia are extensions of the apical cell membrane that are supported by microtubules. These extensions beat in unison, allowing for the movement of fluids and particles along the surface.\xa0 Such ciliated epithelia line the ventricles of the brain where it helps circulate cerebrospinal fluid and line the respirtatory system where it helps sweep particles of dust and pathogens up and out of the respiratory tract.', '318613f5-8089-41fb-a36a-a2d9880a9470': 'Epithelial cells in close contact with underlying connective tissues secrete glycoproteins and collagen from their basal surface which forms the basal lamina.\xa0 The basal lamina interacts with the reticular lamina secreted by the underlying connective tissue, forming a basement membrane that helps anchor the layers together.', 'c499dd0f-d0e3-4255-be69-c28bb00930bc': 'Cells of epithelia are closely connected with limited extracellular material present. Three basic types of connections may be present: tight junctions, anchoring junctions, and gap junctions (Figure 4.2.1).'}"
+Figure 4.2.2,Anatomy_And_Physio/images/Figure 4.2.2.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.,"All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.","{'b36e9a62-990a-4410-a36e-af0c88a9fc90': 'All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.', '702d5ace-849a-4199-835d-d0809b936b9e': 'Epithelial tissues are classified according to the shape of the cells composing the tissue and by the number of cell layers present in the tissue.(Figure 4.2.2) Cell shapes are classified as being either squamous (flattened and thin), cuboidal (boxy, as wide as it is tall), or columnar (rectangular, taller than it is wide). Similarly, cells in the tissue can be arranged in a single layer, which is called simple epithelium, or more than one layer, which is called stratified epithelium.\xa0 Pseudostratified (pseudo- = “false”) describes an epithelial tissue with a single layer of irregularly shaped cells that give the appearance of more than one layer.\xa0 Transitional describes a form of specialized stratified epithelium in which the shape of the cells, and the number of layers present, can vary depending on the degree of stretch within a tissue.', '1f16231d-0eaa-402b-8d1c-569b6618dd66': 'Epithelial tissue is classified based on the shape of the cells present and the number of cell layers present.\xa0 Figure 4.2.2 summarizes the different categories of epithelial cell tissue cells.'}"
+Figure 4.2.2,Anatomy_And_Physio/images/Figure 4.2.2.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.,"All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.","{'b36e9a62-990a-4410-a36e-af0c88a9fc90': 'All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.', '702d5ace-849a-4199-835d-d0809b936b9e': 'Epithelial tissues are classified according to the shape of the cells composing the tissue and by the number of cell layers present in the tissue.(Figure 4.2.2) Cell shapes are classified as being either squamous (flattened and thin), cuboidal (boxy, as wide as it is tall), or columnar (rectangular, taller than it is wide). Similarly, cells in the tissue can be arranged in a single layer, which is called simple epithelium, or more than one layer, which is called stratified epithelium.\xa0 Pseudostratified (pseudo- = “false”) describes an epithelial tissue with a single layer of irregularly shaped cells that give the appearance of more than one layer.\xa0 Transitional describes a form of specialized stratified epithelium in which the shape of the cells, and the number of layers present, can vary depending on the degree of stretch within a tissue.', '1f16231d-0eaa-402b-8d1c-569b6618dd66': 'Epithelial tissue is classified based on the shape of the cells present and the number of cell layers present.\xa0 Figure 4.2.2 summarizes the different categories of epithelial cell tissue cells.'}"
+Figure 4.2.4,Anatomy_And_Physio/images/Figure 4.2.4.jpg,Figure 4.2.4 – Types of Exocrine Glands: Exocrine glands are classified by their structure.,"Multicellular exocrine glands are composed of two or more cells which either secrete their contents directly into an inner body cavity (e.g., serous glands), or release their contents into a duct.  If there is a single duct carrying the contents to the external environment then the gland is referred to as a simple gland.  Multicellular glands that have ducts divided into one or more branches is called a compound gland (Figure 4.2.4).  In addition to the number of ducts present, multicellular glands are also classified based on the shape of the secretory portion of the gland.  Tubular glands have enlongated secretory regions (similar to a test tube in shape) while alveolar (acinar) glands have a secretory region that is spherical in shape.   Combinations of the two secretory regions are known as tubuloalveolar (tubuloacinar) glands.","{'d955cb2c-1280-4341-b36c-a3860f641d6d': 'Exocrine glands are classified as either unicellular or multicellular. Unicellular glands are individual cells which are scattered throughout an epithelial lining.\xa0 Goblet cells are an example of a unicellular gland type found extensively in the mucous membranes of the small and large intestine.', '168ad969-0a30-40bd-b119-075a67211dc6': 'Multicellular exocrine glands are composed of two or more cells which either secrete their contents directly into an inner body cavity (e.g., serous glands), or release their contents into a duct.\xa0 If there is a single duct carrying the contents to the external environment then the gland is referred to as a simple gland.\xa0 Multicellular glands that have ducts divided into one or more branches is called a compound gland (Figure 4.2.4).\xa0 In addition to the number of ducts present, multicellular glands are also classified based on the shape of the secretory portion of the gland.\xa0 Tubular glands have enlongated secretory regions (similar to a test tube in shape) while alveolar (acinar) glands have a secretory region that is spherical in shape.\xa0\xa0 Combinations of the two secretory regions are known as tubuloalveolar (tubuloacinar) glands.', '0de0dd56-7804-448b-a47e-759ebe7507ee': 'Exocrine glands are classified by the arrangement of ducts emptying the gland and the shape of the secretory region.', '7fdb37b5-4812-4e78-ba58-9de725f24f4c': 'Methods and Types of Secretion\n\nIn addition to the glandular structure, exocrine glands can be classified by their mode of secretion and the nature of the substances released (Figure 4.2.5). Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles that move to the apical surface of the cell where the contents are released by exocytosis. For example, saliva containing the glycoprotein mucin is a merocrine secretion.\xa0 The glands that produce and secrete sweat are another example of merocrine secretion.', 'ed21b3eb-1fef-4b35-b2a6-148c6d82e354': 'Apocrine secretion occurs when secretions accumulate near the apical portion of a secretory cell. That portion of the cell and its secretory contents pinch off from the cell and are released. The sweat glands of the armpit are classified as apocrine glands. Like merocrine glands, apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and golgi regions remain intact after the secretory event.', '69cb1d32-8f59-4d89-b7dd-cd1c8bd7595d': 'In contrast, the process of holocrine secretion involves the rupture and destruction of the entire gland cell. The cell accumulates its secretory products and releases them only when the cell bursts. New gland cells differentiate from cells in the surrounding tissue to replace those lost by secretion. The sebaceous glands that produce the oils on the skin and hair are an example of a holocrine glands (Figure 4.2.6).', '099dbc78-e5a5-4b2c-806b-cd842dc8464e': 'Glands are also named based on the\xa0 products they produce. A serous gland produces watery, blood-plasma-like secretions rich in enzymes, whereas a mucous gland releases a more viscous product rich in the glycoprotein mucin. Both serous and mucous secretions are common in the salivary glands of the digestive system.\xa0 Such glands releasing both serous and mucous secretions are often referred to as seromucous glands.', '8e6add6a-a1e9-4ca6-a12c-1571b47e9040': 'The term tissue is used to describe a group of cells that are similar in structure and perform a specific function.\xa0\xa0 Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function.', 'e2cb147a-9471-494b-96cb-a5eb6b6b1a31': 'Tissues are organized into four broad categories based on structural and functional similarities.\xa0 These categories are\xa0 epithelial, connective, muscle, and nervous.\xa0\xa0 The primary tissue types work together to contribute to the overall health and maintenance of the human body.\xa0\xa0 Thus, any disruption in the structure of a tissue can lead to injury or disease.'}"
+Figure 4.2.5,Anatomy_And_Physio/images/Figure 4.2.5.jpg,"Figure 4.2.5 – Modes of Glandular Secretion: (a) In merocrine secretion, the cell remains intact. (b) In apocrine secretion, the apical portion of the cell is released, as well. (c) In holocrine secretion, the cell is destroyed as it releases its product and the cell itself becomes part of the secretion.","Methods and Types of Secretion
+
+In addition to the glandular structure, exocrine glands can be classified by their mode of secretion and the nature of the substances released (Figure 4.2.5). Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles that move to the apical surface of the cell where the contents are released by exocytosis. For example, saliva containing the glycoprotein mucin is a merocrine secretion.  The glands that produce and secrete sweat are another example of merocrine secretion.","{'d955cb2c-1280-4341-b36c-a3860f641d6d': 'Exocrine glands are classified as either unicellular or multicellular. Unicellular glands are individual cells which are scattered throughout an epithelial lining.\xa0 Goblet cells are an example of a unicellular gland type found extensively in the mucous membranes of the small and large intestine.', '168ad969-0a30-40bd-b119-075a67211dc6': 'Multicellular exocrine glands are composed of two or more cells which either secrete their contents directly into an inner body cavity (e.g., serous glands), or release their contents into a duct.\xa0 If there is a single duct carrying the contents to the external environment then the gland is referred to as a simple gland.\xa0 Multicellular glands that have ducts divided into one or more branches is called a compound gland (Figure 4.2.4).\xa0 In addition to the number of ducts present, multicellular glands are also classified based on the shape of the secretory portion of the gland.\xa0 Tubular glands have enlongated secretory regions (similar to a test tube in shape) while alveolar (acinar) glands have a secretory region that is spherical in shape.\xa0\xa0 Combinations of the two secretory regions are known as tubuloalveolar (tubuloacinar) glands.', '0de0dd56-7804-448b-a47e-759ebe7507ee': 'Exocrine glands are classified by the arrangement of ducts emptying the gland and the shape of the secretory region.', '7fdb37b5-4812-4e78-ba58-9de725f24f4c': 'Methods and Types of Secretion\n\nIn addition to the glandular structure, exocrine glands can be classified by their mode of secretion and the nature of the substances released (Figure 4.2.5). Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles that move to the apical surface of the cell where the contents are released by exocytosis. For example, saliva containing the glycoprotein mucin is a merocrine secretion.\xa0 The glands that produce and secrete sweat are another example of merocrine secretion.', 'ed21b3eb-1fef-4b35-b2a6-148c6d82e354': 'Apocrine secretion occurs when secretions accumulate near the apical portion of a secretory cell. That portion of the cell and its secretory contents pinch off from the cell and are released. The sweat glands of the armpit are classified as apocrine glands. Like merocrine glands, apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and golgi regions remain intact after the secretory event.', '69cb1d32-8f59-4d89-b7dd-cd1c8bd7595d': 'In contrast, the process of holocrine secretion involves the rupture and destruction of the entire gland cell. The cell accumulates its secretory products and releases them only when the cell bursts. New gland cells differentiate from cells in the surrounding tissue to replace those lost by secretion. The sebaceous glands that produce the oils on the skin and hair are an example of a holocrine glands (Figure 4.2.6).', '099dbc78-e5a5-4b2c-806b-cd842dc8464e': 'Glands are also named based on the\xa0 products they produce. A serous gland produces watery, blood-plasma-like secretions rich in enzymes, whereas a mucous gland releases a more viscous product rich in the glycoprotein mucin. Both serous and mucous secretions are common in the salivary glands of the digestive system.\xa0 Such glands releasing both serous and mucous secretions are often referred to as seromucous glands.', '8e6add6a-a1e9-4ca6-a12c-1571b47e9040': 'The term tissue is used to describe a group of cells that are similar in structure and perform a specific function.\xa0\xa0 Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function.', 'e2cb147a-9471-494b-96cb-a5eb6b6b1a31': 'Tissues are organized into four broad categories based on structural and functional similarities.\xa0 These categories are\xa0 epithelial, connective, muscle, and nervous.\xa0\xa0 The primary tissue types work together to contribute to the overall health and maintenance of the human body.\xa0\xa0 Thus, any disruption in the structure of a tissue can lead to injury or disease.'}"
+Figure 4.2.6,Anatomy_And_Physio/images/Figure 4.2.6.jpg,Figure 4.2.6 – Sebaceous Glands: These glands secrete oils that lubricate and protect the skin. They are holocrine glands and they are destroyed after releasing their contents. New glandular cells form to replace the cells that are lost (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012),"In contrast, the process of holocrine secretion involves the rupture and destruction of the entire gland cell. The cell accumulates its secretory products and releases them only when the cell bursts. New gland cells differentiate from cells in the surrounding tissue to replace those lost by secretion. The sebaceous glands that produce the oils on the skin and hair are an example of a holocrine glands (Figure 4.2.6).","{'d955cb2c-1280-4341-b36c-a3860f641d6d': 'Exocrine glands are classified as either unicellular or multicellular. Unicellular glands are individual cells which are scattered throughout an epithelial lining.\xa0 Goblet cells are an example of a unicellular gland type found extensively in the mucous membranes of the small and large intestine.', '168ad969-0a30-40bd-b119-075a67211dc6': 'Multicellular exocrine glands are composed of two or more cells which either secrete their contents directly into an inner body cavity (e.g., serous glands), or release their contents into a duct.\xa0 If there is a single duct carrying the contents to the external environment then the gland is referred to as a simple gland.\xa0 Multicellular glands that have ducts divided into one or more branches is called a compound gland (Figure 4.2.4).\xa0 In addition to the number of ducts present, multicellular glands are also classified based on the shape of the secretory portion of the gland.\xa0 Tubular glands have enlongated secretory regions (similar to a test tube in shape) while alveolar (acinar) glands have a secretory region that is spherical in shape.\xa0\xa0 Combinations of the two secretory regions are known as tubuloalveolar (tubuloacinar) glands.', '0de0dd56-7804-448b-a47e-759ebe7507ee': 'Exocrine glands are classified by the arrangement of ducts emptying the gland and the shape of the secretory region.', '7fdb37b5-4812-4e78-ba58-9de725f24f4c': 'Methods and Types of Secretion\n\nIn addition to the glandular structure, exocrine glands can be classified by their mode of secretion and the nature of the substances released (Figure 4.2.5). Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles that move to the apical surface of the cell where the contents are released by exocytosis. For example, saliva containing the glycoprotein mucin is a merocrine secretion.\xa0 The glands that produce and secrete sweat are another example of merocrine secretion.', 'ed21b3eb-1fef-4b35-b2a6-148c6d82e354': 'Apocrine secretion occurs when secretions accumulate near the apical portion of a secretory cell. That portion of the cell and its secretory contents pinch off from the cell and are released. The sweat glands of the armpit are classified as apocrine glands. Like merocrine glands, apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and golgi regions remain intact after the secretory event.', '69cb1d32-8f59-4d89-b7dd-cd1c8bd7595d': 'In contrast, the process of holocrine secretion involves the rupture and destruction of the entire gland cell. The cell accumulates its secretory products and releases them only when the cell bursts. New gland cells differentiate from cells in the surrounding tissue to replace those lost by secretion. The sebaceous glands that produce the oils on the skin and hair are an example of a holocrine glands (Figure 4.2.6).', '099dbc78-e5a5-4b2c-806b-cd842dc8464e': 'Glands are also named based on the\xa0 products they produce. A serous gland produces watery, blood-plasma-like secretions rich in enzymes, whereas a mucous gland releases a more viscous product rich in the glycoprotein mucin. Both serous and mucous secretions are common in the salivary glands of the digestive system.\xa0 Such glands releasing both serous and mucous secretions are often referred to as seromucous glands.', '8e6add6a-a1e9-4ca6-a12c-1571b47e9040': 'The term tissue is used to describe a group of cells that are similar in structure and perform a specific function.\xa0\xa0 Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function.', 'e2cb147a-9471-494b-96cb-a5eb6b6b1a31': 'Tissues are organized into four broad categories based on structural and functional similarities.\xa0 These categories are\xa0 epithelial, connective, muscle, and nervous.\xa0\xa0 The primary tissue types work together to contribute to the overall health and maintenance of the human body.\xa0\xa0 Thus, any disruption in the structure of a tissue can lead to injury or disease.'}"
+Figure 4.1.1,Anatomy_And_Physio/images/Figure 4.1.1.jpg,"Figure 4.1.1 – The Four Primary Tissue Types: Examples of nervous tissue, epithelial tissue, muscle tissue, and connective tissue found throughout the human body. Clockwise from nervous tissue, LM × 872, LM × 282, LM × 460, LM × 800. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","Epithelial tissue refers to groups of cells that cover the exterior surfaces of the body, line internal cavities and passageways, and form certain glands. Connective tissue, as its name implies, binds the cells and organs of the body together. Muscle tissue contracts forcefully when excited, providing movement.  Nervous tissue is also excitable, allowing for the generation and propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body (Figure 4.1.1).","{'984ec6c3-464c-4974-bdb3-960c1cd373a9': 'Epithelial tissue refers to groups of cells that cover the exterior surfaces of the body, line internal cavities and passageways, and form certain glands. Connective tissue, as its name implies, binds the cells and organs of the body together. Muscle tissue contracts forcefully when excited, providing movement.\xa0 Nervous tissue is also excitable, allowing for the generation and propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body (Figure 4.1.1).', '2296d3c3-8c73-4f80-9cde-b5c72810592d': 'An understanding of the various primary tissue types present in the human body is essential for understanding the structure and function of organs which are composed of two or more primary tissue types.\xa0 This chapter will focus on examining epithelial and connective tissues.\xa0 Muscle and nervous tissue will be discussed in detail in future chapters.'}"
+Figure 4.1.2,Anatomy_And_Physio/images/Figure 4.1.2.jpg,Figure 4.1.2 – Embryonic Origin of Tissues and Major Organs: Embryonic germ layers and the resulting primary tissue types formed by each.,"The cells composing a tissue share a common embryonic origin. The zygote, or fertilized egg, is a single cell formed by the fusion of an egg and sperm cell. After fertilization, the zygote gives rise many cells to form the embryo. The first embryonic cells generated have the ability to differentiate into any type of cell in the body and, as such, are called omnipotent, meaning each has the capacity to divide, differentiate, and develop into a new organism. As cell proliferation progresses, three major cell lines are established within the embryo. Each of these lines of embryonic cells forms the distinct germ layers from which all the tissues and organs of the human body eventually form. Each germ layer is identified by its relative position: ectoderm (ecto- = “outer”), mesoderm (meso- = “middle”), and endoderm (endo- = “inner”). Figure 4.1.2 shows the types of tissues and organs associated with each of the three germ layers. Note that epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue derives from the mesoderm.","{'b9155d22-8128-42a6-b460-522439381f3f': 'The cells composing a tissue share a common embryonic origin. The zygote, or fertilized egg, is a single cell formed by the fusion of an egg and sperm cell. After fertilization, the zygote gives rise many cells to form the embryo. The first embryonic cells generated have the ability to differentiate into any type of cell in the body and, as such, are called omnipotent, meaning each has the capacity to divide, differentiate, and develop into a new organism. As cell proliferation progresses, three major cell lines are established within the embryo. Each of these lines of embryonic cells forms the distinct germ layers from which all the tissues and organs of the human body eventually form. Each germ layer is identified by its relative position: ectoderm (ecto- = “outer”), mesoderm (meso- = “middle”), and endoderm (endo- = “inner”). Figure 4.1.2 shows the types of tissues and organs associated with each of the three germ layers. Note that epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue derives from the mesoderm.'}"
+Figure 4.1.3,Anatomy_And_Physio/images/Figure 4.1.3.jpg,"Figure 4.1.3 – Tissue Membranes: The two broad categories of tissue membranes in the body are (1) connective tissue membranes, which include synovial membranes, and (2) epithelial membranes, which include mucous membranes, serous membranes, and the cutaneous membrane, in other words, the skin.","A tissue membrane is a thin layer or sheet of cells that either covers the outside of the body (e.g., skin), lines an internal body cavity (e.g., peritoneal cavity),  lines a vessel (e.g., blood vessel),  or lines a movable joint cavity (e.g., synovial joint).   Two basic types of tissue membranes are recognized based on the primary tissue type composing each: connective tissue membranes and epithelial membranes (Figure 4.1.3).","{'c8723788-ca5c-42ca-a39b-98aac709ca96': 'A tissue membrane is a thin layer or sheet of cells that either covers the outside of the body (e.g., skin), lines an internal body cavity (e.g., peritoneal cavity),\xa0 lines a vessel (e.g., blood vessel),\xa0 or lines a movable joint cavity (e.g., synovial joint).\xa0\xa0 Two basic types of tissue membranes are recognized based on the primary tissue type composing each: connective tissue membranes and epithelial membranes (Figure 4.1.3).'}"
+Figure 3.5.1,Anatomy_And_Physio/images/Figure 3.5.1.jpg,"Figure 3.5.1 – Cell Cycle: The two major phases of the cell cycle include mitosis (cell division), and interphase, when the cell grows and performs all of its normal functions. Interphase is further subdivided into G1, S, and G2 phases.","A cell grows and carries out all normal metabolic functions and processes in a period called G1 (Figure 3.5.1). G1 phase (gap 1 phase) is the first gap, or growth phase in the cell cycle. For cells that will divide again, G1 is followed by replication of the DNA, during the S phase. The S phase (synthesis phase) is the period during which a cell replicates its DNA.","{'534666a1-49f5-4dbf-9f6b-2e03d91dd96e': 'A cell grows and carries out all normal metabolic functions and processes in a period called G1 (Figure 3.5.1). G1 phase (gap 1 phase) is the first gap, or growth phase in the cell cycle. For cells that will divide again, G1 is followed by replication of the DNA, during the S phase. The S phase (synthesis phase) is the period during which a cell replicates its DNA.', '0115eda2-09dd-4f3b-a23f-abf6cb9edbc8': 'After the synthesis phase, the cell proceeds through the G2 phase. The G2 phase is a second gap phase, during which the cell continues to grow and makes the necessary preparations for mitosis. Between G1, S, and G2 phases, cells will vary the most in their duration of the G1 phase. It is here that a cell might spend a couple of hours, or many days. The S phase typically lasts between 8-10 hours and the G2 phase approximately 5 hours. In contrast to these phases, the G0 phase is a resting phase of the cell cycle. Cells that have temporarily stopped dividing and are resting (a common condition) and cells that have permanently ceased dividing (like nerve cells) are said to be in G0.'}"
+Figure 3.5.3,Anatomy_And_Physio/images/Figure 3.5.3.jpg,"Figure 3.5.3 – Cell Division: Mitosis Followed by Cytokinesis: The stages of cell division oversee the separation of identical genetic material into two new nuclei, followed by the division of the cytoplasm.","The mitotic phase of the cell typically takes between 1 and 2 hours. During this phase, a cell undergoes two major processes. First, it completes mitosis, during which the contents of the nucleus are equitably pulled apart and distributed between its two halves. Cytokinesis then occurs, dividing the cytoplasm and cell body into two new cells. Mitosis is divided into four major stages that take place after interphase (Figure 3.5.3) and in the following order: prophase, metaphase, anaphase, and telophase. The process is then followed by cytokinesis.","{'1b9452b7-efa8-44ba-b1cf-adedc6674ed7': 'The mitotic phase of the cell typically takes between 1 and 2 hours. During this phase, a cell undergoes two major processes. First, it completes mitosis, during which the contents of the nucleus are equitably pulled apart and distributed between its two halves. Cytokinesis then occurs, dividing the cytoplasm and cell body into two new cells. Mitosis is divided into four major stages that take place after interphase (Figure 3.5.3) and in the following order: prophase, metaphase, anaphase, and telophase. The process is then followed by cytokinesis.', 'fcfe84a2-6701-436c-857c-45287824edb6': 'Prophase is the first phase of mitosis, during which the loosely packed chromatin coils and condenses into visible chromosomes. During prophase, each chromosome becomes visible with its identical partner attached, forming the familiar X-shape of sister chromatids. The nucleolus disappears early during this phase, and the nuclear envelope also disintegrates.', '66a86e1c-d862-4f2b-8ebe-be90fdb117ca': 'A major occurrence during prophase concerns a very important structure that contains the origin site for microtubule growth. Recall the cellular structures called centrioles that serve as origin points from which microtubules extend. These tiny structures also play a very important role during mitosis. A centrosome is a pair of centrioles together. The cell contains two centrosomes side-by-side, which begin to move apart during prophase. As the centrosomes migrate to two different sides of the cell, microtubules begin to extend from each like long fingers from two hands extending toward each other. The mitotic spindle is the structure composed of the centrosomes and their emerging microtubules.', 'eb5e08ad-869d-47d5-8c8d-7f86aa9171de': 'Near the end of prophase there is an invasion of the nuclear area by microtubules from the mitotic spindle. The nuclear membrane has disintegrated, and the microtubules attach themselves to the centromeres that adjoin pairs of sister chromatids. The kinetochore is a protein structure on the centromere that is the point of attachment between the mitotic spindle and the sister chromatids. This stage is referred to as late prophase or “prometaphase” to indicate the transition between prophase and metaphase.', '4734a62d-04cc-4a25-8faa-bdea6fd961c2': 'Metaphase is the second stage of mitosis. During this stage, the sister chromatids, with their attached microtubules, line up along a linear plane in the middle of the cell. A metaphase plate forms between the centrosomes that are now located at either end of the cell. The metaphase plate is the name for the plane through the center of the spindle on which the sister chromatids are positioned. The microtubules are now poised to pull apart the sister chromatids and bring one from each pair to each side of the cell.', '1268e8fb-3536-4503-9747-699126663ba5': 'Anaphase is the third stage of mitosis. Anaphase takes place over a few minutes, when the pairs of sister chromatids are separated from one another, forming individual chromosomes once again. These chromosomes are pulled to opposite ends of the cell by their kinetochores, as the microtubules shorten. Each end of the cell receives one partner from each pair of sister chromatids, ensuring that the two new daughter cells will contain identical genetic material.', 'bae2bbd8-3ab5-4692-af5c-03addaeb084a': 'Telophase is the final stage of mitosis. Telophase is characterized by the formation of two new daughter nuclei at either end of the dividing cell. These newly formed nuclei surround the genetic material, which uncoils in such a way that the chromosomes return to loosely packed chromatin. Nucleoli also reappear within the new nuclei, and the mitotic spindle breaks apart, each new cell receiving its own complement of DNA, organelles, membranes, and centrioles. At this point, the cell is already beginning to split in half as cytokinesis begins.', 'b7277274-5431-48b8-b32a-b5567654741f': 'The cleavage furrow is a contractile band made up of microfilaments that forms around the midline of the cell during cytokinesis. (Recall that microfilaments consist of actin). This contractile band squeezes the two cells apart until they finally separate. Two new cells are now formed. One of these cells (the “stem cell”) enters its own cell cycle; able to grow and divide again at some future time. The other cell transforms into the functional cell of the tissue, typically replacing an “old” cell there.', '426e6c52-f65a-4c23-94af-0abd58ab5120': 'Imagine a cell that completed mitosis but never underwent cytokinesis. In some cases, a cell may divide its genetic material and grow in size, but fail to undergo cytokinesis. This results in larger cells with more than one nucleus. Usually this is an unwanted aberration and can be a sign of cancerous cells.'}"
+Figure 3.5.4,Anatomy_And_Physio/images/Figure 3.5.4.jpg,"Figure 3.5.4 – Control of the Cell Cycle: Cells proceed through the cell cycle under the control of a variety of molecules, such as cyclins and cyclin-dependent kinases. These control molecules determine whether or not the cell is prepared to move into the following stage.","As the cell proceeds through its cycle, each phase involves certain processes that must be completed before the cell should advance to the next phase. A checkpoint is a point in the cell cycle at which the cycle can be signaled to move forward or stopped. At each of these checkpoints, different varieties of molecules provide the stop or go signals, depending on certain conditions within the cell. A cyclin is one of the primary classes of cell cycle control molecules (Figure 3.5.4). A cyclin-dependent kinase (CDK) is one of a group of molecules that work together with cyclins to determine progression past cell checkpoints. By interacting with many additional molecules, these triggers push the cell cycle forward (unless prevented from doing so by “stop” signals, if for some reason the cell is not ready). At the G1 checkpoint, the cell must be ready for DNA synthesis to occur. At the G2 checkpoint the cell must be fully prepared for mitosis. Even during mitosis, a crucial stop and go checkpoint in metaphase ensures that the cell is fully prepared to complete cell division. The metaphase checkpoint ensures that all sister chromatids are properly attached to their respective microtubules and lined up at the metaphase plate before the signal is given to separate them during anaphase.","{'f64c3845-964c-47fe-91e0-0326b048c4d4': 'As the cell proceeds through its cycle, each phase involves certain processes that must be completed before the cell should advance to the next phase. A checkpoint is a point in the cell cycle at which the cycle can be signaled to move forward or stopped. At each of these checkpoints, different varieties of molecules provide the stop or go signals, depending on certain conditions within the cell. A cyclin is one of the primary classes of cell cycle control molecules (Figure 3.5.4). A cyclin-dependent kinase (CDK) is one of a group of molecules that work together with cyclins to determine progression past cell checkpoints. By interacting with many additional molecules, these triggers push the cell cycle forward (unless prevented from doing so by “stop” signals, if for some reason the cell is not ready). At the G1 checkpoint, the cell must be ready for DNA synthesis to occur. At the G2 checkpoint the cell must be fully prepared for mitosis. Even during mitosis, a crucial stop and go checkpoint in metaphase ensures that the cell is fully prepared to complete cell division. The metaphase checkpoint ensures that all sister chromatids are properly attached to their respective microtubules and lined up at the metaphase plate before the signal is given to separate them during anaphase.'}"
+Figure 3.4.1,Anatomy_And_Physio/images/Figure 3.4.1.jpg,Figure 3.4.1 – The Genetic Code: DNA holds all of the genetic information necessary to build a cell’s proteins. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein.,"The interpretation of genes works in the following way. Recall that proteins are polymers, or chains, of many amino acid building blocks. The sequence of bases in a gene (that is, its sequence of A, T, C, G nucleotides) translates to an amino acid sequence. A triplet is a section of three DNA bases in a row that codes for a specific amino acid. For example, the DNA triplet CAC (cytosine, adenine, and cytosine) specifies the amino acid valine. Therefore, a gene, which is composed of multiple triplets in a unique sequence, provides the code to build an entire protein, with multiple amino acids in the proper sequence (Figure 3.4.1). The mechanism by which cells turn the DNA code into a protein product is a two-step process, with an RNA molecule as the intermediate.","{'d0201333-b698-4320-aec2-5cb6c405e951': 'Cancer is an extremely complex condition, capable of arising from a wide variety of genetic and environmental causes. Typically, mutations or aberrations in a cell’s DNA that compromise normal cell cycle control systems lead to cancerous tumors. Cell cycle control is an example of a homeostatic mechanism that maintains proper cell function and health. While progressing through the phases of the cell cycle, a large variety of intracellular molecules provide stop and go signals to regulate movement forward to the next phase. These signals are maintained in an intricate balance so that the cell only proceeds to the next phase when it is ready. This homeostatic control of the cell cycle can be thought of like a car’s cruise control. Cruise control will continually apply just the right amount of acceleration to maintain a desired speed, unless the driver hits the brakes, in which case the car will slow down. Similarly, the cell includes molecular messengers, such as cyclins, that push the cell forward in its cycle.', 'ae1b881b-005d-41ff-baef-24f80c7f0de7': 'In addition to cyclins, a class of proteins that are encoded by genes called proto-oncogenes provide important signals that regulate the cell cycle and move it forward. Examples of proto-oncogene products include cell-surface receptors for growth factors, or cell-signaling molecules, two classes of molecules that can promote DNA replication and cell division. In contrast, a second class of genes known as tumor suppressor genes sends stop signals during a cell cycle. For example, certain protein products of tumor suppressor genes signal potential problems with the DNA and thus stop the cell from dividing, while other proteins signal the cell to die if it is damaged beyond repair. Some tumor suppressor proteins also signal a sufficient surrounding cellular density, which indicates that the cell need not presently divide. The latter function is uniquely important in preventing tumor growth. Normal cells exhibit a phenomenon called “contact inhibition”, thus, extensive cellular contact with neighboring cells causes a signal that stops further cell division.', 'b8e5b3b5-2f7c-45bc-97a0-721769fc95c4': 'These two contrasting classes of genes, proto-oncogenes and tumor suppressor genes, are like the accelerator and brake pedal of the cell’s own “cruise control system,” respectively. Under normal conditions, these stop and go signals are maintained in a homeostatic balance. Generally speaking, there are two ways that the cell’s cruise control can lose control: a malfunctioning (overactive) accelerator, or a malfunctioning (underactive) brake. When compromised through a mutation, or otherwise altered, proto-oncogenes can be converted to oncogenes, which produce oncoproteins that push a cell forward in its cycle and stimulate cell division even when it is undesirable to do so. For example, a cell that should be programmed to self-destruct (a process called apoptosis) due to extensive DNA damage might instead be triggered to proliferate by an oncoprotein. On the other hand, a dysfunctional tumor suppressor gene may fail to provide the cell with a necessary stop signal, also resulting in unwanted cell division and proliferation.', '1f96781d-ac03-417b-ad43-62862086c596': 'A delicate homeostatic balance between the many proto-oncogenes and tumor suppressor genes delicately controls the cell cycle and ensures that only healthy cells replicate. Therefore, a disruption of this homeostatic balance can cause aberrant cell division and cancerous growths.', '12dc0b9a-bfdb-4b3b-a5e3-d369aafbdae8': 'It was mentioned earlier that DNA provides a “blueprint” for the cell structure and physiology. This refers to the fact that DNA contains the information necessary for the cell to build one very important type of molecule: the protein. Most structural components of the cell are made up, at least in part, by proteins and virtually all the functions that a cell carries out are completed with the help of proteins. One of the most important classes of proteins is enzymes, which help speed up necessary biochemical reactions that take place inside the cell. Some of these critical biochemical reactions include building larger molecules from smaller components (such as what occurs during DNA replication or synthesis of microtubules) and breaking down larger molecules into smaller components (such as when harvesting chemical energy from nutrient molecules). Whatever the cellular process may be, it is almost sure to involve proteins. Just as the cell’s genome describes its full complement of DNA, a cell’s proteome is its full complement of proteins. Protein synthesis begins with genes. A gene is a functional segment of DNA that provides the genetic information necessary to build a protein. Each particular gene provides the code necessary to construct a particular protein. Gene expression, which transforms the information coded in a gene to a final gene product, ultimately dictates the structure and function of a cell by determining which proteins are made.', '3a636569-9360-4d5b-85bc-626ced4bf113': 'The interpretation of genes works in the following way. Recall that proteins are polymers, or chains, of many amino acid building blocks. The sequence of bases in a gene (that is, its sequence of A, T, C, G nucleotides) translates to an amino acid sequence. A triplet is a section of three DNA bases in a row that codes for a specific amino acid. For example, the DNA triplet CAC (cytosine, adenine, and cytosine) specifies the amino acid valine. Therefore, a gene, which is composed of multiple triplets in a unique sequence, provides the code to build an entire protein, with multiple amino acids in the proper sequence (Figure 3.4.1). The mechanism by which cells turn the DNA code into a protein product is a two-step process, with an RNA molecule as the intermediate.'}"
+Figure 3.4.2,Anatomy_And_Physio/images/Figure 3.4.2.jpg,"Figure 3.4.2 – Transcription: from DNA to mRNA: In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule.","Gene expression begins with the process called transcription, which is the synthesis of a strand of mRNA that is complementary to the gene of interest. This process is called transcription because the mRNA is like a transcript, or copy, of the gene’s DNA code. Transcription begins in a fashion somewhat like DNA replication, in that a region of DNA unwinds and the two strands separate, however, only that small portion of the DNA will be split apart. The triplets within the gene on this section of the DNA molecule are used as the template to transcribe the complementary strand of RNA (Figure 3.4.2). A codon is a three-base sequence of mRNA, so-called because they directly encode amino acids. Like DNA replication, there are three stages to transcription: initiation, elongation, and termination.","{'f205220f-e196-44c2-b58f-8769dd939fc9': 'DNA is housed within the nucleus, and protein synthesis takes place in the cytoplasm, thus there must be some sort of intermediate messenger that leaves the nucleus and manages protein synthesis. This intermediate messenger is messenger RNA (mRNA), (Figure 3.29), a single-stranded nucleic acid that carries a copy of the genetic code for a single gene out of the nucleus and into the cytoplasm where it is used to produce proteins.', '46049e2a-3524-45e0-a823-d42ac6b03d80': 'There are several different types of RNA, each having different functions in the cell. The structure of RNA is similar to DNA with a few small exceptions. For one thing, unlike DNA, most types of RNA, including mRNA, are single-stranded and contain no complementary strand. Second, the ribose sugar in RNA contains an additional oxygen atom compared with DNA. Finally, instead of the base thymine, RNA contains the base uracil. This means that adenine will always pair up with uracil during the protein synthesis process.', 'fa061c15-8b04-4b34-8776-62561b409ff2': 'Gene expression begins with the process called transcription, which is the synthesis of a strand of mRNA that is complementary to the gene of interest. This process is called transcription because the mRNA is like a transcript, or copy, of the gene’s DNA code. Transcription begins in a fashion somewhat like DNA replication, in that a region of DNA unwinds and the two strands separate, however, only that small portion of the DNA will be split apart. The triplets within the gene on this section of the DNA molecule are used as the template to transcribe the complementary strand of RNA (Figure 3.4.2). A codon is a three-base sequence of mRNA, so-called because they directly encode amino acids. Like DNA replication, there are three stages to transcription: initiation, elongation, and termination.', '9c0dbcb6-0626-4334-adda-b124ef22f7e5': 'In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule.', 'f1bda863-fe5e-4765-a5d1-d7d29e5b5d7e': 'Stage 1: Initiation. A region at the beginning of the gene called a promoter—a particular sequence of nucleotides—triggers the start of transcription.', '2a69d593-7f59-4f41-a3fa-ed9127b6f87e': 'Stage 2: Elongation. Transcription starts when RNA polymerase unwinds the DNA segment. One strand, referred to as the coding strand, becomes the template with the genes to be coded. The polymerase then aligns the correct nucleic acid (A, C, G, or U) with its complementary base on the coding strand of DNA. RNA polymerase is an enzyme that adds new nucleotides to a growing strand of RNA. This process builds a strand of mRNA.', 'fd9dcde9-f55b-4c80-a165-af1739eded5c': 'Stage 3: Termination. When the polymerase has reached the end of the gene, one of three specific triplets (UAA, UAG, or UGA) codes a “stop” signal, which triggers the enzymes to terminate transcription and release the mRNA transcript.', '021f52a2-4f78-4bf8-a3c7-9c97bf47ab21': 'The transcription process is regulated by a class of proteins called transcription factors, which bind to the gene sequence and either promote or inhibit their transcription. \xa0(move Figure 3.35 here).', '1930210e-abff-423a-885b-30afa15e91ac': 'Before the mRNA molecule leaves the nucleus and proceeds to protein synthesis, it is modified in a number of ways. For this reason, it is often called a pre-mRNA at this stage. For example, your DNA, and thus complementary mRNA, contains long regions called non-coding regions that do not code for amino acids. Their function is still a mystery, but the process called splicing removes these non-coding regions from the pre-mRNA transcript (Figure 3.4.3). A spliceosome—a structure composed of various proteins and other molecules—attaches to the mRNA and “splices” or cuts out the non-coding regions. The removed segment of the transcript is called an intron. The remaining exons are pasted together. An exon is a segment of RNA that remains after splicing. Interestingly, some introns that are removed from mRNA are not always non-coding. When different coding regions of mRNA are spliced out, different variations of the protein will eventually result, with differences in structure and function. This process results in a much larger variety of possible proteins and protein functions. When the mRNA transcript is ready, it travels out of the nucleus and into the cytoplasm.'}"
+Figure 3.4.3,Anatomy_And_Physio/images/Figure 3.4.3.jpg,"Figure 3.4.3 – Splicing DNA: In the nucleus, a structure called a spliceosome cuts out introns (noncoding regions) within a pre-mRNA transcript and reconnects the exons.","Before the mRNA molecule leaves the nucleus and proceeds to protein synthesis, it is modified in a number of ways. For this reason, it is often called a pre-mRNA at this stage. For example, your DNA, and thus complementary mRNA, contains long regions called non-coding regions that do not code for amino acids. Their function is still a mystery, but the process called splicing removes these non-coding regions from the pre-mRNA transcript (Figure 3.4.3). A spliceosome—a structure composed of various proteins and other molecules—attaches to the mRNA and “splices” or cuts out the non-coding regions. The removed segment of the transcript is called an intron. The remaining exons are pasted together. An exon is a segment of RNA that remains after splicing. Interestingly, some introns that are removed from mRNA are not always non-coding. When different coding regions of mRNA are spliced out, different variations of the protein will eventually result, with differences in structure and function. This process results in a much larger variety of possible proteins and protein functions. When the mRNA transcript is ready, it travels out of the nucleus and into the cytoplasm.","{'f205220f-e196-44c2-b58f-8769dd939fc9': 'DNA is housed within the nucleus, and protein synthesis takes place in the cytoplasm, thus there must be some sort of intermediate messenger that leaves the nucleus and manages protein synthesis. This intermediate messenger is messenger RNA (mRNA), (Figure 3.29), a single-stranded nucleic acid that carries a copy of the genetic code for a single gene out of the nucleus and into the cytoplasm where it is used to produce proteins.', '46049e2a-3524-45e0-a823-d42ac6b03d80': 'There are several different types of RNA, each having different functions in the cell. The structure of RNA is similar to DNA with a few small exceptions. For one thing, unlike DNA, most types of RNA, including mRNA, are single-stranded and contain no complementary strand. Second, the ribose sugar in RNA contains an additional oxygen atom compared with DNA. Finally, instead of the base thymine, RNA contains the base uracil. This means that adenine will always pair up with uracil during the protein synthesis process.', 'fa061c15-8b04-4b34-8776-62561b409ff2': 'Gene expression begins with the process called transcription, which is the synthesis of a strand of mRNA that is complementary to the gene of interest. This process is called transcription because the mRNA is like a transcript, or copy, of the gene’s DNA code. Transcription begins in a fashion somewhat like DNA replication, in that a region of DNA unwinds and the two strands separate, however, only that small portion of the DNA will be split apart. The triplets within the gene on this section of the DNA molecule are used as the template to transcribe the complementary strand of RNA (Figure 3.4.2). A codon is a three-base sequence of mRNA, so-called because they directly encode amino acids. Like DNA replication, there are three stages to transcription: initiation, elongation, and termination.', '9c0dbcb6-0626-4334-adda-b124ef22f7e5': 'In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule.', 'f1bda863-fe5e-4765-a5d1-d7d29e5b5d7e': 'Stage 1: Initiation. A region at the beginning of the gene called a promoter—a particular sequence of nucleotides—triggers the start of transcription.', '2a69d593-7f59-4f41-a3fa-ed9127b6f87e': 'Stage 2: Elongation. Transcription starts when RNA polymerase unwinds the DNA segment. One strand, referred to as the coding strand, becomes the template with the genes to be coded. The polymerase then aligns the correct nucleic acid (A, C, G, or U) with its complementary base on the coding strand of DNA. RNA polymerase is an enzyme that adds new nucleotides to a growing strand of RNA. This process builds a strand of mRNA.', 'fd9dcde9-f55b-4c80-a165-af1739eded5c': 'Stage 3: Termination. When the polymerase has reached the end of the gene, one of three specific triplets (UAA, UAG, or UGA) codes a “stop” signal, which triggers the enzymes to terminate transcription and release the mRNA transcript.', '021f52a2-4f78-4bf8-a3c7-9c97bf47ab21': 'The transcription process is regulated by a class of proteins called transcription factors, which bind to the gene sequence and either promote or inhibit their transcription. \xa0(move Figure 3.35 here).', '1930210e-abff-423a-885b-30afa15e91ac': 'Before the mRNA molecule leaves the nucleus and proceeds to protein synthesis, it is modified in a number of ways. For this reason, it is often called a pre-mRNA at this stage. For example, your DNA, and thus complementary mRNA, contains long regions called non-coding regions that do not code for amino acids. Their function is still a mystery, but the process called splicing removes these non-coding regions from the pre-mRNA transcript (Figure 3.4.3). A spliceosome—a structure composed of various proteins and other molecules—attaches to the mRNA and “splices” or cuts out the non-coding regions. The removed segment of the transcript is called an intron. The remaining exons are pasted together. An exon is a segment of RNA that remains after splicing. Interestingly, some introns that are removed from mRNA are not always non-coding. When different coding regions of mRNA are spliced out, different variations of the protein will eventually result, with differences in structure and function. This process results in a much larger variety of possible proteins and protein functions. When the mRNA transcript is ready, it travels out of the nucleus and into the cytoplasm.'}"
+Figure 3.4.4,Anatomy_And_Physio/images/Figure 3.4.4.jpg,"Figure 3.4.4 – Translation from RNA to Protein: During translation, the mRNA transcript is “read” by a functional complex consisting of the ribosome and tRNA molecules. tRNAs bring the appropriate amino acids in sequence to the growing polypeptide chain by matching their anti-codons with codons on the mRNA strand.","The other major requirement for protein synthesis is the translator molecules that physically “read” the mRNA codons. Transfer RNA (tRNA) is a type of RNA that ferries the appropriate corresponding amino acids to the ribosome, and attaches each new amino acid to the last, building the polypeptide chain one-by-one. Thus tRNA transfers specific amino acids from the cytoplasm to a growing polypeptide. The tRNA molecules must be able to recognize the codons on mRNA and match them with the correct amino acid. The tRNA is modified for this function. On one end of its structure is a binding site for a specific amino acid. On the other end is a base sequence that matches the codon specifying its particular amino acid. This sequence of three bases on the tRNA molecule is called an anticodon. For example, a tRNA responsible for shuttling the amino acid glycine contains a binding site for glycine on one end. On the other end it contains an anticodon that complements the glycine codon (GGA is a codon for glycine, and so the tRNAs anticodon would read CCU). Equipped with its particular cargo and matching anticodon, a tRNA molecule can read its recognized mRNA codon and bring the corresponding amino acid to the growing chain (Figure 3.4.4).","{'c10429ad-edee-4de0-8029-880b332dd621': 'Like translating a book from one language into another, the codons on a strand of mRNA must be translated into the amino acid alphabet of proteins. Translation is the process of synthesizing a chain of amino acids called a polypeptide. Translation requires two major aids: first, a “translator,” the molecule that will conduct the translation, and second, a substrate on which the mRNA strand is translated into a new protein, like the translator’s “desk.” Both of these requirements are fulfilled by other types of RNA. The substrate on which translation takes place is the ribosome.', '428bbbe0-9cd3-4f48-9d47-4e84b61edd3a': 'Remember that many of a cell’s ribosomes are found associated with the rough ER, and carry out the synthesis of proteins destined for the Golgi apparatus. Ribosomal RNA (rRNA) is a type of RNA that, together with proteins, composes the structure of the ribosome. Ribosomes exist in the cytoplasm as two distinct components, a small and a large subunit. When an mRNA molecule is ready to be translated, the two subunits come together and attach to the mRNA. The ribosome provides a substrate for translation, bringing together and aligning the mRNA molecule with the molecular “translators” that must decipher its code.', '96084e02-376c-4b79-818d-0626b462e212': 'The other major requirement for protein synthesis is the translator molecules that physically “read” the mRNA codons. Transfer RNA (tRNA) is a type of RNA that ferries the appropriate corresponding amino acids to the ribosome, and attaches each new amino acid to the last, building the polypeptide chain one-by-one. Thus tRNA transfers specific amino acids from the cytoplasm to a growing polypeptide. The tRNA molecules must be able to recognize the codons on mRNA and match them with the correct amino acid. The tRNA is modified for this function. On one end of its structure is a binding site for a specific amino acid. On the other end is a base sequence that matches the codon specifying its particular amino acid. This sequence of three bases on the tRNA molecule is called an anticodon. For example, a tRNA responsible for shuttling the amino acid glycine contains a binding site for glycine on one end. On the other end it contains an anticodon that complements the glycine codon (GGA is a codon for glycine, and so the tRNAs anticodon would read CCU). Equipped with its particular cargo and matching anticodon, a tRNA molecule can read its recognized mRNA codon and bring the corresponding amino acid to the growing chain (Figure 3.4.4).', 'b28f8ce5-baf3-419b-8817-ef21469de035': 'Much like the processes of DNA replication and transcription, translation consists of three main stages: initiation, elongation, and termination. Initiation takes place with the binding of a ribosome to an mRNA transcript. The elongation stage involves the recognition of a tRNA anticodon with the next mRNA codon in the sequence. Once the anticodon and codon sequences are bound (remember, they are complementary base pairs), the tRNA presents its amino acid cargo and the growing polypeptide strand is attached to this next amino acid. This attachment takes place with the assistance of various enzymes and requires energy. The tRNA molecule then releases the mRNA strand, the mRNA strand shifts one codon over in the ribosome, and the next appropriate tRNA arrives with its matching anticodon. This process continues until the final codon on the mRNA is reached which provides a “stop” message that signals termination of translation and triggers the release of the complete, newly synthesized protein. Thus, a gene within the DNA molecule is transcribed into mRNA, which is then translated into a protein product (Figure 3.4.5).', '174d3acf-9392-4231-a8bf-f344f6895bea': 'Commonly, an mRNA transcription will be translated simultaneously by several adjacent ribosomes. This increases the efficiency of protein synthesis. A single ribosome might translate an mRNA molecule in approximately one minute; so multiple ribosomes aboard a single transcript could produce multiple times the number of the same protein in the same minute. A polyribosome is a string of ribosomes translating a single mRNA strand.', '6ad17f3b-9d3d-4ba8-9f95-bb08f1915ef6': 'The nucleus is the largest and most prominent of a cell’s organelles (Figure 3.3.1). The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. Interestingly, some cells in the body, such as muscle cells, contain more than one nucleus (Figure 3.3.2), which is known as multinucleated. Other cells, such as mammalian red blood cells (RBCs), do not contain nuclei at all. RBCs eject their nuclei as they mature, making space for the large numbers of hemoglobin molecules that carry oxygen throughout the body (Figure 3.3.3). Without nuclei, the life span of RBCs is short, and so the body must produce new ones constantly.', '81546f7b-8027-495f-a590-ed0ba736c768': 'Inside the nucleus lies the blueprint that dictates everything a cell will do and all of the products it will make. This information is stored within DNA. The nucleus sends “commands” to the cell via molecular messengers that translate the information from the DNA. Each cell in your body (with the exception of germ cells) contains the complete set of your DNA. When a cell divides, the DNA must be duplicated so that each new cell receives a full complement of DNA. The following section will explore the structure of the nucleus and its contents, as well as the process of DNA replication.'}"
+Figure 3.4.5,Anatomy_And_Physio/images/Figure 3.4.5.jpg,"Figure 3.4.5 – From DNA to Protein: Transcription through Translation: Transcription within the cell nucleus produces an mRNA molecule, which is modified and then sent into the cytoplasm for translation. The transcript is decoded into a protein with the help of a ribosome and tRNA molecules.","Much like the processes of DNA replication and transcription, translation consists of three main stages: initiation, elongation, and termination. Initiation takes place with the binding of a ribosome to an mRNA transcript. The elongation stage involves the recognition of a tRNA anticodon with the next mRNA codon in the sequence. Once the anticodon and codon sequences are bound (remember, they are complementary base pairs), the tRNA presents its amino acid cargo and the growing polypeptide strand is attached to this next amino acid. This attachment takes place with the assistance of various enzymes and requires energy. The tRNA molecule then releases the mRNA strand, the mRNA strand shifts one codon over in the ribosome, and the next appropriate tRNA arrives with its matching anticodon. This process continues until the final codon on the mRNA is reached which provides a “stop” message that signals termination of translation and triggers the release of the complete, newly synthesized protein. Thus, a gene within the DNA molecule is transcribed into mRNA, which is then translated into a protein product (Figure 3.4.5).","{'c10429ad-edee-4de0-8029-880b332dd621': 'Like translating a book from one language into another, the codons on a strand of mRNA must be translated into the amino acid alphabet of proteins. Translation is the process of synthesizing a chain of amino acids called a polypeptide. Translation requires two major aids: first, a “translator,” the molecule that will conduct the translation, and second, a substrate on which the mRNA strand is translated into a new protein, like the translator’s “desk.” Both of these requirements are fulfilled by other types of RNA. The substrate on which translation takes place is the ribosome.', '428bbbe0-9cd3-4f48-9d47-4e84b61edd3a': 'Remember that many of a cell’s ribosomes are found associated with the rough ER, and carry out the synthesis of proteins destined for the Golgi apparatus. Ribosomal RNA (rRNA) is a type of RNA that, together with proteins, composes the structure of the ribosome. Ribosomes exist in the cytoplasm as two distinct components, a small and a large subunit. When an mRNA molecule is ready to be translated, the two subunits come together and attach to the mRNA. The ribosome provides a substrate for translation, bringing together and aligning the mRNA molecule with the molecular “translators” that must decipher its code.', '96084e02-376c-4b79-818d-0626b462e212': 'The other major requirement for protein synthesis is the translator molecules that physically “read” the mRNA codons. Transfer RNA (tRNA) is a type of RNA that ferries the appropriate corresponding amino acids to the ribosome, and attaches each new amino acid to the last, building the polypeptide chain one-by-one. Thus tRNA transfers specific amino acids from the cytoplasm to a growing polypeptide. The tRNA molecules must be able to recognize the codons on mRNA and match them with the correct amino acid. The tRNA is modified for this function. On one end of its structure is a binding site for a specific amino acid. On the other end is a base sequence that matches the codon specifying its particular amino acid. This sequence of three bases on the tRNA molecule is called an anticodon. For example, a tRNA responsible for shuttling the amino acid glycine contains a binding site for glycine on one end. On the other end it contains an anticodon that complements the glycine codon (GGA is a codon for glycine, and so the tRNAs anticodon would read CCU). Equipped with its particular cargo and matching anticodon, a tRNA molecule can read its recognized mRNA codon and bring the corresponding amino acid to the growing chain (Figure 3.4.4).', 'b28f8ce5-baf3-419b-8817-ef21469de035': 'Much like the processes of DNA replication and transcription, translation consists of three main stages: initiation, elongation, and termination. Initiation takes place with the binding of a ribosome to an mRNA transcript. The elongation stage involves the recognition of a tRNA anticodon with the next mRNA codon in the sequence. Once the anticodon and codon sequences are bound (remember, they are complementary base pairs), the tRNA presents its amino acid cargo and the growing polypeptide strand is attached to this next amino acid. This attachment takes place with the assistance of various enzymes and requires energy. The tRNA molecule then releases the mRNA strand, the mRNA strand shifts one codon over in the ribosome, and the next appropriate tRNA arrives with its matching anticodon. This process continues until the final codon on the mRNA is reached which provides a “stop” message that signals termination of translation and triggers the release of the complete, newly synthesized protein. Thus, a gene within the DNA molecule is transcribed into mRNA, which is then translated into a protein product (Figure 3.4.5).', '174d3acf-9392-4231-a8bf-f344f6895bea': 'Commonly, an mRNA transcription will be translated simultaneously by several adjacent ribosomes. This increases the efficiency of protein synthesis. A single ribosome might translate an mRNA molecule in approximately one minute; so multiple ribosomes aboard a single transcript could produce multiple times the number of the same protein in the same minute. A polyribosome is a string of ribosomes translating a single mRNA strand.', '6ad17f3b-9d3d-4ba8-9f95-bb08f1915ef6': 'The nucleus is the largest and most prominent of a cell’s organelles (Figure 3.3.1). The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. Interestingly, some cells in the body, such as muscle cells, contain more than one nucleus (Figure 3.3.2), which is known as multinucleated. Other cells, such as mammalian red blood cells (RBCs), do not contain nuclei at all. RBCs eject their nuclei as they mature, making space for the large numbers of hemoglobin molecules that carry oxygen throughout the body (Figure 3.3.3). Without nuclei, the life span of RBCs is short, and so the body must produce new ones constantly.', '81546f7b-8027-495f-a590-ed0ba736c768': 'Inside the nucleus lies the blueprint that dictates everything a cell will do and all of the products it will make. This information is stored within DNA. The nucleus sends “commands” to the cell via molecular messengers that translate the information from the DNA. Each cell in your body (with the exception of germ cells) contains the complete set of your DNA. When a cell divides, the DNA must be duplicated so that each new cell receives a full complement of DNA. The following section will explore the structure of the nucleus and its contents, as well as the process of DNA replication.'}"
+Figure 3.3.1,Anatomy_And_Physio/images/Figure 3.3.1.jpg,Figure 3.3.1 – The Nucleus: The nucleus is the control center of the cell. The nucleus of living cells contains the genetic material that determines the entire structure and function of that cell.,"The nucleus is the largest and most prominent of a cell’s organelles (Figure 3.3.1). The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. Interestingly, some cells in the body, such as muscle cells, contain more than one nucleus (Figure 3.3.2), which is known as multinucleated. Other cells, such as mammalian red blood cells (RBCs), do not contain nuclei at all. RBCs eject their nuclei as they mature, making space for the large numbers of hemoglobin molecules that carry oxygen throughout the body (Figure 3.3.3). Without nuclei, the life span of RBCs is short, and so the body must produce new ones constantly.","{'c10429ad-edee-4de0-8029-880b332dd621': 'Like translating a book from one language into another, the codons on a strand of mRNA must be translated into the amino acid alphabet of proteins. Translation is the process of synthesizing a chain of amino acids called a polypeptide. Translation requires two major aids: first, a “translator,” the molecule that will conduct the translation, and second, a substrate on which the mRNA strand is translated into a new protein, like the translator’s “desk.” Both of these requirements are fulfilled by other types of RNA. The substrate on which translation takes place is the ribosome.', '428bbbe0-9cd3-4f48-9d47-4e84b61edd3a': 'Remember that many of a cell’s ribosomes are found associated with the rough ER, and carry out the synthesis of proteins destined for the Golgi apparatus. Ribosomal RNA (rRNA) is a type of RNA that, together with proteins, composes the structure of the ribosome. Ribosomes exist in the cytoplasm as two distinct components, a small and a large subunit. When an mRNA molecule is ready to be translated, the two subunits come together and attach to the mRNA. The ribosome provides a substrate for translation, bringing together and aligning the mRNA molecule with the molecular “translators” that must decipher its code.', '96084e02-376c-4b79-818d-0626b462e212': 'The other major requirement for protein synthesis is the translator molecules that physically “read” the mRNA codons. Transfer RNA (tRNA) is a type of RNA that ferries the appropriate corresponding amino acids to the ribosome, and attaches each new amino acid to the last, building the polypeptide chain one-by-one. Thus tRNA transfers specific amino acids from the cytoplasm to a growing polypeptide. The tRNA molecules must be able to recognize the codons on mRNA and match them with the correct amino acid. The tRNA is modified for this function. On one end of its structure is a binding site for a specific amino acid. On the other end is a base sequence that matches the codon specifying its particular amino acid. This sequence of three bases on the tRNA molecule is called an anticodon. For example, a tRNA responsible for shuttling the amino acid glycine contains a binding site for glycine on one end. On the other end it contains an anticodon that complements the glycine codon (GGA is a codon for glycine, and so the tRNAs anticodon would read CCU). Equipped with its particular cargo and matching anticodon, a tRNA molecule can read its recognized mRNA codon and bring the corresponding amino acid to the growing chain (Figure 3.4.4).', 'b28f8ce5-baf3-419b-8817-ef21469de035': 'Much like the processes of DNA replication and transcription, translation consists of three main stages: initiation, elongation, and termination. Initiation takes place with the binding of a ribosome to an mRNA transcript. The elongation stage involves the recognition of a tRNA anticodon with the next mRNA codon in the sequence. Once the anticodon and codon sequences are bound (remember, they are complementary base pairs), the tRNA presents its amino acid cargo and the growing polypeptide strand is attached to this next amino acid. This attachment takes place with the assistance of various enzymes and requires energy. The tRNA molecule then releases the mRNA strand, the mRNA strand shifts one codon over in the ribosome, and the next appropriate tRNA arrives with its matching anticodon. This process continues until the final codon on the mRNA is reached which provides a “stop” message that signals termination of translation and triggers the release of the complete, newly synthesized protein. Thus, a gene within the DNA molecule is transcribed into mRNA, which is then translated into a protein product (Figure 3.4.5).', '174d3acf-9392-4231-a8bf-f344f6895bea': 'Commonly, an mRNA transcription will be translated simultaneously by several adjacent ribosomes. This increases the efficiency of protein synthesis. A single ribosome might translate an mRNA molecule in approximately one minute; so multiple ribosomes aboard a single transcript could produce multiple times the number of the same protein in the same minute. A polyribosome is a string of ribosomes translating a single mRNA strand.', '6ad17f3b-9d3d-4ba8-9f95-bb08f1915ef6': 'The nucleus is the largest and most prominent of a cell’s organelles (Figure 3.3.1). The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. Interestingly, some cells in the body, such as muscle cells, contain more than one nucleus (Figure 3.3.2), which is known as multinucleated. Other cells, such as mammalian red blood cells (RBCs), do not contain nuclei at all. RBCs eject their nuclei as they mature, making space for the large numbers of hemoglobin molecules that carry oxygen throughout the body (Figure 3.3.3). Without nuclei, the life span of RBCs is short, and so the body must produce new ones constantly.', '81546f7b-8027-495f-a590-ed0ba736c768': 'Inside the nucleus lies the blueprint that dictates everything a cell will do and all of the products it will make. This information is stored within DNA. The nucleus sends “commands” to the cell via molecular messengers that translate the information from the DNA. Each cell in your body (with the exception of germ cells) contains the complete set of your DNA. When a cell divides, the DNA must be duplicated so that each new cell receives a full complement of DNA. The following section will explore the structure of the nucleus and its contents, as well as the process of DNA replication.'}"
+Figure 3.3.4,Anatomy_And_Physio/images/Figure 3.3.4.jpg,"Figure 3.3.4 – DNA Macrostructure: Strands of DNA are wrapped around supporting histones. These proteins are increasingly bundled and condensed into chromatin, which is packed tightly into chromosomes when the cell is ready to divide.","The genetic instructions that are used to build and maintain an organism are arranged in an orderly manner in strands of DNA. Within the nucleus are threads of chromatin composed of DNA and associated proteins (Figure 3.3.4). Along the chromatin threads, the DNA is wrapped around a set of histone proteins. A nucleosome is a single, wrapped DNA-histone complex. Multiple nucleosomes along the entire molecule of DNA appear like a beaded necklace, in which the string is the DNA and the beads are the associated histones. When a cell is in the process of division, the chromatin condenses into chromosomes, so that the DNA can be safely transported to the “daughter cells.” The chromosome is composed of DNA and proteins; it is the condensed form of chromatin. It is estimated that humans have almost 22,000 genes distributed on 46 chromosomes.","{'06efc7bd-03ac-4ecf-a4a2-8b8d68c571e7': 'Like most other cellular organelles, the nucleus is surrounded by a membrane called the nuclear envelope. This membranous covering consists of two adjacent lipid bilayers with a thin fluid space in between them. Spanning these two bilayers are nuclear pores. A nuclear pore is a tiny passageway for the passage of proteins, RNA, and solutes between the nucleus and the cytoplasm. Proteins called pore complexes lining the nuclear pores regulate the passage of materials into and out of the nucleus.', '4f39f150-7c27-4f5c-afbf-9e5549c1f1cc': 'Inside the nuclear envelope is a gel-like nucleoplasm with solutes that include the building blocks of nucleic acids. There also can be a dark-staining mass often visible under a simple light microscope, called a nucleolus (plural = nucleoli). The nucleolus is a region of the nucleus that is responsible for manufacturing the RNA necessary for construction of ribosomes. Once synthesized, newly made ribosomal subunits exit the cell’s nucleus through the nuclear pores.', '1d312cc6-0527-4dd3-9f80-01f668ac5a8b': 'The genetic instructions that are used to build and maintain an organism are arranged in an orderly manner in strands of DNA. Within the nucleus are threads of chromatin composed of DNA and associated proteins (Figure 3.3.4). Along the chromatin threads, the DNA is wrapped around a set of histone proteins. A nucleosome is a single, wrapped DNA-histone complex. Multiple nucleosomes along the entire molecule of DNA appear like a beaded necklace, in which the string is the DNA and the beads are the associated histones. When a cell is in the process of division, the chromatin condenses into chromosomes, so that the DNA can be safely transported to the “daughter cells.” The chromosome is composed of DNA and proteins; it is the condensed form of chromatin. It is estimated that humans have almost 22,000 genes distributed on 46 chromosomes.'}"
+Figure 3.3.5,Anatomy_And_Physio/images/Figure 3.3.5.jpg,Figure 3.3.5 – Molecular Structure of DNA: The DNA double helix is composed of two complementary strands. The strands are bonded together via their nitrogenous base pairs using hydrogen bonds.,"A DNA molecule is made of two strands that “complement” each other in the sense that the molecules that compose the strands fit together and bind to each other, creating a double-stranded molecule that looks much like a long, twisted ladder. Each side rail of the DNA ladder is composed of alternating sugar and phosphate groups (Figure 3.3.5). The two sides of the ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. The four DNA bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Because of their shape and charge, the two bases that compose a pair always bond together. Adenine always binds with thymine, and cytosine always binds with guanine. The particular sequence of bases along the DNA molecule determines the genetic code. Therefore, if the two complementary strands of DNA were pulled apart, you could infer the order of the bases in one strand from the bases in the other, complementary strand. For example, if one strand has a region with the sequence AGTGCCT, then the sequence of the complementary strand would be TCACGGA.","{'c08336cf-687c-4a6c-af89-de773c29fbd4': 'In order for an organism to grow, develop, and maintain its health, cells must reproduce themselves by dividing to produce two new daughter cells, each with the full complement of DNA as found in the original cell. Billions of new cells are produced in an adult human every day. Only very few cell types in the body do not divide, including nerve cells, skeletal muscle fibers, and cardiac muscle cells. The division time of different cell types varies. Epithelial cells of the skin and gastrointestinal lining, for instance, divide very frequently to replace those that are constantly being rubbed off of the surface by friction.', '96590628-3fa8-42c7-8cab-509422be2208': 'A DNA molecule is made of two strands that “complement” each other in the sense that the molecules that compose the strands fit together and bind to each other, creating a double-stranded molecule that looks much like a long, twisted ladder. Each side rail of the DNA ladder is composed of alternating sugar and phosphate groups (Figure 3.3.5). The two sides of the ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. The four DNA bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Because of their shape and charge, the two bases that compose a pair always bond together. Adenine always binds with thymine, and cytosine always binds with guanine. The particular sequence of bases along the DNA molecule determines the genetic code. Therefore, if the two complementary strands of DNA were pulled apart, you could infer the order of the bases in one strand from the bases in the other, complementary strand. For example, if one strand has a region with the sequence AGTGCCT, then the sequence of the complementary strand would be TCACGGA.', '25de5251-8a1c-47e9-affd-a2706b0cce3c': 'DNA replication is the copying of DNA that occurs before cell division can take place. After a great deal of debate and experimentation, the general method of DNA replication was deduced in 1958 by two scientists in California, Matthew Meselson and Franklin Stahl. This method is illustrated in Figure 3.3.6 and described below.', '6a9e8150-0eb5-4a5b-ba65-d0c34f2a358a': 'Stage 1: Initiation. The two complementary strands are separated, much like unzipping a zipper. Special enzymes, including helicase, untwist and separate the two strands of DNA.', '95430b4d-3b98-4693-8458-ab8ed52cbfeb': 'Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. A DNA polymerase is an enzyme that adds free nucleotides to the end of a chain of DNA, making a new double strand. This growing strand continues to be built until it has fully complemented the template strand.', '114594bc-2bc4-4600-aad6-4660f7ac1635': 'Stage 3: Termination. Once the two original strands are bound to their own, finished, complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete.', 'eea2b449-4c8c-4c1b-8694-28cb307e4c18': 'Each new DNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is “semiconservative,” because half of the original DNA molecule is conserved in each new DNA molecule. This process continues until the cell’s entire genome, the entire complement of an organism’s DNA, is replicated. As you might imagine, it is very important that DNA replication take place precisely so that new cells in the body contain the exact same genetic material as their parent cells. Mistakes made during DNA replication, such as the accidental addition of an inappropriate nucleotide, have the potential to render a gene dysfunctional or useless. Fortunately, there are mechanisms in place to minimize such mistakes. A DNA proofreading process enlists the help of special enzymes that scan the newly synthesized molecule for mistakes and corrects them. Once the process of DNA replication is complete, the cell is ready to divide. You will explore the process of cell division later in the chapter.', '34062ec2-d57d-4d7c-a3cb-bdd3112b0004': 'Now that you have learned that the cell membrane surrounds all cells, you can dive inside of a prototypical human cell to learn about its internal components and their functions. All living cells in multicellular organisms contain an internal cytoplasmic compartment, and a nucleus within the cytoplasm. Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. Eukaryotic cells, including all animal cells, also contain various cellular organelles. An organelle (“little organ”) is one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. Just as the various bodily organs work together in harmony to perform all of a human’s functions, the many different cellular organelles work together to keep the cell healthy and performing all of its important functions. The organelles and cytosol, taken together, compose the cell’s cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.2.1).'}"
+Figure 3.3.6,Anatomy_And_Physio/images/Figure 3.3.6.jpg,"Figure 3.3.6 – DNA Replication: DNA replication faithfully duplicates the entire genome of the cell. During DNA replication, a number of different enzymes work together to pull apart the two strands so each strand can be used as a template to synthesize new complementary strands. The two new daughter DNA molecules each contain one pre-existing strand and one newly synthesized strand. Thus, DNA replication is said to be “semiconservative.”","DNA replication is the copying of DNA that occurs before cell division can take place. After a great deal of debate and experimentation, the general method of DNA replication was deduced in 1958 by two scientists in California, Matthew Meselson and Franklin Stahl. This method is illustrated in Figure 3.3.6 and described below.","{'c08336cf-687c-4a6c-af89-de773c29fbd4': 'In order for an organism to grow, develop, and maintain its health, cells must reproduce themselves by dividing to produce two new daughter cells, each with the full complement of DNA as found in the original cell. Billions of new cells are produced in an adult human every day. Only very few cell types in the body do not divide, including nerve cells, skeletal muscle fibers, and cardiac muscle cells. The division time of different cell types varies. Epithelial cells of the skin and gastrointestinal lining, for instance, divide very frequently to replace those that are constantly being rubbed off of the surface by friction.', '96590628-3fa8-42c7-8cab-509422be2208': 'A DNA molecule is made of two strands that “complement” each other in the sense that the molecules that compose the strands fit together and bind to each other, creating a double-stranded molecule that looks much like a long, twisted ladder. Each side rail of the DNA ladder is composed of alternating sugar and phosphate groups (Figure 3.3.5). The two sides of the ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. The four DNA bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Because of their shape and charge, the two bases that compose a pair always bond together. Adenine always binds with thymine, and cytosine always binds with guanine. The particular sequence of bases along the DNA molecule determines the genetic code. Therefore, if the two complementary strands of DNA were pulled apart, you could infer the order of the bases in one strand from the bases in the other, complementary strand. For example, if one strand has a region with the sequence AGTGCCT, then the sequence of the complementary strand would be TCACGGA.', '25de5251-8a1c-47e9-affd-a2706b0cce3c': 'DNA replication is the copying of DNA that occurs before cell division can take place. After a great deal of debate and experimentation, the general method of DNA replication was deduced in 1958 by two scientists in California, Matthew Meselson and Franklin Stahl. This method is illustrated in Figure 3.3.6 and described below.', '6a9e8150-0eb5-4a5b-ba65-d0c34f2a358a': 'Stage 1: Initiation. The two complementary strands are separated, much like unzipping a zipper. Special enzymes, including helicase, untwist and separate the two strands of DNA.', '95430b4d-3b98-4693-8458-ab8ed52cbfeb': 'Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. A DNA polymerase is an enzyme that adds free nucleotides to the end of a chain of DNA, making a new double strand. This growing strand continues to be built until it has fully complemented the template strand.', '114594bc-2bc4-4600-aad6-4660f7ac1635': 'Stage 3: Termination. Once the two original strands are bound to their own, finished, complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete.', 'eea2b449-4c8c-4c1b-8694-28cb307e4c18': 'Each new DNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is “semiconservative,” because half of the original DNA molecule is conserved in each new DNA molecule. This process continues until the cell’s entire genome, the entire complement of an organism’s DNA, is replicated. As you might imagine, it is very important that DNA replication take place precisely so that new cells in the body contain the exact same genetic material as their parent cells. Mistakes made during DNA replication, such as the accidental addition of an inappropriate nucleotide, have the potential to render a gene dysfunctional or useless. Fortunately, there are mechanisms in place to minimize such mistakes. A DNA proofreading process enlists the help of special enzymes that scan the newly synthesized molecule for mistakes and corrects them. Once the process of DNA replication is complete, the cell is ready to divide. You will explore the process of cell division later in the chapter.', '34062ec2-d57d-4d7c-a3cb-bdd3112b0004': 'Now that you have learned that the cell membrane surrounds all cells, you can dive inside of a prototypical human cell to learn about its internal components and their functions. All living cells in multicellular organisms contain an internal cytoplasmic compartment, and a nucleus within the cytoplasm. Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. Eukaryotic cells, including all animal cells, also contain various cellular organelles. An organelle (“little organ”) is one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. Just as the various bodily organs work together in harmony to perform all of a human’s functions, the many different cellular organelles work together to keep the cell healthy and performing all of its important functions. The organelles and cytosol, taken together, compose the cell’s cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.2.1).'}"
+Figure 3.2.1,Anatomy_And_Physio/images/Figure 3.2.1.jpg,"Figure 3.2.1 – Prototypical Human Cell: While this image is not indicative of any one particular human cell, it is a prototypical example of a cell containing the primary organelles and internal structures.","Now that you have learned that the cell membrane surrounds all cells, you can dive inside of a prototypical human cell to learn about its internal components and their functions. All living cells in multicellular organisms contain an internal cytoplasmic compartment, and a nucleus within the cytoplasm. Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. Eukaryotic cells, including all animal cells, also contain various cellular organelles. An organelle (“little organ”) is one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. Just as the various bodily organs work together in harmony to perform all of a human’s functions, the many different cellular organelles work together to keep the cell healthy and performing all of its important functions. The organelles and cytosol, taken together, compose the cell’s cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.2.1).","{'c08336cf-687c-4a6c-af89-de773c29fbd4': 'In order for an organism to grow, develop, and maintain its health, cells must reproduce themselves by dividing to produce two new daughter cells, each with the full complement of DNA as found in the original cell. Billions of new cells are produced in an adult human every day. Only very few cell types in the body do not divide, including nerve cells, skeletal muscle fibers, and cardiac muscle cells. The division time of different cell types varies. Epithelial cells of the skin and gastrointestinal lining, for instance, divide very frequently to replace those that are constantly being rubbed off of the surface by friction.', '96590628-3fa8-42c7-8cab-509422be2208': 'A DNA molecule is made of two strands that “complement” each other in the sense that the molecules that compose the strands fit together and bind to each other, creating a double-stranded molecule that looks much like a long, twisted ladder. Each side rail of the DNA ladder is composed of alternating sugar and phosphate groups (Figure 3.3.5). The two sides of the ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. The four DNA bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Because of their shape and charge, the two bases that compose a pair always bond together. Adenine always binds with thymine, and cytosine always binds with guanine. The particular sequence of bases along the DNA molecule determines the genetic code. Therefore, if the two complementary strands of DNA were pulled apart, you could infer the order of the bases in one strand from the bases in the other, complementary strand. For example, if one strand has a region with the sequence AGTGCCT, then the sequence of the complementary strand would be TCACGGA.', '25de5251-8a1c-47e9-affd-a2706b0cce3c': 'DNA replication is the copying of DNA that occurs before cell division can take place. After a great deal of debate and experimentation, the general method of DNA replication was deduced in 1958 by two scientists in California, Matthew Meselson and Franklin Stahl. This method is illustrated in Figure 3.3.6 and described below.', '6a9e8150-0eb5-4a5b-ba65-d0c34f2a358a': 'Stage 1: Initiation. The two complementary strands are separated, much like unzipping a zipper. Special enzymes, including helicase, untwist and separate the two strands of DNA.', '95430b4d-3b98-4693-8458-ab8ed52cbfeb': 'Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. A DNA polymerase is an enzyme that adds free nucleotides to the end of a chain of DNA, making a new double strand. This growing strand continues to be built until it has fully complemented the template strand.', '114594bc-2bc4-4600-aad6-4660f7ac1635': 'Stage 3: Termination. Once the two original strands are bound to their own, finished, complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete.', 'eea2b449-4c8c-4c1b-8694-28cb307e4c18': 'Each new DNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is “semiconservative,” because half of the original DNA molecule is conserved in each new DNA molecule. This process continues until the cell’s entire genome, the entire complement of an organism’s DNA, is replicated. As you might imagine, it is very important that DNA replication take place precisely so that new cells in the body contain the exact same genetic material as their parent cells. Mistakes made during DNA replication, such as the accidental addition of an inappropriate nucleotide, have the potential to render a gene dysfunctional or useless. Fortunately, there are mechanisms in place to minimize such mistakes. A DNA proofreading process enlists the help of special enzymes that scan the newly synthesized molecule for mistakes and corrects them. Once the process of DNA replication is complete, the cell is ready to divide. You will explore the process of cell division later in the chapter.', '34062ec2-d57d-4d7c-a3cb-bdd3112b0004': 'Now that you have learned that the cell membrane surrounds all cells, you can dive inside of a prototypical human cell to learn about its internal components and their functions. All living cells in multicellular organisms contain an internal cytoplasmic compartment, and a nucleus within the cytoplasm. Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. Eukaryotic cells, including all animal cells, also contain various cellular organelles. An organelle (“little organ”) is one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. Just as the various bodily organs work together in harmony to perform all of a human’s functions, the many different cellular organelles work together to keep the cell healthy and performing all of its important functions. The organelles and cytosol, taken together, compose the cell’s cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.2.1).'}"
+Figure 3.2.2,Anatomy_And_Physio/images/Figure 3.2.2.jpg,"Figure 3.2.2 – Endoplasmic Reticulum (ER): (a) The ER is a winding network of thin membranous sacs found in close association with the cell nucleus. The smooth and rough endoplasmic reticula are very different in appearance and function (source: mouse tissue). (b) Rough ER is studded with numerous ribosomes, which are sites of protein synthesis (source: mouse tissue, EM × 110,000). (c) Smooth ER synthesizes phospholipids, steroid hormones, regulates the concentration of cellular Ca++, metabolizes some carbohydrates, and breaks down certain toxins (source: mouse tissue, EM × 110,510). (Micrographs provided by the Regents of University of Michigan Medical School © 2012)","The endoplasmic reticulum (ER) is a system of channels that is continuous with the nuclear membrane (or “envelope”) covering the nucleus and composed of the same lipid bilayer material. The ER can be thought of as a series of winding thoroughfares similar to the waterway canals in Venice. The ER provides passages throughout much of the cell that function in transporting, synthesizing, and storing materials. The winding structure of the ER results in a large membranous surface area that supports its many functions (Figure 3.2.2).","{'591ddddc-bcff-4fce-ac3c-bce4c8a4c08d': 'The endoplasmic reticulum (ER) is a system of channels that is continuous with the nuclear membrane (or “envelope”) covering the nucleus and composed of the same lipid bilayer material. The ER can be thought of as a series of winding thoroughfares similar to the waterway canals in Venice. The ER provides passages throughout much of the cell that function in transporting, synthesizing, and storing materials. The winding structure of the ER results in a large membranous surface area that supports its many functions (Figure 3.2.2).', 'ce99ba0c-28cb-4a39-ba38-4b726b0db653': 'Endoplasmic reticulum can exist in two forms: rough ER and smooth ER. These two types of ER perform some very different functions and can be found in very different amounts depending on the type of cell. Rough ER (RER) is so-called because its membrane is dotted with embedded granules—organelles called ribosomes, giving the RER a bumpy appearance. A ribosome is an organelle that serves as the site of protein synthesis. It is composed of two ribosomal RNA subunits that wrap around mRNA to start the process of translation, followed by protein synthesis. Smooth ER (SER) lacks these ribosomes.', 'b63ee12e-4a97-41d7-a008-7ae5e57538b9': 'One of the main functions of the smooth ER is in the synthesis of lipids. The smooth ER synthesizes phospholipids, the main component of biological membranes, as well as steroid hormones. For this reason, cells that produce large quantities of such hormones, such as those of the female ovaries and male testes, contain large amounts of smooth ER. In addition to lipid synthesis, the smooth ER also sequesters (i.e., stores) and regulates the concentration of cellular Ca++, a function extremely important in cells of the nervous system where Ca++ is the trigger for neurotransmitter release. The smooth ER additionally metabolizes some carbohydrates and performs a detoxification role, breaking down certain toxins.', 'f9df5283-2e07-4906-b568-fd8568d65f67': 'In contrast with the smooth ER, the primary job of the rough ER is the synthesis and modification of proteins destined for the cell membrane or for export from the cell. For this protein synthesis, many ribosomes attach to the ER (giving it the studded appearance of rough ER). Typically, a protein is synthesized within the ribosome and released inside the channel of the rough ER, where sugars can be added to it (by a process called glycosylation) before it is transported within a vesicle to the next stage in the packaging and shipping process: the Golgi apparatus.'}"
+Figure 3.2.4,Anatomy_And_Physio/images/Figure 3.2.4.jpg,"Figure 3.2.4 – Mitochondrion: The mitochondria are the energy-conversion factories of the cell. (a) A mitochondrion is composed of two separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell’s major energy currency. (b) An electron micrograph of mitochondria (EM × 236,000). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)","A mitochondrion (plural = mitochondria) is a membranous, bean-shaped organelle that is the “energy transformer” of the cell. Mitochondria consist of an outer lipid bilayer membrane as well as an additional inner lipid bilayer membrane (Figure 3.2.4). The inner membrane is highly folded into winding structures with a great deal of surface area, called cristae. It is along this inner membrane that a series of proteins, enzymes, and other molecules perform the biochemical reactions of cellular respiration. These reactions convert energy stored in nutrient molecules (such as glucose) into adenosine triphosphate (ATP), which provides usable cellular energy to the cell. Cells use ATP constantly, and so the mitochondria are constantly at work. Oxygen molecules are required during cellular respiration, which is why you must constantly breathe it in. One of the organ systems in the body that uses huge amounts of ATP is the muscular system because ATP is required to sustain muscle contraction. As a result, muscle cells are packed full of mitochondria. Nerve cells also need large quantities of ATP to run their sodium-potassium pumps. Therefore, an individual neuron will be loaded with over a thousand mitochondria. On the other hand, a bone cell, which is not nearly as metabolically-active, might only have a couple hundred mitochondria.","{'9c9dd03e-b29d-484f-91ae-1e553404f69c': 'A mitochondrion (plural = mitochondria) is a membranous, bean-shaped organelle that is the “energy transformer” of the cell. Mitochondria consist of an outer lipid bilayer membrane as well as an additional inner lipid bilayer membrane (Figure 3.2.4). The inner membrane is highly folded into winding structures with a great deal of surface area, called cristae. It is along this inner membrane that a series of proteins, enzymes, and other molecules perform the biochemical reactions of cellular respiration. These reactions convert energy stored in nutrient molecules (such as glucose) into adenosine triphosphate (ATP), which provides usable cellular energy to the cell. Cells use ATP constantly, and so the mitochondria are constantly at work. Oxygen molecules are required during cellular respiration, which is why you must constantly breathe it in. One of the organ systems in the body that uses huge amounts of ATP is the muscular system because ATP is required to sustain muscle contraction. As a result, muscle cells are packed full of mitochondria. Nerve cells also need large quantities of ATP to run their sodium-potassium pumps. Therefore, an individual neuron will be loaded with over a thousand mitochondria. On the other hand, a bone cell, which is not nearly as metabolically-active, might only have a couple hundred mitochondria.'}"
+Figure 3.2.5,Anatomy_And_Physio/images/Figure 3.2.5.jpg,Figure 3.2.5 – Peroxisome: Peroxisomes are membrane-bound organelles that contain an abundance of enzymes for detoxifying harmful substances and lipid metabolism.,"Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.","{'56774be0-1a8e-4a24-a373-61317ab4caf7': 'Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.', '013f9b4b-8172-47fb-b1b3-91df9261d7ba': 'Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (O2−). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.\n\nPeroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but also contain enzymes that convert H2O2 into water and oxygen. These byproducts are safely released into the cytoplasm. Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells. The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.\n\nDefense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties. Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.\n\nOxidative stress is the term used to describe damage to cellular components caused by ROS. Due to their distinctive unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive; they do the same to other molecules, causing a chain reaction. ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. Damaged DNA can lead to genetic mutations and even cancer. A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene. Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.', '7401e79b-3ac2-4de5-b644-e1074b36d144': 'The Cytoskeleton\n\nMuch like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.\n\nThe cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.', 'bd291edf-f894-4d99-9f4a-2ef067f481f7': 'A very important function of microtubules is to set the paths (somewhat like railroad tracks) along where the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.', '90515d56-94db-482d-8fc7-b0c428e138ec': 'In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.2.6b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.', 'a9944193-94ff-4059-8912-a5d9eb728a13': 'Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.', '76043244-a898-4a0d-a7de-40f55e4bde62': 'The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.2.6c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.'}"
+Figure 3.2.6,Anatomy_And_Physio/images/Figure 3.2.6.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division.","The Cytoskeleton
+
+Much like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.
+
+The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.","{'56774be0-1a8e-4a24-a373-61317ab4caf7': 'Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.', '013f9b4b-8172-47fb-b1b3-91df9261d7ba': 'Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (O2−). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.\n\nPeroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but also contain enzymes that convert H2O2 into water and oxygen. These byproducts are safely released into the cytoplasm. Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells. The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.\n\nDefense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties. Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.\n\nOxidative stress is the term used to describe damage to cellular components caused by ROS. Due to their distinctive unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive; they do the same to other molecules, causing a chain reaction. ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. Damaged DNA can lead to genetic mutations and even cancer. A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene. Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.', '7401e79b-3ac2-4de5-b644-e1074b36d144': 'The Cytoskeleton\n\nMuch like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.\n\nThe cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.', 'bd291edf-f894-4d99-9f4a-2ef067f481f7': 'A very important function of microtubules is to set the paths (somewhat like railroad tracks) along where the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.', '90515d56-94db-482d-8fc7-b0c428e138ec': 'In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.2.6b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.', 'a9944193-94ff-4059-8912-a5d9eb728a13': 'Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.', '76043244-a898-4a0d-a7de-40f55e4bde62': 'The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.2.6c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.'}"
+Figure 3.2.6,Anatomy_And_Physio/images/Figure 3.2.6.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division.","The Cytoskeleton
+
+Much like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.
+
+The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.","{'56774be0-1a8e-4a24-a373-61317ab4caf7': 'Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.', '013f9b4b-8172-47fb-b1b3-91df9261d7ba': 'Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (O2−). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.\n\nPeroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but also contain enzymes that convert H2O2 into water and oxygen. These byproducts are safely released into the cytoplasm. Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells. The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.\n\nDefense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties. Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.\n\nOxidative stress is the term used to describe damage to cellular components caused by ROS. Due to their distinctive unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive; they do the same to other molecules, causing a chain reaction. ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. Damaged DNA can lead to genetic mutations and even cancer. A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene. Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.', '7401e79b-3ac2-4de5-b644-e1074b36d144': 'The Cytoskeleton\n\nMuch like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.\n\nThe cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.', 'bd291edf-f894-4d99-9f4a-2ef067f481f7': 'A very important function of microtubules is to set the paths (somewhat like railroad tracks) along where the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.', '90515d56-94db-482d-8fc7-b0c428e138ec': 'In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.2.6b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.', 'a9944193-94ff-4059-8912-a5d9eb728a13': 'Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.', '76043244-a898-4a0d-a7de-40f55e4bde62': 'The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.2.6c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.'}"
+Figure 3.2.6,Anatomy_And_Physio/images/Figure 3.2.6.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division.","The Cytoskeleton
+
+Much like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.
+
+The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.","{'56774be0-1a8e-4a24-a373-61317ab4caf7': 'Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.', '013f9b4b-8172-47fb-b1b3-91df9261d7ba': 'Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (O2−). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.\n\nPeroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but also contain enzymes that convert H2O2 into water and oxygen. These byproducts are safely released into the cytoplasm. Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells. The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.\n\nDefense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties. Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.\n\nOxidative stress is the term used to describe damage to cellular components caused by ROS. Due to their distinctive unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive; they do the same to other molecules, causing a chain reaction. ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. Damaged DNA can lead to genetic mutations and even cancer. A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene. Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.', '7401e79b-3ac2-4de5-b644-e1074b36d144': 'The Cytoskeleton\n\nMuch like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.\n\nThe cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.', 'bd291edf-f894-4d99-9f4a-2ef067f481f7': 'A very important function of microtubules is to set the paths (somewhat like railroad tracks) along where the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.', '90515d56-94db-482d-8fc7-b0c428e138ec': 'In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.2.6b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.', 'a9944193-94ff-4059-8912-a5d9eb728a13': 'Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.', '76043244-a898-4a0d-a7de-40f55e4bde62': 'The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.2.6c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.'}"
+Figure 3.1.1,Anatomy_And_Physio/images/Figure 3.1.1.jpg,"Figure 3.1.1 – Phospholipid Structure and Bilayer: A phospholipid molecule consists of a polar phosphate “head,” which is hydrophilic and a non-polar lipid “tail,” which is hydrophobic. Unsaturated fatty acids result in kinks in the hydrophobic tails. The phospholipid bilayer consists of two adjacent sheets of phospholipids, arranged tail to tail. The hydrophobic tails associate with one another, forming the interior of the membrane. The polar heads contact the fluid inside and outside of the cell.","A single phospholipid molecule has a phosphate group on one end, called the “head,” and two side-by-side chains of fatty acids that make up the lipid “tails” (Figure 3.1.1). The lipid tails of one layer face the lipid tails of the other layer, meeting at the interface of the two layers. The phospholipid heads face outward, one layer exposed to the interior of the cell and one layer exposed to the exterior (Figure 3.1.1).","{'4b556f1f-0a59-4e61-8e07-cbb9b5e3626a': 'The cell membrane is an extremely pliable structure composed primarily of two layers of phospholipids (a “bilayer”). Cholesterol and various proteins are also embedded within the membrane giving the membrane a variety of functions described below.', '4d1ea911-5bdf-46e4-98e0-2d594accc618': 'A single phospholipid molecule has a phosphate group on one end, called the “head,” and two side-by-side chains of fatty acids that make up the lipid “tails” (Figure 3.1.1). The lipid tails of one layer face the lipid tails of the other layer, meeting at the interface of the two layers. The phospholipid heads face outward, one layer exposed to the interior of the cell and one layer exposed to the exterior (Figure 3.1.1).', '9f80a617-f594-4b85-8a91-98a38a87cc25': 'The phosphate group is negatively charged, making the head polar and hydrophilic—or “water loving.” A hydrophilic molecule (or region of a molecule) is one that is attracted to water. The phosphate heads are thus attracted to the water molecules of both the extracellular and intracellular environments. The lipid tails, on the other hand, are uncharged, or nonpolar, and are hydrophobic—or “water fearing.” A hydrophobic molecule (or region of a molecule) repels and is repelled by water. Phospholipids are thus amphipathic molecules. An amphipathic molecule is one that contains both a hydrophilic and a hydrophobic region. In fact, soap works to remove oil and grease stains because it has amphipathic properties. The hydrophilic portion can dissolve in the wash water while the hydrophobic portion can trap grease in stains that then can be washed away. A similar process occurs in your digestive system when bile salts (made from cholesterol, phospholipids and salt) help to break up ingested lipids.', '6f611561-802f-4ba5-bd8f-01a1357a60e7': 'Since the phosphate groups are polar and hydrophilic, they are attracted to water in the intracellular fluid. Intracellular fluid (ICF) is the fluid interior of the cell. The phosphate groups are also attracted to the extracellular fluid. Extracellular fluid (ECF) is the fluid environment outside the enclosure of the cell membrane (see above Figure). Since the lipid tails are hydrophobic, they meet in the inner region of the membrane, excluding watery intracellular and extracellular fluid from this space. In addition to phospholipids and cholesterol, the cell membrane has many proteins detailed in the next section.'}"
+Figure 3.1.2,Anatomy_And_Physio/images/Figure 3.1.2.jpg,"Figure 3.1.2- Cell Membrane:  The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrate groups attached.","The lipid bilayer forms the basis of the cell membrane, but it is peppered throughout with various proteins. Two different types of proteins that are commonly associated with the cell membrane are the integral protein and peripheral protein (Figure 3.1.2). As its name suggests, an integral protein is a protein that is embedded in the membrane. Many different types of integral proteins exist, each with different functions. For example, an integral protein that extends an opening through the membrane for ions to enter or exit the cell is known as a channel protein. Peripheral proteins are typically found on the inner or outer surface of the lipid bilayer but can also be attached to the internal or external surface of an integral protein.","{'7ae9b4c5-b7ef-4c37-a54a-24a06a64d466': 'The lipid bilayer forms the basis of the cell membrane, but it is peppered throughout with various proteins. Two different types of proteins that are commonly associated with the cell membrane are the integral protein and peripheral protein (Figure 3.1.2). As its name suggests, an integral protein is a protein that is embedded in the membrane. Many different types of integral proteins exist, each with different functions. For example, an integral protein that extends an opening through the membrane for ions to enter or exit the cell is known as a channel protein. Peripheral proteins are typically found on the inner or outer surface of the lipid bilayer but can also be attached to the internal or external surface of an integral protein.', 'ab518e89-05b3-47ea-9de4-8a1a3d8d014c': 'Some integral proteins serve as cell recognition or surface identity proteins, which mark a cell’s identity so that it can be recognized by other cells. Some integral proteins act as enzymes, or in cell adhesion, between neighboring cells. A receptor is a type of recognition protein that can selectively bind a specific molecule outside the cell, and this binding induces a chemical reaction within the cell. Some integral proteins serve dual roles as both a receptor and an ion channel. One example of a receptor-channel interaction is the receptors on nerve cells that bind neurotransmitters, such as dopamine. When a dopamine molecule binds to a dopamine receptor protein, a channel within the transmembrane protein opens to allow certain ions to flow into the cell. Peripheral proteins are often associated with integral proteins along the inner cell membrane where they play a role in cell signaling or anchoring to internal cellular components (ie: cytoskeleton discussed later).', '8ed327e9-f602-4e8e-b279-f40852305dec': 'Some integral membrane proteins are glycoproteins. A glycoprotein is a protein that has carbohydrate molecules attached, which extend into the extracellular environment. The attached carbohydrate tags on glycoproteins aid in cell recognition. The carbohydrates that extend from membrane proteins and even from some membrane lipids collectively form the glycocalyx. The glycocalyx is a fuzzy-appearing coating around the cell formed from glycoproteins and other carbohydrates attached to the cell membrane. The glycocalyx can have various roles. For example, it may have molecules that allow the cell to bind to another cell, it may contain receptors for hormones, or it might have enzymes to break down nutrients. The glycocalyces found in a person’s body are products of that person’s genetic makeup. They give each of the individual’s trillions of cells the “identity” of belonging in the person’s body. This identity is the primary way that a person’s immune defense cells “know” not to attack the person’s own body cells, but it also is the reason organs donated by another person might be rejected.'}"
+Figure 3.1.3,Anatomy_And_Physio/images/Figure 3.1.3.jpg,"Figure 3.1.3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.","Before moving on, it is important to realize that the concentration gradients for oxygen and carbon dioxide will always exist across a living cell and never reach equal distribution. This is because cells rapidly use up oxygen during metabolism and so, there is typically a lower concentration of O2 inside the cell than outside. As a result, oxygen will diffuse from outside the cell directly through the lipid bilayer of the membrane and into the cytoplasm within the cell. On the other hand, because cells produce CO2 as a byproduct of metabolism, CO2 concentrations rise within the cytoplasm; therefore, CO2 will move from the cell through the lipid bilayer and into the extracellular fluid, where its concentration is lower. (Figure 3.1.3).","{'e5527054-d280-45f9-be22-2e7893caab5b': 'In order to understand how substances move passively across a cell membrane, it is necessary to understand concentration gradients and diffusion. A concentration gradient is the difference in concentration of a substance across a space. Molecules (or ions) will spread/diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space. (When molecules move in this way, they are said to move down their concentration gradient, from high concentration to low concentration.) Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. A couple of common examples will help to illustrate this concept. Imagine being inside a closed room. If a bottle of perfume were sprayed, the scent molecules would naturally diffuse from the spot where they left the bottle to all corners of the room, and this diffusion would go on until the molecules were equally distributed in the room. Another example is a spoonful of sugar placed in a cup of tea. Eventually the sugar will diffuse throughout the tea until no concentration gradient remains. In both cases, if the room is warmer or the tea hotter, diffusion occurs even faster as the molecules are bumping into each other and spreading out faster than at cooler temperatures.', 'a3006b94-266d-4544-99e4-6c610d9e6e9b': 'Whenever a substance exists in greater concentration on one side of a semipermeable membrane, such as cell membranes, any substance that can move down its concentration gradient across the membrane will do so. If the substances can move across the cell membrane without the cell expending energy, the movement of molecules is called passive transport. Consider substances that can easily diffuse through the lipid bilayer of the cell membrane, such as the gases oxygen (O2) and carbon dioxide (CO2). These small, fat soluble gasses and other small lipid soluble molecules can dissolve in the membrane and enter or exit the cell following their concentration gradient. This mechanism of molecules moving across a cell membrane from the side where they are more concentrated to the side where they are less concentrated is a form of passive transport called simple diffusion. O2 generally diffuses into cells because it is more concentrated outside of them, and CO2 typically diffuses out of cells because it is more concentrated inside of them.', '9ba1a9f6-e278-4a2a-814c-336846f5d765': 'Before moving on, it is important to realize that the concentration gradients for oxygen and carbon dioxide will always exist across a living cell and never reach equal distribution. This is because cells rapidly use up oxygen during metabolism and so, there is typically a lower concentration of O2 inside the cell than outside. As a result, oxygen will diffuse from outside the cell directly through the lipid bilayer of the membrane and into the cytoplasm within the cell. On the other hand, because cells produce CO2 as a byproduct of metabolism, CO2 concentrations rise within the cytoplasm; therefore, CO2 will move from the cell through the lipid bilayer and into the extracellular fluid, where its concentration is lower. (Figure 3.1.3).', 'cd7e17d4-d5c9-45e0-be22-23dbfd1c687d': 'Large polar or ionic molecules, which are hydrophilic, cannot easily cross the phospholipid bilayer. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer. Solutes dissolved in water on either side of the cell membrane will tend to diffuse down their concentration gradients, but because most substances cannot pass freely through the lipid bilayer of the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane. Facilitated diffusion is the diffusion process used for those substances that cannot cross the lipid bilayer due to their size, charge, and/or polarity but do so down their concentration gradients (Figure 3.1.4). As an example, even though sodium ions (Na+) are highly concentrated outside of cells, these electrolytes are charged and cannot pass through the nonpolar lipid bilayer of the membrane. Their diffusion is facilitated by membrane proteins that form sodium channels (or “pores”), so that Na+ ions can move down their concentration gradient from outside the cells to inside the cells. \xa0A common example of facilitated diffusion using a carrier protein is the movement of glucose into the cell, where it is used to make ATP. Although glucose can be more concentrated outside of a cell, it cannot cross the lipid bilayer via simple diffusion because it is both large and polar, and therefore, repelled by the phospholipid membrane. To resolve this, a specialized carrier protein called the glucose transporter will transfer glucose molecules into the cell to facilitate its inward diffusion. The difference between a channel and a carrier is that the carrier usually changes shape during the diffusion process, while the channel does not. There are many other solutes that must undergo facilitated diffusion to move into a cell, such as amino acids, or to move out of a cell, such as wastes.'}"
+Figure 3.1.4,Anatomy_And_Physio/images/Figure 3.1.4.jpg,"Figure 3.1.4 – Facilitated Diffusion: (a) Facilitated diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carrier proteins. Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. (b) Carrier proteins are more selective, often only allowing one particular type of molecule to cross.","Large polar or ionic molecules, which are hydrophilic, cannot easily cross the phospholipid bilayer. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer. Solutes dissolved in water on either side of the cell membrane will tend to diffuse down their concentration gradients, but because most substances cannot pass freely through the lipid bilayer of the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane. Facilitated diffusion is the diffusion process used for those substances that cannot cross the lipid bilayer due to their size, charge, and/or polarity but do so down their concentration gradients (Figure 3.1.4). As an example, even though sodium ions (Na+) are highly concentrated outside of cells, these electrolytes are charged and cannot pass through the nonpolar lipid bilayer of the membrane. Their diffusion is facilitated by membrane proteins that form sodium channels (or “pores”), so that Na+ ions can move down their concentration gradient from outside the cells to inside the cells.  A common example of facilitated diffusion using a carrier protein is the movement of glucose into the cell, where it is used to make ATP. Although glucose can be more concentrated outside of a cell, it cannot cross the lipid bilayer via simple diffusion because it is both large and polar, and therefore, repelled by the phospholipid membrane. To resolve this, a specialized carrier protein called the glucose transporter will transfer glucose molecules into the cell to facilitate its inward diffusion. The difference between a channel and a carrier is that the carrier usually changes shape during the diffusion process, while the channel does not. There are many other solutes that must undergo facilitated diffusion to move into a cell, such as amino acids, or to move out of a cell, such as wastes.","{'e5527054-d280-45f9-be22-2e7893caab5b': 'In order to understand how substances move passively across a cell membrane, it is necessary to understand concentration gradients and diffusion. A concentration gradient is the difference in concentration of a substance across a space. Molecules (or ions) will spread/diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space. (When molecules move in this way, they are said to move down their concentration gradient, from high concentration to low concentration.) Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. A couple of common examples will help to illustrate this concept. Imagine being inside a closed room. If a bottle of perfume were sprayed, the scent molecules would naturally diffuse from the spot where they left the bottle to all corners of the room, and this diffusion would go on until the molecules were equally distributed in the room. Another example is a spoonful of sugar placed in a cup of tea. Eventually the sugar will diffuse throughout the tea until no concentration gradient remains. In both cases, if the room is warmer or the tea hotter, diffusion occurs even faster as the molecules are bumping into each other and spreading out faster than at cooler temperatures.', 'a3006b94-266d-4544-99e4-6c610d9e6e9b': 'Whenever a substance exists in greater concentration on one side of a semipermeable membrane, such as cell membranes, any substance that can move down its concentration gradient across the membrane will do so. If the substances can move across the cell membrane without the cell expending energy, the movement of molecules is called passive transport. Consider substances that can easily diffuse through the lipid bilayer of the cell membrane, such as the gases oxygen (O2) and carbon dioxide (CO2). These small, fat soluble gasses and other small lipid soluble molecules can dissolve in the membrane and enter or exit the cell following their concentration gradient. This mechanism of molecules moving across a cell membrane from the side where they are more concentrated to the side where they are less concentrated is a form of passive transport called simple diffusion. O2 generally diffuses into cells because it is more concentrated outside of them, and CO2 typically diffuses out of cells because it is more concentrated inside of them.', '9ba1a9f6-e278-4a2a-814c-336846f5d765': 'Before moving on, it is important to realize that the concentration gradients for oxygen and carbon dioxide will always exist across a living cell and never reach equal distribution. This is because cells rapidly use up oxygen during metabolism and so, there is typically a lower concentration of O2 inside the cell than outside. As a result, oxygen will diffuse from outside the cell directly through the lipid bilayer of the membrane and into the cytoplasm within the cell. On the other hand, because cells produce CO2 as a byproduct of metabolism, CO2 concentrations rise within the cytoplasm; therefore, CO2 will move from the cell through the lipid bilayer and into the extracellular fluid, where its concentration is lower. (Figure 3.1.3).', 'cd7e17d4-d5c9-45e0-be22-23dbfd1c687d': 'Large polar or ionic molecules, which are hydrophilic, cannot easily cross the phospholipid bilayer. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer. Solutes dissolved in water on either side of the cell membrane will tend to diffuse down their concentration gradients, but because most substances cannot pass freely through the lipid bilayer of the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane. Facilitated diffusion is the diffusion process used for those substances that cannot cross the lipid bilayer due to their size, charge, and/or polarity but do so down their concentration gradients (Figure 3.1.4). As an example, even though sodium ions (Na+) are highly concentrated outside of cells, these electrolytes are charged and cannot pass through the nonpolar lipid bilayer of the membrane. Their diffusion is facilitated by membrane proteins that form sodium channels (or “pores”), so that Na+ ions can move down their concentration gradient from outside the cells to inside the cells. \xa0A common example of facilitated diffusion using a carrier protein is the movement of glucose into the cell, where it is used to make ATP. Although glucose can be more concentrated outside of a cell, it cannot cross the lipid bilayer via simple diffusion because it is both large and polar, and therefore, repelled by the phospholipid membrane. To resolve this, a specialized carrier protein called the glucose transporter will transfer glucose molecules into the cell to facilitate its inward diffusion. The difference between a channel and a carrier is that the carrier usually changes shape during the diffusion process, while the channel does not. There are many other solutes that must undergo facilitated diffusion to move into a cell, such as amino acids, or to move out of a cell, such as wastes.'}"
+Figure 3.1.5,Anatomy_And_Physio/images/Figure 3.1.5.jpg,"Figure 3.1.5 – Osmosis: Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic.","A specialized example of facilitated transport is water moving across the cell membrane of all cells, through protein channels known as aquaporins. Osmosis is the diffusion of water through a semipermeable membrane from where there is more relative water to where there is less relative water (down its water concentration gradient) (Figure 3.1.5).","{'5d8a6ee4-b0ba-454c-8d9e-b99ea76750f5': 'A specialized example of facilitated transport is water moving across the cell membrane of all cells, through protein channels known as aquaporins. Osmosis is the diffusion of water through a semipermeable membrane from where there is more relative water to where there is less relative water (down its water concentration gradient) (Figure 3.1.5).', '396d0ef5-7357-43ff-8b0d-3c5fa2753dea': 'On their own, cells cannot regulate the movement of water molecules across their membrane, so it is important that cells are exposed to an environment in which the concentration of solutes outside of the cells (in the extracellular fluid) is equal to the concentration of solutes inside the cells (in the cytoplasm). Two solutions that have the same concentration of solutes are said to be isotonic (equal tension). When cells and their extracellular environments are isotonic, the concentration of water molecules is the same outside and inside the cells, and the cells maintain their normal shape (and function).', 'ec321808-a5ab-4860-892e-ce216bf70d3c': 'Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution (Figure 3.1.6). Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution. Cells in a hypotonic solution will take on too much water and swell, with the risk of eventually bursting. A critical aspect of homeostasis in living things is to create an internal environment in which all of the body’s cells are in an isotonic solution. Various organ systems, particularly the kidneys, work to maintain this homeostasis.'}"
+Figure 3.1.6,Anatomy_And_Physio/images/Figure 3.1.6.jpg,Figure 3.1.6 – Concentration of Solution: A hypertonic solution has a solute concentration higher than another solution. An isotonic solution has a solute concentration equal to another solution. A hypotonic solution has a solute concentration lower than another solution.,"Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution (Figure 3.1.6). Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution. Cells in a hypotonic solution will take on too much water and swell, with the risk of eventually bursting. A critical aspect of homeostasis in living things is to create an internal environment in which all of the body’s cells are in an isotonic solution. Various organ systems, particularly the kidneys, work to maintain this homeostasis.","{'5d8a6ee4-b0ba-454c-8d9e-b99ea76750f5': 'A specialized example of facilitated transport is water moving across the cell membrane of all cells, through protein channels known as aquaporins. Osmosis is the diffusion of water through a semipermeable membrane from where there is more relative water to where there is less relative water (down its water concentration gradient) (Figure 3.1.5).', '396d0ef5-7357-43ff-8b0d-3c5fa2753dea': 'On their own, cells cannot regulate the movement of water molecules across their membrane, so it is important that cells are exposed to an environment in which the concentration of solutes outside of the cells (in the extracellular fluid) is equal to the concentration of solutes inside the cells (in the cytoplasm). Two solutions that have the same concentration of solutes are said to be isotonic (equal tension). When cells and their extracellular environments are isotonic, the concentration of water molecules is the same outside and inside the cells, and the cells maintain their normal shape (and function).', 'ec321808-a5ab-4860-892e-ce216bf70d3c': 'Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution (Figure 3.1.6). Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution. Cells in a hypotonic solution will take on too much water and swell, with the risk of eventually bursting. A critical aspect of homeostasis in living things is to create an internal environment in which all of the body’s cells are in an isotonic solution. Various organ systems, particularly the kidneys, work to maintain this homeostasis.'}"
+Figure 3.1.8,Anatomy_And_Physio/images/Figure 3.1.8.jpg,"Figure 3.1.8 – Three Forms of Endocytosis: Endocytosis is a form of active transport in which a cell envelopes extracellular materials using its cell membrane. (a) In phagocytosis, which is relatively nonselective, the cell takes in large particles into larger vesicles known as vacuoles. (b) In pinocytosis, the cell takes in small particles in fluid. (c) In contrast, receptor-mediated endocytosis is quite selective. When external receptors bind a specific ligand, the cell responds by endocytosing the ligand.","Other forms of active transport do not involve membrane carriers. Endocytosis (bringing “into the cell”) is the process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane (Figure 3.1.8). Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. Endocytosis often brings materials into the cell that must to be broken down or digested. Phagocytosis (“cell eating”) is the endocytosis of large particles. Many immune cells engage in phagocytosis of invading pathogens. Like little Pac-men, their job is to patrol body tissues for unwanted matter, such as invading bacterial cells, phagocytize them, and digest them. In contrast to phagocytosis, pinocytosis (“cell drinking”) brings fluid containing dissolved substances into a cell through membrane vesicles.","{'05905a4b-d7ef-48b1-8b62-da289d6eb6af': 'Other forms of active transport do not involve membrane carriers. Endocytosis (bringing “into the cell”) is the process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane (Figure 3.1.8). Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. Endocytosis often brings materials into the cell that must to be broken down or digested. Phagocytosis (“cell eating”) is the endocytosis of large particles. Many immune cells engage in phagocytosis of invading pathogens. Like little Pac-men, their job is to patrol body tissues for unwanted matter, such as invading bacterial cells, phagocytize them, and digest them. In contrast to phagocytosis, pinocytosis (“cell drinking”) brings fluid containing dissolved substances into a cell through membrane vesicles.', '630669b3-ed61-48b2-b77b-ab12297408b0': 'Phagocytosis and pinocytosis take in large portions of extracellular material, and they are typically not highly selective in the substances they bring in. Cells regulate the endocytosis of specific substances via receptor-mediated endocytosis. Receptor-mediated endocytosis is endocytosis by a portion of the cell membrane which contains many receptors that are specific for a certain substance. Once the surface receptors have bound sufficient amounts of the specific substance (the receptor’s ligand), the cell will endocytose the part of the cell membrane containing the receptor-ligand complexes. Iron, a required component of hemoglobin, is endocytosed by red blood cells in this way. Iron is bound to a protein called transferrin in the blood. Specific transferrin receptors on red blood cell surfaces bind the iron-transferrin molecules, and the cell endocytoses the receptor-ligand complexes.', '13d635e0-aae2-40e8-a0ac-7a64d214a0dc': 'In contrast with endocytosis, exocytosis (taking “out of the cell”) is the process of a cell exporting material using vesicular transport (Figure 3.1.9). Many cells manufacture substances that must be secreted, like a factory manufacturing a product for export. These substances are typically packaged into membrane-bound vesicles within the cell. When the vesicle membrane fuses with the cell membrane, the vesicle releases its contents into the interstitial fluid. The vesicle membrane then becomes part of the cell membrane.', '039940cf-1296-464e-aff5-39b5cc3211a8': 'Specific examples of exocytosis include cells of the stomach and pancreas producing and secreting digestive enzymes through exocytosis (Figure 3.1.10) and endocrine cells producing and secreting hormones that are sent throughout the body.', '8f090f7d-63a5-443c-be2c-cc256afa42d9': 'The addition of new membrane to the plasma membrane is usually coupled with endocytosis so that the cell is not constantly enlarging. Through these processes, the cell membrane is constantly renewing and changing as needed by the cell.', 'e88fbfe1-43b6-4c58-84d2-b30bb2d8adc3': 'You developed from a single fertilized egg cell into the complex organism that you see when you look in a mirror, containing trillions of cells. During this developmental process, early, unspecialized cells become specialized in their structure and function (this is known as differentiation). These different cell types join to form specialized tissues that work in concert to perform all of the functions necessary for the living organism. Cellular and developmental biologists study how the continued division of a single cell leads to such complexity and differentiation.', 'e6a2c1bd-4073-46fa-a54d-5364dba0fc4d': 'Consider the difference between a structural cell in the skin and a nerve cell. A structural skin cell may be shaped like a flat plate (squamous) and live only for a short time before it is shed and replaced. Packed tightly into rows and sheets, the squamous skin cells provide a protective barrier for the cells and tissues that lie beneath. A nerve cell, on the other hand, may be shaped something like a star, sending out long processes up to a meter in length and may live for the entire lifetime of the organism. With their long winding appendages, nerve cells can communicate with one another and with other types of body cells and send rapid signals that inform the organism about its environment and allow it to interact with that environment. These differences illustrate one very important theme that is consistent at all organizational levels of biology: the form of a structure is optimally suited to perform particular functions assigned to that structure. Keep this theme in mind as you tour the inside of a cell and are introduced to the various types of cells in the body.', '1e8d1e19-90d9-41b4-b0ed-34d5cd79674d': 'A primary responsibility of each cell is to contribute to homeostasis. Homeostasis is a term used in biology that refers to a dynamic state of balance within parameters that are compatible with life. For example, living cells require a water-based environment to survive in, and there are various physical (anatomical) and physiological mechanisms that keep all of the trillions of living cells in the human body moist. This is one aspect of homeostasis. When a particular parameter, such as blood pressure or blood oxygen content, moves far enough out of homeostasis (generally becoming too high or too low), illness or disease—and sometimes death—inevitably results.', 'ee58bf7a-c34b-44b5-a156-0da95ada0eb6': 'The concept of a cell started with microscopic observations of dead cork tissue by scientist Robert Hooke in 1665. Without realizing their function or importance, Hooke coined the term “cell” based on the resemblance of the small subdivisions in the cork to the rooms that monks inhabited, called cells. About ten years later, Antonie van Leeuwenhoek became the first person to observe living and moving cells under a microscope. In the century that followed, the theory that cells represented the basic unit of life would develop. These tiny fluid-filled sacs house components responsible for the thousands of biochemical reactions necessary for an organism to grow and survive. In this chapter, you will learn about the major components and functions of cells and discover some of the different types of cells in the human body.', '1f2fcfa3-d3d8-4bd8-968a-5f6090b951a4': 'Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, they are found throughout the world, in soils and seas, commercial products, and every cell of the human body. The four types most important to human structure and function are: carbohydrates, lipids, proteins, and nucleotides. Before exploring these compounds, you need to first understand the chemistry of carbon.'}"
+Figure 3.1.9,Anatomy_And_Physio/images/Figure 3.1.9.jpg,"Figure 3.1.9 – Exocytosis: Exocytosis is much like endocytosis in reverse. Material destined for export is packaged into a vesicle inside the cell. The membrane of the vesicle fuses with the cell membrane, and the contents are released into the extracellular space.","In contrast with endocytosis, exocytosis (taking “out of the cell”) is the process of a cell exporting material using vesicular transport (Figure 3.1.9). Many cells manufacture substances that must be secreted, like a factory manufacturing a product for export. These substances are typically packaged into membrane-bound vesicles within the cell. When the vesicle membrane fuses with the cell membrane, the vesicle releases its contents into the interstitial fluid. The vesicle membrane then becomes part of the cell membrane.","{'05905a4b-d7ef-48b1-8b62-da289d6eb6af': 'Other forms of active transport do not involve membrane carriers. Endocytosis (bringing “into the cell”) is the process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane (Figure 3.1.8). Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. Endocytosis often brings materials into the cell that must to be broken down or digested. Phagocytosis (“cell eating”) is the endocytosis of large particles. Many immune cells engage in phagocytosis of invading pathogens. Like little Pac-men, their job is to patrol body tissues for unwanted matter, such as invading bacterial cells, phagocytize them, and digest them. In contrast to phagocytosis, pinocytosis (“cell drinking”) brings fluid containing dissolved substances into a cell through membrane vesicles.', '630669b3-ed61-48b2-b77b-ab12297408b0': 'Phagocytosis and pinocytosis take in large portions of extracellular material, and they are typically not highly selective in the substances they bring in. Cells regulate the endocytosis of specific substances via receptor-mediated endocytosis. Receptor-mediated endocytosis is endocytosis by a portion of the cell membrane which contains many receptors that are specific for a certain substance. Once the surface receptors have bound sufficient amounts of the specific substance (the receptor’s ligand), the cell will endocytose the part of the cell membrane containing the receptor-ligand complexes. Iron, a required component of hemoglobin, is endocytosed by red blood cells in this way. Iron is bound to a protein called transferrin in the blood. Specific transferrin receptors on red blood cell surfaces bind the iron-transferrin molecules, and the cell endocytoses the receptor-ligand complexes.', '13d635e0-aae2-40e8-a0ac-7a64d214a0dc': 'In contrast with endocytosis, exocytosis (taking “out of the cell”) is the process of a cell exporting material using vesicular transport (Figure 3.1.9). Many cells manufacture substances that must be secreted, like a factory manufacturing a product for export. These substances are typically packaged into membrane-bound vesicles within the cell. When the vesicle membrane fuses with the cell membrane, the vesicle releases its contents into the interstitial fluid. The vesicle membrane then becomes part of the cell membrane.', '039940cf-1296-464e-aff5-39b5cc3211a8': 'Specific examples of exocytosis include cells of the stomach and pancreas producing and secreting digestive enzymes through exocytosis (Figure 3.1.10) and endocrine cells producing and secreting hormones that are sent throughout the body.', '8f090f7d-63a5-443c-be2c-cc256afa42d9': 'The addition of new membrane to the plasma membrane is usually coupled with endocytosis so that the cell is not constantly enlarging. Through these processes, the cell membrane is constantly renewing and changing as needed by the cell.', 'e88fbfe1-43b6-4c58-84d2-b30bb2d8adc3': 'You developed from a single fertilized egg cell into the complex organism that you see when you look in a mirror, containing trillions of cells. During this developmental process, early, unspecialized cells become specialized in their structure and function (this is known as differentiation). These different cell types join to form specialized tissues that work in concert to perform all of the functions necessary for the living organism. Cellular and developmental biologists study how the continued division of a single cell leads to such complexity and differentiation.', 'e6a2c1bd-4073-46fa-a54d-5364dba0fc4d': 'Consider the difference between a structural cell in the skin and a nerve cell. A structural skin cell may be shaped like a flat plate (squamous) and live only for a short time before it is shed and replaced. Packed tightly into rows and sheets, the squamous skin cells provide a protective barrier for the cells and tissues that lie beneath. A nerve cell, on the other hand, may be shaped something like a star, sending out long processes up to a meter in length and may live for the entire lifetime of the organism. With their long winding appendages, nerve cells can communicate with one another and with other types of body cells and send rapid signals that inform the organism about its environment and allow it to interact with that environment. These differences illustrate one very important theme that is consistent at all organizational levels of biology: the form of a structure is optimally suited to perform particular functions assigned to that structure. Keep this theme in mind as you tour the inside of a cell and are introduced to the various types of cells in the body.', '1e8d1e19-90d9-41b4-b0ed-34d5cd79674d': 'A primary responsibility of each cell is to contribute to homeostasis. Homeostasis is a term used in biology that refers to a dynamic state of balance within parameters that are compatible with life. For example, living cells require a water-based environment to survive in, and there are various physical (anatomical) and physiological mechanisms that keep all of the trillions of living cells in the human body moist. This is one aspect of homeostasis. When a particular parameter, such as blood pressure or blood oxygen content, moves far enough out of homeostasis (generally becoming too high or too low), illness or disease—and sometimes death—inevitably results.', 'ee58bf7a-c34b-44b5-a156-0da95ada0eb6': 'The concept of a cell started with microscopic observations of dead cork tissue by scientist Robert Hooke in 1665. Without realizing their function or importance, Hooke coined the term “cell” based on the resemblance of the small subdivisions in the cork to the rooms that monks inhabited, called cells. About ten years later, Antonie van Leeuwenhoek became the first person to observe living and moving cells under a microscope. In the century that followed, the theory that cells represented the basic unit of life would develop. These tiny fluid-filled sacs house components responsible for the thousands of biochemical reactions necessary for an organism to grow and survive. In this chapter, you will learn about the major components and functions of cells and discover some of the different types of cells in the human body.', '1f2fcfa3-d3d8-4bd8-968a-5f6090b951a4': 'Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, they are found throughout the world, in soils and seas, commercial products, and every cell of the human body. The four types most important to human structure and function are: carbohydrates, lipids, proteins, and nucleotides. Before exploring these compounds, you need to first understand the chemistry of carbon.'}"
+Figure 3.1.10,Anatomy_And_Physio/images/Figure 3.1.10.jpg,Figure 3.1.10 – Pancreatic Cells’ Enzyme Products: The pancreatic acinar cells produce and secrete many enzymes that digest food. The tiny black granules in this electron micrograph are secretory vesicles filled with enzymes that will be exported from the cells via exocytosis. LM × 2900. (Micrograph provided by the Regents of University of Michigan Medical School © 2012),Specific examples of exocytosis include cells of the stomach and pancreas producing and secreting digestive enzymes through exocytosis (Figure 3.1.10) and endocrine cells producing and secreting hormones that are sent throughout the body.,"{'05905a4b-d7ef-48b1-8b62-da289d6eb6af': 'Other forms of active transport do not involve membrane carriers. Endocytosis (bringing “into the cell”) is the process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane (Figure 3.1.8). Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. Endocytosis often brings materials into the cell that must to be broken down or digested. Phagocytosis (“cell eating”) is the endocytosis of large particles. Many immune cells engage in phagocytosis of invading pathogens. Like little Pac-men, their job is to patrol body tissues for unwanted matter, such as invading bacterial cells, phagocytize them, and digest them. In contrast to phagocytosis, pinocytosis (“cell drinking”) brings fluid containing dissolved substances into a cell through membrane vesicles.', '630669b3-ed61-48b2-b77b-ab12297408b0': 'Phagocytosis and pinocytosis take in large portions of extracellular material, and they are typically not highly selective in the substances they bring in. Cells regulate the endocytosis of specific substances via receptor-mediated endocytosis. Receptor-mediated endocytosis is endocytosis by a portion of the cell membrane which contains many receptors that are specific for a certain substance. Once the surface receptors have bound sufficient amounts of the specific substance (the receptor’s ligand), the cell will endocytose the part of the cell membrane containing the receptor-ligand complexes. Iron, a required component of hemoglobin, is endocytosed by red blood cells in this way. Iron is bound to a protein called transferrin in the blood. Specific transferrin receptors on red blood cell surfaces bind the iron-transferrin molecules, and the cell endocytoses the receptor-ligand complexes.', '13d635e0-aae2-40e8-a0ac-7a64d214a0dc': 'In contrast with endocytosis, exocytosis (taking “out of the cell”) is the process of a cell exporting material using vesicular transport (Figure 3.1.9). Many cells manufacture substances that must be secreted, like a factory manufacturing a product for export. These substances are typically packaged into membrane-bound vesicles within the cell. When the vesicle membrane fuses with the cell membrane, the vesicle releases its contents into the interstitial fluid. The vesicle membrane then becomes part of the cell membrane.', '039940cf-1296-464e-aff5-39b5cc3211a8': 'Specific examples of exocytosis include cells of the stomach and pancreas producing and secreting digestive enzymes through exocytosis (Figure 3.1.10) and endocrine cells producing and secreting hormones that are sent throughout the body.', '8f090f7d-63a5-443c-be2c-cc256afa42d9': 'The addition of new membrane to the plasma membrane is usually coupled with endocytosis so that the cell is not constantly enlarging. Through these processes, the cell membrane is constantly renewing and changing as needed by the cell.', 'e88fbfe1-43b6-4c58-84d2-b30bb2d8adc3': 'You developed from a single fertilized egg cell into the complex organism that you see when you look in a mirror, containing trillions of cells. During this developmental process, early, unspecialized cells become specialized in their structure and function (this is known as differentiation). These different cell types join to form specialized tissues that work in concert to perform all of the functions necessary for the living organism. Cellular and developmental biologists study how the continued division of a single cell leads to such complexity and differentiation.', 'e6a2c1bd-4073-46fa-a54d-5364dba0fc4d': 'Consider the difference between a structural cell in the skin and a nerve cell. A structural skin cell may be shaped like a flat plate (squamous) and live only for a short time before it is shed and replaced. Packed tightly into rows and sheets, the squamous skin cells provide a protective barrier for the cells and tissues that lie beneath. A nerve cell, on the other hand, may be shaped something like a star, sending out long processes up to a meter in length and may live for the entire lifetime of the organism. With their long winding appendages, nerve cells can communicate with one another and with other types of body cells and send rapid signals that inform the organism about its environment and allow it to interact with that environment. These differences illustrate one very important theme that is consistent at all organizational levels of biology: the form of a structure is optimally suited to perform particular functions assigned to that structure. Keep this theme in mind as you tour the inside of a cell and are introduced to the various types of cells in the body.', '1e8d1e19-90d9-41b4-b0ed-34d5cd79674d': 'A primary responsibility of each cell is to contribute to homeostasis. Homeostasis is a term used in biology that refers to a dynamic state of balance within parameters that are compatible with life. For example, living cells require a water-based environment to survive in, and there are various physical (anatomical) and physiological mechanisms that keep all of the trillions of living cells in the human body moist. This is one aspect of homeostasis. When a particular parameter, such as blood pressure or blood oxygen content, moves far enough out of homeostasis (generally becoming too high or too low), illness or disease—and sometimes death—inevitably results.', 'ee58bf7a-c34b-44b5-a156-0da95ada0eb6': 'The concept of a cell started with microscopic observations of dead cork tissue by scientist Robert Hooke in 1665. Without realizing their function or importance, Hooke coined the term “cell” based on the resemblance of the small subdivisions in the cork to the rooms that monks inhabited, called cells. About ten years later, Antonie van Leeuwenhoek became the first person to observe living and moving cells under a microscope. In the century that followed, the theory that cells represented the basic unit of life would develop. These tiny fluid-filled sacs house components responsible for the thousands of biochemical reactions necessary for an organism to grow and survive. In this chapter, you will learn about the major components and functions of cells and discover some of the different types of cells in the human body.', '1f2fcfa3-d3d8-4bd8-968a-5f6090b951a4': 'Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, they are found throughout the world, in soils and seas, commercial products, and every cell of the human body. The four types most important to human structure and function are: carbohydrates, lipids, proteins, and nucleotides. Before exploring these compounds, you need to first understand the chemistry of carbon.'}"
+Figure 2.4.1,Anatomy_And_Physio/images/Figure 2.4.1.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water.","Monomers form polymers by engaging in dehydration synthesis (see Figure 2.4.1). As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes; one gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis (-lysis = “rupture”). The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.","{'fc5a063f-bc4e-418d-8f95-b32042a082db': 'What makes organic compounds ubiquitous is the chemistry of their carbon core. Recall that carbon atoms have four electrons in their valence shell, and that the octet rule dictates that atoms tend to react in such a way as to complete their valence shell with eight electrons. Carbon atoms do not complete their valence shells by donating or accepting four electrons. Instead, they readily share electrons via covalent bonds.', '09a35eed-09ce-4a52-9c85-7fd34d0d47d1': 'Normally, carbon atoms share with other carbon atoms, often forming a long carbon chain referred to as a carbon skeleton. When they share, however, they do not share all their electrons exclusively with each other. Rather, carbon atoms tend to share electrons with a variety of other elements, one of which is always hydrogen. Carbon and hydrogen groupings are called hydrocarbons. If you study the figures of organic compounds in the remainder of this chapter, you will see several with chains of hydrocarbons in one region of the compound.', '6ed03df1-ee8a-4850-9446-70c01231639d': 'Many combinations are possible to fill carbon’s four “vacancies.” Carbon may share electrons with oxygen or nitrogen or other atoms in a particular region of an organic compound. Moreover, the atoms to which carbon atoms bond may also be part of a functional group. A functional group is a group of atoms linked by strong covalent bonds and tend to function in chemical reactions as a single unit. You can think of functional groups as tightly knit “cliques” whose members are unlikely to be parted. Five functional groups are important in human physiology: the hydroxyl, carboxyl, amino, methyl and phosphate groups (Table 2.1).', 'e3122472-c7fc-47de-8a09-f0d3678d91e6': 'Carbon’s affinity for covalent bonding means that many distinct and relatively stable organic molecules readily form larger, more complex molecules. Any large molecule is referred to as macromolecule (macro- = “large”), and the organic compounds in this section all fit this description. However, some macromolecules are made up of several “copies” of single units called monomer (mono- = “one”; -mer = “part”). Like beads in a long necklace, these monomers link by covalent bonds to form long polymers (poly- = “many”). There are many examples of monomers and polymers among the organic compounds.', '951af231-0bf0-43e1-baa7-7fb0a9a78e69': 'Monomers form polymers by engaging in dehydration synthesis (see Figure 2.4.1). As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes; one gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis (-lysis = “rupture”). The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.', 'aca7be7c-fbcb-4981-81fd-759a06d72906': 'Two types of chemical reactions involve the creation or the consumption of water: dehydration synthesis and hydrolysis.', '2758d534-6987-4f43-8a10-66caa2ae9490': 'In dehydration synthesis, one reactant gives up an atom of hydrogen and another reactant gives up a hydroxyl group (OH) in the synthesis of a new product. In the formation of their covalent bond, a molecule of water is released as a byproduct (Figure 2.4.1). This is also sometimes referred to as a condensation reaction.', 'f22bc758-65c8-4b37-b0d1-5a694e5ad5de': 'In hydrolysis, a molecule of water disrupts a compound, breaking its bonds. The water is itself split into H and OH. One portion of the severed compound then bonds with the hydrogen atom, and the other portion bonds with the hydroxyl group.', 'd3b0e853-7013-4a41-afca-0efb311a8e2b': 'These reactions are reversible, and play an important role in the chemistry of organic compounds (which will be discussed shortly).'}"
+Figure 2.5.1,Anatomy_And_Physio/images/Figure 2.5.1.jpg,Figure 2.5.1 Five Important Monosaccharides,"A monosaccharide is a monomer of carbohydrates. Five monosaccharides are important in the body. Three of these are the hexose sugars, so called because they each contain six atoms of carbon. These are glucose, fructose, and galactose, shown in Figure 2.5.1a. The remaining monosaccharides are the two pentose sugars, each of which contains five atoms of carbon. They are ribose and deoxyribose, shown in Figure 2.5.1b.","{'4491a0fd-d30a-4b01-9ffc-cf095085bcb2': 'A monosaccharide is a monomer of carbohydrates. Five monosaccharides are important in the body. Three of these are the hexose sugars, so called because they each contain six atoms of carbon. These are glucose, fructose, and galactose, shown in Figure 2.5.1a. The remaining monosaccharides are the two pentose sugars, each of which contains five atoms of carbon. They are ribose and deoxyribose, shown in Figure 2.5.1b.'}"
+Figure 2.5.2,Anatomy_And_Physio/images/Figure 2.5.2.jpg,Figure 2.5.2 – Three Important Disaccharides: All three important disaccharides form by dehydration synthesis.,"A disaccharide is a pair of monosaccharides. Disaccharides are formed via dehydration synthesis, and the bond linking them is referred to as a glycosidic bond (glyco- = “sugar”). Three disaccharides (shown in Figure 2.5.2) are important to humans. These are sucrose, commonly referred to as table sugar, lactose, or milk sugar, and maltose, or malt sugar. As you can tell from their common names, you consume these in your diet, however, your body cannot use them directly. Instead, in the digestive tract, they are split into their component monosaccharides via hydrolysis.","{'a9a6b48d-4d5a-4cad-9392-95a2d19a5c5f': 'A disaccharide is a pair of monosaccharides. Disaccharides are formed via dehydration synthesis, and the bond linking them is referred to as a glycosidic bond (glyco- = “sugar”). Three disaccharides (shown in Figure 2.5.2) are important to humans. These are sucrose, commonly referred to as table sugar, lactose, or milk sugar, and maltose, or malt sugar. As you can tell from their common names, you consume these in your diet, however, your body cannot use them directly. Instead, in the digestive tract, they are split into their component monosaccharides via hydrolysis.'}"
+Figure 2.5.3,Anatomy_And_Physio/images/Figure 2.5.3.jpg,"Figure 2.5.3 – Three Important Polysaccharides: Three important polysaccharides are starches, glycogen, and fiber.",Polysaccharides can contain a few to a thousand or more monosaccharides. Three are important to the body (Figure 2.5.3):,"{'c9e4dfed-3e32-491f-8364-7168e408c258': 'Polysaccharides can contain a few to a thousand or more monosaccharides. Three are important to the body (Figure 2.5.3):', '7ab96ff3-3de3-4ff8-b18f-7f24e17109b9': 'Starches are polymers of glucose. They occur in long chains called amylose or branched chains called amylopectin, both of which are stored in plant-based foods and are relatively easy to digest.', '5f4dd29c-8b59-4e16-abce-8aaa149e20d6': 'Glycogen is also a polymer of glucose, but it is stored in the tissues of animals, especially in the muscles and liver. It is not considered a dietary carbohydrate because very little glycogen remains in animal tissues after slaughter, however, the human body stores excess glucose as glycogen, again, in the muscles and liver.', '4db57601-0ea9-4b15-8900-6e5e3ce0489a': 'Cellulose, a polysaccharide that is the primary component of the cell wall of green plants, is the component of plant food referred to as “fiber”. In humans, cellulose/fiber is not digestible, however, dietary fiber has many health benefits. It helps you feel full so you eat less, it promotes a healthy digestive tract, and a diet high in fiber is thought to reduce the risk of heart disease and possibly some forms of cancer.'}"
+Figure 2.5.4,Anatomy_And_Physio/images/Figure 2.5.4.jpg,"Figure 2.5.4 – Triglycerides: Triglycerides are composed of glycerol attached to three fatty acids via dehydration synthesis. Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group","A triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules (Figure 2.5.4):","{'fdc882c6-15b6-441d-bf89-a7f1195a0648': 'A triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules (Figure 2.5.4):', '210c3746-1f6a-4819-9e14-9faa2da74eab': 'A glycerol backbone at the core of triglycerides, consisting of three carbon atoms.', '7b8b6278-54d4-4856-88b4-2c5cc7fea360': 'Three fatty acids, long chains of hydrocarbons with a carboxyl group and a methyl group at opposite ends, extending from each of the carbons of the glycerol.', '54455327-3649-4d92-9053-3adad1b34280': 'Triglycerides form via dehydration synthesis. Glycerol gives up hydrogen atoms from its hydroxyl groups at each bond, and the carboxyl group on each fatty acid chain gives up a hydroxyl group. A total of three water molecules are thereby released.', '065d0793-3af0-4927-8213-834fa7b18fab': 'Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature (Figure 2.5.5a). Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond (Figure 2.5.5b). These monounsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature. Polyunsaturated fatty acids contain two or more double carbon bonds, and are also liquid at room temperature. Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.', '4dfcae0c-6409-4680-b0c3-1352e9dbb65b': 'Whereas a diet high in saturated fatty acids increases the risk of heart disease, a diet high in unsaturated fatty acids is thought to reduce the risk. This is especially true for the omega-3 unsaturated fatty acids found in cold-water fish such as salmon. These fatty acids have their first double carbon bond at the third hydrocarbon from the methyl group (referred to as the omega end of the molecule).', '7783ce3b-123c-49b0-9d10-b843749e3c6b': 'Finally, trans fatty acids found in some processed foods, including some stick and tub margarines, are thought to be even more harmful to the heart and blood vessels than saturated fatty acids. Trans fats are created from unsaturated fatty acids (such as corn oil) when chemically treated to produce partially hydrogenated fats.', '3c7ef0ca-fe0f-4899-9ad9-96579861abad': 'As a group, triglycerides are a major fuel source for the body. When you are resting or asleep, a majority of the energy used to keep you alive is derived from triglycerides stored in your fat (adipose) tissues. Triglycerides also fuel long, slow physical activity such as gardening or hiking, and contribute a modest percentage of energy for vigorous physical activity. Dietary fat also assists the absorption and transport of the nonpolar fat-soluble vitamins A, D, E, and K. Additionally, stored body fat protects and cushions the body’s bones and internal organs, and acts as insulation to retain body heat.', '74f2c532-4c71-425e-8213-034f34ebdf0d': 'Fatty acids are also components of glycolipids, which are sugar-fat compounds found in the cell membrane. Lipoproteins are compounds in which the hydrophobic triglycerides are packaged in protein envelopes for transport in body fluids.'}"
+Figure 2.5.5,Anatomy_And_Physio/images/Figure 2.5.5.jpg,Figure 2.5.5 – Fatty Acid Shapes: The level of saturation of a fatty acid affects its shape. (a) Saturated fatty acid chains are straight. (b) Unsaturated fatty acid chains are kinked.,"Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature (Figure 2.5.5a). Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond (Figure 2.5.5b). These monounsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature. Polyunsaturated fatty acids contain two or more double carbon bonds, and are also liquid at room temperature. Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.","{'fdc882c6-15b6-441d-bf89-a7f1195a0648': 'A triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules (Figure 2.5.4):', '210c3746-1f6a-4819-9e14-9faa2da74eab': 'A glycerol backbone at the core of triglycerides, consisting of three carbon atoms.', '7b8b6278-54d4-4856-88b4-2c5cc7fea360': 'Three fatty acids, long chains of hydrocarbons with a carboxyl group and a methyl group at opposite ends, extending from each of the carbons of the glycerol.', '54455327-3649-4d92-9053-3adad1b34280': 'Triglycerides form via dehydration synthesis. Glycerol gives up hydrogen atoms from its hydroxyl groups at each bond, and the carboxyl group on each fatty acid chain gives up a hydroxyl group. A total of three water molecules are thereby released.', '065d0793-3af0-4927-8213-834fa7b18fab': 'Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature (Figure 2.5.5a). Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond (Figure 2.5.5b). These monounsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature. Polyunsaturated fatty acids contain two or more double carbon bonds, and are also liquid at room temperature. Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.', '4dfcae0c-6409-4680-b0c3-1352e9dbb65b': 'Whereas a diet high in saturated fatty acids increases the risk of heart disease, a diet high in unsaturated fatty acids is thought to reduce the risk. This is especially true for the omega-3 unsaturated fatty acids found in cold-water fish such as salmon. These fatty acids have their first double carbon bond at the third hydrocarbon from the methyl group (referred to as the omega end of the molecule).', '7783ce3b-123c-49b0-9d10-b843749e3c6b': 'Finally, trans fatty acids found in some processed foods, including some stick and tub margarines, are thought to be even more harmful to the heart and blood vessels than saturated fatty acids. Trans fats are created from unsaturated fatty acids (such as corn oil) when chemically treated to produce partially hydrogenated fats.', '3c7ef0ca-fe0f-4899-9ad9-96579861abad': 'As a group, triglycerides are a major fuel source for the body. When you are resting or asleep, a majority of the energy used to keep you alive is derived from triglycerides stored in your fat (adipose) tissues. Triglycerides also fuel long, slow physical activity such as gardening or hiking, and contribute a modest percentage of energy for vigorous physical activity. Dietary fat also assists the absorption and transport of the nonpolar fat-soluble vitamins A, D, E, and K. Additionally, stored body fat protects and cushions the body’s bones and internal organs, and acts as insulation to retain body heat.', '74f2c532-4c71-425e-8213-034f34ebdf0d': 'Fatty acids are also components of glycolipids, which are sugar-fat compounds found in the cell membrane. Lipoproteins are compounds in which the hydrophobic triglycerides are packaged in protein envelopes for transport in body fluids.'}"
+Figure 2.5.6,Anatomy_And_Physio/images/Figure 2.5.6.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups.","As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.","{'4150323d-609d-44c8-8054-84c055da3806': 'As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.', '5a32ea19-6365-4ae9-abfe-d14dfe77e24a': 'A steroid compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules (see Figure 2.5.6b). Although both plants and animals synthesize sterols, the type that makes the most important contribution to human structure and function is cholesterol, which is synthesized by the liver in humans and animals and is also present in most animal-based foods. Like other lipids, cholesterol’s hydrocarbons make it hydrophobic, however, it has a polar hydroxyl head that is hydrophilic. Cholesterol is an important component of bile acids and compounds that help emulsify dietary fats. In fact, the word’s root chole- refers to bile. Cholesterol is also a building block of many hormones, signaling molecules that the body releases to regulate processes at distant sites. Finally, like phospholipids, cholesterol molecules are found in the cell membrane, where their hydrophobic and hydrophilic regions help regulate the flow of substances into and out of the cell.', '53207311-0e77-4c45-9423-9a492db4d88b': 'Like a hormone, a prostaglandin is one of a group of signaling molecules, but prostaglandins are derived from unsaturated fatty acids (see Figure 2.5.6c). One reason that the omega-3 fatty acids found in fish are beneficial is that they stimulate the production of certain prostaglandins that help regulate aspects of blood pressure and inflammation, and thereby reduce the risk for heart disease. Prostaglandins also sensitize nerves to pain. One class of pain-relieving medications called nonsteroidal anti-inflammatory drugs (NSAIDs) works by reducing the effects of prostaglandins.'}"
+Figure 2.5.6,Anatomy_And_Physio/images/Figure 2.5.6.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups.","As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.","{'4150323d-609d-44c8-8054-84c055da3806': 'As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.', '5a32ea19-6365-4ae9-abfe-d14dfe77e24a': 'A steroid compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules (see Figure 2.5.6b). Although both plants and animals synthesize sterols, the type that makes the most important contribution to human structure and function is cholesterol, which is synthesized by the liver in humans and animals and is also present in most animal-based foods. Like other lipids, cholesterol’s hydrocarbons make it hydrophobic, however, it has a polar hydroxyl head that is hydrophilic. Cholesterol is an important component of bile acids and compounds that help emulsify dietary fats. In fact, the word’s root chole- refers to bile. Cholesterol is also a building block of many hormones, signaling molecules that the body releases to regulate processes at distant sites. Finally, like phospholipids, cholesterol molecules are found in the cell membrane, where their hydrophobic and hydrophilic regions help regulate the flow of substances into and out of the cell.', '53207311-0e77-4c45-9423-9a492db4d88b': 'Like a hormone, a prostaglandin is one of a group of signaling molecules, but prostaglandins are derived from unsaturated fatty acids (see Figure 2.5.6c). One reason that the omega-3 fatty acids found in fish are beneficial is that they stimulate the production of certain prostaglandins that help regulate aspects of blood pressure and inflammation, and thereby reduce the risk for heart disease. Prostaglandins also sensitize nerves to pain. One class of pain-relieving medications called nonsteroidal anti-inflammatory drugs (NSAIDs) works by reducing the effects of prostaglandins.'}"
+Figure 2.5.6,Anatomy_And_Physio/images/Figure 2.5.6.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups.","As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.","{'4150323d-609d-44c8-8054-84c055da3806': 'As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.', '5a32ea19-6365-4ae9-abfe-d14dfe77e24a': 'A steroid compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules (see Figure 2.5.6b). Although both plants and animals synthesize sterols, the type that makes the most important contribution to human structure and function is cholesterol, which is synthesized by the liver in humans and animals and is also present in most animal-based foods. Like other lipids, cholesterol’s hydrocarbons make it hydrophobic, however, it has a polar hydroxyl head that is hydrophilic. Cholesterol is an important component of bile acids and compounds that help emulsify dietary fats. In fact, the word’s root chole- refers to bile. Cholesterol is also a building block of many hormones, signaling molecules that the body releases to regulate processes at distant sites. Finally, like phospholipids, cholesterol molecules are found in the cell membrane, where their hydrophobic and hydrophilic regions help regulate the flow of substances into and out of the cell.', '53207311-0e77-4c45-9423-9a492db4d88b': 'Like a hormone, a prostaglandin is one of a group of signaling molecules, but prostaglandins are derived from unsaturated fatty acids (see Figure 2.5.6c). One reason that the omega-3 fatty acids found in fish are beneficial is that they stimulate the production of certain prostaglandins that help regulate aspects of blood pressure and inflammation, and thereby reduce the risk for heart disease. Prostaglandins also sensitize nerves to pain. One class of pain-relieving medications called nonsteroidal anti-inflammatory drugs (NSAIDs) works by reducing the effects of prostaglandins.'}"
+Figure 2.5.7,Anatomy_And_Physio/images/Figure 2.5.7.jpg,Figure 2.5.7 Structure of an Amino Acid,"Proteins are polymers made up of nitrogen-containing monomers called amino acids. An amino acid is a molecule composed of an amino group and a carboxyl group, together with a variable side chain. Just 20 different amino acids contribute to nearly all of the thousands of different proteins important in human structure and function. Body proteins contain a unique combination of a few dozen to a few hundred of these 20 amino acid monomers. All 20 of these amino acids share a similar structure (Figure 2.5.7). All consist of a central carbon atom to which the following are bonded:","{'0d03df70-341c-418b-b4a4-f10b792c69c5': 'Proteins are polymers made up of nitrogen-containing monomers called amino acids. An amino acid is a molecule composed of an amino group and a carboxyl group, together with a variable side chain. Just 20 different amino acids contribute to nearly all of the thousands of different proteins important in human structure and function. Body proteins contain a unique combination of a few dozen to a few hundred of these 20 amino acid monomers. All 20 of these amino acids share a similar structure (Figure 2.5.7). All consist of a central carbon atom to which the following are bonded:'}"
+Figure 2.5.8,Anatomy_And_Physio/images/Figure 2.5.8.jpg,"Figure 2.5.8 – Structure of an Amino Acid: Different amino acids join together to form peptides, polypeptides, or proteins via dehydration synthesis. The bonds between the amino acids are peptide bonds.","Amino acids join via dehydration synthesis to form protein polymers (Figure 2.5.8). The unique bond holding amino acids together is called a peptide bond. A peptide bond is a covalent bond between two amino acids that is formed by dehydration synthesis. A peptide, in fact, is a very short chain of amino acids. Strands containing fewer than about 100 amino acids are generally referred to as polypeptides rather than proteins.","{'f47b1a51-f876-499b-ba84-2010086bd4c3': 'Notice that all amino acids contain both an acid (the carboxyl group) and a base (the amino group) (amine = “nitrogen-containing”). For this reason, they make excellent buffers, helping the body regulate acid–base balance. What distinguishes the 20 amino acids from one another is their variable group, which is referred to as a side chain or an R-group. This group can vary in size and can be polar or nonpolar, giving each amino acid its unique characteristics. For example, the side chains of two amino acids—cysteine and methionine—contain sulfur. Sulfur does not readily participate in hydrogen bonds, whereas all other amino acids do. This variation influences the way that proteins containing cysteine and methionine are assembled.', '60a56828-d2fc-41e6-9057-f4f451d6c330': 'Amino acids join via dehydration synthesis to form protein polymers (Figure 2.5.8). The unique bond holding amino acids together is called a peptide bond. A peptide bond is a covalent bond between two amino acids that is formed by dehydration synthesis. A peptide, in fact, is a very short chain of amino acids. Strands containing fewer than about 100 amino acids are generally referred to as polypeptides rather than proteins.', 'c5d78337-10f4-4fa6-b4bd-cdce8773c17f': 'The body is able to synthesize most of the amino acids from components of other molecules, however, nine cannot be synthesized and have to be consumed in the diet. These are known as the essential amino acids.', '67256027-f88c-4971-9e39-5d9113181b0c': 'Free amino acids available for protein construction are said to reside in the amino acid pool within cells. Structures within cells use these amino acids when assembling proteins. If a particular essential amino acid is not available in sufficient quantities in the amino acid pool, however, synthesis of proteins containing it can slow or even cease.'}"
+Figure 2.5.9,Anatomy_And_Physio/images/Figure 2.5.9.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues.","Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.","{'6ff9dd51-dc58-442f-9733-b0d70ef11f16': 'Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.', 'a6b2257e-652f-4f8b-ad26-fa67f9fd8a47': 'Although some polypeptides exist as linear chains, most are twisted or folded into more complex secondary structures that form when bonding occurs between amino acids with different properties at different regions of the polypeptide. The most common secondary structure is a spiral called an alpha-helix. If you were to take a length of string and simply twist it into a spiral, it would not hold the shape. Similarly, a strand of amino acids could not maintain a stable spiral shape without the help of hydrogen bonds, which create bridges between different regions of the same strand (see Figure 2.5.9b). Less commonly, a polypeptide chain can form a beta-pleated sheet, in which hydrogen bonds form bridges between different regions of a single polypeptide that has folded back upon itself, or between two or more adjacent polypeptide chains.', '49d95bf9-a593-4abb-8eaa-dcf14d40f45b': 'The secondary structure of proteins further folds into a compact three-dimensional shape, referred to as the protein’s tertiary structure (see Figure 2.5.9c). In this configuration, amino acids that had been very distant in the primary chain can be brought quite close via hydrogen bonds or, in proteins containing cysteine, via disulfide bonds. A disulfide bond is a covalent bond between sulfur atoms in a polypeptide. Often, two or more separate polypeptides bond to form an even larger protein with a quaternary structure (see Figure 2.5.9d). The polypeptide subunits forming a quaternary structure can be identical or different. For instance, hemoglobin, the protein found in red blood cells is composed of four tertiary polypeptides, two of which are called alpha chains and two of which are called beta chains.', '19a14adc-aefa-4d27-b69e-86157a553e3c': 'When they are exposed to extreme heat, acids, bases, and certain other substances, proteins will denature. Denaturation is a change in the structure of a molecule through physical or chemical means. Denatured proteins lose their functional shape and are no longer able to carry out their jobs. An everyday example of protein denaturation is the curdling of milk when acidic lemon juice is added.', 'db63b94c-14c9-4878-84bf-90b6a6136634': 'The contribution of the shape of a protein to its function can hardly be exaggerated. For example, the long, slender shape of protein strands that make up muscle tissue is essential to their ability to contract (shorten) and relax (lengthen). As another example, bones contain long threads of a protein called collagen that acts as scaffolding upon which bone minerals are deposited. These elongated proteins, called fibrous proteins, are strong and durable and typically hydrophobic.', 'e8b29d4d-0b3c-41e3-a07b-d6034cef26f7': 'In contrast, globular proteins are globes or spheres that tend to be highly reactive and are hydrophilic. The hemoglobin proteins packed into red blood cells are an example (see Figure 2.59d), however, globular proteins are abundant throughout the body, playing critical roles in most body functions. Enzymes, introduced earlier as protein catalysts, are examples of this. The next section takes a closer look at the action of enzymes.'}"
+Figure 2.5.9,Anatomy_And_Physio/images/Figure 2.5.9.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues.","Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.","{'6ff9dd51-dc58-442f-9733-b0d70ef11f16': 'Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.', 'a6b2257e-652f-4f8b-ad26-fa67f9fd8a47': 'Although some polypeptides exist as linear chains, most are twisted or folded into more complex secondary structures that form when bonding occurs between amino acids with different properties at different regions of the polypeptide. The most common secondary structure is a spiral called an alpha-helix. If you were to take a length of string and simply twist it into a spiral, it would not hold the shape. Similarly, a strand of amino acids could not maintain a stable spiral shape without the help of hydrogen bonds, which create bridges between different regions of the same strand (see Figure 2.5.9b). Less commonly, a polypeptide chain can form a beta-pleated sheet, in which hydrogen bonds form bridges between different regions of a single polypeptide that has folded back upon itself, or between two or more adjacent polypeptide chains.', '49d95bf9-a593-4abb-8eaa-dcf14d40f45b': 'The secondary structure of proteins further folds into a compact three-dimensional shape, referred to as the protein’s tertiary structure (see Figure 2.5.9c). In this configuration, amino acids that had been very distant in the primary chain can be brought quite close via hydrogen bonds or, in proteins containing cysteine, via disulfide bonds. A disulfide bond is a covalent bond between sulfur atoms in a polypeptide. Often, two or more separate polypeptides bond to form an even larger protein with a quaternary structure (see Figure 2.5.9d). The polypeptide subunits forming a quaternary structure can be identical or different. For instance, hemoglobin, the protein found in red blood cells is composed of four tertiary polypeptides, two of which are called alpha chains and two of which are called beta chains.', '19a14adc-aefa-4d27-b69e-86157a553e3c': 'When they are exposed to extreme heat, acids, bases, and certain other substances, proteins will denature. Denaturation is a change in the structure of a molecule through physical or chemical means. Denatured proteins lose their functional shape and are no longer able to carry out their jobs. An everyday example of protein denaturation is the curdling of milk when acidic lemon juice is added.', 'db63b94c-14c9-4878-84bf-90b6a6136634': 'The contribution of the shape of a protein to its function can hardly be exaggerated. For example, the long, slender shape of protein strands that make up muscle tissue is essential to their ability to contract (shorten) and relax (lengthen). As another example, bones contain long threads of a protein called collagen that acts as scaffolding upon which bone minerals are deposited. These elongated proteins, called fibrous proteins, are strong and durable and typically hydrophobic.', 'e8b29d4d-0b3c-41e3-a07b-d6034cef26f7': 'In contrast, globular proteins are globes or spheres that tend to be highly reactive and are hydrophilic. The hemoglobin proteins packed into red blood cells are an example (see Figure 2.59d), however, globular proteins are abundant throughout the body, playing critical roles in most body functions. Enzymes, introduced earlier as protein catalysts, are examples of this. The next section takes a closer look at the action of enzymes.'}"
+Figure 2.5.9,Anatomy_And_Physio/images/Figure 2.5.9.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues.","Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.","{'6ff9dd51-dc58-442f-9733-b0d70ef11f16': 'Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.', 'a6b2257e-652f-4f8b-ad26-fa67f9fd8a47': 'Although some polypeptides exist as linear chains, most are twisted or folded into more complex secondary structures that form when bonding occurs between amino acids with different properties at different regions of the polypeptide. The most common secondary structure is a spiral called an alpha-helix. If you were to take a length of string and simply twist it into a spiral, it would not hold the shape. Similarly, a strand of amino acids could not maintain a stable spiral shape without the help of hydrogen bonds, which create bridges between different regions of the same strand (see Figure 2.5.9b). Less commonly, a polypeptide chain can form a beta-pleated sheet, in which hydrogen bonds form bridges between different regions of a single polypeptide that has folded back upon itself, or between two or more adjacent polypeptide chains.', '49d95bf9-a593-4abb-8eaa-dcf14d40f45b': 'The secondary structure of proteins further folds into a compact three-dimensional shape, referred to as the protein’s tertiary structure (see Figure 2.5.9c). In this configuration, amino acids that had been very distant in the primary chain can be brought quite close via hydrogen bonds or, in proteins containing cysteine, via disulfide bonds. A disulfide bond is a covalent bond between sulfur atoms in a polypeptide. Often, two or more separate polypeptides bond to form an even larger protein with a quaternary structure (see Figure 2.5.9d). The polypeptide subunits forming a quaternary structure can be identical or different. For instance, hemoglobin, the protein found in red blood cells is composed of four tertiary polypeptides, two of which are called alpha chains and two of which are called beta chains.', '19a14adc-aefa-4d27-b69e-86157a553e3c': 'When they are exposed to extreme heat, acids, bases, and certain other substances, proteins will denature. Denaturation is a change in the structure of a molecule through physical or chemical means. Denatured proteins lose their functional shape and are no longer able to carry out their jobs. An everyday example of protein denaturation is the curdling of milk when acidic lemon juice is added.', 'db63b94c-14c9-4878-84bf-90b6a6136634': 'The contribution of the shape of a protein to its function can hardly be exaggerated. For example, the long, slender shape of protein strands that make up muscle tissue is essential to their ability to contract (shorten) and relax (lengthen). As another example, bones contain long threads of a protein called collagen that acts as scaffolding upon which bone minerals are deposited. These elongated proteins, called fibrous proteins, are strong and durable and typically hydrophobic.', 'e8b29d4d-0b3c-41e3-a07b-d6034cef26f7': 'In contrast, globular proteins are globes or spheres that tend to be highly reactive and are hydrophilic. The hemoglobin proteins packed into red blood cells are an example (see Figure 2.59d), however, globular proteins are abundant throughout the body, playing critical roles in most body functions. Enzymes, introduced earlier as protein catalysts, are examples of this. The next section takes a closer look at the action of enzymes.'}"
+Figure 2.5.10,Anatomy_And_Physio/images/Figure 2.5.10.jpg,"Figure 2.5.10 – Steps in an Enzymatic Reaction: (a) Substrates approach active sites on enzyme. (b) Substrates bind to active sites, producing an enzyme–substrate complex. (c) Changes internal to the enzyme–substrate complex facilitate interaction of the substrates. (d) Products are released and the enzyme returns to its original form, ready to facilitate another enzymatic reaction.","Enzymatic reactions—chemical reactions catalyzed by enzymes—begin when substrates bind to the enzyme. A substrate is a reactant in an enzymatic reaction. This occurs on regions of the enzyme known as active sites (Figure 2.5.10). Any given enzyme catalyzes just one type of chemical reaction. This characteristic, called specificity, is due to the fact that a substrate with a particular shape and electrical charge can bind only to an active site corresponding to that substrate.","{'cae76b48-5c1f-448d-beaf-4e5deeb983d4': 'If you were trying to type a paper, and every time you hit a key on your laptop there was a delay of six or seven minutes before you got a response, you would probably get a new laptop. In a similar way, without enzymes to catalyze chemical reactions, the human body would be nonfunctional. It functions only because enzymes function.', 'e66aa9fa-6f79-4488-aa65-37b26cf45f15': 'Enzymatic reactions—chemical reactions catalyzed by enzymes—begin when substrates bind to the enzyme. A substrate is a reactant in an enzymatic reaction. This occurs on regions of the enzyme known as active sites (Figure 2.5.10). Any given enzyme catalyzes just one type of chemical reaction. This characteristic, called specificity, is due to the fact that a substrate with a particular shape and electrical charge can bind only to an active site corresponding to that substrate.', '53245d61-7aa2-463a-bde6-8bcb448c7396': 'Binding of a substrate produces an enzyme–substrate complex. It is likely that enzymes speed up chemical reactions in part because the enzyme–substrate complex undergoes a set of temporary and reversible changes that cause the substrates to be oriented toward each other in an optimal position to facilitate their interaction. This promotes increased reaction speed. The enzyme then releases the product(s), and resumes its original shape. The enzyme is then free to engage in the process again, and will do so as long as substrate remains.'}"
+Figure 2.5.11,Anatomy_And_Physio/images/Figure 2.5.11.jpg,"Figure 2.5.11 – Nucleotides: (a) The building blocks of all nucleotides are one or more phosphate groups, a pentose sugar, and a nitrogen-containing base. (b) The nitrogen-containing bases of nucleotides. (c) The two pentose sugars of DNA and RNA.",The fourth type of organic compound important to human structure and function are the nucleotides (Figure 2.5.11). A nucleotide is one of a class of organic compounds composed of three subunits:,{'e8679e48-9085-49e6-9eca-1db05ff4e0dd': 'The fourth type of organic compound important to human structure and function are the nucleotides (Figure 2.5.11). A nucleotide is one of a class of organic compounds composed of three subunits:'}
+Figure 2.5.12,Anatomy_And_Physio/images/Figure 2.5.12.jpg,"Figure 2.5.12 – DNA: In the DNA double helix, two strands attach via hydrogen bonds between the bases of the component nucleotides.","Bonds formed by dehydration synthesis between the pentose sugar of one nucleic acid monomer and the phosphate group of another form a “backbone,” from which the components’ nitrogen-containing bases protrude. In DNA, two such backbones attach at their protruding bases via hydrogen bonds. These twist to form a shape known as a double helix (Figure 2.5.12). The sequence of nitrogen-containing bases within a strand of DNA form the genes that act as a molecular code instructing cells in the assembly of amino acids into proteins. Humans have almost 22,000 genes in their DNA, locked up in the 46 chromosomes inside the nucleus of each cell (except red blood cells which lose their nuclei during development). These genes carry the genetic code to build one’s body, and are unique for each individual except identical twins.","{'86d5af2c-e999-4f55-9eaf-cbac2aa5ed32': 'The nucleic acids differ in their type of pentose sugar. Deoxyribonucleic acid (DNA) is nucleotide that stores genetic information. DNA contains deoxyribose (so-called because it has one less atom of oxygen than ribose) plus one phosphate group and one nitrogen-containing base. The “choices” of base for DNA are adenine, cytosine, guanine, and thymine. Ribonucleic acid (RNA) is a ribose-containing nucleotide that helps manifest the genetic code as protein. RNA contains ribose, one phosphate group, and one nitrogen-containing base, but the “choices” of base for RNA are adenine, cytosine, guanine, and uracil.', '1b940302-508f-478f-8537-e166e082f921': 'The nitrogen-containing bases adenine and guanine are classified as purines. A purine is a nitrogen-containing molecule with a double ring structure, which accommodates several nitrogen atoms. The bases cytosine, thymine (found in DNA only) and uracil (found in RNA only) are pyramidines. A pyramidine is a nitrogen-containing base with a single ring structure', '188b388b-b317-4e7c-ba5a-d4d448d8493e': 'Bonds formed by dehydration synthesis between the pentose sugar of one nucleic acid monomer and the phosphate group of another form a “backbone,” from which the components’ nitrogen-containing bases protrude. In DNA, two such backbones attach at their protruding bases via hydrogen bonds. These twist to form a shape known as a double helix (Figure 2.5.12). The sequence of nitrogen-containing bases within a strand of DNA form the genes that act as a molecular code instructing cells in the assembly of amino acids into proteins. Humans have almost 22,000 genes in their DNA, locked up in the 46 chromosomes inside the nucleus of each cell (except red blood cells which lose their nuclei during development). These genes carry the genetic code to build one’s body, and are unique for each individual except identical twins.', '2f4223d6-3ca8-4efc-921c-1d3395091f84': 'In contrast, RNA consists of a single strand of sugar-phosphate backbone studded with bases. Messenger RNA (mRNA) is created during protein synthesis to carry the genetic instructions from the DNA to the cell’s protein manufacturing plants in the cytoplasm and the ribosomes.'}"
+Figure 2.5.13,Anatomy_And_Physio/images/Figure 2.5.13.jpg,Figure 2.5.13 Structure of Adenosine Triphosphate (ATP),"The nucleotide adenosine triphosphate (ATP), is composed of a ribose sugar, an adenine base, and three phosphate groups (Figure 2.5.13). ATP is classified as a high energy compound because the two covalent bonds linking its three phosphates store a significant amount of potential energy. In the body, the energy released from these high energy bonds helps fuel the body’s activities, from muscle contraction to the transport of substances in and out of cells to anabolic chemical reactions.","{'90acbf4c-5532-4d92-a565-669c28a871b8': 'The nucleotide adenosine triphosphate (ATP), is composed of a ribose sugar, an adenine base, and three phosphate groups (Figure 2.5.13). ATP is classified as a high energy compound because the two covalent bonds linking its three phosphates store a significant amount of potential energy. In the body, the energy released from these high energy bonds helps fuel the body’s activities, from muscle contraction to the transport of substances in and out of cells to anabolic chemical reactions.', '996b427b-145f-45f2-9d32-398d765e7d9d': 'When a phosphate group is cleaved from ATP, the products are adenosine diphosphate (ADP) and inorganic phosphate (Pi). This hydrolysis reaction can be written:'}"
+Figure 2.4.1,Anatomy_And_Physio/images/Figure 2.4.1.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water.","Monomers form polymers by engaging in dehydration synthesis (see Figure 2.4.1). As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes; one gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis (-lysis = “rupture”). The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.","{'fc5a063f-bc4e-418d-8f95-b32042a082db': 'What makes organic compounds ubiquitous is the chemistry of their carbon core. Recall that carbon atoms have four electrons in their valence shell, and that the octet rule dictates that atoms tend to react in such a way as to complete their valence shell with eight electrons. Carbon atoms do not complete their valence shells by donating or accepting four electrons. Instead, they readily share electrons via covalent bonds.', '09a35eed-09ce-4a52-9c85-7fd34d0d47d1': 'Normally, carbon atoms share with other carbon atoms, often forming a long carbon chain referred to as a carbon skeleton. When they share, however, they do not share all their electrons exclusively with each other. Rather, carbon atoms tend to share electrons with a variety of other elements, one of which is always hydrogen. Carbon and hydrogen groupings are called hydrocarbons. If you study the figures of organic compounds in the remainder of this chapter, you will see several with chains of hydrocarbons in one region of the compound.', '6ed03df1-ee8a-4850-9446-70c01231639d': 'Many combinations are possible to fill carbon’s four “vacancies.” Carbon may share electrons with oxygen or nitrogen or other atoms in a particular region of an organic compound. Moreover, the atoms to which carbon atoms bond may also be part of a functional group. A functional group is a group of atoms linked by strong covalent bonds and tend to function in chemical reactions as a single unit. You can think of functional groups as tightly knit “cliques” whose members are unlikely to be parted. Five functional groups are important in human physiology: the hydroxyl, carboxyl, amino, methyl and phosphate groups (Table 2.1).', 'e3122472-c7fc-47de-8a09-f0d3678d91e6': 'Carbon’s affinity for covalent bonding means that many distinct and relatively stable organic molecules readily form larger, more complex molecules. Any large molecule is referred to as macromolecule (macro- = “large”), and the organic compounds in this section all fit this description. However, some macromolecules are made up of several “copies” of single units called monomer (mono- = “one”; -mer = “part”). Like beads in a long necklace, these monomers link by covalent bonds to form long polymers (poly- = “many”). There are many examples of monomers and polymers among the organic compounds.', '951af231-0bf0-43e1-baa7-7fb0a9a78e69': 'Monomers form polymers by engaging in dehydration synthesis (see Figure 2.4.1). As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes; one gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis (-lysis = “rupture”). The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.', 'aca7be7c-fbcb-4981-81fd-759a06d72906': 'Two types of chemical reactions involve the creation or the consumption of water: dehydration synthesis and hydrolysis.', '2758d534-6987-4f43-8a10-66caa2ae9490': 'In dehydration synthesis, one reactant gives up an atom of hydrogen and another reactant gives up a hydroxyl group (OH) in the synthesis of a new product. In the formation of their covalent bond, a molecule of water is released as a byproduct (Figure 2.4.1). This is also sometimes referred to as a condensation reaction.', 'f22bc758-65c8-4b37-b0d1-5a694e5ad5de': 'In hydrolysis, a molecule of water disrupts a compound, breaking its bonds. The water is itself split into H and OH. One portion of the severed compound then bonds with the hydrogen atom, and the other portion bonds with the hydroxyl group.', 'd3b0e853-7013-4a41-afca-0efb311a8e2b': 'These reactions are reversible, and play an important role in the chemistry of organic compounds (which will be discussed shortly).'}"
+Figure 2.4.2,Anatomy_And_Physio/images/Figure 2.4.2.jpg,"Figure 2.4.2 – Dissociation of Sodium Chloride in Water: Notice that the crystals of sodium chloride dissociate not into molecules of NaCl, but into Na+ cations and Cl– anions, each completely surrounded by water molecules.","A typical salt, NaCl, dissociates completely in water (Figure 2.4.2). The positive and negative regions on the water molecule (the hydrogen and oxygen ends respectively) attract the negative chloride and positive sodium ions, pulling them away from each other. Again, whereas nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions. These ions are electrolytes; they are capable of conducting an electrical current in solution. This property is critical to the function of ions in transmitting nerve impulses and prompting muscle contraction.","{'b2a29369-c0da-4161-bb7e-7a913aaa96f0': 'Recall that salts are formed when ions form ionic bonds. In these reactions, one atom gives up one or more electrons, and thus becomes positively charged, whereas the other accepts one or more electrons and becomes negatively charged. You can now define a salt as a substance that, when dissolved in water, dissociates into ions other than H+ or OH–. This fact is important in distinguishing salts from acids and bases, discussed next.', 'f7fb7745-0953-409b-9e99-c237f7d13b83': 'A typical salt, NaCl, dissociates completely in water (Figure 2.4.2). The positive and negative regions on the water molecule (the hydrogen and oxygen ends respectively) attract the negative chloride and positive sodium ions, pulling them away from each other. Again, whereas nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions. These ions are electrolytes; they are capable of conducting an electrical current in solution. This property is critical to the function of ions in transmitting nerve impulses and prompting muscle contraction.', 'eb33d0c1-c616-4213-aea7-659502c53aac': 'Many other salts are important in the body. For example, bile salts produced by the liver help break apart dietary fats, and calcium phosphate salts form the mineral portion of teeth and bones.'}"
+Figure 2.4.3,Anatomy_And_Physio/images/Figure 2.4.3.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–.","An acid is a substance that releases hydrogen ions (H+) in solution (Figure 2.4.3a). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H+ in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H+ in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.","{'63f01267-1039-4149-bbca-0fcffc88034b': 'An acid is a substance that releases hydrogen ions (H+) in solution (Figure 2.4.3a). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H+ in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H+ in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.', 'b0698cbb-eb1a-4f9a-ab4a-940271905891': 'A base is a substance that releases hydroxyl ions (OH–) in solution, or one that accepts H+ already present in solution (see Figure 2.4.3b). The hydroxyl ions (also known as hydroxide ions) or other basic substances combine with H+ present to form a water molecule, thereby removing H+ and reducing the solution’s acidity. Strong bases release most or all of their hydroxyl ions; weak bases release only some hydroxyl ions or absorb only a few H+. Food mixed with hydrochloric acid from the stomach would burn the small intestine (the next portion of the digestive tract after the stomach), if it were not for the release of bicarbonate (HCO3–), a weak base that attracts H+. Bicarbonate accepts some of the H+ protons, thereby reducing the acidity of the solution.'}"
+Figure 2.4.3,Anatomy_And_Physio/images/Figure 2.4.3.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–.","An acid is a substance that releases hydrogen ions (H+) in solution (Figure 2.4.3a). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H+ in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H+ in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.","{'63f01267-1039-4149-bbca-0fcffc88034b': 'An acid is a substance that releases hydrogen ions (H+) in solution (Figure 2.4.3a). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H+ in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H+ in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.', 'b0698cbb-eb1a-4f9a-ab4a-940271905891': 'A base is a substance that releases hydroxyl ions (OH–) in solution, or one that accepts H+ already present in solution (see Figure 2.4.3b). The hydroxyl ions (also known as hydroxide ions) or other basic substances combine with H+ present to form a water molecule, thereby removing H+ and reducing the solution’s acidity. Strong bases release most or all of their hydroxyl ions; weak bases release only some hydroxyl ions or absorb only a few H+. Food mixed with hydrochloric acid from the stomach would burn the small intestine (the next portion of the digestive tract after the stomach), if it were not for the release of bicarbonate (HCO3–), a weak base that attracts H+. Bicarbonate accepts some of the H+ protons, thereby reducing the acidity of the solution.'}"
+Figure 2.4.4,Anatomy_And_Physio/images/Figure 2.4.4.jpg,Figure 2.4.4 The pH Scale,"The relative acidity or alkalinity of a solution can be indicated by its pH. A solution’s pH is the negative, base-10 logarithm of the hydrogen ion (H+) concentration of the solution. As an example, a pH 4 solution has an H+ concentration that is ten times greater than that of a pH 5 solution. That is, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5. The concept of pH will begin to make more sense when you study the pH scale, as shown in Figure 2.4.4. The scale consists of a series of increments ranging from 0 to 14. A solution with a pH of 7 is considered neutral—neither acidic nor basic. Pure water has a pH of 7. The lower the number below 7, the more acidic the solution, or the greater the concentration of H+. The concentration of hydrogen ions at each pH value is 10 times different than the next pH. For instance, a pH value of 4 corresponds to a proton concentration of 10–4 M, or 0.0001M, while a pH value of 5 corresponds to a proton concentration of 10–5 M, or 0.00001M. The higher the number above 7, the more basic (alkaline) the solution, or the lower the concentration of H+. Human urine, for example, is ten times more acidic than pure water, and HCl is 10,000,000 times more acidic than water.","{'0c651b76-3bbd-4ebf-a1e1-be5ae599a8b5': 'The relative acidity or alkalinity of a solution can be indicated by its pH. A solution’s pH is the negative, base-10 logarithm of the hydrogen ion (H+) concentration of the solution. As an example, a pH 4 solution has an H+ concentration that is ten times greater than that of a pH 5 solution. That is, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5. The concept of pH will begin to make more sense when you study the pH scale, as shown in Figure 2.4.4. The scale consists of a series of increments ranging from 0 to 14. A solution with a pH of 7 is considered neutral—neither acidic nor basic. Pure water has a pH of 7. The lower the number below 7, the more acidic the solution, or the greater the concentration of H+. The concentration of hydrogen ions at each pH value is 10 times different than the next pH. For instance, a pH value of 4 corresponds to a proton concentration of 10–4 M, or 0.0001M, while a pH value of 5 corresponds to a proton concentration of 10–5 M, or 0.00001M. The higher the number above 7, the more basic (alkaline) the solution, or the lower the concentration of H+. Human urine, for example, is ten times more acidic than pure water, and HCl is 10,000,000 times more acidic than water.'}"
+Figure 2.3.2,Anatomy_And_Physio/images/Figure 2.3.2.jpg,"Figure 2.3.2 – Enzymes:  Enzymes decrease the activation energy required for a given chemical reaction to occur. (a) Without an enzyme, the energy input needed for a reaction to begin is high. (b) With the help of an enzyme, less energy is needed for a reaction to begin.","The most important catalysts in the human body are enzymes. An enzyme is a catalyst composed of protein or ribonucleic acid (RNA), both of which will be discussed later in this chapter. Like all catalysts, enzymes work by lowering the level of energy that needs to be invested in a chemical reaction. A chemical reaction’s activation energy is the “threshold” level of energy needed to break the bonds in the reactants. Once those bonds are broken, new arrangements can form. Without an enzyme to act as a catalyst, a much larger investment of energy is needed to ignite a chemical reaction (Figure 2.3.2).","{'0f27aa03-afe8-4ebb-87f2-4950e9176f58': 'For two chemicals in nature to react with each other they first have to come into contact, and this occurs through random collisions. Since heat helps increase the kinetic energy of atoms, ions, and molecules, it promotes their collision. However, in the body, extremely high heat—such as a very high fever—can damage body cells and be life-threatening. On the other hand, normal body temperature is not high enough to promote the chemical reactions that sustain life. That is where catalysts come in.', 'f4dea024-6cf4-4270-8087-4e7136a1b63e': 'In chemistry, a catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any change. You can think of a catalyst as a chemical change agent. They help increase the rate and force at which atoms, ions, and molecules collide, thereby increasing the probability that their valence shell electrons will interact.', 'a8669c84-eba6-41ae-8a6e-72d0215ea052': 'The most important catalysts in the human body are enzymes. An enzyme is a catalyst composed of protein or ribonucleic acid (RNA), both of which will be discussed later in this chapter. Like all catalysts, enzymes work by lowering the level of energy that needs to be invested in a chemical reaction. A chemical reaction’s activation energy is the “threshold” level of energy needed to break the bonds in the reactants. Once those bonds are broken, new arrangements can form. Without an enzyme to act as a catalyst, a much larger investment of energy is needed to ignite a chemical reaction (Figure 2.3.2).', 'e5cd5791-6522-493c-80f2-4e8da0a3c298': 'Enzymes are critical to the body’s healthy functioning. They assist, for example, with the breakdown of food and its conversion to energy. In fact, most of the chemical reactions in the body are facilitated by enzymes.', '90140b00-e955-4fc3-8ebd-bdd43f06dbc9': 'Atoms separated by a great distance cannot link; rather, they must come close enough for the electrons in their valence shells to interact. But do atoms ever actually touch one another? Most physicists would say no, because the negatively charged electrons in their valence shells repel one another. No force within the human body—or anywhere in the natural world—is strong enough to overcome this electrical repulsion. So when you read about atoms linking together or colliding, bear in mind that the atoms are not merging in a physical sense.', '5e38c418-56ee-4769-b788-07b5387101e1': 'Instead, atoms link by forming a chemical bond. A bond is a weak or strong electrical attraction that holds atoms in the same vicinity. The new grouping is typically more stable—less likely to react again—than its component atoms were when they were separate. A more or less stable grouping of two or more atoms held together by chemical bonds is called a molecule. The bonded atoms may be of the same element, as in the case of H2, which is called molecular hydrogen or hydrogen gas. When a molecule is made up of two or more atoms of different elements, it is called a chemical compound. A unit of water, or H2O, is a compound, as is a single molecule of the gas methane, or CH4.', '6109ca19-ca1e-4931-9797-7e39e2c7ce17': 'Three types of chemical bonds are important in human physiology, because they hold together substances that are used by the body for critical aspects of homeostasis, signaling, and energy production, to name just a few important processes. These are ionic bonds, covalent bonds, and hydrogen bonds.'}"
+Figure 2.2.1,Anatomy_And_Physio/images/Figure 2.2.1.jpg,"Figure 2.2.1 – Ionic Bonding: (a) Sodium readily donates the solitary electron in its valence shell to chlorine, which needs only one electron to have a full valence shell. (b) The opposite electrical charges of the resulting sodium cation and chloride anion result in the formation of a bond of attraction called an ionic bond. (c) The attraction of many sodium and chloride ions results in the formation of large groupings called crystals.","The opposite charges of cations and anions exert a moderately strong mutual attraction that keeps the atoms in close proximity forming an ionic bond. An ionic bond is an ongoing, close association between ions of opposite charge. The table salt you sprinkle on your food owes its existence to ionic bonding. As shown in Figure 2.2.1, sodium commonly donates an electron to chlorine, becoming the cation Na+. When chlorine accepts the electron, it becomes the chloride anion, Cl–. With their opposing charges, these two ions strongly attract each other.","{'8e00930e-833d-46ff-ad90-45ea0f26d615': 'Recall that an atom typically has the same number of positively charged protons and negatively charged electrons. As long as this situation remains, the atom is electrically neutral. When an atom participates in a chemical reaction that results in the donation or acceptance of one or more electrons, the atom will then become positively or negatively charged. This happens frequently for most atoms in order to have a full valence shell, as described previously. This can happen either by gaining electrons to fill a shell that is more than half-full, or by giving away electrons to empty a shell that is less than half-full, thereby leaving the next smaller electron shell as the new, full, valence shell. An atom that has an electrical charge—whether positive or negative—is an ion.', '44d3b0d1-cda5-4b3a-b4ee-9e7222b7a168': 'Potassium (K), for instance, is an important element in all body cells. Its atomic number is 19 and it has just one electron in its valence shell. This characteristic makes potassium highly likely to participate in chemical reactions in which it donates one electron (it is easier for potassium to donate one electron than to gain seven electrons). The loss will cause the positive charge of potassium’s protons to be more influential than the negative charge of potassium’s electrons. In other words, the resulting potassium ion will be slightly positive. A potassium ion is written K+, indicating that it has lost a single electron. A positively charged ion is known as a cation.', 'cd1c3f1b-5026-41e0-bd81-6b64422a06f6': 'Now consider fluorine (F), a component of bones and teeth. Its atomic number is nine and it has seven electrons in its valence shell. Thus, it is highly likely to bond with other atoms in such a way that fluorine accepts one electron (it is easier for fluorine to gain one electron than to donate seven electrons). When it does, its electrons will outnumber its protons by one and it will have an overall negative charge. The ionized form of fluorine is called fluoride, and is written as F–. A negatively charged ion is known as an anion.', 'a8d21014-fc27-4bc5-a0af-99d793447851': 'Atoms that have more than one electron to donate or accept will end up with stronger positive or negative charges. A cation that has donated two electrons has a net charge of +2. Using magnesium (Mg) as an example, this can be written as Mg++ or Mg2+. An anion that has accepted two electrons has a net charge of –2. The ionic form of selenium (Se), for example, is typically written Se2–.', 'c1a8528e-9a99-49d9-987b-ceff8237b55f': 'The opposite charges of cations and anions exert a moderately strong mutual attraction that keeps the atoms in close proximity forming an ionic bond. An ionic bond is an ongoing, close association between ions of opposite charge. The table salt you sprinkle on your food owes its existence to ionic bonding. As shown in Figure 2.2.1, sodium commonly donates an electron to chlorine, becoming the cation Na+. When chlorine accepts the electron, it becomes the chloride anion, Cl–. With their opposing charges, these two ions strongly attract each other.', '34043d67-c0af-48a9-9b3d-4851139d1427': 'Water is an essential component of life because it is able to break the ionic bonds in salts to free the ions. In fact, in biological fluids, most individual atoms exist as ions. These dissolved ions produce electrical charges within the body. The behavior of these ions produces the tracings of heart and brain function observed as waves on an electrocardiogram (EKG or ECG) or an electroencephalogram (EEG). The electrical activity that derives from the interactions of the charged ions is why they are also called electrolytes.'}"
+Figure 2.2.2,Anatomy_And_Physio/images/Figure 2.2.2.jpg,Figure 2.2.2 Covalent Bonding,"Figure 2.2.2 shows several common types of covalent bonds. Notice that the two covalently bonded atoms typically share just one or two electron pairs, though larger sharings are possible. The important concept to take from this is that in covalent bonds, electrons in the outermost valence shell are shared to fill the valence shells of both atoms, ultimately stabilizing both of the atoms involved. In a single covalent bond, a single electron is shared between two atoms, while in a double covalent bond, two pairs of electrons are shared between two atoms. There are even triple covalent bonds, where three atoms are shared.","{'0103dac9-7173-4f9a-b28c-c3b7fd737d24': 'Figure 2.2.2 shows several common types of covalent bonds. Notice that the two covalently bonded atoms typically share just one or two electron pairs, though larger sharings are possible. The important concept to take from this is that in covalent bonds, electrons in the outermost valence shell are shared to fill the valence shells of both atoms, ultimately stabilizing both of the atoms involved. In a single covalent bond, a single electron is shared between two atoms, while in a double covalent bond, two pairs of electrons are shared between two atoms. There are even triple covalent bonds, where three atoms are shared.', '69eb49c8-58a9-447b-9e08-b3739b0bded5': 'You can see that the covalent bonds shown in Figure 2.2.2 are balanced. The sharing of the negative electrons is relatively equal, as is the electrical pull of the positive protons in the nucleus of the atoms involved. This is why covalently bonded molecules that are electrically balanced in this way are described as nonpolar; that is, no region of the molecule is either more positive or more negative than any other.'}"
+Figure 2.2.2,Anatomy_And_Physio/images/Figure 2.2.2.jpg,Figure 2.2.2 Covalent Bonding,"Figure 2.2.2 shows several common types of covalent bonds. Notice that the two covalently bonded atoms typically share just one or two electron pairs, though larger sharings are possible. The important concept to take from this is that in covalent bonds, electrons in the outermost valence shell are shared to fill the valence shells of both atoms, ultimately stabilizing both of the atoms involved. In a single covalent bond, a single electron is shared between two atoms, while in a double covalent bond, two pairs of electrons are shared between two atoms. There are even triple covalent bonds, where three atoms are shared.","{'0103dac9-7173-4f9a-b28c-c3b7fd737d24': 'Figure 2.2.2 shows several common types of covalent bonds. Notice that the two covalently bonded atoms typically share just one or two electron pairs, though larger sharings are possible. The important concept to take from this is that in covalent bonds, electrons in the outermost valence shell are shared to fill the valence shells of both atoms, ultimately stabilizing both of the atoms involved. In a single covalent bond, a single electron is shared between two atoms, while in a double covalent bond, two pairs of electrons are shared between two atoms. There are even triple covalent bonds, where three atoms are shared.', '69eb49c8-58a9-447b-9e08-b3739b0bded5': 'You can see that the covalent bonds shown in Figure 2.2.2 are balanced. The sharing of the negative electrons is relatively equal, as is the electrical pull of the positive protons in the nucleus of the atoms involved. This is why covalently bonded molecules that are electrically balanced in this way are described as nonpolar; that is, no region of the molecule is either more positive or more negative than any other.'}"
+Figure 2.2.3,Anatomy_And_Physio/images/Figure 2.2.3.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule,"The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.","{'cd8772ca-cf76-4e5b-9027-1517429f839f': 'Groups of legislators with completely opposite views on a particular issue are often described as “polarized” by news writers. In chemistry, a polar molecule is a molecule that contains regions that have opposite electrical charges. Polar molecules occur when atoms share electrons unequally, in polar covalent bonds.', '672d21cf-c415-4bff-bec0-dce12200ffb6': 'The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.', '0b7025e5-2388-4c21-a4a0-8ed1839a98cd': 'What is true for the bonds is true for the water molecule as a whole; that is, the oxygen region has a slightly negative charge and the regions of the hydrogen atoms have a slightly positive charge. These charges are often referred to as “partial charges” because the strength of the charge is less than one full electron, as would occur in an ionic bond. As shown in Figure 2.2.3, regions of weak polarity are indicated with the Greek letter delta (∂) and a plus (+) or minus (–) sign.', '096c443d-3514-4b12-b021-e2bc173d2764': 'Even though a single water molecule is unimaginably tiny, it has mass, and the opposing electrical charges on the molecule pull that mass in such a way that it creates a shape somewhat like a triangular tent (see Figure 2.2.3b). This dipole, with the positive charges at one end formed by the hydrogen atoms at the “bottom” of the tent and the negative charge at the opposite end (the oxygen atom at the “top” of the tent) makes the charged regions highly likely to interact with charged regions of other polar molecules. For human physiology, the resulting bond, formed by water, is one of the most important—the hydrogen bond.'}"
+Figure 2.2.3,Anatomy_And_Physio/images/Figure 2.2.3.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule,"The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.","{'cd8772ca-cf76-4e5b-9027-1517429f839f': 'Groups of legislators with completely opposite views on a particular issue are often described as “polarized” by news writers. In chemistry, a polar molecule is a molecule that contains regions that have opposite electrical charges. Polar molecules occur when atoms share electrons unequally, in polar covalent bonds.', '672d21cf-c415-4bff-bec0-dce12200ffb6': 'The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.', '0b7025e5-2388-4c21-a4a0-8ed1839a98cd': 'What is true for the bonds is true for the water molecule as a whole; that is, the oxygen region has a slightly negative charge and the regions of the hydrogen atoms have a slightly positive charge. These charges are often referred to as “partial charges” because the strength of the charge is less than one full electron, as would occur in an ionic bond. As shown in Figure 2.2.3, regions of weak polarity are indicated with the Greek letter delta (∂) and a plus (+) or minus (–) sign.', '096c443d-3514-4b12-b021-e2bc173d2764': 'Even though a single water molecule is unimaginably tiny, it has mass, and the opposing electrical charges on the molecule pull that mass in such a way that it creates a shape somewhat like a triangular tent (see Figure 2.2.3b). This dipole, with the positive charges at one end formed by the hydrogen atoms at the “bottom” of the tent and the negative charge at the opposite end (the oxygen atom at the “top” of the tent) makes the charged regions highly likely to interact with charged regions of other polar molecules. For human physiology, the resulting bond, formed by water, is one of the most important—the hydrogen bond.'}"
+Figure 2.2.3,Anatomy_And_Physio/images/Figure 2.2.3.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule,"The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.","{'cd8772ca-cf76-4e5b-9027-1517429f839f': 'Groups of legislators with completely opposite views on a particular issue are often described as “polarized” by news writers. In chemistry, a polar molecule is a molecule that contains regions that have opposite electrical charges. Polar molecules occur when atoms share electrons unequally, in polar covalent bonds.', '672d21cf-c415-4bff-bec0-dce12200ffb6': 'The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.', '0b7025e5-2388-4c21-a4a0-8ed1839a98cd': 'What is true for the bonds is true for the water molecule as a whole; that is, the oxygen region has a slightly negative charge and the regions of the hydrogen atoms have a slightly positive charge. These charges are often referred to as “partial charges” because the strength of the charge is less than one full electron, as would occur in an ionic bond. As shown in Figure 2.2.3, regions of weak polarity are indicated with the Greek letter delta (∂) and a plus (+) or minus (–) sign.', '096c443d-3514-4b12-b021-e2bc173d2764': 'Even though a single water molecule is unimaginably tiny, it has mass, and the opposing electrical charges on the molecule pull that mass in such a way that it creates a shape somewhat like a triangular tent (see Figure 2.2.3b). This dipole, with the positive charges at one end formed by the hydrogen atoms at the “bottom” of the tent and the negative charge at the opposite end (the oxygen atom at the “top” of the tent) makes the charged regions highly likely to interact with charged regions of other polar molecules. For human physiology, the resulting bond, formed by water, is one of the most important—the hydrogen bond.'}"
+Figure 2.2.4,Anatomy_And_Physio/images/Figure 2.2.4.jpg,"Figure 2.2.4 – Hydrogen Bonds between Water Molecules: Notice that the bonds occur between the weakly positive charge on the hydrogen atoms and the weakly negative charge on the oxygen atoms. Hydrogen bonds are relatively weak, and therefore are indicated with a dotted (rather than a solid) line.","The most common example of hydrogen bonding in the natural world occurs between molecules of water. It happens before your eyes whenever two raindrops merge into a larger bead, or a creek spills into a river. Hydrogen bonding occurs because the weakly negative oxygen atom in one water molecule is attracted to the weakly positive hydrogen atoms of two other water molecules (Figure 2.2.4).","{'8ee9e2fc-68eb-4809-b025-0fd2c7ff5474': 'A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another molecule. In other words, hydrogen bonds always include hydrogen that is already part of a polar molecule.', 'a8446460-b31d-43ad-93e4-20ed7e7b010c': 'The most common example of hydrogen bonding in the natural world occurs between molecules of water. It happens before your eyes whenever two raindrops merge into a larger bead, or a creek spills into a river. Hydrogen bonding occurs because the weakly negative oxygen atom in one water molecule is attracted to the weakly positive hydrogen atoms of two other water molecules (Figure 2.2.4).', '6f34d191-d706-4ae3-9c13-0f00743f7214': 'Notice that the bonds occur between the weakly positive charge on the hydrogen atoms and the weakly negative charge on the oxygen atoms. Hydrogen bonds are relatively weak, and therefore are indicated with a dotted (rather than a solid) line.', '96d62591-d626-41e5-ba31-cedab5eafe97': 'Water molecules also strongly attract other types of charged molecules as well as ions. This explains why “table salt,” for example, actually is a molecule called a “salt” in chemistry; it consists of equal numbers of positively-charged sodium (Na+) and negatively-charged chloride (Cl–), dissolves so readily in water, in this case, forming dipole-ion bonds between the water and the electrically-charged ions (electrolytes). Water molecules also repel molecules with nonpolar covalent bonds, like fats, lipids, and oils. You can demonstrate this with a simple kitchen experiment: pour a teaspoon of vegetable oil, a compound formed by nonpolar covalent bonds, into a glass of water. Instead of instantly dissolving in the water, the oil forms a distinct bead because the polar water molecules repel the nonpolar oil.', 'be2e2e42-0069-4cc0-9efa-2d70c2ca91e2': 'The substance of the universe—from a grain of sand to a star—is called matter. Scientists define matter as anything that occupies space and has mass. An object’s mass and its weight are related concepts, but not quite the same. An object’s mass is the amount of matter contained in the object, and is the same whether that object is on Earth or in the zero-gravity environment of outer space. An object’s weight, on the other hand, is its mass as affected by the pull of gravity. An object’s weight is greater where the pull of gravity is stronger than where the gravity is less strong. For example, an object of a certain mass weighs less on the moon than it does on Earth because the gravity of the moon is less than that of Earth. In other words, weight is variable, and is influenced by gravity. A piece of cheese that weighs a pound on Earth weighs only a few ounces on the moon.'}"
+Figure 2.1.1,Anatomy_And_Physio/images/Figure 2.1.1.jpg,Figure 2.1.1 – Elements of the Human Body: The main elements that compose the human body are shown from most abundant to least abundant.,"All matter in the natural world is composed of one or more of the 92 fundamental substances called elements. An element is a pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means. While your body can assemble many of the chemical compounds needed for life from their constituent elements, it cannot make elements. They must come from the environment. A familiar example of an element that you must take in is calcium (Ca++). Calcium is essential to the human body; it is absorbed and used for a number of processes, including strengthening bones. When you consume dairy products your digestive system breaks down the food into components small enough to cross into the bloodstream. Among these is calcium, which, because it is an element, cannot be broken down further. The elemental calcium in cheese, therefore, is the same as the calcium that forms your bones. Some other elements you might be familiar with are oxygen, sodium, and iron. The elements in the human body are shown in Figure 2.1.1, beginning with the most abundant: oxygen (O), carbon (C), hydrogen (H), and nitrogen (N). Each element’s name can be replaced by a one- or two-letter symbol; you will become familiar with some of these during this course. All the elements in your body are derived from the foods you eat and the air you breathe.","{'215ae162-cea0-4a6f-a385-4cfd3b15ec89': 'All matter in the natural world is composed of one or more of the 92 fundamental substances called elements. An element is a pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means. While your body can assemble many of the chemical compounds needed for life from their constituent elements, it cannot make elements. They must come from the environment. A familiar example of an element that you must take in is calcium (Ca++). Calcium is essential to the human body; it is absorbed and used for a number of processes, including strengthening bones. When you consume dairy products your digestive system breaks down the food into components small enough to cross into the bloodstream. Among these is calcium, which, because it is an element, cannot be broken down further. The elemental calcium in cheese, therefore, is the same as the calcium that forms your bones. Some other elements you might be familiar with are oxygen, sodium, and iron. The elements in the human body are shown in Figure 2.1.1, beginning with the most abundant: oxygen (O), carbon (C), hydrogen (H), and nitrogen (N). Each element’s name can be replaced by a one- or two-letter symbol; you will become familiar with some of these during this course. All the elements in your body are derived from the foods you eat and the air you breathe.', '463b49e4-9620-4fe8-ad5c-07a5892f7641': 'In nature, elements rarely occur alone. Instead, they combine to form compounds. A compound is a substance composed of two or more elements joined by chemical bonds. For example, the compound glucose is an important body fuel. It is always composed of the same three elements: carbon, hydrogen, and oxygen. Moreover, the elements that make up any given compound always occur in the same relative amounts. In glucose, there are always six carbon and six oxygen units for every twelve hydrogen units. But what, exactly, are these “units” of elements?'}"
+Figure 2.1.2,Anatomy_And_Physio/images/Figure 2.1.2.jpg,"Figure 2.1.2 – Two Models of Atomic Structure: (a) In the planetary model, the electrons of helium are shown in fixed orbits, depicted as rings, at a precise distance from the nucleus, somewhat like planets orbiting the sun. (b) In the electron cloud model, the electrons of carbon are shown in the variety of locations they would have at different distances from the nucleus over time.","Figure 2.1.2 shows two models that can help you imagine the structure of an atom—in this case, helium (He). In the planetary model, helium’s two electrons are shown circling the nucleus in a fixed orbit depicted as a ring. Although this model is helpful in visualizing atomic structure, in reality, electrons do not travel in fixed orbits, but whiz around the nucleus erratically in a so-called electron cloud.","{'801c37c5-219e-4259-96d6-58b653cd186e': 'Atoms are made up of even smaller subatomic particles, which include three important types: the proton, neutron, and electron. The number of positively-charged protons and non-charged (“neutral”) neutrons, gives mass to the atom, and the number of each in the nucleus of the atom determines the element. The number of negatively-charged electrons that “spin” around the nucleus at close to the speed of light equals the number of protons. An electron has about 1/2000th the mass of a proton or neutron.', 'e50cf937-166d-472d-9ca5-eb673e005257': 'Figure 2.1.2 shows two models that can help you imagine the structure of an atom—in this case, helium (He). In the planetary model, helium’s two electrons are shown circling the nucleus in a fixed orbit depicted as a ring. Although this model is helpful in visualizing atomic structure, in reality, electrons do not travel in fixed orbits, but whiz around the nucleus erratically in a so-called electron cloud.', 'f4cfb698-a9c6-43e7-83af-57d42d2ca026': 'An atom’s protons and electrons carry electrical charges. Protons, with their positive charge, are designated p+. Electrons, which have a negative charge, are designated e–. An atom’s neutrons have no charge: they are electrically neutral. Just as a magnet sticks to a steel refrigerator because their opposite charges attract, the positively charged protons attract the negatively charged electrons. This mutual attraction gives the atom some structural stability. The attraction by the positively charged nucleus helps keep electrons from straying far. The number of protons and electrons within a neutral atom are equal, thus, the atom’s overall charge is balanced.'}"
+Figure 2.1.3,Anatomy_And_Physio/images/Figure 2.1.3.jpg,"Figure 2.1.3 – The Periodic Table of the Elements (credit: R.A. Dragoset, A. Musgrove, C.W. Clark, W.C. Martin)","The periodic table of the elements, shown in Figure 2.1.3, is a chart identifying the 92 elements found in nature, as well as several larger, unstable elements discovered experimentally. The elements are arranged in order of their atomic number, with hydrogen and helium at the top of the table, and the more massive elements below. The periodic table is a useful device because for each element, it identifies the chemical symbol, the atomic number, and the mass number, while organizing elements according to their propensity to react with other elements. The number of protons and electrons in an element are equal. The number of protons and neutrons may be equal for some elements, but are not equal for all.","{'f1d6775e-4b98-4c0d-b193-431c3bad60f4': 'An atom of carbon is unique to carbon, but a proton of carbon is not. One proton is the same as another, whether it is found in an atom of carbon, sodium (Na), or iron (Fe). The same is true for neutrons and electrons. So, what gives an element its distinctive properties—what makes carbon so different from sodium or iron? The answer is the unique quantity of protons each contains. Carbon by definition is an element whose atoms contain six protons. No other element has exactly six protons in its atoms. Moreover, all atoms of carbon, whether found in your liver or in a lump of coal, contain six protons. Thus, the atomic number, which is the number of protons in the nucleus of the atom, identifies the element. Since an atom usually has the same number of electrons as protons, the atomic number identifies the usual number of electrons as well.', '3a7f3ee4-e695-42f6-84e9-84444dca5ace': 'In their most common form, many elements also contain the same number of neutrons as protons. The most common form of carbon, for example, has six neutrons as well as six protons, for a total of 12 subatomic particles in its nucleus. An element’s mass number is the sum of the number of protons and neutrons in its nucleus. So the most common form of carbon’s mass number is 12. Electrons have so little mass that they do not appreciably contribute to the mass of an atom. Carbon is a relatively light element; Uranium (U), in contrast, has a mass number of 238 and is referred to as a heavy metal. Its atomic number is 92 (it has 92 protons) but it contains 146 neutrons; it has the most mass of all the naturally occurring elements.', '2d9c8413-90c1-4d7a-b8c1-cb01f4774c34': 'The periodic table of the elements, shown in Figure 2.1.3, is a chart identifying the 92 elements found in nature, as well as several larger, unstable elements discovered experimentally. The elements are arranged in order of their atomic number, with hydrogen and helium at the top of the table, and the more massive elements below. The periodic table is a useful device because for each element, it identifies the chemical symbol, the atomic number, and the mass number, while organizing elements according to their propensity to react with other elements. The number of protons and electrons in an element are equal. The number of protons and neutrons may be equal for some elements, but are not equal for all.'}"
+Figure 2.1.4,Anatomy_And_Physio/images/Figure 2.1.4.jpg,"Figure 2.1.4  -Isotopes of Hydrogen: Protium, designated 1H, has one proton and no neutrons. It is by far the most abundant isotope of hydrogen in nature. Deuterium, designated 2H, has one proton and one neutron. Tritium, designated 3H, has two neutrons.","Although each element has a unique number of protons, it can exist as different isotopes. An isotope is one of the different forms of an element, distinguished from one another by different numbers of neutrons. The standard isotope of carbon is 12C, commonly called carbon twelve. 12C has six protons and six neutrons, for a mass number of twelve. All of the isotopes of carbon have the same number of protons; therefore, 13C has seven neutrons, and 14C has eight neutrons. The different isotopes of an element can also be indicated with the mass number hyphenated (for example, C-12 instead of 12C). Hydrogen has three common isotopes, shown in Figure 2.1.4.","{'5e1055f3-fa26-436a-be1f-c29b7a01da2e': 'Although each element has a unique number of protons, it can exist as different isotopes. An isotope is one of the different forms of an element, distinguished from one another by different numbers of neutrons. The standard isotope of carbon is 12C, commonly called carbon twelve. 12C has six protons and six neutrons, for a mass number of twelve. All of the isotopes of carbon have the same number of protons; therefore, 13C has seven neutrons, and 14C has eight neutrons. The different isotopes of an element can also be indicated with the mass number hyphenated (for example, C-12 instead of 12C). Hydrogen has three common isotopes, shown in Figure 2.1.4.', 'ae33c006-1fd9-40fa-b9ca-fba49eeb797b': 'An isotope that contains more than the usual number of neutrons is referred to as a heavy isotope. An example is 14C. Heavy isotopes tend to be unstable, and unstable isotopes are radioactive. A radioactive isotope is an isotope whose nucleus readily decays, giving off subatomic particles and electromagnetic energy. Different radioactive isotopes (also called radioisotopes) differ in their half-life, the time it takes for half of any size sample of an isotope to decay. For example, the half-life of tritium—a radioisotope of hydrogen—is about 12 years, indicating it takes 12 years for half of the tritium nuclei in a sample to decay. Excessive exposure to radioactive isotopes can damage human cells and even cause cancer and birth defects, but when exposure is controlled, some radioactive isotopes can be useful in medicine. For more information, see the Career Connections.'}"
+Figure 2.1.6,Anatomy_And_Physio/images/Figure 2.1.6.jpg,"Figure 2.1.6 Electron Shells: Electrons orbit the atomic nucleus at distinct levels of energy called electron shells. (a) With one electron, hydrogen only half-fills its electron shell. Helium also has a single shell, but its two electrons completely fill it. (b) The electrons of carbon completely fill its first electron shell, but only half-fills its second. (c) Neon, an element that does not occur in the body, has 10 electrons, filling both of its electron shells.","The atoms of the elements found in the human body have from one to five electron shells, and all electron shells hold eight electrons except the first shell, which can only hold two. This configuration of electron shells is the same for all atoms. The precise number of shells depends on the number of electrons in the atom. Hydrogen and helium have just one and two electrons, respectively. If you take a look at the periodic table of the elements, you will notice that hydrogen and helium are placed alone on either sides of the top row; they are the only elements that have just one electron shell (Figure 2.1.6). A second shell is necessary to hold the electrons in all elements larger than hydrogen and helium.","{'3a174e8e-3a5d-4155-8543-508e39bd7cb3': 'In the human body, atoms do not exist as independent entities. Rather, they are constantly reacting with other atoms to form and to break down more complex substances. To fully understand anatomy and physiology you must grasp how atoms participate in such reactions. The key is understanding the behavior of electrons.', 'ffbca70d-7dc7-415d-8a63-923e50045b97': 'Although electrons do not follow rigid orbits a set distance away from the atom’s nucleus, they do tend to stay within certain regions of space called electron shells. An electron shell is a layer of electrons that encircle the nucleus at a distinct energy level.', 'd3446886-12a5-4be6-995d-20a3605bbd12': 'The atoms of the elements found in the human body have from one to five electron shells, and all electron shells hold eight electrons except the first shell, which can only hold two. This configuration of electron shells is the same for all atoms. The precise number of shells depends on the number of electrons in the atom. Hydrogen and helium have just one and two electrons, respectively. If you take a look at the periodic table of the elements, you will notice that hydrogen and helium are placed alone on either sides of the top row; they are the only elements that have just one electron shell (Figure 2.1.6). A second shell is necessary to hold the electrons in all elements larger than hydrogen and helium.', 'c165a4ad-1abf-454c-b5bf-0e14be886df2': 'Lithium (Li), whose atomic number is 3, has three electrons. Two of these fill the first electron shell, and the third spills over into a second shell. The second electron shell can accommodate as many as eight electrons. Carbon, with its six electrons, entirely fills its first shell, and half-fills its second. With ten electrons, neon (Ne) entirely fills its two electron shells. Again, a look at the periodic table reveals that all of the elements in the second row, from lithium to neon, have just two electron shells. Atoms with more than ten electrons require more than two shells. These elements occupy the third and subsequent rows of the periodic table.', '8204706a-0ee8-49af-9eab-bfeab545d7d4': 'The factor that most strongly governs the tendency of an atom to participate in chemical reactions is the number of electrons in its valence shell. A valence shell is an atom’s outermost electron shell. If the valence shell is full, the atom is stable, meaning its electrons are unlikely to be pulled away from the nucleus by the electrical charge of other atoms. If the valence shell is not full, the atom is reactive, meaning it will tend to react with other atoms in ways that make the valence shell full. Consider hydrogen, with its one electron only half-filling its valence shell. This single electron is likely to be drawn into relationships with the atoms of other elements, so that hydrogen’s single valence shell can be stabilized.', 'b2f3784b-4e51-4043-bd25-516e307c1f00': 'All atoms (except hydrogen and helium with their single electron shells) are most stable when there are exactly eight electrons in their valence shell. This principle is referred to as the octet rule, and it states that an atom will give up, gain, or share electrons with another atom so that it ends up with eight electrons in its own valence shell. For example, oxygen, with six electrons in its valence shell, is likely to react with other atoms in a way that results in the addition of two electrons to oxygen’s valence shell, bringing the number to eight. When two hydrogen atoms each share their single electron with oxygen, covalent bonds are formed, resulting in a molecule of water, H2O.', '7b8f9b0c-a65f-4890-8b6e-40bdf4beb8d2': 'In nature, atoms of one element tend to join with atoms of other elements in characteristic ways. For example, carbon commonly fills its valence shell by linking up with four atoms of hydrogen. In so doing, the two elements form the simplest of organic molecules—methane—which also is one of the most abundant and stable carbon-containing compounds on Earth. As stated above, another example is water; oxygen needs two electrons to fill its valence shell. It commonly interacts with two atoms of hydrogen, forming H2O. Incidentally, the name “hydrogen” reflects its contribution to water (hydro- = “water”; -gen = “maker”). Thus, hydrogen is the “water maker.”', 'e0b06513-da5b-40f9-b832-49be3e41a1df': 'The smallest, most fundamental material components of the human body are basic chemical elements. In fact, chemicals called nucleotide bases are the foundation of the genetic code with the instructions on how to build and maintain the human body from conception through old age. There are about three billion of these base pairs in human DNA.', '7913d6ae-ee5d-4cb9-bb2d-84445d99fdb8': 'Human chemistry includes organic molecules (carbon-based) and biochemicals (those produced by the body). Human chemistry also includes elements. In fact, life cannot exist without many of the elements that are part of the earth. All of the elements that contribute to chemical reactions, to the transformation of energy, and to electrical activity and muscle contraction—elements that include phosphorus, carbon, sodium, and calcium, to name a few—originated in stars.', '7e889b38-cbb8-4291-b662-698375ab69f7': 'These elements, in turn, can form both the inorganic and organic chemical compounds important to life, including, water, glucose, and proteins. This chapter begins by examining elements and how the structures of atoms, the basic units of matter, determine the characteristics of elements by the number of protons, neutrons, and electrons in the atoms. The chapter then builds the framework of life from there.', 'dd7a1898-24d5-48de-be31-1a0fced62efb': 'For thousands of years, fear of the dead and legal sanctions limited the ability of anatomists and physicians to study the internal structures of the human body. An inability to control bleeding, infection, and pain made surgeries infrequent, and those that were performed—such as wound suturing, amputations, tooth and tumor removals, skull drilling, and cesarean births—did not greatly advance knowledge about internal anatomy. Theories about the function of the body and about disease were therefore largely based on external observations and imagination. During the fourteenth and fifteenth centuries, however, the detailed anatomical drawings of Italian artist and anatomist Leonardo da Vinci and Flemish anatomist Andreas Vesalius were published, and interest in human anatomy began to increase. Medical schools began to teach anatomy using human dissection; some resorted to grave robbing to obtain corpses. Laws were eventually passed that enabled students to dissect the corpses of criminals and those who donated their bodies for research. Still, it was not until the late nineteenth century that medical researchers discovered non-surgical methods to look inside the living body.'}"
+Figure 1.5.1,Anatomy_And_Physio/images/Figure 1.5.1.jpg,"Figure 1.5.1 – X-Ray of a Hand:  High energy electromagnetic radiation allows the internal structures of the body, such as bones, to be seen in X-rays like these. (credit: Trace Meek/flickr)","The X-ray is a form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases. As they are used in medicine, X-rays are emitted from an X-ray machine and directed toward a specially treated metallic plate placed behind the patient’s body. The beam of radiation results in darkening of the X-ray plate. X-rays are slightly impeded by soft tissues, which show up as gray on the X-ray plate, whereas hard tissues, such as bone, largely block the rays, producing a light-toned “shadow.” Thus, X-rays are best used to visualize hard body structures such as teeth and bones (Figure 1.5.1). Like many forms of high energy radiation, however, X-rays are capable of damaging cells and initiating changes that can lead to cancer. This danger of excessive exposure to X-rays was not fully appreciated for many years after their widespread use.","{'7c6bda9e-914e-431d-8434-3b69f902fbc8': 'German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible “ray” would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an “X-ray” image (as it came to be called) of his wife’s hand. Scientists around the world quickly began their own experiments with X-rays, and by 1900, X-rays were widely used to detect a variety of injuries and diseases. In 1901, Röntgen was awarded the first Nobel Prize for physics for his work in this field.', '4bd0060a-a31e-4534-b7ea-17bc13ae2306': 'The X-ray is a form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases. As they are used in medicine, X-rays are emitted from an X-ray machine and directed toward a specially treated metallic plate placed behind the patient’s body. The beam of radiation results in darkening of the X-ray plate. X-rays are slightly impeded by soft tissues, which show up as gray on the X-ray plate, whereas hard tissues, such as bone, largely block the rays, producing a light-toned “shadow.” Thus, X-rays are best used to visualize hard body structures such as teeth and bones (Figure 1.5.1). Like many forms of high energy radiation, however, X-rays are capable of damaging cells and initiating changes that can lead to cancer. This danger of excessive exposure to X-rays was not fully appreciated for many years after their widespread use.', 'fc9f539b-34a2-4094-a771-aa67c6750766': 'Refinements and enhancements of X-ray techniques have continued throughout the twentieth and twenty-first centuries. Although often supplanted by more sophisticated imaging techniques, the X-ray remains a “workhorse” in medical imaging, especially for viewing fractures and for dentistry. The disadvantage of irradiation to the patient and the operator is now attenuated by proper shielding and by limiting exposure.'}"
+Figure 1.5.2,Anatomy_And_Physio/images/Figure 1.5.2.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons),"Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”","{'a2adbef1-bfa5-4e92-b7c2-6aa988e3c0a5': 'Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”', '2746074e-cab6-414d-bea7-6bc2c68185fa': 'Since 1970, the development of more powerful computers and more sophisticated software has made CT scanning routine for many types of diagnostic evaluations. It is especially useful for soft tissue scanning, such as of the brain and the thoracic and abdominal viscera. Its level of detail is so precise that it can allow physicians to measure the size of a mass down to a millimeter. The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. In fact, children who undergo CT scans are at increased risk of developing cancer, as are adults who have multiple CT scans.', '75376e78-e424-457f-b0cc-2f612bfd4733': 'Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device, which was in use clinically by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially to discover tumors. MRI also has the major advantage of not exposing patients to radiation.', '89a7dce4-b250-4f3f-bfc6-84cbf4969327': 'Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan (see Figure 1.5.2b), sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, and so on) cannot undergo MRI scanning because it can dislodge these implants.', '97349173-edc2-4dae-86fd-f0d57af07192': 'Functional MRIs (fMRIs), which detect the concentration of blood flow in certain parts of the body, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions, abnormalities, and diseases.', '05da35bc-47bc-4083-ba08-9c9855c3ca40': 'Positron emission tomography (PET) is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body. Although the first PET scanner was introduced in 1961, it took 15 more years before radiopharmaceuticals were combined with the technique and revolutionized its potential. The main advantage is that PET (see Figure 1.5.2c) can illustrate physiologic activity—including nutrient metabolism and blood flow—of the organ or organs being targeted, whereas CT and MRI scans can only show static images. PET is widely used to diagnose a multitude of conditions, such as heart disease, the spread of cancer, certain forms of infection, brain abnormalities, bone disease, and thyroid disease.', '43195399-ddc5-4a8a-a107-2fd854fa96fe': 'Ultrasonography is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology (see Figure 1.5.2d). Ultrasonography is the least invasive of all imaging techniques, and it is therefore used more freely in sensitive situations such as pregnancy. The technology was first developed in the 1940s and 1950s. Ultrasonography is used to study heart function, blood flow in the neck or extremities, certain conditions such as gallbladder disease, and fetal growth and development. The main disadvantages of ultrasonography are that the image quality is heavily operator-dependent and that it is unable to penetrate bone and gas.'}"
+Figure 1.5.2,Anatomy_And_Physio/images/Figure 1.5.2.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons),"Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”","{'a2adbef1-bfa5-4e92-b7c2-6aa988e3c0a5': 'Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”', '2746074e-cab6-414d-bea7-6bc2c68185fa': 'Since 1970, the development of more powerful computers and more sophisticated software has made CT scanning routine for many types of diagnostic evaluations. It is especially useful for soft tissue scanning, such as of the brain and the thoracic and abdominal viscera. Its level of detail is so precise that it can allow physicians to measure the size of a mass down to a millimeter. The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. In fact, children who undergo CT scans are at increased risk of developing cancer, as are adults who have multiple CT scans.', '75376e78-e424-457f-b0cc-2f612bfd4733': 'Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device, which was in use clinically by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially to discover tumors. MRI also has the major advantage of not exposing patients to radiation.', '89a7dce4-b250-4f3f-bfc6-84cbf4969327': 'Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan (see Figure 1.5.2b), sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, and so on) cannot undergo MRI scanning because it can dislodge these implants.', '97349173-edc2-4dae-86fd-f0d57af07192': 'Functional MRIs (fMRIs), which detect the concentration of blood flow in certain parts of the body, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions, abnormalities, and diseases.', '05da35bc-47bc-4083-ba08-9c9855c3ca40': 'Positron emission tomography (PET) is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body. Although the first PET scanner was introduced in 1961, it took 15 more years before radiopharmaceuticals were combined with the technique and revolutionized its potential. The main advantage is that PET (see Figure 1.5.2c) can illustrate physiologic activity—including nutrient metabolism and blood flow—of the organ or organs being targeted, whereas CT and MRI scans can only show static images. PET is widely used to diagnose a multitude of conditions, such as heart disease, the spread of cancer, certain forms of infection, brain abnormalities, bone disease, and thyroid disease.', '43195399-ddc5-4a8a-a107-2fd854fa96fe': 'Ultrasonography is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology (see Figure 1.5.2d). Ultrasonography is the least invasive of all imaging techniques, and it is therefore used more freely in sensitive situations such as pregnancy. The technology was first developed in the 1940s and 1950s. Ultrasonography is used to study heart function, blood flow in the neck or extremities, certain conditions such as gallbladder disease, and fetal growth and development. The main disadvantages of ultrasonography are that the image quality is heavily operator-dependent and that it is unable to penetrate bone and gas.'}"
+Figure 1.5.2,Anatomy_And_Physio/images/Figure 1.5.2.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons),"Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”","{'a2adbef1-bfa5-4e92-b7c2-6aa988e3c0a5': 'Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”', '2746074e-cab6-414d-bea7-6bc2c68185fa': 'Since 1970, the development of more powerful computers and more sophisticated software has made CT scanning routine for many types of diagnostic evaluations. It is especially useful for soft tissue scanning, such as of the brain and the thoracic and abdominal viscera. Its level of detail is so precise that it can allow physicians to measure the size of a mass down to a millimeter. The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. In fact, children who undergo CT scans are at increased risk of developing cancer, as are adults who have multiple CT scans.', '75376e78-e424-457f-b0cc-2f612bfd4733': 'Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device, which was in use clinically by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially to discover tumors. MRI also has the major advantage of not exposing patients to radiation.', '89a7dce4-b250-4f3f-bfc6-84cbf4969327': 'Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan (see Figure 1.5.2b), sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, and so on) cannot undergo MRI scanning because it can dislodge these implants.', '97349173-edc2-4dae-86fd-f0d57af07192': 'Functional MRIs (fMRIs), which detect the concentration of blood flow in certain parts of the body, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions, abnormalities, and diseases.', '05da35bc-47bc-4083-ba08-9c9855c3ca40': 'Positron emission tomography (PET) is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body. Although the first PET scanner was introduced in 1961, it took 15 more years before radiopharmaceuticals were combined with the technique and revolutionized its potential. The main advantage is that PET (see Figure 1.5.2c) can illustrate physiologic activity—including nutrient metabolism and blood flow—of the organ or organs being targeted, whereas CT and MRI scans can only show static images. PET is widely used to diagnose a multitude of conditions, such as heart disease, the spread of cancer, certain forms of infection, brain abnormalities, bone disease, and thyroid disease.', '43195399-ddc5-4a8a-a107-2fd854fa96fe': 'Ultrasonography is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology (see Figure 1.5.2d). Ultrasonography is the least invasive of all imaging techniques, and it is therefore used more freely in sensitive situations such as pregnancy. The technology was first developed in the 1940s and 1950s. Ultrasonography is used to study heart function, blood flow in the neck or extremities, certain conditions such as gallbladder disease, and fetal growth and development. The main disadvantages of ultrasonography are that the image quality is heavily operator-dependent and that it is unable to penetrate bone and gas.'}"
+Figure 1.5.2,Anatomy_And_Physio/images/Figure 1.5.2.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons),"Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”","{'a2adbef1-bfa5-4e92-b7c2-6aa988e3c0a5': 'Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”', '2746074e-cab6-414d-bea7-6bc2c68185fa': 'Since 1970, the development of more powerful computers and more sophisticated software has made CT scanning routine for many types of diagnostic evaluations. It is especially useful for soft tissue scanning, such as of the brain and the thoracic and abdominal viscera. Its level of detail is so precise that it can allow physicians to measure the size of a mass down to a millimeter. The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. In fact, children who undergo CT scans are at increased risk of developing cancer, as are adults who have multiple CT scans.', '75376e78-e424-457f-b0cc-2f612bfd4733': 'Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device, which was in use clinically by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially to discover tumors. MRI also has the major advantage of not exposing patients to radiation.', '89a7dce4-b250-4f3f-bfc6-84cbf4969327': 'Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan (see Figure 1.5.2b), sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, and so on) cannot undergo MRI scanning because it can dislodge these implants.', '97349173-edc2-4dae-86fd-f0d57af07192': 'Functional MRIs (fMRIs), which detect the concentration of blood flow in certain parts of the body, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions, abnormalities, and diseases.', '05da35bc-47bc-4083-ba08-9c9855c3ca40': 'Positron emission tomography (PET) is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body. Although the first PET scanner was introduced in 1961, it took 15 more years before radiopharmaceuticals were combined with the technique and revolutionized its potential. The main advantage is that PET (see Figure 1.5.2c) can illustrate physiologic activity—including nutrient metabolism and blood flow—of the organ or organs being targeted, whereas CT and MRI scans can only show static images. PET is widely used to diagnose a multitude of conditions, such as heart disease, the spread of cancer, certain forms of infection, brain abnormalities, bone disease, and thyroid disease.', '43195399-ddc5-4a8a-a107-2fd854fa96fe': 'Ultrasonography is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology (see Figure 1.5.2d). Ultrasonography is the least invasive of all imaging techniques, and it is therefore used more freely in sensitive situations such as pregnancy. The technology was first developed in the 1940s and 1950s. Ultrasonography is used to study heart function, blood flow in the neck or extremities, certain conditions such as gallbladder disease, and fetal growth and development. The main disadvantages of ultrasonography are that the image quality is heavily operator-dependent and that it is unable to penetrate bone and gas.'}"
+Figure 1.4.1,Anatomy_And_Physio/images/Figure 1.4.1.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.,"To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.4.1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.","{'2f7fea39-44da-49eb-809f-95c79cc0452b': 'To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.4.1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.', 'b956492f-1f54-41c1-ac70-0dc067ea1607': 'The human body’s numerous regions have specific terms to help increase precision (see Figure 1.4.1). Notice that the term “brachium” or “arm” is reserved for the “upper arm” and “antebrachium” or “forearm” is used rather than “lower arm.” Similarly, “femur” or “thigh” is correct, and “leg” or “crus” is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body’s regions using the terms from the figure.'}"
+Figure 1.4.1,Anatomy_And_Physio/images/Figure 1.4.1.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.,"To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.4.1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.","{'2f7fea39-44da-49eb-809f-95c79cc0452b': 'To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.4.1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.', 'b956492f-1f54-41c1-ac70-0dc067ea1607': 'The human body’s numerous regions have specific terms to help increase precision (see Figure 1.4.1). Notice that the term “brachium” or “arm” is reserved for the “upper arm” and “antebrachium” or “forearm” is used rather than “lower arm.” Similarly, “femur” or “thigh” is correct, and “leg” or “crus” is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body’s regions using the terms from the figure.'}"
+Figure 1.4.2,Anatomy_And_Physio/images/Figure 1.4.2.jpg,Figure 1.4.2 – Directional Terms Applied to the Human Body: Paired directional terms are shown as applied to the human body.,"Certain directional anatomical terms appear throughout this and any other anatomy textbook (Figure 1.4.2). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.","{'7a2b8164-5049-4810-9f53-383c9ef75d02': 'Certain directional anatomical terms appear throughout this and any other anatomy textbook (Figure 1.4.2). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.', '0b490cf8-2b55-4dab-a9ad-be8910489c42': 'Anterior (or ventral) describes the front or direction toward the front of the body. The toes are anterior to the foot.', '075709c0-4fb5-4f3d-9eca-fb1005a8dc33': 'Posterior (or dorsal) describes the back or direction toward the back of the body. The popliteus is posterior to the patella.', '953f5365-0c0e-4112-afa4-3ecd97aaa9d5': 'Superior (or cranial) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.', 'b0ce2bf7-a568-45ec-9279-8177b238efa2': 'Inferior (or caudal) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.', '288a3f4e-265e-4d73-b636-51c02c640505': 'Lateral describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.', '17ed0547-c0ff-432a-8564-a400ee05a681': 'Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe.', 'f2b70443-4484-4b2e-b03c-519072353db6': 'Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.', 'a3a330e4-3990-480c-9750-2fdf01a71757': 'Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.', '5ce40270-2990-4898-baaa-e9ac51757348': 'Superficial describes a position closer to the surface of the body. The skin is superficial to the bones.', '5eb3e16e-6a34-4025-a0c5-290d4c06704f': 'Deep describes a position farther from the surface of the body. The brain is deep to the skull.'}"
+Figure 1.4.3,Anatomy_And_Physio/images/Figure 1.4.3.jpg,"Figure 1.4.3 – Planes of the Body: The three planes most commonly used in anatomical and medical imaging are the sagittal, frontal (or coronal), and transverse planes.","A section is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain “virtual sections” of living bodies. We call these scans. Body sections and scans can be correctly interpreted, only if the viewer understands the plane along which the section was made. A plane is an imaginary, two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure 1.4.3.","{'3325b3b8-99a0-4726-b239-a858e98af825': 'A section is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain “virtual sections” of living bodies. We call these scans. Body sections and scans can be correctly interpreted, only if the viewer understands the plane along which the section was made. A plane is an imaginary, two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure 1.4.3.'}"
+Figure 1.4.4,Anatomy_And_Physio/images/Figure 1.4.4.jpg,Figure 1.4.4 – Regions and Quadrants of the Peritoneal Cavity: There are (a) nine abdominal regions and (b) four abdominal quadrants in the peritoneal cavity.,"To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).","{'846b8121-4f7a-4128-a8ac-7e8e70d48cd9': 'To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).', 'abcdf987-860c-490a-8a20-b253c75df6f1': 'The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).', '65f8d785-acd2-4e9f-b377-f6092a7ff402': 'Maintaining a stable system requires the body to continuously monitor its internal conditions. Though certain physiological systems operate within frequently larger ranges, certain body parameters are tightly controlled homeostatically. For example, body temperature and blood pressure are controlled within a very narrow range. A set point is the physiological value around which the normal range fluctuates. For example, the set point for typical human body temperature is approximately 37°C (98.6°F). Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a range of a few degrees above and below that point. Receptors located in the body’s key places detect changes from this set point and relay information to the control centers located in the brain. The control centers monitor and send information to effector organs to control the body’s response. If these effectors reverse the original condition, the system is said to be regulated through negative feedback.', '0bd5dffa-52d4-408a-a548-f33cb9f2c6fc': 'Control centers in the brain and other parts of the body monitor and react to deviations from this set point using negative feedback. Negative feedback is a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range. The maintenance of homeostasis by negative feedback goes on throughout the body at all times and an understanding of negative feedback is thus fundamental to an understanding of human physiology.', '8dafcb7b-0756-445d-9345-aeba6c8f841f': 'A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.', 'bd96d4e5-6d63-4cf0-b511-7577f90dd506': 'In order to set the system in motion, a stimulus must drive a physiological parameter beyond its normal range (that is, beyond homeostasis). This stimulus is “heard” by a specific sensor. For example, in the control of blood glucose, specific endocrine cells in the pancreas detect excess glucose (the stimulus) in the bloodstream. These pancreatic beta cells respond to the increased level of blood glucose by releasing the hormone (insulin) into the bloodstream. The insulin signals skeletal muscle fibers, fat cells (adipocytes), and liver cells to take up the excess glucose, removing it from the bloodstream. As glucose concentration in the bloodstream drops, the decrease in concentration—the actual negative feedback—is detected by pancreatic alpha cells, and insulin release stops. This prevents blood sugar levels from continuing to drop below the normal range.', 'c8706d9f-e2d4-476f-afa1-c8457e4a531f': 'Humans have a similar temperature regulation feedback system that works by promoting either heat loss or heat gain (Figure 1.3.2b). When the brain’s temperature regulation center receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the “heat-loss center.” This stimulation has three major effects:', '45f3f158-b221-4d88-8182-30f3f3c11795': 'Blood vessels in the skin begin to dilate allowing more blood from the body core to flow to the surface of the skin allowing the heat to radiate into the environment.', 'da1d3cda-4eca-43e0-ace9-5b84595182ba': 'As blood flow to the skin increases, sweat glands are activated to increase their output. As the sweat evaporates from the skin surface into the surrounding air, it takes heat with it.', 'c0f48bf5-e340-485c-a77f-d6196cafd138': 'The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the lungs.', '0089ad1d-b980-4678-9a39-c408eb77167d': 'In contrast, activation of the brain’s heat-gain center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of deep veins. This arrangement traps heat closer to the body core and restricts heat loss. If heat loss is severe, the brain triggers an increase in random signals to skeletal muscles, causing them to contract, producing shivering. The muscle contractions of shivering release heat while using up ATP. The brain triggers the thyroid gland in the endocrine system to release thyroid hormone, which increases metabolic activity and heat production in cells throughout the body. The brain also signals the adrenal glands to release epinephrine (adrenaline), a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production.', 'b51f3796-55f9-4094-b233-3836c94f1c7f': 'Positive feedback intensifies a change in the body’s physiological condition rather than reversing it. A deviation from the normal range results in more change, and the system moves farther away from the normal range. Positive feedback in the body is normal only when there is a definite end point. Childbirth and the body’s response to blood loss are two examples of positive feedback loops that are normal but are activated only when needed.', '02ba0313-acc4-443a-b377-864067a8a583': 'Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).', '8a4b14f3-b3a7-4b52-aa04-f744896f22ce': 'The first contractions of labor (the stimulus) push the baby toward the cervix (the lowest part of the uterus). The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching (the sensors). These nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain to release the hormone oxytocin into the bloodstream. Oxytocin causes stronger contractions of the smooth muscles in of the uterus (the effectors), pushing the baby further down the birth canal. This causes even greater stretching of the cervix. The cycle of stretching, oxytocin release, and increasingly more forceful contractions stops only when the baby is born. At this point, the stretching of the cervix halts, stopping the release of oxytocin.', 'f9b3238e-228c-4389-b578-7b611478be8b': 'A second example of positive feedback centers on reversing extreme damage to the body. Following a penetrating wound, the most immediate threat is excessive blood loss. Less blood circulating means reduced blood pressure and reduced perfusion (penetration of blood) to the brain and other vital organs. If perfusion is severely reduced, vital organs will shut down and the person will die. The body responds to this potential catastrophe by releasing substances in the injured blood vessel wall that begin the process of blood clotting. As each step of clotting occurs, it stimulates the release of more clotting substances. This accelerates the processes of clotting and sealing off the damaged area. Clotting is contained in a local area based on the tightly controlled availability of clotting proteins. This is an adaptive, life-saving cascade of events.', '7595f975-1a68-4e72-9c86-434916c05ba6': 'Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity, such as (from smallest to largest): chemicals, cells, tissues, organs, organ systems, and an organism.', '6416f373-ee5f-4848-a60b-69cddb7afe29': 'The organization of the body often is discussed in terms of the distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.'}"
+Figure 1.3.2,Anatomy_And_Physio/images/Figure 1.3.2.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback.","A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.","{'846b8121-4f7a-4128-a8ac-7e8e70d48cd9': 'To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).', 'abcdf987-860c-490a-8a20-b253c75df6f1': 'The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).', '65f8d785-acd2-4e9f-b377-f6092a7ff402': 'Maintaining a stable system requires the body to continuously monitor its internal conditions. Though certain physiological systems operate within frequently larger ranges, certain body parameters are tightly controlled homeostatically. For example, body temperature and blood pressure are controlled within a very narrow range. A set point is the physiological value around which the normal range fluctuates. For example, the set point for typical human body temperature is approximately 37°C (98.6°F). Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a range of a few degrees above and below that point. Receptors located in the body’s key places detect changes from this set point and relay information to the control centers located in the brain. The control centers monitor and send information to effector organs to control the body’s response. If these effectors reverse the original condition, the system is said to be regulated through negative feedback.', '0bd5dffa-52d4-408a-a548-f33cb9f2c6fc': 'Control centers in the brain and other parts of the body monitor and react to deviations from this set point using negative feedback. Negative feedback is a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range. The maintenance of homeostasis by negative feedback goes on throughout the body at all times and an understanding of negative feedback is thus fundamental to an understanding of human physiology.', '8dafcb7b-0756-445d-9345-aeba6c8f841f': 'A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.', 'bd96d4e5-6d63-4cf0-b511-7577f90dd506': 'In order to set the system in motion, a stimulus must drive a physiological parameter beyond its normal range (that is, beyond homeostasis). This stimulus is “heard” by a specific sensor. For example, in the control of blood glucose, specific endocrine cells in the pancreas detect excess glucose (the stimulus) in the bloodstream. These pancreatic beta cells respond to the increased level of blood glucose by releasing the hormone (insulin) into the bloodstream. The insulin signals skeletal muscle fibers, fat cells (adipocytes), and liver cells to take up the excess glucose, removing it from the bloodstream. As glucose concentration in the bloodstream drops, the decrease in concentration—the actual negative feedback—is detected by pancreatic alpha cells, and insulin release stops. This prevents blood sugar levels from continuing to drop below the normal range.', 'c8706d9f-e2d4-476f-afa1-c8457e4a531f': 'Humans have a similar temperature regulation feedback system that works by promoting either heat loss or heat gain (Figure 1.3.2b). When the brain’s temperature regulation center receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the “heat-loss center.” This stimulation has three major effects:', '45f3f158-b221-4d88-8182-30f3f3c11795': 'Blood vessels in the skin begin to dilate allowing more blood from the body core to flow to the surface of the skin allowing the heat to radiate into the environment.', 'da1d3cda-4eca-43e0-ace9-5b84595182ba': 'As blood flow to the skin increases, sweat glands are activated to increase their output. As the sweat evaporates from the skin surface into the surrounding air, it takes heat with it.', 'c0f48bf5-e340-485c-a77f-d6196cafd138': 'The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the lungs.', '0089ad1d-b980-4678-9a39-c408eb77167d': 'In contrast, activation of the brain’s heat-gain center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of deep veins. This arrangement traps heat closer to the body core and restricts heat loss. If heat loss is severe, the brain triggers an increase in random signals to skeletal muscles, causing them to contract, producing shivering. The muscle contractions of shivering release heat while using up ATP. The brain triggers the thyroid gland in the endocrine system to release thyroid hormone, which increases metabolic activity and heat production in cells throughout the body. The brain also signals the adrenal glands to release epinephrine (adrenaline), a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production.', 'b51f3796-55f9-4094-b233-3836c94f1c7f': 'Positive feedback intensifies a change in the body’s physiological condition rather than reversing it. A deviation from the normal range results in more change, and the system moves farther away from the normal range. Positive feedback in the body is normal only when there is a definite end point. Childbirth and the body’s response to blood loss are two examples of positive feedback loops that are normal but are activated only when needed.', '02ba0313-acc4-443a-b377-864067a8a583': 'Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).', '8a4b14f3-b3a7-4b52-aa04-f744896f22ce': 'The first contractions of labor (the stimulus) push the baby toward the cervix (the lowest part of the uterus). The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching (the sensors). These nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain to release the hormone oxytocin into the bloodstream. Oxytocin causes stronger contractions of the smooth muscles in of the uterus (the effectors), pushing the baby further down the birth canal. This causes even greater stretching of the cervix. The cycle of stretching, oxytocin release, and increasingly more forceful contractions stops only when the baby is born. At this point, the stretching of the cervix halts, stopping the release of oxytocin.', 'f9b3238e-228c-4389-b578-7b611478be8b': 'A second example of positive feedback centers on reversing extreme damage to the body. Following a penetrating wound, the most immediate threat is excessive blood loss. Less blood circulating means reduced blood pressure and reduced perfusion (penetration of blood) to the brain and other vital organs. If perfusion is severely reduced, vital organs will shut down and the person will die. The body responds to this potential catastrophe by releasing substances in the injured blood vessel wall that begin the process of blood clotting. As each step of clotting occurs, it stimulates the release of more clotting substances. This accelerates the processes of clotting and sealing off the damaged area. Clotting is contained in a local area based on the tightly controlled availability of clotting proteins. This is an adaptive, life-saving cascade of events.', '7595f975-1a68-4e72-9c86-434916c05ba6': 'Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity, such as (from smallest to largest): chemicals, cells, tissues, organs, organ systems, and an organism.', '6416f373-ee5f-4848-a60b-69cddb7afe29': 'The organization of the body often is discussed in terms of the distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.'}"
+Figure 1.3.2,Anatomy_And_Physio/images/Figure 1.3.2.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback.","A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.","{'846b8121-4f7a-4128-a8ac-7e8e70d48cd9': 'To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).', 'abcdf987-860c-490a-8a20-b253c75df6f1': 'The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).', '65f8d785-acd2-4e9f-b377-f6092a7ff402': 'Maintaining a stable system requires the body to continuously monitor its internal conditions. Though certain physiological systems operate within frequently larger ranges, certain body parameters are tightly controlled homeostatically. For example, body temperature and blood pressure are controlled within a very narrow range. A set point is the physiological value around which the normal range fluctuates. For example, the set point for typical human body temperature is approximately 37°C (98.6°F). Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a range of a few degrees above and below that point. Receptors located in the body’s key places detect changes from this set point and relay information to the control centers located in the brain. The control centers monitor and send information to effector organs to control the body’s response. If these effectors reverse the original condition, the system is said to be regulated through negative feedback.', '0bd5dffa-52d4-408a-a548-f33cb9f2c6fc': 'Control centers in the brain and other parts of the body monitor and react to deviations from this set point using negative feedback. Negative feedback is a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range. The maintenance of homeostasis by negative feedback goes on throughout the body at all times and an understanding of negative feedback is thus fundamental to an understanding of human physiology.', '8dafcb7b-0756-445d-9345-aeba6c8f841f': 'A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.', 'bd96d4e5-6d63-4cf0-b511-7577f90dd506': 'In order to set the system in motion, a stimulus must drive a physiological parameter beyond its normal range (that is, beyond homeostasis). This stimulus is “heard” by a specific sensor. For example, in the control of blood glucose, specific endocrine cells in the pancreas detect excess glucose (the stimulus) in the bloodstream. These pancreatic beta cells respond to the increased level of blood glucose by releasing the hormone (insulin) into the bloodstream. The insulin signals skeletal muscle fibers, fat cells (adipocytes), and liver cells to take up the excess glucose, removing it from the bloodstream. As glucose concentration in the bloodstream drops, the decrease in concentration—the actual negative feedback—is detected by pancreatic alpha cells, and insulin release stops. This prevents blood sugar levels from continuing to drop below the normal range.', 'c8706d9f-e2d4-476f-afa1-c8457e4a531f': 'Humans have a similar temperature regulation feedback system that works by promoting either heat loss or heat gain (Figure 1.3.2b). When the brain’s temperature regulation center receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the “heat-loss center.” This stimulation has three major effects:', '45f3f158-b221-4d88-8182-30f3f3c11795': 'Blood vessels in the skin begin to dilate allowing more blood from the body core to flow to the surface of the skin allowing the heat to radiate into the environment.', 'da1d3cda-4eca-43e0-ace9-5b84595182ba': 'As blood flow to the skin increases, sweat glands are activated to increase their output. As the sweat evaporates from the skin surface into the surrounding air, it takes heat with it.', 'c0f48bf5-e340-485c-a77f-d6196cafd138': 'The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the lungs.', '0089ad1d-b980-4678-9a39-c408eb77167d': 'In contrast, activation of the brain’s heat-gain center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of deep veins. This arrangement traps heat closer to the body core and restricts heat loss. If heat loss is severe, the brain triggers an increase in random signals to skeletal muscles, causing them to contract, producing shivering. The muscle contractions of shivering release heat while using up ATP. The brain triggers the thyroid gland in the endocrine system to release thyroid hormone, which increases metabolic activity and heat production in cells throughout the body. The brain also signals the adrenal glands to release epinephrine (adrenaline), a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production.', 'b51f3796-55f9-4094-b233-3836c94f1c7f': 'Positive feedback intensifies a change in the body’s physiological condition rather than reversing it. A deviation from the normal range results in more change, and the system moves farther away from the normal range. Positive feedback in the body is normal only when there is a definite end point. Childbirth and the body’s response to blood loss are two examples of positive feedback loops that are normal but are activated only when needed.', '02ba0313-acc4-443a-b377-864067a8a583': 'Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).', '8a4b14f3-b3a7-4b52-aa04-f744896f22ce': 'The first contractions of labor (the stimulus) push the baby toward the cervix (the lowest part of the uterus). The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching (the sensors). These nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain to release the hormone oxytocin into the bloodstream. Oxytocin causes stronger contractions of the smooth muscles in of the uterus (the effectors), pushing the baby further down the birth canal. This causes even greater stretching of the cervix. The cycle of stretching, oxytocin release, and increasingly more forceful contractions stops only when the baby is born. At this point, the stretching of the cervix halts, stopping the release of oxytocin.', 'f9b3238e-228c-4389-b578-7b611478be8b': 'A second example of positive feedback centers on reversing extreme damage to the body. Following a penetrating wound, the most immediate threat is excessive blood loss. Less blood circulating means reduced blood pressure and reduced perfusion (penetration of blood) to the brain and other vital organs. If perfusion is severely reduced, vital organs will shut down and the person will die. The body responds to this potential catastrophe by releasing substances in the injured blood vessel wall that begin the process of blood clotting. As each step of clotting occurs, it stimulates the release of more clotting substances. This accelerates the processes of clotting and sealing off the damaged area. Clotting is contained in a local area based on the tightly controlled availability of clotting proteins. This is an adaptive, life-saving cascade of events.', '7595f975-1a68-4e72-9c86-434916c05ba6': 'Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity, such as (from smallest to largest): chemicals, cells, tissues, organs, organ systems, and an organism.', '6416f373-ee5f-4848-a60b-69cddb7afe29': 'The organization of the body often is discussed in terms of the distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.'}"
+Figure 1.3.3,Anatomy_And_Physio/images/Figure 1.3.3.jpg,"Figure 1.3.3 – Positive Feedback Loop: Normal childbirth is driven by a positive feedback loop. A positive feedback loop results in a change in the body’s status, rather than a return to homeostasis.","Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).","{'846b8121-4f7a-4128-a8ac-7e8e70d48cd9': 'To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).', 'abcdf987-860c-490a-8a20-b253c75df6f1': 'The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).', '65f8d785-acd2-4e9f-b377-f6092a7ff402': 'Maintaining a stable system requires the body to continuously monitor its internal conditions. Though certain physiological systems operate within frequently larger ranges, certain body parameters are tightly controlled homeostatically. For example, body temperature and blood pressure are controlled within a very narrow range. A set point is the physiological value around which the normal range fluctuates. For example, the set point for typical human body temperature is approximately 37°C (98.6°F). Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a range of a few degrees above and below that point. Receptors located in the body’s key places detect changes from this set point and relay information to the control centers located in the brain. The control centers monitor and send information to effector organs to control the body’s response. If these effectors reverse the original condition, the system is said to be regulated through negative feedback.', '0bd5dffa-52d4-408a-a548-f33cb9f2c6fc': 'Control centers in the brain and other parts of the body monitor and react to deviations from this set point using negative feedback. Negative feedback is a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range. The maintenance of homeostasis by negative feedback goes on throughout the body at all times and an understanding of negative feedback is thus fundamental to an understanding of human physiology.', '8dafcb7b-0756-445d-9345-aeba6c8f841f': 'A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.', 'bd96d4e5-6d63-4cf0-b511-7577f90dd506': 'In order to set the system in motion, a stimulus must drive a physiological parameter beyond its normal range (that is, beyond homeostasis). This stimulus is “heard” by a specific sensor. For example, in the control of blood glucose, specific endocrine cells in the pancreas detect excess glucose (the stimulus) in the bloodstream. These pancreatic beta cells respond to the increased level of blood glucose by releasing the hormone (insulin) into the bloodstream. The insulin signals skeletal muscle fibers, fat cells (adipocytes), and liver cells to take up the excess glucose, removing it from the bloodstream. As glucose concentration in the bloodstream drops, the decrease in concentration—the actual negative feedback—is detected by pancreatic alpha cells, and insulin release stops. This prevents blood sugar levels from continuing to drop below the normal range.', 'c8706d9f-e2d4-476f-afa1-c8457e4a531f': 'Humans have a similar temperature regulation feedback system that works by promoting either heat loss or heat gain (Figure 1.3.2b). When the brain’s temperature regulation center receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the “heat-loss center.” This stimulation has three major effects:', '45f3f158-b221-4d88-8182-30f3f3c11795': 'Blood vessels in the skin begin to dilate allowing more blood from the body core to flow to the surface of the skin allowing the heat to radiate into the environment.', 'da1d3cda-4eca-43e0-ace9-5b84595182ba': 'As blood flow to the skin increases, sweat glands are activated to increase their output. As the sweat evaporates from the skin surface into the surrounding air, it takes heat with it.', 'c0f48bf5-e340-485c-a77f-d6196cafd138': 'The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the lungs.', '0089ad1d-b980-4678-9a39-c408eb77167d': 'In contrast, activation of the brain’s heat-gain center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of deep veins. This arrangement traps heat closer to the body core and restricts heat loss. If heat loss is severe, the brain triggers an increase in random signals to skeletal muscles, causing them to contract, producing shivering. The muscle contractions of shivering release heat while using up ATP. The brain triggers the thyroid gland in the endocrine system to release thyroid hormone, which increases metabolic activity and heat production in cells throughout the body. The brain also signals the adrenal glands to release epinephrine (adrenaline), a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production.', 'b51f3796-55f9-4094-b233-3836c94f1c7f': 'Positive feedback intensifies a change in the body’s physiological condition rather than reversing it. A deviation from the normal range results in more change, and the system moves farther away from the normal range. Positive feedback in the body is normal only when there is a definite end point. Childbirth and the body’s response to blood loss are two examples of positive feedback loops that are normal but are activated only when needed.', '02ba0313-acc4-443a-b377-864067a8a583': 'Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).', '8a4b14f3-b3a7-4b52-aa04-f744896f22ce': 'The first contractions of labor (the stimulus) push the baby toward the cervix (the lowest part of the uterus). The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching (the sensors). These nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain to release the hormone oxytocin into the bloodstream. Oxytocin causes stronger contractions of the smooth muscles in of the uterus (the effectors), pushing the baby further down the birth canal. This causes even greater stretching of the cervix. The cycle of stretching, oxytocin release, and increasingly more forceful contractions stops only when the baby is born. At this point, the stretching of the cervix halts, stopping the release of oxytocin.', 'f9b3238e-228c-4389-b578-7b611478be8b': 'A second example of positive feedback centers on reversing extreme damage to the body. Following a penetrating wound, the most immediate threat is excessive blood loss. Less blood circulating means reduced blood pressure and reduced perfusion (penetration of blood) to the brain and other vital organs. If perfusion is severely reduced, vital organs will shut down and the person will die. The body responds to this potential catastrophe by releasing substances in the injured blood vessel wall that begin the process of blood clotting. As each step of clotting occurs, it stimulates the release of more clotting substances. This accelerates the processes of clotting and sealing off the damaged area. Clotting is contained in a local area based on the tightly controlled availability of clotting proteins. This is an adaptive, life-saving cascade of events.', '7595f975-1a68-4e72-9c86-434916c05ba6': 'Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity, such as (from smallest to largest): chemicals, cells, tissues, organs, organ systems, and an organism.', '6416f373-ee5f-4848-a60b-69cddb7afe29': 'The organization of the body often is discussed in terms of the distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.'}"
+Figure 1.2.2,Anatomy_And_Physio/images/Figure 1.2.2.jpg,Figure 1.2.2 – Organ Systems of the Human Body: Organs that work together are grouped into organ systems.,"This book covers eleven distinct organ systems in the human body (Figure 1.2.2). Assigning organs to organ systems can be imprecise since organs that “belong” to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.","{'e97bee57-ac0d-4038-8fb7-34b2dc2e293b': 'To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements. Examples of these elements are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an atom. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a molecule, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures.', '07ab2479-e16d-4fcf-9af4-7de5f591f94f': 'A cell is the smallest independently functioning unit of a living organism. Single celled organisms, like bacteria, are extremely small, independently-living organisms with a cellular structure. Humans are multicellular organisms with independent cells working in concert together. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells.', '6cd4930c-ad56-4b24-a666-540437d45d56': 'A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid, with a variety of tiny functioning units called organelles. In humans, as in all organisms, cells perform all functions of life.', 'b100e6a6-b4e3-45e4-9c72-877f58b05c28': 'A tissue is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. An organ is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions. An organ system is a group of organs that work together to perform major functions or meet physiological needs of the body.', 'bc65b489-5db0-42f8-a50e-c2edc6254049': 'This book covers eleven distinct organ systems in the human body (Figure 1.2.2). Assigning organs to organ systems can be imprecise since organs that “belong” to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.', '63d4f050-3d67-49d7-96ac-6aa99aa731e3': 'The organism level is the highest level of organization. An organism is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In multi-cellular organisms, including humans, all cells, tissues, organs, and organ systems of the body work together to maintain the life and health of the organism.', '32e3acf5-411d-473c-bfbc-e953fd403a1c': 'Human anatomy is the scientific study of the body’s structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope, while other, larger structures can readily be seen, manipulated, measured, and weighed. The word “anatomy” comes from the Greek root “ana” which means “to cut apart” and “tomia” which means “to cut.” Human anatomy was first studied by observing the exterior of the body, wounds of soldiers, and other injuries. Later, physicians were allowed to dissect bodies of the dead to augment their knowledge. When a body is dissected, its structures are cut apart in order to observe their physical attributes and their relationships to one another. Dissection is still used in medical schools, anatomy courses, and in pathology labs. In order to observe structures in living people, however, a number of imaging techniques have been developed. These techniques allow clinicians to visualize structures inside the living body such as a cancerous tumor or a fractured bone.', 'e28f50ec-cd69-4ee6-a2bf-0fdf166d193f': 'Like most scientific disciplines, anatomy has areas of specialization. Gross anatomy is the study of the larger structures of the body, those visible without the aid of magnification (image below, Figure 1.1.1a). Gross and macro both mean “large,” thus, gross anatomy is also referred to as macroscopic anatomy. In contrast, micro means “small,” and microscopic anatomy is the study of structures that can be observed only with the use of a microscope or other magnification devices (image below, Figure 1.1.1b). Microscopic anatomy includes cytology, the study of cells, and histology, the study of tissues. As the technology of microscopes has advanced, anatomists have been able to observe smaller and smaller structures of the body, from slices of large structures like the heart, to the three-dimensional structures of large molecules in the body.', '94b8d645-b89e-4e42-b66e-d549524c7606': 'Anatomists take two general approaches to the study of the body’s structures: regional and systemic. Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. In contrast, systemic anatomy is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function. For example, a systemic anatomical study of the muscular system would consider all of the skeletal muscles of the body.', '5262367e-e192-4b5f-ab66-14e824d40f9d': 'Whereas anatomy is about structure, physiology is about function. Human physiology is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life. Much of the study of physiology centers on the body’s tendency toward homeostasis. Homeostasis is the state of steady internal conditions maintained by living things. The study of physiology certainly includes observation, both with the naked eye and with microscopes, as well as manipulations and measurements. Current advances in physiology usually depend on carefully designed laboratory experiments that reveal the functions of the many structures and chemical compounds that make up the human body.', '713d3772-59d9-4216-a482-c3829cddae2a': 'Like anatomists, physiologists typically specialize in a particular branch of physiology. For example, neurophysiology is the study of the brain, spinal cord, and nerves and how these work together to perform functions as complex and diverse as vision, movement, and thinking. Physiologists may work from the organ level (exploring, for example, what different parts of the brain does) to the molecular level (such as exploring how an electrochemical signal travels along nerves).', '2fc53a39-e50d-46e4-a37e-4502c3a1f6da': 'Form is closely related to function in all living things. For example, the thin flap of your eyelid can snap down to clear away dust particles and almost instantaneously slide back up to allow you to see again. At the microscopic level, the arrangement and function of the nerves and muscles that serve the eyelid allow for its quick action and retreat. At a smaller level of analysis, the function of these nerves and muscles likewise relies on the interactions of specific molecules and ions. Even the three-dimensional structure of certain molecules is essential to their function.', '51af7b80-b238-4869-b0cf-bb52caafe957': 'Your study of anatomy and physiology will make more sense if you continually relate the form of the structures you are studying to their function. In fact, it can be somewhat frustrating to attempt to study anatomy without an understanding of the physiology that a body structure supports. Imagine, for example, trying to appreciate the unique arrangement of the bones of the human hand if you had no conception of the function of the hand. Fortunately, your understanding of how the human hand manipulates tools—from pens to cell phones—helps you appreciate the unique alignment of the thumb in opposition to the four fingers, making your hand a structure that allows you to pinch and grasp objects and type text messages.'}"
+Figure 1.1.1,Anatomy_And_Physio/images/Figure 1.1.1.jpg,"Figure 1.1.1 – Gross and Microscopic Anatomy: (a) Gross anatomy considers large structures such as the brain. (b) Microscopic anatomy can deal with the same structures, though at a different scale. This is a micrograph of nerve cells from the brain. LM × 1600. (credit a: “WriterHound”/Wikimedia Commons; credit b: Micrograph provided by the Regents of University of Michigan Medical School © 2012)","Like most scientific disciplines, anatomy has areas of specialization. Gross anatomy is the study of the larger structures of the body, those visible without the aid of magnification (image below, Figure 1.1.1a). Gross and macro both mean “large,” thus, gross anatomy is also referred to as macroscopic anatomy. In contrast, micro means “small,” and microscopic anatomy is the study of structures that can be observed only with the use of a microscope or other magnification devices (image below, Figure 1.1.1b). Microscopic anatomy includes cytology, the study of cells, and histology, the study of tissues. As the technology of microscopes has advanced, anatomists have been able to observe smaller and smaller structures of the body, from slices of large structures like the heart, to the three-dimensional structures of large molecules in the body.","{'e97bee57-ac0d-4038-8fb7-34b2dc2e293b': 'To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements. Examples of these elements are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an atom. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a molecule, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures.', '07ab2479-e16d-4fcf-9af4-7de5f591f94f': 'A cell is the smallest independently functioning unit of a living organism. Single celled organisms, like bacteria, are extremely small, independently-living organisms with a cellular structure. Humans are multicellular organisms with independent cells working in concert together. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells.', '6cd4930c-ad56-4b24-a666-540437d45d56': 'A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid, with a variety of tiny functioning units called organelles. In humans, as in all organisms, cells perform all functions of life.', 'b100e6a6-b4e3-45e4-9c72-877f58b05c28': 'A tissue is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. An organ is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions. An organ system is a group of organs that work together to perform major functions or meet physiological needs of the body.', 'bc65b489-5db0-42f8-a50e-c2edc6254049': 'This book covers eleven distinct organ systems in the human body (Figure 1.2.2). Assigning organs to organ systems can be imprecise since organs that “belong” to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.', '63d4f050-3d67-49d7-96ac-6aa99aa731e3': 'The organism level is the highest level of organization. An organism is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In multi-cellular organisms, including humans, all cells, tissues, organs, and organ systems of the body work together to maintain the life and health of the organism.', '32e3acf5-411d-473c-bfbc-e953fd403a1c': 'Human anatomy is the scientific study of the body’s structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope, while other, larger structures can readily be seen, manipulated, measured, and weighed. The word “anatomy” comes from the Greek root “ana” which means “to cut apart” and “tomia” which means “to cut.” Human anatomy was first studied by observing the exterior of the body, wounds of soldiers, and other injuries. Later, physicians were allowed to dissect bodies of the dead to augment their knowledge. When a body is dissected, its structures are cut apart in order to observe their physical attributes and their relationships to one another. Dissection is still used in medical schools, anatomy courses, and in pathology labs. In order to observe structures in living people, however, a number of imaging techniques have been developed. These techniques allow clinicians to visualize structures inside the living body such as a cancerous tumor or a fractured bone.', 'e28f50ec-cd69-4ee6-a2bf-0fdf166d193f': 'Like most scientific disciplines, anatomy has areas of specialization. Gross anatomy is the study of the larger structures of the body, those visible without the aid of magnification (image below, Figure 1.1.1a). Gross and macro both mean “large,” thus, gross anatomy is also referred to as macroscopic anatomy. In contrast, micro means “small,” and microscopic anatomy is the study of structures that can be observed only with the use of a microscope or other magnification devices (image below, Figure 1.1.1b). Microscopic anatomy includes cytology, the study of cells, and histology, the study of tissues. As the technology of microscopes has advanced, anatomists have been able to observe smaller and smaller structures of the body, from slices of large structures like the heart, to the three-dimensional structures of large molecules in the body.', '94b8d645-b89e-4e42-b66e-d549524c7606': 'Anatomists take two general approaches to the study of the body’s structures: regional and systemic. Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. In contrast, systemic anatomy is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function. For example, a systemic anatomical study of the muscular system would consider all of the skeletal muscles of the body.', '5262367e-e192-4b5f-ab66-14e824d40f9d': 'Whereas anatomy is about structure, physiology is about function. Human physiology is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life. Much of the study of physiology centers on the body’s tendency toward homeostasis. Homeostasis is the state of steady internal conditions maintained by living things. The study of physiology certainly includes observation, both with the naked eye and with microscopes, as well as manipulations and measurements. Current advances in physiology usually depend on carefully designed laboratory experiments that reveal the functions of the many structures and chemical compounds that make up the human body.', '713d3772-59d9-4216-a482-c3829cddae2a': 'Like anatomists, physiologists typically specialize in a particular branch of physiology. For example, neurophysiology is the study of the brain, spinal cord, and nerves and how these work together to perform functions as complex and diverse as vision, movement, and thinking. Physiologists may work from the organ level (exploring, for example, what different parts of the brain does) to the molecular level (such as exploring how an electrochemical signal travels along nerves).', '2fc53a39-e50d-46e4-a37e-4502c3a1f6da': 'Form is closely related to function in all living things. For example, the thin flap of your eyelid can snap down to clear away dust particles and almost instantaneously slide back up to allow you to see again. At the microscopic level, the arrangement and function of the nerves and muscles that serve the eyelid allow for its quick action and retreat. At a smaller level of analysis, the function of these nerves and muscles likewise relies on the interactions of specific molecules and ions. Even the three-dimensional structure of certain molecules is essential to their function.', '51af7b80-b238-4869-b0cf-bb52caafe957': 'Your study of anatomy and physiology will make more sense if you continually relate the form of the structures you are studying to their function. In fact, it can be somewhat frustrating to attempt to study anatomy without an understanding of the physiology that a body structure supports. Imagine, for example, trying to appreciate the unique arrangement of the bones of the human hand if you had no conception of the function of the hand. Fortunately, your understanding of how the human hand manipulates tools—from pens to cell phones—helps you appreciate the unique alignment of the thumb in opposition to the four fingers, making your hand a structure that allows you to pinch and grasp objects and type text messages.'}"
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+unique_id,web-scraper-start-url,sub_chapters_x,sub_chapters-href,paragraph,is_paragraph,sub_section_headings,fig_num,sub_chapters_y,images-src,image_caption
+fc4243d2-0e05-4177-a171-cf5c4561a839,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,From Genotype to Phenotype,False,From Genotype to Phenotype,,,,
+5e7951f8-2ebe-441a-ba29-56256b203922,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Each human body cell has a full complement of DNA stored in 23 pairs of chromosomes. Figure 28.7.1 shows the pairs in a systematic arrangement called a karyotype. Among these is one pair of chromosomes, called the sex chromosomes, that determines the sex of the individual (XX in females, XY in males). The remaining 22 chromosome pairs are called autosomal chromosomes. Each of these chromosomes carries hundreds or even thousands of genes, each of which codes for the assembly of a particular protein—that is, genes are “expressed” as proteins. An individual’s complete genetic makeup is referred to as his or her genotype. The characteristics that the genes express, whether they are physical, behavioral, or biochemical, are a person’s phenotype.",True,From Genotype to Phenotype,Figure 28.7.1,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2923_Male_Chromosomes.jpg,"Figure 28.7.1 – Chromosomal Complement of a Male: Each pair of chromosomes contains hundreds to thousands of genes. The banding patterns are nearly identical for the two chromosomes within each pair, indicating the same organization of genes. As is visible in this karyotype, the only exception to this is the XY sex chromosome pair in males. (credit: National Human Genome Research Institute)"
+b5df4607-9b5a-4f82-a7fa-43f44c9c1b3c,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"You inherit one chromosome in each pair—a full complement of 23—from each parent. This occurs when the sperm and oocyte combine at the moment of your conception. Homologous chromosomes—those that make up a complementary pair—have genes for the same characteristics in the same location on the chromosome. Because one copy of a gene, an allele, is inherited from each parent, the alleles in these complementary pairs may vary. Take for example an allele that encodes for dimples. A child may inherit the allele encoding for dimples on the chromosome from the father and the allele that encodes for smooth skin (no dimples) on the chromosome from the mother.",True,From Genotype to Phenotype,,,,
+c19f5d8a-e42b-418e-a133-c2b02e0b29c3,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Although a person can have two identical alleles for a single gene (a homozygous state), it is also possible for a person to have two different alleles (a heterozygous state). The two alleles can interact in several different ways. The expression of an allele can be dominant, for which the activity of this gene will mask the expression of a nondominant, or recessive, allele. Sometimes dominance is complete; at other times, it is incomplete. In some cases, both alleles are expressed at the same time in a form of expression known as codominance.",True,From Genotype to Phenotype,,,,
+43f30d40-14a3-41ab-bb9d-dcdc77559e8b,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"In the simplest scenario, a single pair of genes will determine a single heritable characteristic. However, it is quite common for multiple genes to interact to confer a feature. For instance, eight or more genes—each with their own alleles—determine eye color in humans. Moreover, although any one person can only have two alleles corresponding to a given gene, more than two alleles commonly exist in a population. This phenomenon is called multiple alleles. For example, there are three different alleles that encode ABO blood type; these are designated IA, IB, and i.",True,From Genotype to Phenotype,,,,
+21c79aa3-993d-4eb2-a232-e9b0c80571cc,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Over 100 years of theoretical and experimental genetics studies, and the more recent sequencing and annotation of the human genome, have helped scientists to develop a better understanding of how an individual’s genotype is expressed as their phenotype. This body of knowledge can help scientists and medical professionals to predict, or at least estimate, some of the features that an offspring will inherit by examining the genotypes or phenotypes of the parents. One important application of this knowledge is to identify an individual’s risk for certain heritable genetic disorders. However, most diseases have a multigenic pattern of inheritance and can also be affected by the environment, so examining the genotypes or phenotypes of a person’s parents will provide only limited information about the risk of inheriting a disease. Only for a handful of single-gene disorders can genetic testing allow clinicians to calculate the probability with which a child born to the two parents tested may inherit a specific disease.",True,From Genotype to Phenotype,,,,
+abe2371a-8804-4095-a1d0-6f4d2a842957,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Mendel’s Theory of Inheritance,False,Mendel’s Theory of Inheritance,,,,
+bac86291-a46e-4c2a-9fcc-c7b0c712f258,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Our contemporary understanding of genetics rests on the work of a nineteenth-century monk. Working in the mid-1800s, long before anyone knew about genes or chromosomes, Gregor Mendel discovered that garden peas transmit their physical characteristics to subsequent generations in a discrete and predictable fashion. When he mated, or crossed, two pure-breeding pea plants that differed by a certain characteristic, the first-generation offspring all looked like one of the parents. For instance, when he crossed tall and dwarf pure-breeding pea plants, all of the offspring were tall. Mendel called tallness dominant because it was expressed in offspring when it was present in a purebred parent. He called dwarfism recessive because it was masked in the offspring if one of the purebred parents possessed the dominant characteristic. Note that tallness and dwarfism are variations on the characteristic of height. Mendel called such a variation a trait. We now know that these traits are the expression of different alleles of the gene encoding height.",True,Mendel’s Theory of Inheritance,,,,
+51263e42-cf11-4190-aa80-2f1c5093b28f,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Mendel performed thousands of crosses in pea plants with differing traits for a variety of characteristics. And he repeatedly came up with the same results—among the traits he studied, one was always dominant, and the other was always recessive. (Remember, however, that this dominant–recessive relationship between alleles is not always the case; some alleles are codominant, and sometimes dominance is incomplete.)",True,Mendel’s Theory of Inheritance,,,,
+8d841c32-8ba8-40e3-84ef-0dc6a70af9c3,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Using his understanding of dominant and recessive traits, Mendel tested whether a recessive trait could be lost altogether in a pea lineage or whether it would resurface in a later generation. By crossing the second-generation offspring of purebred parents with each other, he showed that the latter was true: recessive traits reappeared in third-generation plants in a ratio of 3:1 (three offspring having the dominant trait and one having the recessive trait). Mendel then proposed that characteristics such as height were determined by heritable “factors” that were transmitted, one from each parent, and inherited in pairs by offspring.",True,Mendel’s Theory of Inheritance,,,,
+f19b3056-ba03-4123-8bf8-f2f8194c1f5e,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"In the language of genetics, Mendel’s theory applied to humans says that if an individual receives two dominant alleles, one from each parent, the individual’s phenotype will express the dominant trait. If an individual receives two recessive alleles, then the recessive trait will be expressed in the phenotype. Individuals who have two identical alleles for a given gene, whether dominant or recessive, are said to be homozygous for that gene (homo- = “same”). Conversely, an individual who has one dominant allele and one recessive allele is said to be heterozygous for that gene (hetero- = “different” or “other”). In this case, the dominant trait will be expressed, and the individual will be phenotypically identical to an individual who possesses two dominant alleles for the trait.",True,Mendel’s Theory of Inheritance,,,,
+b43b1d00-3b76-4d0c-a532-32d2fe40f85d,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"It is common practice in genetics to use capital and lowercase letters to represent dominant and recessive alleles. Using Mendel’s pea plants as an example, if a tall pea plant is homozygous, it will possess two tall alleles (TT). A dwarf pea plant must be homozygous because its dwarfism can only be expressed when two recessive alleles are present (tt). A heterozygous pea plant (Tt) would be tall and phenotypically indistinguishable from a tall homozygous pea plant because of the dominant tall allele. Mendel deduced that a 3:1 ratio of dominant to recessive would be produced by the random segregation of heritable factors (genes) when crossing two heterozygous pea plants. In other words, for any given gene, parents are equally likely to pass down either one of their alleles to their offspring in a haploid gamete, and the result will be expressed in a dominant–recessive pattern if both parents are heterozygous for the trait.",True,Mendel’s Theory of Inheritance,,,,
+05615087-feef-40e5-86c0-721ce7df2652,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Because of the random segregation of gametes, the laws of chance and probability come into play when predicting the likelihood of a given phenotype. Consider a cross between an individual with two dominant alleles for a trait (AA) and an individual with two recessive alleles for the same trait (aa). All of the parental gametes from the dominant individual would be A, and all of the parental gametes from the recessive individual would be a (Figure 28.7.2). All of the offspring of that second generation, inheriting one allele from each parent, would have the genotype Aa, and the probability of expressing the phenotype of the dominant allele would be 4 out of 4, or 100 percent.",True,Mendel’s Theory of Inheritance,Figure 28.7.2,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2924_Mendelian_Pea_Plant_Cross.jpg,"Figure 28.7.2 – Random Segregation: In the formation of gametes, it is equally likely that either one of a pair alleles from one parent will be passed on to the offspring. This figure follows the possible combinations of alleles through two generations following a first-generation cross of homozygous dominant and homozygous recessive parents. The recessive phenotype, which is masked in the second generation, has a 1 in 4, or 25 percent, chance of reappearing in the third generation."
+38838748-0c01-4b2a-9227-a6d2a4b05b41,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"This seems simple enough, but the inheritance pattern gets interesting when the second-generation Aa individuals are crossed. In this generation, 50 percent of each parent’s gametes are A and the other 50 percent are a. By Mendel’s principle of random segregation, the possible combinations of gametes that the offspring can receive are AA, Aa, aA (which is the same as Aa), and aa. Because segregation and fertilization are random, each offspring has a 25 percent chance of receiving any of these combinations. Therefore, if an Aa × Aa cross were performed 1000 times, approximately 250 (25 percent) of the offspring would be AA; 500 (50 percent) would be Aa (that is, Aa plus aA); and 250 (25 percent) would be aa. The genotypic ratio for this inheritance pattern is 1:2:1. However, we have already established that AA and Aa (and aA) individuals all express the dominant trait (i.e., share the same phenotype), and can therefore be combined into one group. The result is Mendel’s third-generation phenotype ratio of 3:1.",True,Mendel’s Theory of Inheritance,,,,
+36028006-d049-4631-8d10-7d96dfcfd616,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Mendel’s observation of pea plants also included many crosses that involved multiple traits, which prompted him to formulate the principle of independent assortment. The law states that the members of one pair of genes (alleles) from a parent will sort independently from other pairs of genes during the formation of gametes. Applied to pea plants, that means that the alleles associated with the different traits of the plant, such as color, height, or seed type, will sort independently of one another. This holds true except when two alleles happen to be located close to one other on the same chromosome. Independent assortment provides for a great degree of diversity in offspring.",True,Mendel’s Theory of Inheritance,,,,
+24fd5ef9-fabc-4a7f-b41c-1c7b4f4e1e44,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Mendelian genetics represent the fundamentals of inheritance, but there are two important qualifiers to consider when applying Mendel’s findings to inheritance studies in humans. First, as we’ve already noted, not all genes are inherited in a dominant–recessive pattern. Although all diploid individuals have two alleles for every gene, allele pairs may interact to create several types of inheritance patterns, including incomplete dominance and codominance.",True,Mendel’s Theory of Inheritance,,,,
+3b2ee4f8-486a-4a75-9537-d05a6201c824,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Secondly, Mendel performed his studies using thousands of pea plants. He was able to identify a 3:1 phenotypic ratio in second-generation offspring because his large sample size overcame the influence of variability resulting from chance. In contrast, no human couple has ever had thousands of children. If we know that a man and woman are both heterozygous for a recessive genetic disorder, we would predict that one in every four of their children would be affected by the disease. In real life, however, the influence of chance could change that ratio significantly. For example, if a man and a woman are both heterozygous for cystic fibrosis, a recessive genetic disorder that is expressed only when the individual has two defective alleles, we would expect one in four of their children to have cystic fibrosis. However, it is entirely possible for them to have seven children, none of whom is affected, or for them to have two children, both of whom are affected. For each individual child, the presence or absence of a single gene disorder depends on which alleles that child inherits from his or her parents.",True,Mendel’s Theory of Inheritance,,,,
+b145eb2c-6046-4e61-ace8-4d074e183e90,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Autosomal Dominant Inheritance,False,Autosomal Dominant Inheritance,,,,
+76d2daa9-dc48-4c5d-b426-555273b44b4b,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"In the case of cystic fibrosis, the disorder is recessive to the normal phenotype. However, a genetic abnormality may be dominant to the normal phenotype. When the dominant allele is located on one of the 22 pairs of autosomes (non-sex chromosomes), we refer to its inheritance pattern as autosomal dominant. An example of an autosomal dominant disorder is neurofibromatosis type I, a disease that induces tumor formation within the nervous system that leads to skin and skeletal deformities. Consider a couple in which one parent is heterozygous for this disorder (and who therefore has neurofibromatosis), Nn, and one parent is homozygous for the normal gene, nn. The heterozygous parent would have a 50 percent chance of passing the dominant allele for this disorder to his or her offspring, and the homozygous parent would always pass the normal allele. Therefore, four possible offspring genotypes are equally likely to occur: Nn, Nn, nn, and nn. That is, every child of this couple would have a 50 percent chance of inheriting neurofibromatosis. This inheritance pattern is shown in Figure 28.7.3, in a form called a Punnett square, named after its creator, the British geneticist Reginald Punnett.",True,Autosomal Dominant Inheritance,Figure 28.7.3,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2925_Autosomal_Dominant_Inheritance.jpg,"Figure 28.7.3 – Autosomal Dominant Inheritance: Inheritance pattern of an autosomal dominant disorder, such as neurofibromatosis, is shown in a Punnett square."
+2b90d12e-5c73-4fbe-89f9-007e90205676,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Other genetic diseases that are inherited in this pattern are achondroplastic dwarfism, Marfan syndrome, and Huntington’s disease. Because autosomal dominant disorders are expressed by the presence of just one gene, an individual with the disorder will know that he or she has at least one faulty gene. The expression of the disease may manifest later in life, after the childbearing years, which is the case in Huntington’s disease (discussed in more detail later in this section).",True,Autosomal Dominant Inheritance,,,,
+abfbf054-48fa-4072-a009-cbd39c612a6d,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Autosomal Recessive Inheritance,False,Autosomal Recessive Inheritance,,,,
+50c5046a-cb4b-48d9-8597-83a941974534,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"When a genetic disorder is inherited in an autosomal recessive pattern, the disorder corresponds to the recessive phenotype. Heterozygous individuals will not display symptoms of this disorder, because their unaffected gene will compensate. Such an individual is called a carrier. Carriers for an autosomal recessive disorder may never know their genotype unless they have a child with the disorder.",True,Autosomal Recessive Inheritance,,,,
+6c160eca-2723-4b6d-9ca2-2c29caf85ecf,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"An example of an autosomal recessive disorder is cystic fibrosis (CF), which we introduced earlier. CF is characterized by the chronic accumulation of a thick, tenacious mucus in the lungs and digestive tract. Decades ago, children with CF rarely lived to adulthood. With advances in medical technology, the average lifespan in developed countries has increased into middle adulthood. CF is a relatively common disorder that occurs in approximately 1 in 2000 Caucasians. A child born to two CF carriers would have a 25 percent chance of inheriting the disease. This is the same 3:1 dominant:recessive ratio that Mendel observed in his pea plants would apply here. The pattern is shown in Figure 28.7.4, using a diagram that tracks the likely incidence of an autosomal recessive disorder on the basis of parental genotypes.",True,Autosomal Recessive Inheritance,Figure 28.7.4,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2926_Autosomal_Recessive_Inheritance-new.jpg,Figure 28.7.4 – Autosomal Recessive Inheritance: The inheritance pattern of an autosomal recessive disorder with two carrier parents reflects a 3:1 probability of expression among offspring. (credit: U.S. National Library of Medicine)
+b4eb50df-bd6e-455e-9bda-527c92e47eec,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"On the other hand, a child born to a CF carrier and someone with two unaffected alleles would have a 0 percent probability of inheriting CF, but would have a 50 percent chance of being a carrier. Other examples of autosome recessive genetic illnesses include the blood disorder sickle-cell anemia, the fatal neurological disorder Tay–Sachs disease, and the metabolic disorder phenylketonuria.",True,Autosomal Recessive Inheritance,,,,
+ddd57eb9-b6ef-4574-9bc9-18ae412e5506,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,X-linked Dominant or Recessive Inheritance,False,X-linked Dominant or Recessive Inheritance,,,,
+ce4ae496-4b8d-4fe7-b31b-e9258acd57bf,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair (Figure 28.7.5). Recall that a male has one X and one Y chromosome. When a father transmits a Y chromosome, the child is male, and when he transmits an X chromosome, the child is female. A mother can transmit only an X chromosome, as both her sex chromosomes are X chromosomes.",True,X-linked Dominant or Recessive Inheritance,Figure 28.7.5,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2927_X-linked_Dominant_Inheritance-new.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine)
+6ae46a9d-f4bb-464f-8f8c-3fef2b140f72,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"When an abnormal allele for a gene that occurs on the X chromosome is dominant over the normal allele, the pattern is described as X-linked dominant. This is the case with vitamin D–resistant rickets: an affected father would pass the disease gene to all of his daughters, but none of his sons, because he donates only the Y chromosome to his sons (see Figure 28.7.5a). If it is the mother who is affected, all of her children—male or female—would have a 50 percent chance of inheriting the disorder because she can only pass an X chromosome on to her children (see Figure 28.7.5b). For an affected female, the inheritance pattern would be identical to that of an autosomal dominant inheritance pattern in which one parent is heterozygous and the other is homozygous for the normal gene.",True,X-linked Dominant or Recessive Inheritance,Figure 28.7.5,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2927_X-linked_Dominant_Inheritance-new.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine)
+90c45d87-3097-4fdd-b697-a5c018502449,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"X-linked recessive inheritance is much more common because females can be carriers of the disease yet still have a normal phenotype. Diseases transmitted by X-linked recessive inheritance include color blindness, the blood-clotting disorder hemophilia, and some forms of muscular dystrophy. For an example of X-linked recessive inheritance, consider parents in which the mother is an unaffected carrier and the father is normal. None of the daughters would have the disease because they receive a normal gene from their father. However, they have a 50 percent chance of receiving the disease gene from their mother and becoming a carrier. In contrast, 50 percent of the sons would be affected (Figure 28.7.6).",True,X-linked Dominant or Recessive Inheritance,Figure 28.7.6,28.7 Patterns of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2928_X-linked_Recessive_Inheritance-new.jpg,"Figure 28.7.6 – X-Linked Recessive Inheritance: Given two parents in which the father is normal and the mother is a carrier of an X-linked recessive disorder, a son would have a 50 percent probability of being affected with the disorder, whereas daughters would either be carriers or entirely unaffected. (credit: U.S. National Library of Medicine)"
+0b4a1161-bdc4-4fa0-8155-a5ccfb269daf,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"With X-linked recessive diseases, males either have the disease or are genotypically normal—they cannot be carriers. Females, however, can be genotypically normal, a carrier who is phenotypically normal, or affected with the disease. A daughter can inherit the gene for an X-linked recessive illness when her mother is a carrier or affected, or her father is affected. The daughter will be affected by the disease only if she inherits an X-linked recessive gene from both parents. As you can imagine, X-linked recessive disorders affect many more males than females. For example, color blindness affects at least 1 in 20 males, but only about 1 in 400 females.",True,X-linked Dominant or Recessive Inheritance,,,,
+b8241df8-e658-41f4-ac83-da7dc4725c0f,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",False,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",,,,
+8ac137f9-2c0d-40be-93f1-16095a65891e,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Not all genetic disorders are inherited in a dominant–recessive pattern. In incomplete dominance, the offspring express a heterozygous phenotype that is intermediate between one parent’s homozygous dominant trait and the other parent’s homozygous recessive trait. An example of this can be seen in snapdragons when red-flowered plants and white-flowered plants are crossed to produce pink-flowered plants. In humans, incomplete dominance occurs with one of the genes for hair texture. When one parent passes a curly hair allele (the incompletely dominant allele) and the other parent passes a straight-hair allele, the effect on the offspring will be intermediate, resulting in hair that is wavy.",True,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",,,,
+e945cfc8-2403-4f3e-a5f0-c048a99c6a31,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Codominance is characterized by the equal, distinct, and simultaneous expression of both parents’ different alleles. This pattern differs from the intermediate, blended features seen in incomplete dominance. A classic example of codominance in humans is ABO blood type. People are blood type A if they have an allele for an enzyme that facilitates the production of surface antigen A on their erythrocytes. This allele is designated IA. In the same manner, people are blood type B if they express an enzyme for the production of surface antigen B. People who have alleles for both enzymes (IA and IB) produce both surface antigens A and B. As a result, they are blood type AB. Because the effect of both alleles (or enzymes) is observed, we say that the IA and IB alleles are codominant. There is also a third allele that determines blood type. This allele (i) produces a nonfunctional enzyme. People who have two i alleles do not produce either A or B surface antigens: they have type O blood. If a person has IA and i alleles, the person will have blood type A. Notice that it does not make any difference whether a person has two IA alleles or one IA and one i allele. In both cases, the person is blood type A. Because IA masks i, we say that IA is dominant to i. Table 28.4 summarizes the expression of blood type.",True,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",,,,
+863b87c7-d3de-44e9-971a-07224a8c3f9c,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Certain combinations of alleles can be lethal, meaning they prevent the individual from developing in utero, or cause a shortened life span. In recessive lethal inheritance patterns, a child who is born to two heterozygous (carrier) parents and who inherited the faulty allele from both would not survive. An example of this is Tay–Sachs, a fatal disorder of the nervous system. In this disorder, parents with one copy of the allele for the disorder are carriers. If they both transmit their abnormal allele, their offspring will develop the disease and will die in childhood, usually before age 5.",True,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",,,,
+72b9ef94-d01b-4bf3-834f-2e1495e35fc3,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Dominant lethal inheritance patterns are much more rare because neither heterozygotes nor homozygotes survive. Of course, dominant lethal alleles that arise naturally through mutation and cause miscarriages or stillbirths are never transmitted to subsequent generations. However, some dominant lethal alleles, such as the allele for Huntington’s disease, cause a shortened life span but may not be identified until after the person reaches reproductive age and has children. Huntington’s disease causes irreversible nerve cell degeneration and death in 100 percent of affected individuals, but it may not be expressed until the individual reaches middle age. In this way, dominant lethal alleles can be maintained in the human population. Individuals with a family history of Huntington’s disease are typically offered genetic counseling, which can help them decide whether or not they wish to be tested for the faulty gene.",True,"Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles",,,,
+ee3843f9-fa6e-4cba-87c1-11ee39cfbe6f,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Mutations,False,Mutations,,,,
+86645214-ab10-475d-867d-e7db8a5704f6,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"A mutation is a change in the sequence of DNA nucleotides that may or may not affect a person’s phenotype. Mutations can arise spontaneously from errors during DNA replication, or they can result from environmental insults such as radiation, certain viruses, or exposure to tobacco smoke or other toxic chemicals. Because genes encode for the assembly of proteins, a mutation in the nucleotide sequence of a gene can change amino acid sequence and, consequently, a protein’s structure and function. Spontaneous mutations occurring during meiosis are thought to account for many spontaneous abortions (miscarriages).",True,Mutations,,,,
+0f760de9-21b7-4a93-86ab-5119b371222b,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Chromosomal Disorders,False,Chromosomal Disorders,,,,
+20b1714d-5842-4932-bdf1-07b73e20b8a0,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Sometimes a genetic disease is not caused by a mutation in a gene, but by the presence of an incorrect number of chromosomes. For example, Down syndrome is caused by having three copies of chromosome 21. This is known as trisomy 21. The most common cause of trisomy 21 is chromosomal nondisjunction during meiosis. The frequency of nondisjunction events appears to increase with age, so the frequency of bearing a child with Down syndrome increases in women over 36. The age of the father matters less because nondisjunction is much less likely to occur in a sperm than in an egg.",True,Chromosomal Disorders,,,,
+49eb97c3-4f63-4951-a983-3868b63433fc,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Whereas Down syndrome is caused by having three copies of a chromosome, Turner syndrome is caused by having just one copy of the X chromosome. This is known as monosomy. The affected child is always female. Women with Turner syndrome are sterile because their sexual organs do not mature.",True,Chromosomal Disorders,,,,
+2265e15b-bf66-4919-9230-9f74c1adba08,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,Career Connections,False,Career Connections,,,,
+73143a72-02c9-4f8c-ac17-0a4dfc64ae43,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"Genetic Counselor
+
+Given the intricate orchestration of gene expression, cell migration, and cell differentiation during prenatal development, it is amazing that the vast majority of newborns are healthy and free of major birth defects. When a woman over 35 is pregnant or intends to become pregnant, or her partner is over 55, or if there is a family history of a genetic disorder, she and her partner may want to speak to a genetic counselor to discuss the likelihood that their child may be affected by a genetic or chromosomal disorder. A genetic counselor can interpret a couple’s family history and estimate the risks to their future offspring.",True,Career Connections,,,,
+503b95e0-0183-4470-b57d-fb84b67ccd06,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"For many genetic diseases, a DNA test can determine whether a person is a carrier. For instance, carrier status for Fragile X, an X-linked disorder associated with mental retardation, or for cystic fibrosis can be determined with a simple blood draw to obtain DNA for testing. A genetic counselor can educate a couple about the implications of such a test and help them decide whether to undergo testing. For chromosomal disorders, the available testing options include a blood test, amniocentesis (in which amniotic fluid is tested), and chorionic villus sampling (in which tissue from the placenta is tested). Each of these has advantages and drawbacks. A genetic counselor can also help a couple cope with the news that either one or both partners is a carrier of a genetic illness, or that their unborn child has been diagnosed with a chromosomal disorder or other birth defect.",True,Career Connections,,,,
+30039510-1326-4873-928b-1ba79ce7016e,https://open.oregonstate.education/aandp/,28.7 Patterns of Inheritance,https://open.oregonstate.education/aandp/chapter/28-7-patterns-of-inheritance/,"To become a genetic counselor, one needs to complete a 4-year undergraduate program and then obtain a Master of Science in Genetic Counseling from an accredited university. Board certification is attained after passing examinations by the American Board of Genetic Counseling. Genetic counselors are essential professionals in many branches of medicine, but there is a particular demand for preconception and prenatal genetic counselors.",True,Career Connections,,,,
+faf74190-6a96-4e19-969f-f67674461413,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"Lactation is the process by which milk is synthesized and secreted from the mammary glands of the postpartum female breast in response to an infant sucking at the nipple. Breast milk provides ideal nutrition and passive immunity for the infant, encourages mild uterine contractions to return the uterus to its pre-pregnancy size (i.e., involution), and induces a substantial metabolic increase in the mother, consuming the fat reserves stored during pregnancy.",True,Career Connections,,,,
+87d3f57a-6d33-4901-b3cf-548283d6a754,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,Structure of the Lactating Breast,False,Structure of the Lactating Breast,,,,
+4cd7ce84-fba8-41bf-bcae-4815e3a3255d,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"Mammary glands are modified sweat glands. The non-pregnant and non-lactating female breast is composed primarily of adipose and collagenous tissue, with mammary glands making up a very minor proportion of breast volume. The mammary gland is composed of milk-transporting lactiferous ducts, which expand and branch extensively during pregnancy in response to estrogen, growth hormone, cortisol, and prolactin. Moreover, in response to progesterone, clusters of breast alveoli bud from the ducts and expand outward toward the chest wall. Breast alveoli are balloon-like structures lined with milk-secreting cuboidal cells, or lactocytes, that are surrounded by a net of contractile myoepithelial cells. Milk is secreted from the lactocytes, fills the alveoli, and is squeezed into the ducts. Clusters of alveoli that drain to a common duct are called lobules; the lactating female has 12–20 lobules organized radially around the nipple. Milk drains from lactiferous ducts into lactiferous sinuses that meet at 4 to 18 perforations in the nipple, called nipple pores. The small bumps of the areola (the darkened skin around the nipple) are called Montgomery glands. They secrete oil to cleanse the nipple opening and prevent chapping and cracking of the nipple during breastfeeding.",True,Structure of the Lactating Breast,,,,
+c27453f8-87ab-4d7c-8392-9077bb7c2f16,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,The Process of Lactation,False,The Process of Lactation,,,,
+0bbc0e55-6312-4a51-9d44-2a59074b35d8,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,The pituitary hormone prolactin is instrumental in the establishment and maintenance of breast milk supply. It also is important for the mobilization of maternal micronutrients for breast milk.,True,The Process of Lactation,,,,
+9c70f88e-e161-4f06-a3ef-d79c0cf944e8,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"Near the fifth week of pregnancy, the level of circulating prolactin begins to increase, eventually rising to approximately 10–20 times the pre-pregnancy concentration. We noted earlier that, during pregnancy, prolactin and other hormones prepare the breasts anatomically for the secretion of milk. The level of prolactin plateaus in late pregnancy, at a level high enough to initiate milk production. However, estrogen, progesterone, and other placental hormones inhibit prolactin-mediated milk synthesis during pregnancy. It is not until the placenta is expelled that this inhibition is lifted and milk production commences.",True,The Process of Lactation,,,,
+f8ec265d-9229-41e6-a662-ca9347807caf,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"After childbirth, the baseline prolactin level drops sharply, but it is restored for a 1-hour spike during each feeding to stimulate the production of milk for the next feeding. With each prolactin spike, estrogen and progesterone also increase slightly.",True,The Process of Lactation,,,,
+0614c14e-4192-43d7-983f-4da913d4b255,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"When the infant suckles, sensory nerve fibers in the areola trigger a neuroendocrine reflex that results in milk secretion from lactocytes into the alveoli. The posterior pituitary releases oxytocin, which stimulates myoepithelial cells to squeeze milk from the alveoli so it can drain into the lactiferous ducts, collect in the lactiferous sinuses, and discharge through the nipple pores. It takes less than 1 minute from the time when an infant begins suckling (the latent period) until milk is secreted (the let-down). Figure 28.6.1 summarizes the positive feedback loop of the let-down reflex.",True,The Process of Lactation,Figure 28.6.1,28.6 Lactation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2922_Let_Down_Reflex-new-scaled.jpg,Figure 28.6.1 – Let-Down Reflex: A positive feedback loop ensures continued milk production as long as the infant continues to breastfeed.
+dbc49d50-e8ca-4b7e-871d-651eef288dc4,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"The prolactin-mediated synthesis of milk changes with time. Frequent milk removal by breastfeeding (or pumping) will maintain high circulating prolactin levels for several months. However, even with continued breastfeeding, baseline prolactin will decrease over time to its pre-pregnancy level. In addition to prolactin and oxytocin, growth hormone, cortisol, parathyroid hormone, and insulin contribute to lactation, in part by facilitating the transport of maternal amino acids, fatty acids, glucose, and calcium to breast milk.",True,The Process of Lactation,,,,
+b3b99442-b7cc-443f-bfad-78adbe91f2e7,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,Changes in the Composition of Breast Milk,False,Changes in the Composition of Breast Milk,,,,
+f7e428a2-d2cb-4e0b-905b-61c5ca6b3509,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"In the final weeks of pregnancy, the alveoli swell with colostrum, a thick, yellowish substance that is high in protein but contains less fat and glucose than mature breast milk (Table 28.3). Before childbirth, some women experience leakage of colostrum from the nipples. In contrast, mature breast milk does not leak during pregnancy and is not secreted until several days after childbirth.",True,Changes in the Composition of Breast Milk,,,,
+cad14458-5872-462f-90c0-5f04bc3fbb4e,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"Colostrum is secreted during the first 48–72 hours postpartum. Only a small volume of colostrum is produced—approximately 3 ounces in a 24-hour period—but it is sufficient for the newborn in the first few days of life. Colostrum is rich with immunoglobulins, which confer gastrointestinal, and also likely systemic, immunity as the newborn adjusts to a nonsterile environment.",True,Changes in the Composition of Breast Milk,,,,
+3f1a4d8b-643e-476c-839d-8113173968ca,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"After about the third postpartum day, the mother secretes transitional milk that represents an intermediate between mature milk and colostrum. This is followed by mature milk from approximately postpartum day 10 (see Table 28.3). As you can see in the accompanying table, cow’s milk is not a substitute for breast milk. It contains less lactose, less fat, and more protein and minerals. Moreover, the proteins in cow’s milk are difficult for an infant’s immature digestive system to metabolize and absorb.",True,Changes in the Composition of Breast Milk,,,,
+72bec4fe-ed80-49b2-93e4-95d6db86029d,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"The first few weeks of breastfeeding may involve leakage, soreness, and periods of milk engorgement as the relationship between milk supply and infant demand becomes established. Once this period is complete, the mother will produce approximately 1.5 liters of milk per day for a single infant, and more if she has twins or triplets. As the infant goes through growth spurts, the milk supply constantly adjusts to accommodate changes in demand. A woman can continue to lactate for years, but once breastfeeding is stopped for approximately 1 week, any remaining milk will be reabsorbed; in most cases, no more will be produced, even if suckling or pumping is resumed.",True,Changes in the Composition of Breast Milk,,,,
+97d6419a-d9f3-4ebe-bc30-40262402ba3b,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"Mature milk changes from the beginning to the end of a feeding. The early milk, called foremilk, is watery, translucent, and rich in lactose and protein. Its purpose is to quench the infant’s thirst. Hindmilk is delivered toward the end of a feeding. It is opaque, creamy, and rich in fat, and serves to satisfy the infant’s appetite.",True,Changes in the Composition of Breast Milk,,,,
+ce9bb95b-406a-4119-aca1-476a978076d1,https://open.oregonstate.education/aandp/,28.6 Lactation,https://open.oregonstate.education/aandp/chapter/28-6-lactation/,"During the first days of a newborn’s life, it is important for meconium to be cleared from the intestines and for bilirubin to be kept low in the circulation. Recall that bilirubin, a product of erythrocyte breakdown, is processed by the liver and secreted in bile. It enters the gastrointestinal tract and exits the body in the stool. Breast milk has laxative properties that help expel meconium from the intestines and clear bilirubin through the excretion of bile. A high concentration of bilirubin in the blood causes jaundice. Some degree of jaundice is normal in newborns, but a high level of bilirubin—which is neurotoxic—can cause brain damage. Newborns, who do not yet have a fully functional blood–brain barrier, are highly vulnerable to the bilirubin circulating in the blood. Indeed, hyperbilirubinemia, a high level of circulating bilirubin, is the most common condition requiring medical attention in newborns. Newborns with hyperbilirubinemia are treated with phototherapy because UV light helps to break down the bilirubin quickly.",True,Changes in the Composition of Breast Milk,,,,
+da29bb72-8da0-4c11-9306-c4f712c88c02,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"From a fetal perspective, the process of birth is a crisis. In the womb, the fetus was snuggled in a soft, warm, dark, and quiet world. The placenta provided nutrition and oxygen continuously. Suddenly, the contractions of labor and vaginal childbirth forcibly squeeze the fetus through the birth canal, limiting oxygenated blood flow during contractions and shifting the skull bones to accommodate the small space. After birth, the newborn’s system must make drastic adjustments to a world that is colder, brighter, and louder, and where he or she will experience hunger and thirst. The neonatal period (neo- = “new”; -natal = “birth”) spans the first to the thirtieth day of life outside of the uterus.",True,Changes in the Composition of Breast Milk,,,,
+0a6f00d2-85e1-4d7e-aa66-32220a6318d2,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,Respiratory Adjustments,False,Respiratory Adjustments,,,,
+14205769-2171-4a12-8bfd-06d3594a3bfd,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"Although the fetus “practices” breathing by inhaling amniotic fluid in utero, there is no air in the uterus and thus no true opportunity to breathe. (There is also no need to breathe because the placenta supplies the fetus with all the oxygenated blood it needs.) During gestation, the partially collapsed lungs are filled with amniotic fluid and exhibit very little metabolic activity. Several factors stimulate newborns to take their first breath at birth. First, labor contractions temporarily constrict umbilical blood vessels, reducing oxygenated blood flow to the fetus and elevating carbon dioxide levels in the blood. High carbon dioxide levels cause acidosis and stimulate the respiratory center in the brain, triggering the newborn to take a breath.",True,Respiratory Adjustments,,,,
+eaf1afda-547a-40bc-b406-21d829e73182,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The first breath typically is taken within 10 seconds of birth, after mucus is aspirated from the infant’s mouth and nose. The first breaths inflate the lungs to nearly full capacity and dramatically decrease lung pressure and resistance to blood flow, causing a major circulatory reconfiguration. Pulmonary alveoli open, and alveolar capillaries fill with blood. Amniotic fluid in the lungs drains or is absorbed, and the lungs immediately take over the task of the placenta, exchanging carbon dioxide for oxygen by the process of respiration.",True,Respiratory Adjustments,,,,
+47b6a68a-7fad-4757-b5b1-49530cc88c04,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,Circulatory Adjustments,False,Circulatory Adjustments,,,,
+6bc17aa7-055a-4ed1-b20b-4390cba77b80,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The process of clamping and cutting the umbilical cord collapses the umbilical blood vessels. In the absence of medical assistance, this occlusion would occur naturally within 20 minutes of birth because the Wharton’s jelly within the umbilical cord would swell in response to the lower temperature outside of the mother’s body, and the blood vessels would constrict. Natural occlusion has occurred when the umbilical cord is no longer pulsating. For the most part, the collapsed vessels atrophy and become fibrotic remnants, existing in the mature circulatory system as ligaments of the abdominal wall and liver. The ductus venosus degenerates to become the ligamentum venosum beneath the liver. Only the proximal sections of the two umbilical arteries remain functional, taking on the role of supplying blood to the upper part of the bladder (Figure 28.5.1).",True,Circulatory Adjustments,Figure 28.5.1,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2921_Neonatal_Circulatory_System.jpg,"Figure 28.5.1 – Neonatal Circulatory System: A newborn’s circulatory system reconfigures immediately after birth. The three fetal shunts have been closed permanently, facilitating blood flow to the liver and lungs."
+f0b8c822-4662-406f-b857-2b4d27008206,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The newborn’s first breath is vital to initiate the transition from the fetal to the neonatal circulatory pattern. Inflation of the lungs decreases blood pressure throughout the pulmonary system, as well as in the right atrium and ventricle. In response to this pressure change, the flow of blood temporarily reverses direction through the foramen ovale, moving from the left to the right atrium, and blocking the shunt with two flaps of tissue. Within 1 year, the tissue flaps usually fuse over the shunt, turning the foramen ovale into the fossa ovalis. The ductus arteriosus constricts as a result of increased oxygen concentration, and becomes the ligamentum arteriosum. Closing of the ductus arteriosus ensures that all blood pumped to the pulmonary circuit will be oxygenated by the newly functional neonatal lungs.",True,Circulatory Adjustments,,,,
+bb6d3a90-59a9-4a3f-b93c-d2e8d366b072,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,Thermoregulatory Adjustments,False,Thermoregulatory Adjustments,,,,
+72bb0da6-ced4-4cd8-a27f-6bcb57dcc711,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The fetus floats in warm amniotic fluid that is maintained at a temperature of approximately 98.6°F with very little fluctuation. Birth exposes newborns to a cooler environment in which they have to regulate their own body temperature. Newborns have a higher ratio of surface area to volume than adults. This means that their body has less volume throughout which to produce heat, and more surface area from which to lose heat. As a result, newborns produce heat more slowly and lose it more quickly. Newborns also have immature musculature that limits their ability to generate heat by shivering. Moreover, their nervous systems are underdeveloped, so they cannot quickly constrict superficial blood vessels in response to cold. They also have little subcutaneous fat for insulation. All these factors make it harder for newborns to maintain their body temperature.",True,Thermoregulatory Adjustments,,,,
+f207ee4f-2eac-4213-9522-dd17f7d1c48b,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"Newborns, however, do have a special method for generating heat: nonshivering thermogenesis, which involves the breakdown of brown adipose tissue, or brown fat, which is distributed over the back, chest, and shoulders. Brown fat differs from the more familiar white fat in two ways:",True,Thermoregulatory Adjustments,,,,
+9810e5e4-1b9c-4659-ba74-aa20be63c065,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The breakdown of brown fat occurs automatically upon exposure to cold, so it is an important heat regulator in newborns. During fetal development, the placenta secretes inhibitors that prevent metabolism of brown adipose fat and promote its accumulation in preparation for birth.",True,Thermoregulatory Adjustments,,,,
+db9fb0f7-f112-4efa-ae93-e6325f5a744b,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,Gastrointestinal and Urinary Adjustments,False,Gastrointestinal and Urinary Adjustments,,,,
+b2fb8d96-7e2e-4670-b509-0a6a9e9e400c,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"In adults, the gastrointestinal tract harbors bacterial flora—trillions of bacteria that aid in digestion, produce vitamins, and protect from the invasion or replication of pathogens. In stark contrast, the fetal intestine is sterile. The first consumption of breast milk or formula floods the neonatal gastrointestinal tract with beneficial bacteria that begin to establish the bacterial flora.",True,Gastrointestinal and Urinary Adjustments,,,,
+0da87c55-885f-4d00-8781-1659d04e4e5e,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The fetal kidneys filter blood and produce urine, but the neonatal kidneys are still immature and inefficient at concentrating urine. Therefore, newborns produce very dilute urine, making it particularly important for infants to obtain sufficient fluids from breast milk or formula.",True,Gastrointestinal and Urinary Adjustments,,,,
+ba593ae6-a511-429c-9332-b6cd0dd583b9,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"Five criteria—skin color, heart rate, reflex, muscle tone, and respiration—are assessed, and each criterion is assigned a score of 0, 1, or 2. Scores are taken at 1 minute after birth and again at 5 minutes after birth. Each time that scores are taken, the five scores are added together. High scores (out of a possible 10) indicate the baby has made the transition from the womb well, whereas lower scores indicate that the baby may be in distress.",True,Gastrointestinal and Urinary Adjustments,,,,
+273124cd-319c-4fe6-beb4-19cf969ed3cd,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"The technique for determining an Apgar score is quick and easy, painless for the newborn, and does not require any instruments except for a stethoscope. A convenient way to remember the five scoring criteria is to apply the mnemonic APGAR, for “appearance” (skin color), “pulse” (heart rate), “grimace” (reflex), “activity” (muscle tone), and “respiration.”",True,Gastrointestinal and Urinary Adjustments,,,,
+3fefba63-6303-4aba-bdb1-9eadc9d899fd,https://open.oregonstate.education/aandp/,28.5 Adjustments of the Infant at Birth and Postnatal Stages,https://open.oregonstate.education/aandp/chapter/28-5-adjustments-of-the-infant-at-birth-and-postnatal-stages/,"Of the five Apgar criteria, heart rate and respiration are the most critical. Poor scores for either of these measurements may indicate the need for immediate medical attention to resuscitate or stabilize the newborn. In general, any score lower than 7 at the 5-minute mark indicates that medical assistance may be needed. A total score below 5 indicates an emergency situation. Normally, a newborn will get an intermediate score of 1 for some of the Apgar criteria and will progress to a 2 by the 5-minute assessment. Scores of 8 or above are normal.",True,Gastrointestinal and Urinary Adjustments,,,,
+86b4b2a0-822b-4831-8ac9-a704402ef767,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"A full-term pregnancy lasts approximately 270 days (approximately 38.5 weeks) from conception to birth. Because it is easier to remember the first day of the last menstrual period (LMP) than to estimate the date of conception, obstetricians set the due date as 284 days (approximately 40.5 weeks) from the LMP. This assumes that conception occurred on day 14 of the woman’s cycle, which is usually a good approximation. The 40 weeks of an average pregnancy are usually discussed in terms of three trimesters, each approximately 13 weeks. During the second and third trimesters, the pre-pregnancy uterus—about the size of a fist—grows dramatically to contain the fetus, causing a number of anatomical changes in the mother (Figure 28.4.1).",True,Gastrointestinal and Urinary Adjustments,Figure 28.4.1,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2917_Size_of_Uterus_Throughout_Pregnancy-02.jpg,Figure 28.4.1 – Size of Uterus throughout Pregnancy: The uterus grows throughout pregnancy to accommodate the fetus.
+ce56a138-b924-4d7b-8dbe-2c7c1740804c,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,Effects of Hormones,False,Effects of Hormones,,,,
+48dad1bd-04b0-44e3-9302-d07ee7f53495,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"Virtually all of the effects of pregnancy can be attributed in some way to the influence of hormones—particularly estrogens, progesterone, and hCG. During weeks 7–12 from the LMP, the pregnancy hormones are primarily generated by the corpus luteum. Progesterone secreted by the corpus luteum stimulates the production of decidual cells of the endometrium that nourish the blastocyst before placentation. As the placenta develops and the corpus luteum degenerates during weeks 12–17, the placenta gradually takes over as the endocrine organ of pregnancy.",True,Effects of Hormones,,,,
+ec7f59c5-8a39-4618-9ee5-536828347fae,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"The placenta converts weak androgens secreted by the maternal and fetal adrenal glands to estrogens, which are necessary for pregnancy to progress. Estrogen levels climb throughout the pregnancy, increasing 30-fold by childbirth. Estrogens have the following actions:",True,Effects of Hormones,,,,
+c28770bf-f48b-41be-a975-a9bec948d9f3,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"Relaxin, another hormone secreted by the corpus luteum and then by the placenta, helps prepare the mother’s body for childbirth. It increases the elasticity of the symphysis pubis joint and pelvic ligaments, making room for the growing fetus and allowing expansion of the pelvic outlet for childbirth. Relaxin also helps dilate the cervix during labor.",True,Effects of Hormones,,,,
+1942f8c5-e3b2-40ce-bf45-d48803f78606,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"The placenta takes over the synthesis and secretion of progesterone throughout pregnancy as the corpus luteum degenerates. Like estrogen, progesterone suppresses FSH and LH. It also inhibits uterine contractions, protecting the fetus from preterm birth. This hormone decreases in late gestation, allowing uterine contractions to intensify and eventually progress to true labor. The placenta also produces hCG. In addition to promoting survival of the corpus luteum, hCG stimulates the male fetal gonads to secrete testosterone, which is essential for the development of the male reproductive system.",True,Effects of Hormones,,,,
+4f7caf78-b60d-4978-ade5-b3051d9300ce,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"The anterior pituitary enlarges and ramps up its hormone production during pregnancy, raising the levels of thyrotropin, prolactin, and adrenocorticotropic hormone (ACTH). Thyrotropin, in conjunction with placental hormones, increases the production of thyroid hormone, which raises the maternal metabolic rate. This can markedly augment a pregnant woman’s appetite and cause hot flashes. Prolactin stimulates enlargement of the mammary glands in preparation for milk production. ACTH stimulates maternal cortisol secretion, which contributes to fetal protein synthesis. In addition to the pituitary hormones, increased parathyroid levels mobilize calcium from maternal bones for fetal use.",True,Effects of Hormones,,,,
+e8687fdd-a524-4cbf-858c-b2411d497da0,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,Weight Gain,False,Weight Gain,,,,
+95f8f64f-b228-40dc-a905-eaa34c0a325b,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"The second and third trimesters of pregnancy are associated with dramatic changes in maternal anatomy and physiology. The most obvious anatomical sign of pregnancy is the dramatic enlargement of the abdominal region, coupled with maternal weight gain. This weight results from the growing fetus as well as the enlarged uterus, amniotic fluid, and placenta. Additional breast tissue and dramatically increased blood volume also contribute to weight gain (Table 28.2). Surprisingly, fat storage accounts for only approximately 2.3 kg (5 lbs) in a normal pregnancy and serves as a reserve for the increased metabolic demand of breastfeeding.",True,Weight Gain,,,,
+8f130eb0-4765-4c42-baf1-f2a4fb4338a9,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"During the first trimester, the mother does not need to consume additional calories to maintain a healthy pregnancy. However, a weight gain of approximately 0.45 kg (1 lb) per month is common. During the second and third trimesters, the mother’s appetite increases, but it is only necessary for her to consume an additional 300 calories per day to support the growing fetus. Most women gain approximately 0.45 kg (1 lb) per week.",True,Weight Gain,,,,
+7ca39bab-085d-400a-bbeb-bed7662c6f03,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,Changes in Organ Systems During Pregnancy,False,Changes in Organ Systems During Pregnancy,,,,
+60a85f25-b970-48a5-8eaa-2454ee4a4f00,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"As the woman’s body adapts to pregnancy, characteristic physiologic changes occur. These changes can sometimes prompt symptoms often referred to collectively as the common discomforts of pregnancy.",True,Changes in Organ Systems During Pregnancy,,,,
+807aefd9-efcc-41b7-865a-34c3207e8472,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,Physiology of Labor,False,Physiology of Labor,,,,
+524b43be-a055-4f6d-b07f-d654cf2796e1,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"Childbirth, or parturition, typically occurs within a week of a woman’s due date, unless the woman is pregnant with more than one fetus, which usually causes her to go into labor early. As a pregnancy progresses into its final weeks, several physiological changes occur in response to hormones that trigger labor.",True,Physiology of Labor,,,,
+6c438b70-906c-4a7c-bd29-444101d492ef,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"First, recall that progesterone inhibits uterine contractions throughout the first several months of pregnancy. As the pregnancy enters its seventh month, progesterone levels plateau and then drop. Estrogen levels, however, continue to rise in the maternal circulation (Figure 28.4.3). The increasing ratio of estrogen to progesterone makes the myometrium (the uterine smooth muscle) more sensitive to stimuli that promote contractions (because progesterone no longer inhibits them). Moreover, in the eighth month of pregnancy, fetal cortisol rises, which boosts estrogen secretion by the placenta and further overpowers the uterine-calming effects of progesterone. Some women may feel the result of the decreasing levels of progesterone in late pregnancy as weak and irregular peristaltic Braxton Hicks contractions, also called false labor. These contractions can often be relieved with rest or hydration.",True,Physiology of Labor,Figure 28.4.3,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2919_Hormones_Initiating_Labor-02.jpg,Figure 28.4.3 – Hormones Initiating Labor: A positive feedback loop of hormones works to initiate labor.
+635ec6a4-47fe-459e-8cad-24bbb5c57a36,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"A common sign that labor will be short is the so-called “bloody show.” During pregnancy, a plug of mucus accumulates in the cervical canal, blocking the entrance to the uterus. Approximately 1–2 days prior to the onset of true labor, this plug loosens and is expelled, along with a small amount of blood.",True,Physiology of Labor,,,,
+3985d435-ae79-4630-86bc-81666a162e20,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"Meanwhile, the posterior pituitary has been boosting its secretion of oxytocin, a hormone that stimulates the contractions of labor. At the same time, the myometrium increases its sensitivity to oxytocin by expressing more receptors for this hormone. As labor nears, oxytocin begins to stimulate stronger, more painful uterine contractions, which—in a positive feedback loop—stimulate the secretion of prostaglandins from fetal membranes. Like oxytocin, prostaglandins also enhance uterine contractile strength. The fetal pituitary also secretes oxytocin, which increases prostaglandins even further. Given the importance of oxytocin and prostaglandins to the initiation and maintenance of labor, it is not surprising that, when a pregnancy is not progressing to labor and needs to be induced, a pharmaceutical version of these compounds (called pitocin) is administered by intravenous drip.",True,Physiology of Labor,,,,
+879de23d-1534-47c3-8980-b94d27f21267,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"Finally, stretching of the myometrium and cervix by a full-term fetus in the vertex (head-down) position is regarded as a stimulant to uterine contractions. The sum of these changes initiates the regular contractions known as true labor, which become more powerful and more frequent with time. The pain of labor is attributed to myometrial hypoxia during uterine contractions.",True,Physiology of Labor,,,,
+2bab7729-572d-42a9-9df8-a99463a6546b,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,Stages of Childbirth,False,Stages of Childbirth,,,,
+3e3ea78d-a80e-4427-9db5-8577523c6ce3,https://open.oregonstate.education/aandp/,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/aandp/chapter/28-4-maternal-changes-during-pregnancy-labor-and-birth/,"The process of childbirth can be divided into three stages: cervical dilation, expulsion of the newborn, and afterbirth (Figure 28.4.4).",True,Stages of Childbirth,Figure 28.4.4,"28.4 Maternal Changes During Pregnancy, Labor, and Birth",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2920_Stages_of_Childbirth-02-scaled.jpg,"Figure 28.4.4 – Stages of Childbirth: The stages of childbirth include Stage 1, early cervical dilation; Stage 2, full dilation and expulsion of the newborn; and Stage 3, delivery of the placenta and associated fetal membranes. (The position of the newborn’s shoulder is described relative to the mother.)"
+494d9e30-47db-423a-a677-373cdddf1d2d,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"As you will recall, a developing human is called a fetus from the ninth week of gestation until birth. This 30-week period of development is marked by continued cell growth and differentiation, which fully develop the structures and functions of the immature organ systems formed during the embryonic period. The completion of fetal development results in a newborn who, although still immature in many ways, is capable of survival outside the womb.",True,Stages of Childbirth,,,,
+721aae62-5808-4379-997b-cf0fbfebd816,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,Sexual Differentiation,False,Sexual Differentiation,,,,
+36eed267-0ca8-40fd-80d0-982f6cdacb6e,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"Sexual differentiation does not begin until the fetal period, during weeks 9–12. Embryonic males and females, though genetically distinguishable, are morphologically identical (Figure 28.3.1). Bipotential gonads, or gonads that can develop into male or female sexual organs, are connected to a central cavity called the cloaca via Müllerian ducts and Wolffian ducts. (The cloaca is an extension of the primitive gut.) Several events lead to sexual differentiation during this period.",True,Sexual Differentiation,Figure 28.3.1,28.3 Fetal Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2915_Sexual_Differentation-02.jpg,Figure 28.3.1 – Sexual Differentiation: Differentiation of the male and female reproductive systems does not occur until the fetal period of development.
+4c32e5c6-9121-4617-aa32-05a659cbd1e4,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"During male fetal development, the bipotential gonads become the testes and associated epididymis. The Müllerian ducts degenerate. The Wolffian ducts become the vas deferens, and the cloaca becomes the urethra and rectum.",True,Sexual Differentiation,,,,
+493d7f37-74de-4f28-a307-f2c7cfc5ce43,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"During female fetal development, the bipotential gonads develop into ovaries. The Wolffian ducts degenerate. The Müllerian ducts become the uterine tubes and uterus, and the cloaca divides and develops into a vagina, a urethra, and a rectum.",True,Sexual Differentiation,,,,
+b0997275-9c26-4a68-b822-26e5e5d5de24,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,The Fetal Circulatory System,False,The Fetal Circulatory System,,,,
+83db608a-4655-4308-a04d-fb250c0bb676,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"During prenatal development, the fetal circulatory system is integrated with the placenta via the umbilical cord so that the fetus receives both oxygen and nutrients from the placenta. However, after childbirth, the umbilical cord is severed, and the newborn’s circulatory system must be reconfigured. When the heart first forms in the embryo, it exists as two parallel tubes derived from mesoderm and lined with endothelium, which then fuse together. As the embryo develops into a fetus, the tube-shaped heart folds and further differentiates into the four chambers present in a mature heart. Unlike a mature cardiovascular system, however, the fetal cardiovascular system also includes circulatory shortcuts, or shunts. A shunt is an anatomical (or sometimes surgical) diversion that allows blood flow to bypass immature organs such as the lungs and liver until childbirth.",True,The Fetal Circulatory System,,,,
+65257d19-ee64-44e9-8941-5e25ae94e8b4,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"The placenta provides the fetus with necessary oxygen and nutrients via the umbilical vein. (Remember that veins carry blood toward the heart. In this case, the blood flowing to the fetal heart is oxygenated because it comes from the placenta. The respiratory system is immature and cannot yet oxygenate blood on its own.) From the umbilical vein, the oxygenated blood flows toward the inferior vena cava, all but bypassing the immature liver, via the ductus venosus shunt (Figure 28.3.2). The liver receives just a trickle of blood, which is all that it needs in its immature, semifunctional state. Blood flows from the inferior vena cava to the right atrium, mixing with fetal venous blood along the way.",True,The Fetal Circulatory System,Figure 28.3.2,28.3 Fetal Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2916_Fetal_Circulatory_System-02.jpg,"Figure 28.3.2 – Fetal Circulatory System: The fetal circulatory system includes three shunts to divert blood from undeveloped and partially functioning organs, as well as blood supply to and from the placenta."
+fb68ca60-6654-4cda-bbfd-41d8d515c166,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"Although the fetal liver is semifunctional, the fetal lungs are nonfunctional. The fetal circulation therefore bypasses the lungs by shifting some of the blood through the foramen ovale, a shunt that directly connects the right and left atria and avoids the pulmonary trunk altogether. Most of the rest of the blood is pumped to the right ventricle, and from there, into the pulmonary trunk, which splits into pulmonary arteries. However, a shunt within the pulmonary artery, the ductus arteriosus, diverts a portion of this blood into the aorta. This ensures that only a small volume of oxygenated blood passes through the immature pulmonary circuit, which has only minor metabolic requirements. Blood vessels of uninflated lungs have high resistance to flow, a condition that encourages blood to flow to the aorta, which presents much lower resistance. The oxygenated blood moves through the foramen ovale into the left atrium, where it mixes with the now deoxygenated blood returning from the pulmonary circuit. This blood then moves into the left ventricle, where it is pumped into the aorta. Some of this blood moves through the coronary arteries into the myocardium, and some moves through the carotid arteries to the brain.",True,The Fetal Circulatory System,,,,
+c06548e7-eb05-429a-99e6-6d50d8149c03,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"The descending aorta carries partially oxygenated and partially deoxygenated blood into the lower regions of the body. It eventually passes into the umbilical arteries through branches of the internal iliac arteries. The deoxygenated blood collects waste as it circulates through the fetal body and returns to the umbilical cord. Thus, the two umbilical arteries carry blood low in oxygen and high in carbon dioxide and fetal wastes. This blood is filtered through the placenta, where wastes diffuse into the maternal circulation. Oxygen and nutrients from the mother diffuse into the placenta and from there into the fetal blood, and the process repeats.",True,The Fetal Circulatory System,,,,
+e82ec74b-b692-4703-9ff0-f2132935cca2,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,Other Organ Systems,False,Other Organ Systems,,,,
+ba1c75ff-f38b-464d-8988-1993d40e35f4,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"During weeks 9–12 of fetal development, the brain continues to expand, the body elongates, and ossification continues. Fetal movements are frequent during this period, but are jerky and not well-controlled. The bone marrow begins to take over the process of erythrocyte production—a task that the liver performed during the embryonic period. The liver now secretes bile. The fetus circulates amniotic fluid by swallowing it and producing urine. The eyes are well-developed by this stage, but the eyelids are fused shut. The fingers and toes begin to develop nails. By the end of week 12, the fetus measures approximately 9 cm (3.5 in) from crown to rump.",True,Other Organ Systems,,,,
+6c56d82d-c165-4293-b645-22e84eba4956,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"Weeks 13–16 are marked by sensory organ development. The eyes move closer together; blinking motions begin, although the eyes remain sealed shut. The lips exhibit sucking motions. The ears move upward and lie flatter against the head. The scalp begins to grow hair. The excretory system is also developing: the kidneys are well-formed, and meconium, or fetal feces, begins to accumulate in the intestines. Meconium consists of ingested amniotic fluid, cellular debris, mucus, and bile.",True,Other Organ Systems,,,,
+433610cf-ba84-439d-979d-aae30a82929f,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"During approximately weeks 16–20, as the fetus grows and limb movements become more powerful, the mother may begin to feel quickening, or fetal movements. However, space restrictions limit these movements and typically force the growing fetus into the “fetal position,” with the arms crossed and the legs bent at the knees. Sebaceous glands coat the skin with a waxy, protective substance called vernix caseosa that protects and moisturizes the skin and may provide lubrication during childbirth. A silky hair called lanugo also covers the skin during weeks 17–20, but it is shed as the fetus continues to grow. Extremely premature infants sometimes exhibit residual lanugo.",True,Other Organ Systems,,,,
+30abc054-dce9-4645-92d9-7c5a3bb151ce,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"Developmental weeks 21–30 are characterized by rapid weight gain, which is important for maintaining a stable body temperature after birth. The bone marrow completely takes over erythrocyte synthesis, and the axons of the spinal cord begin to be myelinated, or coated in the electrically insulating glial cell sheaths that are necessary for efficient nervous system functioning. (The process of myelination is not completed until adolescence.) During this period, the fetus grows eyelashes. The eyelids are no longer fused and can be opened and closed. The lungs begin producing surfactant, a substance that reduces surface tension in the lungs and assists proper lung expansion after birth. Inadequate surfactant production in premature newborns may result in respiratory distress syndrome, and as a result, the newborn may require surfactant replacement therapy, supplemental oxygen, or maintenance in a continuous positive airway pressure (CPAP) chamber during their first days or weeks of life. In male fetuses, the testes descend into the scrotum near the end of this period. The fetus at 30 weeks measures 28 cm (11 in) from crown to rump and exhibits the approximate body proportions of a full-term newborn, but still is much leaner.",True,Other Organ Systems,,,,
+f0a937d6-8822-4cce-97a7-84ecfc618ae3,https://open.oregonstate.education/aandp/,28.3 Fetal Development,https://open.oregonstate.education/aandp/chapter/28-3-fetal-development/,"The fetus continues to lay down subcutaneous fat from week 31 until birth. The added fat fills out the hypodermis, and the skin transitions from red and wrinkled to soft and pink. Lanugo is shed, and the nails grow to the tips of the fingers and toes. Immediately before birth, the average crown-to-rump length is 35.5–40.5 cm (14–16 in), and the fetus weighs approximately 2.5–4 kg (5.5–8.8 lbs). Once born, the newborn is no longer confined to the fetal position, so subsequent measurements are made from head-to-toe instead of from crown-to-rump. At birth, the average length is approximately 51 cm (20 in).",True,Other Organ Systems,,,,
+1447f547-740b-4b57-9b71-5c0bb24bc946,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Throughout this chapter, we will express embryonic and fetal ages in terms of weeks from fertilization, commonly called conception. The period of time required for full development of a fetus in utero is referred to as gestation (gestare = “to carry” or “to bear”). It can be subdivided into distinct gestational periods. The first 2 weeks of prenatal development are referred to as the pre-embryonic stage. A developing human is referred to as an embryo during weeks 3–8, and a fetus from the ninth week of gestation until birth. In this section, we’ll cover the pre-embryonic and embryonic stages of development, which are characterized by cell division, migration, and differentiation. By the end of the embryonic period, all of the organ systems are structured in rudimentary form, although the organs themselves are either nonfunctional or only semi-functional.",True,Other Organ Systems,,,,
+20bff5fc-4057-43f9-9762-32cd0a75ae93,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Pre-implantation Embryonic Development,False,Pre-implantation Embryonic Development,,,,
+adcd4aa1-20f5-4c94-8b67-d96a1006632b,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Following fertilization, the zygote and its associated membranes, together referred to as the conceptus, continue to be projected toward the uterus by peristalsis and beating cilia. During its journey to the uterus, the zygote undergoes five or six rapid mitotic cell divisions. Although each cleavage results in more cells, it does not increase the total volume of the conceptus (Figure 28.2.1). Each daughter cell produced by cleavage is called a blastomere (blastos = “germ,” in the sense of a seed or sprout).",True,Pre-implantation Embryonic Development,Figure 28.2.1,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2903_Preembryonic_Cleavages-02-1.jpg,Figure 28.2.1 – Pre-Embryonic Cleavages: Pre-embryonic cleavages make use of the abundant cytoplasm of the conceptus as the cells rapidly divide without changing the total volume.
+e3a5274a-a737-4396-a40c-c2fd3f944eb4,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Approximately 3 days after fertilization, a 16-cell conceptus reaches the uterus. The cells that had been loosely grouped are now compacted and look more like a solid mass. The name given to this structure is the morula (morula = “little mulberry”). Once inside the uterus, the conceptus floats freely for several more days. It continues to divide, creating a ball of approximately 100 cells, and consuming nutritive endometrial secretions called uterine milk while the uterine lining thickens. The ball of now tightly bound cells starts to secrete fluid and organize themselves around a fluid-filled cavity, the blastocoel. At this developmental stage, the conceptus is referred to as a blastocyst. Within this structure, a group of cells forms into an inner cell mass, which is fated to become the embryo. The cells that form the outer shell are called trophoblasts (trophe = “to feed” or “to nourish”). These cells will develop into the chorionic sac and the fetal portion of the placenta (the organ of nutrient, waste, and gas exchange between mother and the developing offspring).",True,Pre-implantation Embryonic Development,,,,
+ed662868-d8f0-4b94-8f8f-37a1e40d6c43,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"The inner mass of embryonic cells is totipotent during this stage, meaning that each cell has the potential to differentiate into any cell type in the human body. Totipotency lasts for only a few days before the cells’ fates are set as being the precursors to a specific lineage of cells.",True,Pre-implantation Embryonic Development,,,,
+b2bfae9e-75fd-42db-967a-11c5036922ac,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"As the blastocyst forms, the trophoblast excretes enzymes that begin to degrade the zona pellucida. In a process called “hatching,” the conceptus breaks free of the zona pellucida in preparation for implantation.",True,Pre-implantation Embryonic Development,,,,
+49109f15-d99f-482d-89c5-9fd04b99800a,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Implantation,False,Implantation,,,,
+04a53e5b-54fe-414e-b9d0-4aa1124552a5,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"At the end of the first week, the blastocyst comes in contact with the uterine wall and adheres to it, embedding itself in the uterine lining via the trophoblast cells. Thus begins the process of implantation, which signals the end of the pre-embryonic stage of development (Figure 28.2.2). Implantation can be accompanied by minor bleeding. The blastocyst typically implants in the fundus of the uterus or on the posterior wall. However, if the endometrium is not fully developed and ready to receive the blastocyst, the blastocyst will detach and find a better spot. A significant percentage (50–75 percent) of blastocysts fail to implant; when this occurs, the blastocyst is shed with the endometrium during menses. The high rate of implantation failure is one reason why pregnancy typically requires several ovulation cycles to achieve.",True,Implantation,Figure 28.2.2,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2904_Preembryonic_Development-02-1.jpg,"Figure 28.2.2 – Pre-Embryonic Development: Ovulation, fertilization, pre-embryonic development, and implantation occur at specific locations within the female reproductive system in a time span of approximately 1 week."
+f8fc8f56-2368-41ce-abe4-2991a05517ef,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"When implantation succeeds and the blastocyst adheres to the endometrium, the superficial cells of the trophoblast fuse with each other, forming the syncytiotrophoblast, a multinucleated body that digests endometrial cells to firmly secure the blastocyst to the uterine wall. In response, the uterine mucosa rebuilds itself and envelops the blastocyst (Figure 28.2.3). The trophoblast secretes human chorionic gonadotropin (hCG), a hormone that directs the corpus luteum to survive, enlarge, and continue producing progesterone and estrogen to suppress menses. These functions of hCG are necessary for creating an environment suitable for the developing embryo. As a result of this increased production, hCG accumulates in the maternal bloodstream and is excreted in the urine. Implantation is complete by the middle of the second week. Just a few days after implantation, the trophoblast has secreted enough hCG for an at-home urine pregnancy test to give a positive result.",True,Implantation,Figure 28.2.3,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2905_Implantation-1.jpg,"Figure 28.2.3 – Implantation: During implantation, the trophoblast cells of the blastocyst adhere to the endometrium and digest endometrial cells until it is attached securely."
+e4d7bde5-53a3-41fe-8739-a7163c0ee784,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Most of the time an embryo implants within the body of the uterus in a location that can support growth and development. However, in one to two percent of cases, the embryo implants either outside the uterus (an ectopic pregnancy) or in a region of uterus that can create complications for the pregnancy. If the embryo implants in the inferior portion of the uterus, the placenta can potentially grow over the opening of the cervix, a condition call placenta previa.",True,Implantation,,,,
+93bb4b27-aac9-4c8e-a361-3817b7e96085,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Embryonic Membranes,False,Embryonic Membranes,,,,
+c9d12da9-447f-4452-8897-f5e4d3e70354,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"During the second week of development, with the embryo implanted in the uterus, cells within the blastocyst start to organize into layers. Some grow to form the extra-embryonic membranes needed to support and protect the growing embryo: the amnion, the yolk sac, the allantois, and the chorion.",True,Embryonic Membranes,,,,
+0232bba0-8797-4113-9f34-c858215e5ed2,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"At the beginning of the second week, the cells of the inner cell mass form into a two-layered disc of embryonic cells, and a space—the amniotic cavity—opens up between it and the trophoblast (Figure 28.2.5). Cells from the upper layer of the disc (the epiblast) extend around the amniotic cavity, creating a membranous sac that forms into the amnion by the end of the second week. The amnion fills with amniotic fluid and eventually grows to surround the embryo. Early in development, amniotic fluid consists almost entirely of a filtrate of maternal plasma, but as the kidneys of the fetus begin to function at approximately the eighth week, they add urine to the volume of amniotic fluid. Floating within the amniotic fluid, the embryo—and later, the fetus—is protected from trauma and rapid temperature changes. It can move freely within the fluid and can prepare for swallowing and breathing out of the uterus.",True,Embryonic Membranes,Figure 28.2.5,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2907_Embroyonic_Disc_Amniotic_Cavity_Yolk_Sac-02-1.jpg,Figure 28.2.5 – Development of the Embryonic Disc: Formation of the embryonic disc leaves spaces on either side that develop into the amniotic cavity and the yolk sac.
+ceb33528-f00f-4c70-96d2-f997ff746863,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"On the ventral side of the embryonic disc, opposite the amnion, cells in the lower layer of the embryonic disk (the hypoblast) extend into the blastocyst cavity and form a yolk sac. The yolk sac supplies some nutrients absorbed from the trophoblast and also provides primitive blood circulation to the developing embryo for the second and third week of development. When the placenta takes over nourishing the embryo at approximately week 4, the yolk sac has been greatly reduced in size and its main function is to serve as the source of blood cells and germ cells (cells that will give rise to gametes). During week 3, a finger-like outpocketing of the yolk sac develops into the allantois, a primitive excretory duct of the embryo that will become part of the urinary bladder. Together, the stalks of the yolk sac and allantois establish the outer structure of the umbilical cord.",True,Embryonic Membranes,,,,
+da78f602-6c55-457d-85a8-da1f2e2acb1e,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"The last of the extra-embryonic membranes is the chorion, which is the one membrane that surrounds all others. The development of the chorion will be discussed in more detail shortly, as it relates to the growth and development of the placenta.",True,Embryonic Membranes,,,,
+4d649c0b-e8c6-42a0-a34c-8104d73c990c,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Embryogenesis,False,Embryogenesis,,,,
+3c09ee70-8866-4b40-a978-15b7b2cfdb73,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"As the third week of development begins, the two-layered disc of cells becomes a three-layered disc through the process of gastrulation, during which the cells transition from totipotency to multipotency. The embryo, which takes the shape of an oval-shaped disc, forms an indentation called the primitive streak along the dorsal surface of the epiblast. A node at the caudal or “tail” end of the primitive streak emits growth factors that direct cells to multiply and migrate. Cells migrate toward and through the primitive streak and then move laterally to create two new layers of cells. The first layer is the endoderm, a sheet of cells that displaces the hypoblast and lies adjacent to the yolk sac. The second layer of cells fills in as the middle layer, or mesoderm. The cells of the epiblast that remain (not having migrated through the primitive streak) become the ectoderm (Figure 28.2.6).",True,Embryogenesis,Figure 28.2.6,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2908_Germ_Layers-02-1.jpg,Figure 28.2.6 – Germ Layers: Formation of the three primary germ layers occurs during the first 2 weeks of development. The embryo at this stage is only a few millimeters in length.
+dbda7534-b8cc-43dd-bafc-f13909454df1,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Each of these germ layers will develop into specific structures in the embryo. Whereas the ectoderm and endoderm form tightly connected epithelial sheets, the mesodermal cells are less organized and exist as a loosely connected cell community. The ectoderm gives rise to cell lineages that differentiate to become the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails. Mesodermal cells ultimately become the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm goes on to form the epithelial lining of the gastrointestinal tract, liver, and pancreas, as well as the lungs (Figure 28.2.7).",True,Embryogenesis,Figure 28.2.7,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2909_Embryo_Week_3-02-1.jpg,"Figure 28.2.7 – Fates of Germ Layers in Embryo: Following gastrulation of the embryo in the third week, embryonic cells of the ectoderm, mesoderm, and endoderm begin to migrate and differentiate into the cell lineages that will give rise to mature organs and organ systems in the infant."
+0568eea1-1316-4502-ad4f-c60bef2fdca7,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Development of the Placenta,False,Development of the Placenta,,,,
+5678e08a-b960-4410-a027-c99103de5d5f,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"During the first several weeks of development, the cells of the endometrium—referred to as decidual cells—nourish the nascent embryo. During prenatal weeks 4–12, the developing placenta gradually takes over the role of feeding the embryo, and the decidual cells are no longer needed. The mature placenta is composed of tissues derived from the embryo, as well as maternal tissues of the endometrium. The placenta connects to the conceptus via the umbilical cord, which carries deoxygenated blood and wastes from the fetus through two umbilical arteries; nutrients and oxygen are carried from the mother to the fetus through the single umbilical vein. The umbilical cord is surrounded by the amnion, and the spaces within the cord around the blood vessels are filled with Wharton’s jelly, a mucous connective tissue.",True,Development of the Placenta,,,,
+6523169d-b898-422d-912e-fc994fe7e79e,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"The maternal portion of the placenta develops from the deepest layer of the endometrium, the decidua basalis. To form the embryonic portion of the placenta, the syncytiotrophoblast and the underlying cells of the trophoblast (cytotrophoblast cells) begin to proliferate along with a layer of extraembryonic mesoderm cells. These form the chorionic membrane, which envelops the entire conceptus as the chorion. The chorionic membrane forms finger-like structures called chorionic villi that burrow into the endometrium like tree roots, making up the fetal portion of the placenta. The cytotrophoblast cells perforate the chorionic villi, burrow farther into the endometrium, and remodel maternal blood vessels to augment maternal blood flow surrounding the villi. Meanwhile, fetal mesenchymal cells derived from the mesoderm fill the villi and differentiate into blood vessels, including the three umbilical blood vessels that connect the embryo to the developing placenta (Figure 28.2.8).",True,Development of the Placenta,Figure 28.2.8,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2910_The_Placenta-02.jpg,"Figure 28.2.8 – Cross-Section of the Placenta: In the placenta, maternal and fetal blood components are conducted through the surface of the chorionic villi, but maternal and fetal bloodstreams never mix directly."
+416948f9-3c5b-4354-876c-28ddaa2cf8b7,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"The placenta develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 14–16. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function (Table 28.1 and Figure 28.2.9). It receives blood from the fetus through the umbilical arteries. Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through the umbilical vein. Nutrients and oxygen are transferred from maternal blood surrounding the villi through the capillaries and into the fetal bloodstream. Some substances move across the placenta by simple diffusion. Oxygen, carbon dioxide, and any other lipid-soluble substances take this route. Other substances move across by facilitated diffusion. This includes water-soluble glucose. The fetus has a high demand for amino acids and iron, and those substances are moved across the placenta by active transport.",True,Development of the Placenta,Figure 28.2.9,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2911_Photo_of_Placenta-02.jpg,Figure 28.2.9 – Placenta: This post-expulsion placenta and umbilical cord (white) are viewed from the fetal side.
+2d40b12d-ef2c-4746-8dd9-0e95e71e2038,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Maternal and fetal blood does not commingle because blood cells cannot move across the placenta. This separation prevents the mother’s cytotoxic T cells from reaching and subsequently destroying the fetus, which bears “non-self” antigens. Further, it ensures the fetal red blood cells do not enter the mother’s circulation and trigger antibody development (if they carry “non-self” antigens)—at least until the final stages of pregnancy or birth. This is the reason that, even in the absence of preventive treatment, an Rh− mother doesn’t develop antibodies that could cause hemolytic disease in her first Rh+ fetus.",True,Development of the Placenta,,,,
+c1be3a17-df5f-43b0-bd5f-3409d786e9ed,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Although blood cells are not exchanged, the chorionic villi provide ample surface area for the two-way exchange of substances between maternal and fetal blood. The rate of exchange increases throughout gestation as the villi become thinner and increasingly branched. The placenta is permeable to lipid-soluble fetotoxic substances: alcohol, nicotine, barbiturates, antibiotics, certain pathogens, and many other substances that can be dangerous or fatal to the developing embryo or fetus. For these reasons, pregnant women should avoid fetotoxic substances. Alcohol consumption by pregnant women, for example, can result in a range of abnormalities referred to as fetal alcohol spectrum disorders (FASD). These include organ and facial malformations, as well as cognitive and behavioral disorders.",True,Development of the Placenta,,,,
+3e7df861-0e1a-4ac4-b87a-a137c5c4305d,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,Organogenesis,False,Organogenesis,,,,
+6dd61c10-7885-4d10-9517-c991b087395c,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Following gastrulation, rudiments of the central nervous system develop from the ectoderm in the process of neurulation (Figure 28.2.10). Specialized neuroectodermal tissues along the length of the embryo thicken into the neural plate. During the fourth week, tissues on either side of the plate fold upward into a neural fold. The two folds converge to form the neural tube. The tube lies atop a rod-shaped, mesoderm-derived notochord, which eventually becomes the nucleus pulposus of intervertebral discs. Block-like structures called somites form on either side of the tube, eventually differentiating into the axial skeleton, skeletal muscle, and dermis. During the fourth and fifth weeks, the anterior neural tube dilates and subdivides to form vesicles that will become the brain structures.",True,Organogenesis,Figure 28.2.10,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2912_Neurulation-02.jpg,Figure 28.2.10 – Neurulation: The embryonic process of neurulation establishes the rudiments of the future central nervous system and skeleton.
+641ecb87-40e7-4621-a83f-a634b2cd4426,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Folate, one of the B vitamins, is important to the healthy development of the neural tube. A deficiency of maternal folate in the first weeks of pregnancy can result in neural tube defects, including spina bifida—a birth defect in which spinal tissue protrudes through the newborn’s vertebral column, which has failed to completely close. A more severe neural tube defect is anencephaly, a partial or complete absence of brain tissue.",True,Organogenesis,,,,
+3b8c5963-dba3-4d33-be33-f58f6f00b883,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"The embryo, which begins as a flat sheet of cells, begins to acquire a cylindrical shape through the process of embryonic folding (Figure 28.2.11). The embryo folds laterally and again at either end, forming a C-shape with distinct head and tail ends. The embryo envelops a portion of the yolk sac, which protrudes with the umbilical cord from what will become the abdomen. The folding essentially creates a tube, called the primitive gut, that is lined by the endoderm. The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.",True,Organogenesis,Figure 28.2.11,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2913_Embryonic_Folding.jpg,"Figure 28.2.11 – Embryonic Folding: Embryonic folding converts a flat sheet of cells into a hollow, tube-like structure."
+9ca108ee-bcb2-4e9b-814f-7dcf40437f4c,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Within the first 8 weeks of gestation, a developing embryo establishes the rudimentary structures of all of its organs and tissues from the ectoderm, mesoderm, and endoderm. This process is called organogenesis.",True,Organogenesis,,,,
+d8382eb1-3bd2-4699-8d42-2386f3c7f3d4,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"Like the central nervous system, the heart also begins its development in the embryo as a tube-like structure, connected via capillaries to the chorionic villi. Cells of the primitive tube-shaped heart are capable of electrical conduction and contraction. The heart begins beating in the beginning of the fourth week, although it does not actually pump embryonic blood until a week later, when the oversized liver has begun producing red blood cells. (This is a temporary responsibility of the embryonic liver that the bone marrow will assume during fetal development.) During weeks 4–5, the eye pits form, limb buds become apparent, and the rudiments of the pulmonary system are formed.",True,Organogenesis,,,,
+b9533943-beca-40e1-8306-67a16cadee23,https://open.oregonstate.education/aandp/,28.2 Embryonic Development,https://open.oregonstate.education/aandp/chapter/28-2-embryonic-development/,"During the sixth week, uncontrolled fetal limb movements begin to occur. The gastrointestinal system develops too rapidly for the embryonic abdomen to accommodate it, and the intestines temporarily loop into the umbilical cord. Paddle-shaped hands and feet develop fingers and toes by the process of apoptosis (programmed cell death), which causes the tissues between the fingers to disintegrate. By week 7, the facial structure is more complex and includes nostrils, outer ears, and lenses (Figure 28.2.12). By the eighth week, the head is nearly as large as the rest of the embryo’s body, and all major brain structures are in place. The external genitalia are apparent, but at this point, male and female embryos are indistinguishable. Bone begins to replace cartilage in the embryonic skeleton through the process of ossification. By the end of the embryonic period, the embryo is approximately 3 cm (1.2 in) from crown to rump and weighs approximately 8 g (0.25 oz).",True,Organogenesis,Figure 28.2.12,28.2 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2914_Photo_of_Embryo-02.jpg,"Figure 28.2.12 – Embryo at 7 Weeks: An embryo at the end of 7 weeks of development is only 10 mm in length, but its developing eyes, limb buds, and tail are already visible. (This embryo was derived from an ectopic pregnancy.) (credit: Ed Uthman)"
+8d47225a-c2de-4c68-9e97-80ca31631b40,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Fertilization occurs when a sperm and an oocyte (egg) combine and their nuclei fuse. Because each of these reproductive cells is a haploid cell containing half of the genetic material needed to form a human being, their combination forms a diploid cell. This new single cell, called a zygote, contains all of the genetic material needed to form a human—half from the mother and half from the father.",True,Organogenesis,,,,
+d092eb77-efc9-45b5-8c9c-08cfffb93d6f,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,Transit of Sperm,False,Transit of Sperm,,,,
+b54dfad3-d9eb-4ba1-ad12-e4a33c8cf175,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Fertilization is a numbers game. During ejaculation, hundreds of millions of sperm (spermatozoa) are released into the vagina. Almost immediately, millions of these sperm are overcome by the acidity of the vagina (approximately pH 3.8), and millions more may be blocked from entering the uterus by thick cervical mucus. Of those that do enter, thousands are destroyed by phagocytic uterine leukocytes. Thus, the race into the uterine tubes, which is the most typical site for sperm to encounter the oocyte, is reduced to a few thousand contenders. Their journey—thought to be facilitated by uterine contractions—usually takes from 30 minutes to 2 hours. If the sperm do not encounter an oocyte immediately, they can survive in the uterine tubes for another 3–5 days. Thus, fertilization can still occur if intercourse takes place a few days before ovulation. In comparison, an oocyte can survive independently for only approximately 24 hours following ovulation. Intercourse more than a day after ovulation will therefore usually not result in fertilization.",True,Transit of Sperm,,,,
+3a12da7b-3840-48de-9d8a-4bca554c2f30,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"During the journey, fluids in the female reproductive tract prepare the sperm for fertilization through a process called capacitation, or priming. The fluids improve the motility of the spermatozoa. They also deplete cholesterol molecules embedded in the membrane of the head of the sperm, thinning the membrane in such a way that will help facilitate the release of the lysosomal (digestive) enzymes needed for the sperm to penetrate the oocyte’s exterior once contact is made. Sperm must undergo the process of capacitation in order to have the “capacity” to fertilize an oocyte. If they reach the oocyte before capacitation is complete, they will be unable to penetrate the oocyte’s thick outer layer of cells.",True,Transit of Sperm,,,,
+fb16a00c-9a48-4c71-b886-c0b339b4dfc2,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,Contact Between Sperm and Oocyte,False,Contact Between Sperm and Oocyte,,,,
+4a4982cf-98af-4f01-b99a-9e73cfb949c4,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Upon ovulation, the oocyte released by the ovary is swept into—and along—the uterine tube. Fertilization must occur in the distal uterine tube because an unfertilized oocyte cannot survive the 72-hour journey to the uterus. As you will recall from your study of the oogenesis, this oocyte (specifically a secondary oocyte) is surrounded by two protective layers. The corona radiata is an outer layer of follicular (granulosa) cells that form around a developing oocyte in the ovary and remain with it upon ovulation. The underlying zona pellucida (pellucid = “transparent”) is a transparent, but thick, glycoprotein membrane that surrounds the cell’s plasma membrane.",True,Contact Between Sperm and Oocyte,,,,
+380035c5-d8fb-4014-9c87-31f6b1cd1515,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"As it is swept along the distal uterine tube, the oocyte encounters the surviving capacitated sperm, which stream toward it in response to chemical attractants released by the cells of the corona radiata. To reach the oocyte itself, the sperm must penetrate the two protective layers. The sperm first burrow through the cells of the corona radiata. Then, upon contact with the zona pellucida, the sperm bind to receptors in the zona pellucida. This initiates a process called the acrosomal reaction in which the enzyme-filled “cap” of the sperm, called the acrosome, releases its stored digestive enzymes. These enzymes clear a path through the zona pellucida that allows sperm to reach the oocyte. Finally, a single sperm makes contact with sperm-binding receptors on the oocyte’s plasma membrane (Figure 28.1.1). The plasma membrane of that sperm then fuses with the oocyte’s plasma membrane, and the head and mid-piece of the “winning” sperm enter the oocyte interior.",True,Contact Between Sperm and Oocyte,Figure 28.1.1,28.1 Fertilization,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2901_Sperm_Fertilization.jpg,"Figure 28.1.1 – Sperm and the Process of Fertilization: Before fertilization, hundreds of capacitated sperm must break through the surrounding corona radiata and zona pellucida so that one can contact and fuse with the oocyte plasma membrane."
+f4bb0e66-dfd7-44a6-bb52-2e130b740d71,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"How do sperm penetrate the corona radiata? Some sperm undergo a spontaneous acrosomal reaction, which is an acrosomal reaction not triggered by contact with the zona pellucida. The digestive enzymes released by this reaction digest the extracellular matrix of the corona radiata. As you can see, the first sperm to reach the oocyte is never the one to fertilize it. Rather, hundreds of sperm cells must undergo the acrosomal reaction, each helping to degrade the corona radiata and zona pellucida until a path is created to allow one sperm to contact and fuse with the plasma membrane of the oocyte. If you consider the loss of millions of sperm between entry into the vagina and degradation of the zona pellucida, you can understand why a low sperm count can cause male infertility.",True,Contact Between Sperm and Oocyte,,,,
+437e1bdf-fe0f-444e-90d4-c299a68ffe70,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"When the first sperm fuses with the oocyte, the oocyte deploys two mechanisms to prevent polyspermy, which is penetration by more than one sperm. This is critical because if more than one sperm were to fertilize the oocyte, the resulting zygote would be a triploid organism with three sets of chromosomes. This is incompatible with life.",True,Contact Between Sperm and Oocyte,,,,
+f8fcd7b7-cba8-4b28-8707-1652faf53736,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"The first mechanism is the fast block, which involves a near instantaneous change in sodium ion permeability upon binding of the first sperm, depolarizing the oocyte plasma membrane and preventing the fusion of additional sperm cells. The fast block sets in almost immediately and lasts for about a minute, during which time an influx of calcium ions following sperm penetration triggers the second mechanism, the slow block. In this process, referred to as the cortical reaction, cortical granules sitting immediately below the oocyte plasma membrane fuse with the membrane and release zonal inhibiting proteins and mucopolysaccharides into the space between the plasma membrane and the zona pellucida. Zonal inhibiting proteins cause the release of any other attached sperm and destroy the oocyte’s sperm receptors, thus preventing any more sperm from binding. The mucopolysaccharides then coat the nascent zygote in an impenetrable barrier that, together with hardened zona pellucida, is called a fertilization membrane.",True,Contact Between Sperm and Oocyte,,,,
+51f5c10d-4501-48c5-a17a-11c9ecde3cb6,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,The Zygote,False,The Zygote,,,,
+c108d485-eb0b-4ea5-bd20-7c0ade4b0829,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Recall that at the point of fertilization, the oocyte has not yet completed meiosis; all secondary oocytes remain arrested in metaphase of meiosis II until fertilization. Only upon fertilization does the oocyte complete meiosis. The unneeded complement of genetic material that results is stored in a second polar body that is eventually ejected. At this moment, the oocyte has become an ovum, the female haploid gamete. The two haploid nuclei derived from the sperm and oocyte and contained within the egg are referred to as pronuclei. They decondense, expand, and replicate their DNA in preparation for mitosis. The pronuclei then migrate toward each other, their nuclear envelopes disintegrate, and the male- and female-derived genetic material intermingles. This step completes the process of fertilization and results in a single-celled diploid zygote with all the genetic instructions it needs to develop into a human.",True,The Zygote,,,,
+f08d3899-01f6-4915-b564-2fc9e7eb352d,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Most of the time, a woman releases a single egg during an ovulation cycle. However, in approximately 1 percent of ovulation cycles, two eggs are released and both are fertilized. Two zygotes form, implant, and develop, resulting in the birth of dizygotic (or fraternal) twins. Because dizygotic twins develop from two eggs fertilized by two sperm, they are no more identical than siblings born at different times.",True,The Zygote,,,,
+b4bb7ecc-a906-4655-b104-6b90ba13a48d,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,"Much less commonly, a zygote can divide into two separate offspring during early development. This results in the birth of monozygotic (or identical) twins. Although the zygote can split as early as the two-cell stage, splitting occurs most commonly during the early blastocyst stage, with roughly 70–100 cells present. These two scenarios are distinct from each other, in that the twin embryos that separated at the two-cell stage will have individual placentas, whereas twin embryos that form from separation at the blastocyst stage will share a placenta and a chorionic cavity.",True,The Zygote,,,,
+d97f50df-b9c1-4bf9-864a-08d794084775,https://open.oregonstate.education/aandp/,28.1 Fertilization,https://open.oregonstate.education/aandp/chapter/28-1-fertilization/,Everyday Connections,False,Everyday Connections,,,,
+0aeb18e9-5bd8-4607-b416-de361d86eba0,https://open.oregonstate.education/aandp/,28.0 Introduction,https://open.oregonstate.education/aandp/chapter/28-0-introduction/,"In approximately nine months, a single cell—a fertilized egg—develops into a fully formed infant consisting of trillions of cells with myriad specialized functions. The dramatic changes of fertilization, embryonic development, and fetal development are followed by remarkable adaptations of the newborn to life outside the womb. An offspring’s normal development depends upon the appropriate synthesis of structural and functional proteins. This, in turn, is governed by the genetic material inherited from the parental egg and sperm, as well as environmental factors.",True,Everyday Connections,,,,
+c0a2b86b-8f30-4734-b528-0c50db76831d,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,Introduction:,False,Introduction:,,,,
+ccc674ac-6b53-470c-a269-f71186f37c95,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,The following chapter will discuss the physiology of arousal and orgasm. Arousal includes the physiology of erection and increased lubrication production due to a combination of mental and physical stimuli. Orgasm typically includes the release of ejaculate and involuntary muscle contractions accompanied by feelings of euphoria. Immediately following orgasm there is resolution of vasocongestion in erectile tissue followed by feelings of contentment and relaxation.,True,Introduction:,,,,
+dfbeaa1b-d1e1-432e-85a5-024c8fdb7fd6,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,Arousal:,False,Arousal:,,,,
+fe209e35-b362-45f6-9c3d-5c3d2e3ab304,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"The physiological process of arousal can begin due to sexual thoughts or from physical stimulation. Mostly commonly, the combination of mental and physical input together – synapsing with the sacral nerves roots – leads to reflexive patterns of physiologic arousal. Due to the reflexive nature of the response, positive mental stimulation is it not a requirement for physical signs of arousal to occur. Also, in the case of spinal cord injury, the location of the injury relative to the sacral nerve roots will dictate whether input from the brain, or from physical stimulation, will lead to physical signs of arousal. Sexual sensations are typically most intense due to physical stimulation of the glans of the clitoris or penis, although arousal can also occur due to stimulation of the nipples, all portions of the clitoris and penis, the vulva and perineal region, prostate, urethra, bladder, anal epithelium, scrotum, testes and vas deferens. Efferent and afferent signals related to sexual arousal travel along many nerves including the pudendal, pelvic splanchnic, hypogastric, vagus, ilioinguinal, posterior femoral cutaneous and genital branch of the genitofemoral nerve.",True,Arousal:,,,,
+a0e7b9aa-eca4-4d0c-89b4-ebb88b6feaf3,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"The clitoris, the bulbs of the vestibule and the penis are erectile tissues. Erections are the result of vasocongestion, or engorgement of the tissues because of more arterial blood flowing into the erectile structure than is leaving in the veins. During sexual arousal, nitric oxide (NO) is released from parasympathetic nerve endings near blood vessels within the corpora cavernosa and spongiosum. Release of NO activates a signaling pathway that results in relaxation of the smooth muscles that surround the arteries, causing them to dilate. This dilation increases the amount of blood that can enter the erectile structures and induces the endothelial cells in the arterial walls to also secrete NO and perpetuate the vasodilation. The rapid increase in blood volume fills the erectile chambers, and the increased pressure of the filled chambers compresses the thin-walled venules, preventing venous drainage. The result of this increased blood flow to the erectile structures, and reduced blood returning from the structure, is called erection.",True,Arousal:,,,,
+6d403a72-5e78-46cb-af13-acf64f0bd92a,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"Parasympathetic impulses during arousal cause the secretion of mucus from the greater vestibular glands into the vestibule of the vulva via a pair of ducts found lateral to the vaginal opening. Instead of mucus, the capillaries of the vaginal walls secrete serous fluid as vaginal lubrication. Arousal also causes the bulbourethral glands of the penis to release mucus into the urethra – which is referred to as pre-ejaculate or pre-cum. This release of mucus removes urine and old sperm from the urethra and provides lubrication for semen during ejaculation. If there has been a recent ejaculation, and the pre-ejaculate may have viable sperm in it.",True,Arousal:,,,,
+673eced5-8064-4891-acc6-cb5dfa580a5d,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,Orgasm:,False,Orgasm:,,,,
+975131e0-619c-4aad-84e5-8beb1206dc7d,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"When the mental and/or physical stimuli have reached a necessary threshold, the spinal cord emits sympathetic impulses that lead to orgasm. Orgasm was defined by sex researcher Alfred Kinsey in 1953 as “The expulsive discharge of neuromuscular tensions at the peak of sexual response.”  Others describe orgasm as climax or an altered state of consciousness. Neuroimaging studies have observed that during orgasm the prefrontal lobe and portions of the temporal lobe have decreased activity, while brain regions such as the nucleus accumbens (award center), amygdala (emotional center), hippocampus (memory), cerebellum (coordinated muscle tension) and hypothalamus (release of oxytocin) have an increased level of activity.",True,Orgasm:,,,,
+e02c625f-7782-4cd9-b606-289f59a2bb9d,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"Overlaying the crus (legs) of the clitoris and penis are the ischiocavernosus muscles, while the bulbs of the vestibule and the bulb of the penis are covered by the bulbospongiosum. During orgasm, these involuntary muscles undergo rhythmic contraction, as do other perineal and pelvic and trunk muscles.  There is evidence to suggest that the cervical canal dilates during orgasm, and that uterine motility is increased. Ejaculation through the urethra has the potential to occur in all individuals due to release of fluid from the prostate or female prostate. In some cases, ejaculation is retrograde, meaning that the fluid moves towards the bladder and may go undetected. The anatomical length of the urethra can influence the likelihood of retrograde ejaculation, and is more common in individuals with a short, rather than long, urethra. Contraction of the vas deferens and ampulla causes expulsion of sperm into the urethra, and contraction of the seminal vesicle and prostate add fluids to fill the urethral and produce reflective ejaculation of semen. The refractory period necessary between one orgasm and the next is highly variable and explains why some individuals can experience multiple orgasms, while others cannot.",True,Orgasm:,,,,
+1a38a4a1-d718-445c-b044-aa32c2e7acfa,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"The health benefits of orgasm have been investigated by some, and the results suggest that regular orgasm can improve sleep, decrease stress, decrease chronic pain, and decrease risk of incontinence and even mortality during aging. If sex will involve vaginal penetration, orgasms prior to penetration may be especially important to ensure that vaginal lubrication levels are sufficient to decrease the chance of laceration of the vaginal walls (vaginal laceration increases transmission of disease). There is also evidence to suggest that orgasms help decrease the chance of urinary tract infection following sexual activity due to the flushing of the urethra during ejaculation.",True,Orgasm:,,,,
+7b978694-87c5-4a82-9696-14fdeddc21e7,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,Resolution:,False,Resolution:,,,,
+0bde25bd-0554-4691-887e-7f94906c3ed6,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"Within 1-2 minutes following orgasm, the resolution of the vasocongestion in the erectile tissues occurs (assuming cessation of the physical and/or mental stimuli, or inability for multiple orgasm due to the absolute refractory period). The smooth muscle of the artery walls is no longer relaxed due to NO release, and returns to its baseline vasomotor tone. This decreases the blood flow to the erectile tissues, equalizing the volume of blood entering and leaving the erectile chambers, and returning the structures to their non-erect size and shape. The hormones released upon orgasm, such as oxytocin, lead to the feelings of contentment and well being.",True,Resolution:,,,,
+dbfc033f-471c-40de-895e-bb93ed7f40cb,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,Erectile Dysfunction:,False,Erectile Dysfunction:,,,,
+cbacd851-232b-42c4-8174-220ba9cc8128,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"Erectile dysfunction (ED) is a condition in which an individual has difficulty either initiating or maintaining an erection of the clitoris or penis. The combined prevalence of minimal, moderate, and complete ED is approximately 40 percent at age 40, and reaches nearly 70 percent by 70 years of age. In addition to aging, ED is associated with diabetes, vascular disease, psychiatric disorders, prostate disorders, and the use of some drugs such as certain antidepressants. These physical and emotional conditions can lead to interruptions in the vasodilation pathway and result in an inability to achieve an erection of the penis or clitoris.",True,Erectile Dysfunction:,,,,
+66893250-4c88-4d58-a902-966af44e4d69,https://open.oregonstate.education/aandp/,27.5 Physiology of Arousal and Orgasm,https://open.oregonstate.education/aandp/chapter/27-5-physiology-of-arousal-and-orgasm/,"Recall that the release of NO induces relaxation of the smooth muscles that surround the erectile tissue arteries, leading to the vasodilation necessary to achieve an erection of the clitoris or penis. To reverse the process of vasodilation, an enzyme called phosphodiesterase (PDE) degrades a key component of the NO signaling pathway called cGMP. There are several different forms of this enzyme, and PDE type 5 is the type of PDE found in the tissues of the penis and clitoris. Scientists discovered that inhibiting PDE5 increases blood flow, and allows vasodilation to occur.",True,Erectile Dysfunction:,,,,
+2132dee5-38a5-4e4a-ab79-90bbc2744397,https://open.oregonstate.education/aandp/,27.4 Physiology of the Male Sexual System,https://open.oregonstate.education/aandp/chapter/27-4-physiology-of-the-male-sexual-system/,Explain the events during spermatogenesis that produce haploid sperm from diploid cells,True,Erectile Dysfunction:,,,,
+68924149-52ce-4598-abfb-9f3b8642d76f,https://open.oregonstate.education/aandp/,27.4 Physiology of the Male Sexual System,https://open.oregonstate.education/aandp/chapter/27-4-physiology-of-the-male-sexual-system/,Identify the importance of testosterone in male reproductive function,False,Identify the importance of testosterone in male reproductive function,,,,
+cad5882e-c24f-49c2-80e5-3d2d0ae818a5,https://open.oregonstate.education/aandp/,27.4 Physiology of the Male Sexual System,https://open.oregonstate.education/aandp/chapter/27-4-physiology-of-the-male-sexual-system/,Sertoli Cells,False,Sertoli Cells,,,,
+72b721ea-a716-4b02-9bb8-6165559f5abe,https://open.oregonstate.education/aandp/,27.4 Physiology of the Male Sexual System,https://open.oregonstate.education/aandp/chapter/27-4-physiology-of-the-male-sexual-system/,"Surrounding all stages of the developing sperm cells are elongate, branching Sertoli cells. Sertoli cells are a type of supporting cell called a sustentacular cell, or sustentocyte, that are typically found in epithelial tissue. Sertoli cells secrete signaling molecules that promote sperm production and can control whether germ cells live or die. They extend physically around the germ cells from the peripheral basement membrane of the seminiferous tubules to the lumen. Tight junctions between these sustentacular cells create the blood–testis barrier, which keeps bloodborne substances from reaching the germ cells and, at the same time, keeps surface antigens on developing germ cells from escaping into the bloodstream and prompting an autoimmune response.",True,Sertoli Cells,,,,
+adf41755-a4b2-4142-8051-1a41d96ca315,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The ovarian cycle is a set of predictable changes in a female’s oocytes and ovarian follicles. During a woman’s reproductive years, it is a roughly 28-day cycle that can be correlated with, but is not the same as, the menstrual cycle (discussed shortly). The cycle includes two interrelated processes: oogenesis (the production of female gametes) and folliculogenesis (the growth and development of ovarian follicles).",True,Sertoli Cells,,,,
+cb6adb61-0aee-4c82-bc1b-e8ee62691345,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,Oogenesis,False,Oogenesis,,,,
+c6889883-80f0-43c9-a12e-cc13a1d4b25e,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.3.1). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause.",True,Oogenesis,Figure 27.3.1,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/cb3a51b134cfa417cf88f924fed1d8731ef8754f.jpeg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell."
+f4aaa073-841b-45e5-9738-ab323a2d0995,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The initiation of ovulation—the release of an oocyte from the ovary—marks the transition from puberty into reproductive maturity for women. From then on, throughout a woman’s reproductive years, ovulation occurs approximately once every 28 days. Just prior to ovulation, a surge of luteinizing hormone triggers the resumption of meiosis in a primary oocyte. This initiates the transition from primary to secondary oocyte. However, as you can see in Figure 27.3.1, this cell division does not result in two identical cells. Instead, the cytoplasm is divided unequally, and one daughter cell is much larger than the other. This larger cell, the secondary oocyte, eventually leaves the ovary during ovulation. The smaller cell, called the first polar body, may or may not complete meiosis and produce second polar bodies; in either case, it eventually disintegrates. Therefore, even though oogenesis produces up to four cells, only one survives.",True,Oogenesis,Figure 27.3.1,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/cb3a51b134cfa417cf88f924fed1d8731ef8754f.jpeg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell."
+62fdbda1-a61a-470d-8a14-daa0061ddea7,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"How does the diploid secondary oocyte become an ovum—the haploid female gamete? Meiosis of a secondary oocyte is completed only if a sperm succeeds in penetrating its barriers. Meiosis II then resumes, producing one haploid ovum that, at the instant of fertilization by a (haploid) sperm, becomes the first diploid cell of the new offspring (a zygote). Thus, the ovum can be thought of as a brief, transitional, haploid stage between the diploid oocyte and diploid zygote.",True,Oogenesis,,,,
+9822c351-b067-4af4-a12c-d2070c293b0d,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The larger amount of cytoplasm contained in the female gamete is used to supply the developing zygote with nutrients during the period between fertilization and implantation into the uterus. Interestingly, sperm contribute only DNA at fertilization —not cytoplasm. Therefore, the cytoplasm and all of the cytoplasmic organelles in the developing embryo are of maternal origin. This includes mitochondria, which contain their own DNA. Scientific research in the 1980s determined that mitochondrial DNA was maternally inherited, meaning that you can trace your mitochondrial DNA directly to your mother, her mother, and so on back through your female ancestors.",True,Oogenesis,,,,
+1b542ecb-81fb-4985-896f-66a77f68075c,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,Folliculogenesis,False,Folliculogenesis,,,,
+9ef0eeb0-668d-4a09-baaa-cb187b8000b1,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"Again, ovarian follicles are oocytes and their supporting cells. They grow and develop in a process called folliculogenesis, which typically leads to ovulation of one follicle approximately every 28 days, along with death to multiple other follicles. The death of ovarian follicles is called atresia, and can occur at any point during follicular development. Recall that, a female infant at birth will have one to two million oocytes within her ovarian follicles, and that this number declines throughout life until menopause, when no follicles remain. As you’ll see next, follicles progress from primordial, to primary, to secondary and tertiary stages prior to ovulation—with the oocyte inside the follicle remaining as a primary oocyte until right before ovulation.",True,Folliculogenesis,,,,
+ef635e06-6087-4afa-a616-47c5e774518d,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"Folliculogenesis begins with follicles in a resting state. These small primordial follicles are present in newborn females and are the prevailing follicle type in the adult ovary (Figure 27.3.2). Primordial follicles have only a single flat layer of support cells, called granulosa cells, that surround the oocyte, and they can stay in this resting state for years—some until right before menopause.",True,Folliculogenesis,Figure 27.3.2,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+ef0873de-b183-4660-ae4f-963ab1f2d8a1,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"After puberty, a few primordial follicles will respond to a recruitment signal each day, and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles—now called secondary follicles (see Figure 27.3.2)—increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells—cells that work with the granulosa cells to produce estrogens.",True,Folliculogenesis,Figure 27.3.2,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+5fd9f857-78d2-40d4-a6a7-da7b47fb86c6,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"Within the growing secondary follicle, the primary oocyte now secretes a thin acellular membrane called the zona pellucida that will play a critical role in fertilization. A thick fluid, called follicular fluid, that has formed between the granulosa cells also begins to collect into one large pool, or antrum. Follicles in which the antrum has become large and fully formed are considered tertiary follicles (or antral follicles). Several follicles reach the tertiary stage at the same time, and most of these will undergo atresia. The one that does not die will continue to grow and develop until ovulation, when it will expel its secondary oocyte surrounded by several layers of granulosa cells from the ovary. Keep in mind that most follicles don’t make it to this point. In fact, roughly 99 percent of the follicles in the ovary will undergo atresia, which can occur at any stage of folliculogenesis.",True,Folliculogenesis,,,,
+c5302138-0d2f-4cd9-92b5-50450972decc,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,Hormonal Control of the Ovarian Cycle,False,Hormonal Control of the Ovarian Cycle,,,,
+090d8717-063f-491c-8012-3ba00d403013,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The process of development that we have just described, from primordial follicle to early tertiary follicle, takes approximately two months in humans. The final stages of development of a small cohort of tertiary follicles, ending with ovulation of a secondary oocyte, occur over a course of approximately 28 days. These changes are regulated by many of the same hormones that regulate the male reproductive system, including GnRH, LH, and FSH.",True,Hormonal Control of the Ovarian Cycle,,,,
+6d1255cc-6bc9-4a91-89d3-cf1cc0fc74ce,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"As in men, the hypothalamus produces GnRH, a hormone that signals the anterior pituitary gland to produce the gonadotropins FSH and LH (Figure 27.3.3). These gonadotropins leave the pituitary and travel through the bloodstream to the ovaries, where they bind to receptors on the granulosa and theca cells of the follicles. FSH stimulates the follicles to grow (hence its name of follicle-stimulating hormone), and the five or six tertiary follicles expand in diameter. The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen. This phase of the ovarian cycle, when the tertiary follicles are growing and secreting estrogen, is known as the follicular phase.",True,Hormonal Control of the Ovarian Cycle,Figure 27.3.3,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0dbf6852b50fac8780909f0855e32e87bdc761af.jpeg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries."
+202e961d-d3d9-4827-b87f-cbd77e344647,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The more granulosa and theca cells a follicle has (that is, the larger and more developed it is), the more estrogen it will produce in response to LH stimulation. As a result of these large follicles producing large amounts of estrogen, systemic plasma estrogen concentrations increase. Following a classic negative feedback loop, the high concentrations of estrogen will stimulate the hypothalamus and pituitary to reduce the production of GnRH, LH, and FSH. Because the large tertiary follicles require FSH to grow and survive at this point, this decline in FSH caused by negative feedback leads most of them to die (atresia). Typically only one follicle, now called the dominant follicle, will survive this reduction in FSH, and this follicle will be the one that releases an oocyte. Scientists have studied many factors that lead to a particular follicle becoming dominant: size, the number of granulosa cells, and the number of FSH receptors on those granulosa cells all contribute to a follicle becoming the one surviving dominant follicle.",True,Hormonal Control of the Ovarian Cycle,,,,
+b5f7bbfe-c23e-4805-b286-ae9832497d8c,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"When only the one dominant follicle remains in the ovary, it again begins to secrete estrogen. It produces more estrogen than all of the developing follicles did together before the negative feedback occurred. It produces so much estrogen that the normal negative feedback doesn’t occur. Instead, these extremely high concentrations of systemic plasma estrogen trigger a regulatory switch in the anterior pituitary that responds by secreting large amounts of LH and FSH into the bloodstream (see Figure 27.3.3). The positive feedback loop by which more estrogen triggers release of more LH and FSH only occurs at this point in the cycle.",True,Hormonal Control of the Ovarian Cycle,Figure 27.3.3,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0dbf6852b50fac8780909f0855e32e87bdc761af.jpeg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries."
+7e248393-a8b1-4449-95f5-2db20d4dc4c4,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"It is this large burst of LH (called the LH surge) that leads to ovulation of the dominant follicle. The LH surge induces many changes in the dominant follicle, including stimulating the resumption of meiosis of the primary oocyte to a secondary oocyte. As noted earlier, the polar body that results from unequal cell division simply degrades. The LH surge also triggers proteases (enzymes that cleave proteins) to break down structural proteins in the ovary wall on the surface of the bulging dominant follicle. This degradation of the wall, combined with pressure from the large, fluid-filled antrum, results in the expulsion of the oocyte surrounded by granulosa cells into the peritoneal cavity. This release is ovulation.",True,Hormonal Control of the Ovarian Cycle,,,,
+e3fb9b5a-de8b-402e-8728-0d2993bd6050,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"In the next section, you will follow the ovulated oocyte as it travels toward the uterus, but there is one more important event that occurs in the ovarian cycle. The surge of LH also stimulates a change in the granulosa and theca cells that remain in the follicle after the oocyte has been ovulated. This change is called luteinization (recall that the full name of LH is luteinizing hormone), and it transforms the collapsed follicle into a new endocrine structure called the corpus luteum, a term meaning “yellowish body” (see Figure 27.3.2). Instead of estrogen, the luteinized granulosa and theca cells of the corpus luteum begin to produce large amounts of the sex steroid hormone progesterone, a hormone that is critical for the establishment and maintenance of pregnancy. Progesterone triggers negative feedback at the hypothalamus and pituitary, which keeps GnRH, LH, and FSH secretions low, so no new dominant follicles develop at this time.",True,Hormonal Control of the Ovarian Cycle,Figure 27.3.2,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+9c5b9b26-24e4-4d8c-8e29-210a4f18238c,https://open.oregonstate.education/aandp/,27.3 Physiology of the Female Sexual System,https://open.oregonstate.education/aandp/chapter/27-3-physiology-of-the-female-sexual-system/,"The post-ovulatory phase of progesterone secretion is known as the luteal phase of the ovarian cycle. If pregnancy does not occur within 10 to 12 days, the corpus luteum will stop secreting progesterone and degrade into the corpus albicans, a nonfunctional “whitish body” that will disintegrate in the ovary over a period of several months. During this time of reduced progesterone secretion, FSH and LH are once again stimulated, and the follicular phase begins again with a new cohort of early tertiary follicles beginning to grow and secrete estrogen.",True,Hormonal Control of the Ovarian Cycle,,,,
+0875ff29-a23d-4454-8990-47031760a95c,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,Introduction,False,Introduction,,,,
+ada6cb8d-3da7-4664-96b0-b9732c05e811,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"The development of the sexual systems begins soon after fertilization of the egg, with primordial gonads beginning to develop approximately one month after conception. Sexual system development continues in utero, but there is little change in the system between infancy and puberty.",True,Introduction,,,,
+839fc6ef-ee0b-456c-9ea3-025adacf971b,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,Development of the Sexual Organs in the Embryo and Fetus,False,Development of the Sexual Organs in the Embryo and Fetus,,,,
+6a007fb6-2207-4107-a814-2a84f269ffc2,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"Without chemical prompting, all fertilized eggs would develop a clitoris and vagina. This would be different if an individual was exposed to the cascade of factors initiated by a single gene on the Y chromosome. This is called the SRY (Sex-determining Region of the Y chromosome). Individuals without a Y chromosome also do not have the SRY gene. Without a functional SRY gene, an individual will typically develop a uterus and ovaries.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+83aadd59-5414-45e4-a6a5-46fbaf6caee2,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"In all embryos, the same group of cells has the potential to develop into either testes and ovaries; this tissue is considered bipotential. The SRY gene actively recruits other genes that begin to develop the testes, and suppresses other genes that would lead to development of ovaries. As part of this SRY-prompted cascade, germ cells in the bipotential gonads differentiate into spermatogonia. Without SRY, different genes are expressed, oogonia form, and primordial follicles develop in the primitive ovary.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+aabac29e-5761-47fe-928a-693f089884bb,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"Soon after the formation of the testis, the interstitial (Leydig) cells begin to secrete testosterone. Testosterone can influence tissues that are bipotential. For example, with exposure to testosterone, cells that could become either the glans penis or the glans clitoris form the glans penis. Without testosterone, these same cells differentiate into the clitoris.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+e5e1f1f6-0136-45b1-aade-0a7d70bfb97c,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"Not all tissues in the reproductive tract are bipotential. The internal reproductive structures (for example the uterus, uterine tubes, and part of the vagina; and the epididymis, ductus deferens, and seminal vesicles) form from one of two rudimentary duct systems in the embryo.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+5c07ed9f-2687-4d1d-9b4a-a32d5b359d02,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"Development of the internal sexual organs requires one set of ducts to develop and the other set to degrade. A hormone secreted from sustentacular (Sertoli) cells trigger a degradation of the paramesonephric (Müllerian) duct, and therefore a uterus is unlikely to develop. At the same time, testosterone secretion stimulates growth of the mesonephric (Wolffian) duct, leading to development of the epididymis and vas deferens. Without such sustentacular cell hormone secretion, the paramesonephric duct will now develop; and without testosterone, the mesonephric duct will degrade. Thus, the offspring in this circumstance will likely develop a uterus, and not an epididymis or vas deferens. For more information and a figure of differentiation of the gonads, seek additional content on fetal development.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+da406941-0f21-45e5-b66c-6c1aaa500813,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"There are many reasons why sexual anatomy would develop differently than previously described, and it is important to locate intersex anatomy on the spectrum of normal human variation between the binary female and male. In some cases, the receptors that the hormones typically bind to do not develop. For example, in the case of androgen insensitivity, an individual with XY chromosomes, and an SRY gene, will still produce hormones from the sustentacular cells that lead to degradation of the paramesonephric duct – meaning that no uterus can develop. They will also develop testes which will produce testosterone, (androgens) but the cells can not react to the hormones because they lack the receptor to bind the hormone. Therefore, the epididymis and vas deferens are not produced, and the external genitalia develop into a clitoris and vagina. The result is an individual with XY chromosomes, non-descended testes, clitoris and vagina but no uterus.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+a58dfe51-ef31-4224-b935-62beec333931,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"In contrast to the example above, an intersex condition can result from having hormone secretion beyond what is expected based on the chromosomes. In Congenital Adrenal Hyperplasia, individuals with XX chromosomes have an increase in androgens produced by adrenal glands. The result is a clitoris that is enlarged in size, and at birth may appear similar to a penis. The following image illustrates the spectrum that can exist in clitoral size during adrenal hyperplasia. The increased androgen production in these XX individuals may also lead to increased body hair, receding hair line, deep voice and muscular physique. In an XY individual, a decrease in the expected androgen production can lead to a penis that is much smaller than average, and termed micropenis. This reinforces the notion that external genitalia are developed across a spectrum of size between a clitoris and penis based on the degree of exposure to androgens. This spectrum of normal human variation does not require surgical treatment, only an open mind to the notion of what normal variation might include. Individuals with intersex anatomy have no additional health risks when left to develop on their own, while surgical intervention at a young age includes the risk of surgical complications including nerve damage and infection.",True,Development of the Sexual Organs in the Embryo and Fetus,,,,
+a4c75d21-96da-4dc4-ae84-7331c77ecc9b,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,Onset of Puberty,False,Onset of Puberty,,,,
+108efd25-0f66-451b-8ed6-cd098f9b3640,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"Puberty is the stage of development at which individuals become sexually mature. As shown in Figure 27.2.1, a concerted release of hormones from the hypothalamus (GnRH), the anterior pituitary (LH and FSH), and the gonads (either testosterone or estrogen) is responsible for the maturation of the reproductive systems and the development of secondary sex characteristics, which are physical changes in the body.",True,Onset of Puberty,Figure 27.2.1,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Figure_28_03_01.jpg,"Figure 27.2.1 – Hormones of Puberty: During puberty, the release of LH and FSH from the anterior pituitary stimulates the gonads to produce sex hormones in adolescents"
+cffded30-290b-4208-9147-310f21454ec5,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"The first changes begin around the age of eight or nine when the production of LH becomes detectable. The release of LH occurs primarily at night during sleep and precedes the physical changes of puberty by several years. In pre-pubescent children, the sensitivity of the negative feedback system in the hypothalamus and pituitary is very high. This means that very low concentrations of androgens or estrogens will negatively feed back onto the hypothalamus and pituitary, keeping the production of GnRH, LH, and FSH low.",True,Onset of Puberty,,,,
+9b5b2adc-c976-4e04-8130-9b04717446c5,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"As an individual approaches puberty, two changes in sensitivity occur. The first is a decrease of sensitivity in the hypothalamus and pituitary to negative feedback, meaning that it takes increasingly larger concentrations of sex steroid hormones to stop the production of LH and FSH. The second change in sensitivity is an increase in sensitivity of the gonads to the FSH and LH signals, meaning the gonads of adults are more responsive to gonadotropins than are the gonads of children. Because of these two changes, the levels of LH and FSH slowly increase and lead to the enlargement and maturation of the gonads, which in turn leads to secretion of higher levels of sex hormones and the initiation of spermatogenesis and folliculogenesis.",True,Onset of Puberty,,,,
+ccf7627a-935a-45b3-acd1-b05d648a9382,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"In addition to age, multiple factors can affect the age of onset of puberty, including genetics, environment, and psychological stress. One of the more important influences may be nutrition; historical data demonstrate the effect of better and more consistent nutrition on the age of menarche in the United States, which decreased from an average age of approximately 17 years of age in 1860 to the current age of approximately 12.75 years in 1960, as it remains today. Some studies indicate a link between puberty onset and the amount of stored fat in an individual. This effect has been documented in both sexes. Body fat, corresponding with secretion of the hormone leptin by adipose cells, appears to have a strong role in determining menarche. This may reflect to some extent the high metabolic costs of gestation and lactation. In individuals who are lean and highly active, such as gymnasts, there is often a delay in the onset of puberty.",True,Onset of Puberty,,,,
+50c35eb9-78b7-4600-80e9-4559be77fe23,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,Signs of Puberty,False,Signs of Puberty,,,,
+06223f44-08ca-4501-9cc2-4fb4fa621cba,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,Different sex steroid hormone concentrations also contribute to the development and function of secondary sexual characteristics. Examples of secondary sexual characteristics due to a predominance of testosterone or estrogen are listed in Table 27.1.,True,Signs of Puberty,,,,
+d55ba12c-c4f6-40e1-9db6-f679183cb603,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"An increased production of estrogen at puberty typically leads to the development of breast tissue. This is followed by the growth of axillary and pubic hair. A growth spurt typically starts at approximately age 9 to 11, and may last two years or more. During this time, an individual’s height can increase an average of 3 inches a year. The next step in puberty due to estrogen is menarche, the start of menstruation.",True,Signs of Puberty,,,,
+3570cff1-b6b2-4b37-b5bf-8d5b7cb7ecd8,https://open.oregonstate.education/aandp/,27.2 Development of Sexual Anatomy,https://open.oregonstate.education/aandp/chapter/27-2-development-of-sexual-anatomy/,"An increased production of testosterone leads to growth of the testes, typically the first physical sign of the beginning of puberty, which is followed by growth and pigmentation of the scrotum and growth of the penis. The next step is the growth of hair, including armpit, pubic, chest, and facial hair. Testosterone stimulates the growth of the larynx and thickening and lengthening of the vocal folds, which causes the voice to drop in pitch. The first fertile ejaculations typically appear at approximately 15 years of age, but this age can vary widely across individuals. The prostate normally doubles in size during puberty. A growth spurt occurs toward the end of puberty, at approximately age 11 to 13, and height can increase as much as 4 inches a year. In some individuals, pubertal development can continue through the early 20s.",True,Signs of Puberty,,,,
+dd636bcb-a9bb-41fb-882a-675fa384d8bc,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"In this section we describe the anatomy at either extreme of the spectrum of sexual anatomical variation. In section 27.2, we will describe the variations of sexual anatomy that occur which are not easily characterized by this binary system of male or female.",True,Signs of Puberty,,,,
+613a9835-d799-4351-aa2c-4d0c5bc7abcc,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The mons pubis is a pad of fat that is located over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of pubic hair-covered skin that extend from the mons pubis to the perineal raphe – the region of skin between the vaginal opening and the anus. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) are medial to the labia majora.  The labia majora and minora naturally vary in shape and size from person to person, and left-right asymmetries are normal and expected. The vestibule is the region between the two labia minora. Therefore, the labia minora protect the mucous membranes and orifices of the urethra and vagina, found in the vestibule. The mons pubis, labia majora, labia minora and vestibule are collectively referred to as the vulva (Figure 27.1.1).",True,Signs of Puberty,Figure 27.1.1,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Figure_28_02_02.jpg,"Figure 27.1.1 – Vulva: The mons pubis, labia minora, labia majora and vestibule are referred to collectively as the vulva."
+e84d77e5-03f3-4a66-87d1-84eba1ce272b,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The superior, anterior portions of the labia minora come together to meet the glans of the clitoris which has an extremely dense network of nerve endings. This is the portion of the clitoris that is partially covered by the prepuce (foreskin) of the clitoris. The clitoris also includes crura or legs (sing.: crus or leg) which are subcutaneous and extend inferiorly, following the contours of the pubic rami. The glans and crura are connected by the body of the clitoris. The glans, crura and body of the clirtoris are made up of corpus cavernosum erectile tissue. In contrast, the bulbs of the vestibule are corpus spongiosum erectile tissue. It is found medial to the crura of the clitoris and surrounds the vaginal and urethral orifices. The non-erect clitoris (including the superficial glans through to the end of the subcutaneous crura) has been recorded to be as long as 9 cm.",True,Signs of Puberty,,,,
+9fe267cc-016e-4016-9b22-e59e46940d2f,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,The Female Prostate,False,The Female Prostate,,,,
+adeb7c3d-e0b0-4e3f-a1b6-934f8dd364cc,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Surrounding the urethra is glandular tissue that has been called the periurethral gland, the paraurethral gland, the lesser vestibular gland and the female prostate. These glands were first identified in the 1600’s, then appear again in the anatomical literature of the 1800’s, and in 2002 the Federative International Programme for Anatomical Terminology committee officially voted to use the term “female prostate” to describe these glands that surround the urethra, which release the fluids of female ejaculation. As with all anatomy, there is a degree of variation in regard to the size, number and location of the ducts leading from the female prostate, but the ducts typically lead to the distal portion of the urethra.",True,The Female Prostate,,,,
+fd33efe4-7587-4bc8-9b2c-f8c03afe1b18,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Greater Vestibular Glands,False,Greater Vestibular Glands,,,,
+9807adcb-be48-4e2e-aa59-845c1eb4dea3,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,The paired greater vestibular glands (Bartholin’s glands) are located inferior and posterior to the bulbs of the vestibule. The glands secrete mucous into the vestibular area through ducts which open on either side of the vaginal orifice.,True,Greater Vestibular Glands,,,,
+c8383973-1fde-4589-96b8-0f7cbfeb3d6e,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Vagina,False,Vagina,,,,
+e9f20932-831a-4d33-baa7-3aba3d0a52b6,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The vagina (Figure 27.1.3) is a muscular canal (approximately 10 cm long) typically leading to the uterus.  The superior portion of the vagina—called the fornix—meets the protruding uterine cervix. The walls of the vagina are lined with an outer fibrous adventitia; a middle layer of smooth muscle; and an inner mucous membrane with transverse folds called rugae. Together, the middle and inner layers allow the expansion of the vagina. The vaginal opening is located between the opening of the urethra and the anus. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body. The opening between the hymen and the vaginal wall can change in size based on the degree in which the hymen is stretched. The membrane will decrease in size due to increased pressure.",True,Vagina,Figure 27.1.3,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_01.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity"
+b3890ef4-90a3-4b98-99e9-a7d73d27070a,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The vagina is home to a normal population of microorganisms that help to protect against infection by pathogenic bacteria, yeast, or other organisms that can enter the vagina. In a healthy vagina, the most predominant type of bacteria is from the genus Lactobacillus. This family of beneficial bacterial flora secretes lactic acid, and thus protects the vagina by maintaining an acidic pH (below 4.5). Potential pathogens are less likely to survive in these acidic conditions. Lactic acid, in combination with other vaginal secretions, makes the vagina a self-cleansing organ. Douching (washing out the vagina with fluid) disrupts the normal balance of healthy microorganisms, and increases the risk for infections and irritation. Indeed, the American College of Obstetricians and Gynecologists recommends against douching, and instead recommends allowing the vagina to maintain its normal healthy population of protective microbial flora.",True,Vagina,,,,
+47e57ac5-2c7c-45aa-9865-27d2fb32ce6b,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Uterus,False,Uterus,,,,
+86e54975-de3c-4f9f-a013-b4b2b3ea2f2e,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The uterus is a muscular organ with an average size 5 cm wide by 7 cm long. It has three regions. The portion of the uterus superior to the opening of the uterine tubes is called the fundus. The middle section of the uterus is called the body. The cervix is the narrow inferior portion of the uterus that projects into the vagina. The cervix produces mucus secretions that vary in consistency and volume across the ovarian cycle. The cervix opens into the vaginal cavity via the os, which allows cervical fluid to move through the vagina and exit the body through the vaginal opening.",True,Uterus,,,,
+e127de37-aaab-4fe6-9486-3c4321953441,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Several ligaments maintain the position of the uterus within the abdominopelvic cavity. The broad ligament is a fold of peritoneum extending laterally from both sides of the uterus and attaching it to the pelvic wall. The round ligament attaches to the uterus near the uterine tubes, and extends to the labia majora. Finally, the uterosacral ligament stabilizes the uterus posteriorly by its connection from the cervix to the pelvic wall.",True,Uterus,,,,
+ac55c7c2-fe0e-4595-ab96-7d5d7497e534,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The wall of the uterus is made up of three layers. The most superficial layer is the serous membrane, or perimetrium, which consists of epithelial tissue that covers the exterior portion of the uterus. The middle layer, or myometrium, is a thick layer of smooth muscle responsible for uterine contractions. Most of the uterus is myometrial tissue, and the muscle fibers run horizontally, vertically, and diagonally, allowing the contractions that occur during orgasm labor or menstruation.",True,Uterus,,,,
+7cdabf8b-79c7-43e3-88b7-b77e834bdeab,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,The innermost layer of the uterus is called the endometrium. The endometrium consists of two layers: the stratum basalis and the stratum functionalis (the basal and functional layers).,True,Uterus,,,,
+56cca815-350b-481f-b0a7-e2c944bd89cc,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The uterine tubes (also called Fallopian tubes) serve as the conduit of the oocyte from the ovary to the uterus. The uterine tubes are divided into multiple regions. The isthmus is the narrow medial end of each uterine tube that is connected to the uterus. The middle region of the tube is called the ampulla. The wide distal infundibulum flares out with slender, finger-like projections called fimbriae.  The uterine tubes also have three layers: an outer serosa, a middle smooth muscle layer, and an inner mucosal layer. In addition to its mucus-secreting cells, the inner mucosa contains ciliated cells that beat in the direction of the uterus, producing a current that will be critical to move the oocyte.",True,Uterus,,,,
+12abcaf2-261f-4835-885d-c21c9cae8b75,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The open-ended structure of the uterine tubes can have significant health consequences if bacteria or other contagions enter through the vagina and move through the uterus, into the tubes, and then into the pelvic cavity. If this is left unchecked, a bacterial infection (sepsis) could quickly become life-threatening. The spread of an infection in this manner is of special concern when unskilled practitioners perform abortions in non-sterile conditions. Sepsis is also associated with sexually transmitted bacterial infections, especially gonorrhea and chlamydia. These increase the risk for pelvic inflammatory disease (PID), infection of the uterine tubes or other reproductive organs. Even when resolved, PID can leave scar tissue in the tubes, leading to infertility.",True,Uterus,,,,
+823a96f0-a744-4f61-80f6-506eb6372b7a,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Ovaries,False,Ovaries,,,,
+cecef381-3789-44fd-acbb-d68ebf70d4b3,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The ovaries are the gonads (see Figure 27.1.3) located at the distal end of the uterine tubes, close to the fimbriae. They are each about 2 to 3 cm in length, about the size of an almond. The ovaries are supported by the mesovarium, a double fold of peritoneum that is part of the broad ligament. The suspensory ligament is the peritoneum that contains the ovarian blood and lymph vessels. The ovary itself is attached to the uterus via the ovarian ligament.",True,Ovaries,Figure 27.1.3,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_01.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity"
+8582cb0e-d2e2-4f07-9d31-c658a5f0e7ad,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The ovary comprises an outer covering of cuboidal epithelium that is superficial to a dense connective tissue covering called the tunica albuginea. Beneath the tunica albuginea is the cortex, or outer portion, of the organ. The cortex is composed of a tissue framework called the ovarian stroma that forms the bulk of the adult ovary.",True,Ovaries,,,,
+df6eea31-a709-4e70-9053-df1ca39f9ebb,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Breasts,False,Breasts,,,,
+ed91885b-6b0a-4247-8abf-98e077d5521f,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The external features of the breast include a nipple surrounded by a pigmented areola (Figure 27.1.4), whose coloration may deepen due to changes in hormone levels. The areola is typically circular and can vary in size from 25 to 100 mm in diameter. The areolar region is characterized by small, raised areolar glands that secrete lubricating fluid under certain hormonal conditions.",True,Breasts,Figure 27.1.4,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_09.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple."
+0ac6c4e0-7777-417d-8ced-985f153a1378,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Breast milk is produced by the mammary glands, which are modified sweat glands. The milk itself exits the breast through the nipple via 15 to 20 lactiferous ducts that open on the surface of the nipple. These lactiferous ducts each extend to a lactiferous sinus that connects to a glandular lobe within the breast itself that contains groups of milk-secreting cells in clusters called alveoli (see Figure 27.1.4). The clusters can change in size depending on the amount of milk in the alveolar lumen. Once milk is made in the alveoli, stimulated myoepithelial cells that surround the alveoli contract to push the milk to the lactiferous sinuses. From here, milk can be drawn through the lactiferous ducts by suckling. The lobes themselves are surrounded by fat tissue, which determines the size of the breast; breast size differs between individuals and does not affect the amount of milk produced. Asymmetry in breast size within an individual is expected and normal. Increased levels of hormones can lead to further development of the mammary tissue and enlargement of the breasts. Supporting the breasts are multiple bands of connective tissue called suspensory ligaments that connect the breast tissue to the dermis of the overlying skin.",True,Breasts,Figure 27.1.4,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_09.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple."
+22284514-494d-41d9-b2b5-7555bcab44df,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,The Penis,False,The Penis,,,,
+42667063-0ec1-4111-a68f-f604b64a6306,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The penis is flaccid for non-sexual actions, such as urination, and turgid and erect during sexual arousal. The shaft of the penis surrounds the urethra (Figure 27.1.5). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, however not as dense and therefore not as sensitive as the glans clitoris (see Figure 27.1.5). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricates and protects the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth. The skin of the glans of a circumcised penis converts from a mucous membrane to a cutaneous membrane, and the friction reducing function of the foreskin is lost.",True,The Penis,Figure 27.1.5,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+0f57d5e2-c923-47b2-89d5-d86c7295bf2e,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Testes,False,Testes,,,,
+a1c80393-d6d2-40cb-95f4-4c8b5e5479e5,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The testes (singular = testis) are the gonads which produce both sperm and androgens, such as testosterone, and are active throughout the sexual lifespan. The testes are spherical in shape, each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.1.7). They are surrounded by two distinct layers of protective connective tissue (Figure 27.1.6). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer (similar to the visceral and parietal serous membranes of the pericardium, peritoneum, and pleura). Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a fetus secreting testosterone, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.",True,Testes,Figure 27.1.7,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_02.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.
+17b8acf2-c22f-40f6-b16a-50c2df103ca5,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The tightly coiled seminiferous tubules form the bulk of each testis. Within the tubules are developing sperm cells. From the lumens of the seminiferous tubules, sperm move into the straight tubules (or tubuli recti), and from there into a fine meshwork of tubules called the rete testes. Sperm leave the rete testes, and the testis itself, through the 15 to 20 efferent ductules that cross the tunica albuginea.",True,Testes,,,,
+a5fa6c8c-138b-435f-b55c-75802a12c59a,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Inside the seminiferous tubules are six different cell types. These include supporting cells called sustentacular cells, as well as five types of developing sperm cells called germ cells. Germ cell development progresses from the basement membrane—at the perimeter of the tubule—toward the lumen.",True,Testes,,,,
+e0c359bb-c56a-4b93-a3a6-d2c40d0c3c88,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Epididymis,False,Epididymis,,,,
+fb4e33fc-ee4b-49a7-8135-c1fd3e217c24,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"From the lumen of the seminiferous tubules, the immotile sperm are surrounded by testicular fluid and moved to the epididymis (plural = epididymides), a coiled tube attached to the testis where newly formed sperm continue to mature (see Figure 27.1.6) Though the epididymis does not take up much room in its tightly coiled state, it would be approximately 6 m (20 feet) long if straightened. It takes an average of 12 days for sperm to move through the coils of the epididymis, with the shortest recorded transit time in humans being one day. Sperm enter the head of the epididymis and are moved along predominantly by the contraction of smooth muscles lining the epididymal tubes. As they are moved along the length of the epididymis, the sperm further mature and acquire the ability to move on their own. The more mature sperm are then stored in the tail of the epididymis (the final section) until ejaculation occurs.",True,Epididymis,Figure 27.1.6,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_03.jpg,"Figure 27.1.6 – Anatomy of a Testis: This sagittal view shows seminiferous tubules, the site of sperm production. Formed sperm are transferred to the epididymis, where they mature. They leave the epididymis during an ejaculation via the ductus deferens."
+ee41e448-4e95-4da8-bdac-360b9bb579a8,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Scrotum,False,Scrotum,,,,
+b3e45d07-8916-40ca-bdc9-6e347225e129,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see Figure 27.1.5). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.",True,Scrotum,Figure 27.1.5,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+07c21a2c-0489-46ba-99ef-1321e7ed5530,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The dartos muscle makes up the subcutaneous muscle layer of the scrotum (Figure 27.1.7). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.",True,Scrotum,Figure 27.1.7,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_02.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.
+cbf3ace4-c5d4-439e-ad06-3b71f367760b,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Duct System,False,Duct System,,,,
+dd6833c8-ce00-472d-86ce-8f2309110740,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"During ejaculation, sperm exit the tail of the epididymis and are pushed by smooth muscle contraction to the ductus deferens (also called the vas deferens). The ductus deferens is a thick, muscular tube that is bundled together inside the scrotum with connective tissue, blood vessels, and nerves into a structure called the spermatic cord (see Figure 27.1.5 and Figure 27.1.7). Because the ductus deferens is physically accessible within the scrotum, surgical sterilization to interrupt ejaculation of sperm can be performed by cutting and sealing a small section of the ductus (vas) deferens. This procedure is called a vasectomy, and it is an effective form of birth control. Although it may be possible to reverse a vasectomy, clinicians consider the procedure permanent.",True,Duct System,Figure 27.1.5,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+0d72d1fc-4a46-425f-bb04-e5107260ef96,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Each ductus deferens extends superiorly into the abdominal cavity through the inguinal canal in the abdominal wall. From here, the ductus deferens continues to the pelvic cavity, ending posterior to the bladder where it dilates in a region called the ampulla (meaning “flask”).",True,Duct System,,,,
+006e541c-249b-4407-a787-f4fd04e747ae,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Sperm make up only 5 percent of the final volume of semen, the thick, milky fluid that is ejaculated. The bulk of semen is produced by three critical accessory glands of the sexual system: the seminal vesicles, the prostate, and the bulbourethral glands.",True,Duct System,,,,
+e411641b-f83a-464d-b268-7585e943e1be,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Seminal Vesicles,False,Seminal Vesicles,,,,
+03f125b6-25ba-42f3-9860-72c610ca9258,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"As sperm pass through the ampulla of the ductus deferens at ejaculation, they mix with fluid from the associated seminal vesicle (see Figure 27.1.5). The paired seminal vesicles are glands that contribute approximately 60 percent of the semen volume. Seminal vesicle fluid contains large amounts of fructose, which is used by the sperm mitochondria to generate ATP to allow movement.",True,Seminal Vesicles,Figure 27.1.5,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+feecdf0d-980a-493b-bc0d-474f5626d372,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The fluid, now containing both sperm and seminal vesicle secretions, next moves into the associated ejaculatory duct, a short structure formed from the ampulla of the ductus deferens and the duct of the seminal vesicle. The paired ejaculatory ducts transport the seminal fluid into the next structure, the prostate gland.",True,Seminal Vesicles,,,,
+d441b2e1-e150-43a7-a9f2-40b452d608b6,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Prostate Gland,False,Prostate Gland,,,,
+284b2bb8-2827-4a8a-9988-36cbb7255d8b,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"As shown in Figure 27.1.5, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid, now called semen.",True,Prostate Gland,Figure 27.1.5,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+2520a9c5-e452-48ca-82fb-80eab409a892,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Bulbourethral Glands,False,Bulbourethral Glands,,,,
+66fd6089-b73a-43c4-873c-35ffb9adf3b0,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"The final addition to semen is made by two bulbourethral glands (or Cowper’s glands) that release a thick fluid that lubricates the urethra, and helps to neutralize urine residues from the penile urethra. The fluid from these glands is released after the male becomes sexually aroused, and shortly before the release of the semen. It is referred to as pre-ejaculate.",True,Bulbourethral Glands,,,,
+141c9241-c3a7-465c-ae07-df5ba616bf1f,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,Disorders of the Prostate gland,False,Disorders of the Prostate gland,,,,
+d5b0766f-2495-406d-9a48-52eeda457fc5,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"At approximately age 25, the prostate gradually begins to enlarge. This enlargement does not usually cause problems; however, abnormal growth of the prostate, or benign prostatic hyperplasia (BPH), can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, such as a frequent and intense urge to urinate, a weak stream, and a sensation that the bladder has not emptied completely. The number of individuals with BPH increases dramatically with age. Treatments for BPH attempt to relieve the pressure on the urethra so that urine can flow more normally. Mild to moderate symptoms are treated with medication, whereas severe enlargement of the prostate is treated by surgery in which a portion of the prostate tissue is removed.",True,Disorders of the Prostate gland,,,,
+6401bf5a-f187-4e45-aa5d-b426ade56750,https://open.oregonstate.education/aandp/,27.1 Anatomy of Sexual Systems,https://open.oregonstate.education/aandp/chapter/27-1-anatomy-of-sexual-systems/,"Another common disorder involving the prostate is prostate cancer. According to the Centers for Disease Control and Prevention (CDC), prostate cancer is one of the most common cancers. However, some forms of prostate cancer grow very slowly and thus may not ever require treatment. Aggressive forms of prostate cancer, in contrast, involve metastasis to vulnerable organs like the lungs and brain. There is no link between BPH and prostate cancer, but the symptoms are similar. Prostate cancer is detected by a medical history, a blood test, and a rectal exam that allows physicians to palpate the prostate and check for unusual masses. If a mass is detected, the cancer diagnosis is confirmed by biopsy of the cells.",True,Disorders of the Prostate gland,,,,
+4004a27e-d4f4-43fa-a674-02044fc274cd,https://open.oregonstate.education/aandp/,27.0 Introduction,https://open.oregonstate.education/aandp/chapter/27-0-introduction/,"The terms sex and gender are often used interchangeably, but these terms have different contexts and meanings. Gender is socially constructed and operates as a way to identify and categorize certain behavioral, cultural, and psychological traits as belonging to specific groups of people. Sex is a biological construct that refers to the structural, functional and behavioral characteristics of living beings determined by sex chromosomes. Although the sexual system is often described as a binary of male and female, in reality there is a spectrum of anatomical and chromosomal variation found in the human population including intersex as well as genitalia considered ambiguous at birth. In addition, sexual anatomy has a long history of surgical intervention such a circumcision, vasectomy, tubal ligation and more recently, sex reassignment surgery.  Sexual anatomy has typically been described using only heterocentric language and binary sexual identity, with an assumption that sex only occurs between a cis-gendered man and woman, for the purpose of reproduction, making it one of the least inclusive and representative topics found in anatomy textbooks. In this chapter, we attempt to present anatomy and physiology in ways that incorporate more lived experiences, rather than only what exists at the binary extremes.",True,Disorders of the Prostate gland,,,,
+2676a251-7248-4ea5-828d-be35a056bf23,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"Normal arterial blood pH is restricted to a very narrow range of 7.35 to 7.45. A person who has a blood pH below 7.35 is considered to be in acidosis (actually, “physiological acidosis,” because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal. Acidosis has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued (Figure 26.5.1). A person who has a blood pH above 7.45 is considered to be in alkalosis, and a pH above 7.8 is fatal. Some symptoms of alkalosis include cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting. Both acidosis and alkalosis can be caused by either metabolic or respiratory disorders.",True,Disorders of the Prostate gland,Figure 26.5.1,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2716_Symptoms_of_Acidosis_Alkalosis.jpg,Figure 26.5.1 – Symptoms of Acidosis and Alkalosis: Symptoms of acidosis affect several organ systems. Both acidosis and alkalosis can be diagnosed using a blood test.
+bf36e036-bc99-401d-afb4-19fa0bd581dd,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"As discussed earlier in this chapter, the concentration of carbonic acid in the blood is dependent on the level of CO2 in the body and the amount of CO2 gas exhaled through the lungs. Thus, the respiratory contribution to acid-base balance is usually discussed in terms of CO2 (rather than of carbonic acid). Remember that a molecule of carbonic acid is lost for every molecule of CO2 exhaled, and a molecule of carbonic acid is formed for every molecule of CO2 retained.",True,Disorders of the Prostate gland,,,,
+b9d8086b-af8b-4580-8dfc-98e16959df75,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Metabolic Acidosis: Primary Bicarbonate Deficiency,False,Metabolic Acidosis: Primary Bicarbonate Deficiency,,,,
+7e64a278-3494-4070-b26e-8a4d17dec9c4,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"Metabolic acidosis occurs when the blood is too acidic (pH below 7.35) due to too little bicarbonate, a condition called primary bicarbonate deficiency. At the normal pH of 7.40, the ratio of bicarbonate to carbonic acid buffer is 20:1. If a person’s blood pH drops below 7.35, then he or she is in metabolic acidosis. The most common cause of metabolic acidosis is the presence of organic acids or excessive ketones in the blood. Table 26.2 lists some other causes of metabolic acidosis.",True,Metabolic Acidosis: Primary Bicarbonate Deficiency,,,,
+84ae3538-d93b-4613-be2a-a29abec949c5,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"The first three of the nine causes of metabolic acidosis listed are medical (or unusual physiological) conditions. Strenuous exercise can cause temporary metabolic acidosis due to the production of lactic acid. The last five causes result from the ingestion of specific substances. The active form of aspirin is its metabolite, sulfasalicylic acid. An overdose of aspirin causes acidosis due to the acidity of this metabolite. Metabolic acidosis can also result from uremia, which is the retention of urea and uric acid. Metabolic acidosis can also arise from diabetic ketoacidosis, wherein an excess of ketones is present in the blood. Other causes of metabolic acidosis are a decrease in the excretion of hydrogen ions, which inhibits the conservation of bicarbonate ions, and excessive loss of bicarbonate ions through the gastrointestinal tract due to diarrhea.",True,Metabolic Acidosis: Primary Bicarbonate Deficiency,,,,
+1248047b-72c0-4418-8814-d5584bc9ad24,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Metabolic Alkalosis: Primary Bicarbonate Excess,False,Metabolic Alkalosis: Primary Bicarbonate Excess,,,,
+aa661325-7372-409a-8ff4-59138ab20718,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Metabolic alkalosis is the opposite of metabolic acidosis. It occurs when the blood is too alkaline (pH above 7.45) due to too much bicarbonate (called primary bicarbonate excess).,True,Metabolic Alkalosis: Primary Bicarbonate Excess,,,,
+ac82acbc-3e25-4db5-8bd6-2e96c3fdc25a,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"A transient excess of bicarbonate in the blood can follow ingestion of excessive amounts of bicarbonate, citrate, or antacids for conditions such as stomach acid reflux—known as heartburn. Cushing’s disease, which is the chronic hypersecretion of adrenocorticotrophic hormone (ACTH) by the anterior pituitary gland, can cause chronic metabolic alkalosis. The oversecretion of ACTH results in elevated aldosterone levels and an increased loss of potassium by urinary excretion. Other causes of metabolic alkalosis include the loss of hydrochloric acid from the stomach through vomiting, potassium depletion due to the use of diuretics for hypertension, and the excessive use of laxatives.",True,Metabolic Alkalosis: Primary Bicarbonate Excess,,,,
+33415abf-6cd6-4387-bdd5-cf01ebfd4292,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Respiratory Acidosis: Primary Carbonic Acid/CO2 Excess,False,Respiratory Acidosis: Primary Carbonic Acid/CO2 Excess,,,,
+c3ba4a74-bdaf-4be1-b453-73897c10fdde,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"Respiratory acidosis occurs when the blood is overly acidic due to an excess of carbonic acid, resulting from too much CO2 in the blood. Respiratory acidosis can result from anything that interferes with respiration, such as pneumonia, emphysema, or congestive heart failure.",True,Respiratory Acidosis: Primary Carbonic Acid/CO2 Excess,,,,
+a7955ae7-780e-43d0-8e48-6f89a8576815,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Respiratory Alkalosis: Primary Carbonic Acid/CO2 Deficiency,False,Respiratory Alkalosis: Primary Carbonic Acid/CO2 Deficiency,,,,
+59f429ea-0841-4083-886b-1f70cc2e31d7,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"Respiratory alkalosis occurs when the blood is overly alkaline due to a deficiency in carbonic acid and CO2 levels in the blood. This condition usually occurs when too much CO2 is exhaled from the lungs, as occurs in hyperventilation, which is breathing that is deeper or more frequent than normal. An elevated respiratory rate leading to hyperventilation can be due to extreme emotional upset or fear, fever, infections, hypoxia, or abnormally high levels of catecholamines, such as epinephrine and norepinephrine. Surprisingly, aspirin overdose—salicylate toxicity—can result in respiratory alkalosis as the body tries to compensate for initial acidosis.",True,Respiratory Alkalosis: Primary Carbonic Acid/CO2 Deficiency,,,,
+709f2488-f0b5-4cb4-afbe-d44da5011b8e,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,Compensation Mechanisms,False,Compensation Mechanisms,,,,
+d9a5ba77-19fe-4a03-ac7c-03a7a43dbaa5,https://open.oregonstate.education/aandp/,26.5 Disorders of Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-5-disorders-of-acid-base-balance/,"Various compensatory mechanisms exist to maintain blood pH within a narrow range, including buffers, respiration, and renal mechanisms. Although compensatory mechanisms usually work very well, when one of these mechanisms is not working properly (like kidney failure or respiratory disease), they have their limits. If the pH and bicarbonate to carbonic acid ratio are changed too drastically, the body may not be able to compensate. Moreover, extreme changes in pH can denature proteins. Extensive damage to proteins in this way can result in disruption of normal metabolic processes, serious tissue damage, and ultimately death.",True,Compensation Mechanisms,,,,
+0b829977-5b05-48ad-aa48-380276947931,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Proper physiological functioning depends on a very tight balance between the concentrations of acids and bases in the blood. Acid-balance balance is measured using the pH scale, as shown in Figure 26.4.1. A variety of buffering systems permits blood and other bodily fluids to maintain a narrow pH range, even in the face of perturbations. A buffer is a chemical system that prevents a radical change in fluid pH by dampening the change in hydrogen ion concentrations in the case of excess acid or base. Most commonly, the substance that absorbs the ions is either a weak acid, which takes up hydroxyl ions, or a weak base, which takes up hydrogen ions.",True,Compensation Mechanisms,Figure 26.4.1,26.4 Acid-Base Balance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2713_pH_Scale-01.jpg,Figure 26.4.1 – The pH Scale: This chart shows where many common substances fall on the pH scale.
+e9aef53e-2e9e-4081-bad3-a83ccd926e01,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Buffer Systems in the Body,False,Buffer Systems in the Body,,,,
+33e0e772-d70d-4bc5-8a1b-9203daa9189f,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The buffer systems in the human body are extremely efficient, and different systems work at different rates. It takes only seconds for the chemical buffers in the blood to make adjustments to pH. The respiratory tract can adjust the blood pH upward in minutes by exhaling CO2 from the body. The renal system can also adjust blood pH through the excretion of hydrogen ions (H+) and the conservation of bicarbonate, but this process takes hours to days to have an effect.",True,Buffer Systems in the Body,,,,
+6546fa7f-e337-4b38-b271-ffb6d1a25399,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The buffer systems functioning in blood plasma include plasma proteins, phosphate, and bicarbonate and carbonic acid buffers. The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range. Protein buffer systems work predominantly inside cells.",True,Buffer Systems in the Body,,,,
+6b0d1975-88fe-499b-a33b-3949eacabeea,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Protein Buffers in Blood Plasma and Cells,False,Protein Buffers in Blood Plasma and Cells,,,,
+9397b6e2-3782-4b8a-8d36-fea7dc2fe218,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Nearly all proteins can function as buffers. Proteins are made up of amino acids, which contain positively charged amino groups and negatively charged carboxyl groups. The charged regions of these molecules can bind hydrogen and hydroxyl ions, and thus function as buffers. Buffering by proteins accounts for two-thirds of the buffering power of the blood and most of the buffering within cells.",True,Protein Buffers in Blood Plasma and Cells,,,,
+76cfc3eb-3905-4083-b9d9-750a09fef3b4,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Hemoglobin as a Buffer,False,Hemoglobin as a Buffer,,,,
+be5b949d-55ce-4117-9518-d8d9355759e3,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Hemoglobin is the principal protein inside of red blood cells and accounts for one-third of the mass of the cell. During the conversion of CO2 into bicarbonate, hydrogen ions liberated in the reaction are buffered by hemoglobin, which is reduced by the dissociation of oxygen. This buffering helps maintain normal pH. The process is reversed in the pulmonary capillaries to re-form CO2, which then can diffuse into the air sacs to be exhaled into the atmosphere. This process is discussed in detail in the chapter on the respiratory system.",True,Hemoglobin as a Buffer,,,,
+32b20ec7-c691-4eb6-9e4e-1dbaecccef74,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Phosphate Buffer,False,Phosphate Buffer,,,,
+15789570-3653-4b7b-a4b7-24ce8b26bf5f,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Phosphates are found in the blood in two forms: sodium dihydrogen phosphate (Na2H2PO4−), which is a weak acid, and sodium monohydrogen phosphate (Na2HPO42-), which is a weak base. When Na2HPO42- comes into contact with a strong acid, such as HCl, the base picks up a second hydrogen ion to form the weak acid Na2H2PO4− and sodium chloride, NaCl. When Na2HPO42− (the weak acid) comes into contact with a strong base, such as sodium hydroxide (NaOH), the weak acid reverts back to the weak base and produces water. Acids and bases are still present, but they hold onto the ions.",True,Phosphate Buffer,,,,
+950fca1f-a6d5-4449-8423-869be08933ee,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Bicarbonate-Carbonic Acid Buffer,False,Bicarbonate-Carbonic Acid Buffer,,,,
+07764223-ccfb-40f8-94f0-77e7366498af,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The bicarbonate-carbonic acid buffer works in a fashion similar to phosphate buffers. The bicarbonate is regulated in the blood by sodium, as are the phosphate ions. When sodium bicarbonate (NaHCO3), comes into contact with a strong acid, such as HCl, carbonic acid (H2CO3), which is a weak acid, and NaCl are formed. When carbonic acid comes into contact with a strong base, such as NaOH, bicarbonate and water are formed.",True,Bicarbonate-Carbonic Acid Buffer,,,,
+3d18ef6c-519d-4ac8-837d-26fb0334a9a3,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"As with the phosphate buffer, a weak acid or weak base captures the free ions, and a significant change in pH is prevented. Bicarbonate ions and carbonic acid are present in the blood in a 20:1 ratio if the blood pH is within the normal range. With 20 times more bicarbonate than carbonic acid, this capture system is most efficient at buffering changes that would make the blood more acidic. This is useful because most of the body’s metabolic wastes, such as lactic acid and ketones, are acids. Carbonic acid levels in the blood are controlled by the expiration of CO2 through the lungs. In red blood cells, carbonic anhydrase forces the dissociation of the acid, rendering the blood less acidic. Because of this acid dissociation, CO2 is exhaled (see equations above). The level of bicarbonate in the blood is controlled through the renal system, where bicarbonate ions in the renal filtrate are conserved and passed back into the blood. However, the bicarbonate buffer is the primary buffering system of the IF surrounding the cells in tissues throughout the body.",True,Bicarbonate-Carbonic Acid Buffer,,,,
+246bd874-ee83-4c1e-ad8d-b11521d8a93e,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3–,False,CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3–,,,,
+d26adb77-155b-448f-9386-b65a53157242,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Respiratory Regulation of Acid-Base Balance,False,Respiratory Regulation of Acid-Base Balance,,,,
+d45ca5ee-1e3d-42ce-88ef-97710d63d8cb,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The chemical reactions that regulate the levels of CO2 and carbonic acid occur in the lungs when blood travels through the lung’s pulmonary capillaries. Minor adjustments in breathing are usually sufficient to adjust the pH of the blood by changing how much CO2 is exhaled. In fact, doubling the respiratory rate for less than 1 minute, removing “extra” CO2, would increase the blood pH by 0.2. This situation is common if you are exercising strenuously over a period of time. To keep up the necessary energy production, you would produce excess CO2 (and lactic acid if exercising beyond your aerobic threshold). In order to balance the increased acid production, the respiration rate goes up to remove the CO2. This helps to keep you from developing acidosis.",True,Respiratory Regulation of Acid-Base Balance,,,,
+3bd3e4c8-6806-4b42-a44f-b1a04e554e5c,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The body regulates the respiratory rate by the use of chemoreceptors, which primarily use CO2 as a signal. Peripheral blood sensors are found in the walls of the aorta and carotid arteries. These sensors signal the brain to provide immediate adjustments to the respiratory rate if CO2 levels rise or fall. Yet other sensors are found in the brain itself. Changes in the pH of CSF affect the respiratory center in the medulla oblongata, which can directly modulate breathing rate to bring the pH back into the normal range.",True,Respiratory Regulation of Acid-Base Balance,,,,
+630aa5e4-bf28-426c-bec3-73501eee7b70,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Hypercapnia, or abnormally elevated blood levels of CO2, occurs in any situation that impairs respiratory functions, including pneumonia and congestive heart failure. Reduced breathing (hypoventilation) due to drugs such as morphine, barbiturates, or ethanol (or even just holding one’s breath) can also result in hypercapnia. Hypocapnia, or abnormally low blood levels of CO2, occurs with any cause of hyperventilation that drives off the CO2, such as salicylate toxicity, elevated room temperatures, fever, or hysteria.",True,Respiratory Regulation of Acid-Base Balance,,,,
+395e10b7-a334-432b-a78c-a87bb68904ad,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,Renal Regulation of Acid-Base Balance,False,Renal Regulation of Acid-Base Balance,,,,
+c998a7b8-94f1-42e8-8c55-9e162e33412a,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The renal regulation of the body’s acid-base balance addresses the metabolic component of the buffering system. Whereas the respiratory system (together with breathing centers in the brain) controls the blood levels of carbonic acid by controlling the exhalation of CO2, the renal system controls the blood levels of bicarbonate. A decrease of blood bicarbonate can result from the inhibition of carbonic anhydrase by certain diuretics or from excessive bicarbonate loss due to diarrhea. Blood bicarbonate levels are also typically lower in people who have Addison’s disease (chronic adrenal insufficiency), in which aldosterone levels are reduced, and in people who have renal damage, such as chronic nephritis. Finally, low bicarbonate blood levels can result from elevated levels of ketones (common in unmanaged diabetes mellitus), which bind bicarbonate in the filtrate and prevent its conservation.",True,Renal Regulation of Acid-Base Balance,,,,
+bf77bb34-3266-4398-89ed-9a46ba5ba56b,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Bicarbonate ions, HCO3–, found in the filtrate, are essential to the bicarbonate buffer system, yet the cells of the tubule are not permeable to bicarbonate ions. The steps involved in supplying bicarbonate ions to the system are seen in Figure 26.4.3 and are summarized below:",True,Renal Regulation of Acid-Base Balance,Figure 26.4.3,26.4 Acid-Base Balance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2715_Conservation_of_Bicarbonate_in_Kidney-01.jpg,"Figure 26.4.3 Conservation of Bicarbonate in the Kidney. Tubular cells are not permeable to bicarbonate; thus, bicarbonate is conserved rather than reabsorbed. Steps 1 and 2 of bicarbonate conservation are indicated."
+d3e5cc21-194d-4441-91a5-53356e452d1a,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"It is also possible that salts in the filtrate, such as sulfates, phosphates, or ammonia, will capture hydrogen ions. If this occurs, the hydrogen ions will not be available to combine with bicarbonate ions and produce CO2. In such cases, bicarbonate ions are not conserved from the filtrate to the blood, which will also contribute to a pH imbalance and acidosis.",True,Renal Regulation of Acid-Base Balance,,,,
+17a7d3b1-25b3-4c17-8f62-c13f59b601b2,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"The hydrogen ions also compete with potassium to exchange with sodium in the renal tubules. If more potassium is present than normal, potassium, rather than the hydrogen ions, will be exchanged, and increased potassium enters the filtrate. When this occurs, fewer hydrogen ions in the filtrate participate in the conversion of bicarbonate into CO2 and less bicarbonate is conserved. If there is less potassium, more hydrogen ions enter the filtrate to be exchanged with sodium and more bicarbonate is conserved.",True,Renal Regulation of Acid-Base Balance,,,,
+3b83413e-c493-476a-af12-b2360ffc46b4,https://open.oregonstate.education/aandp/,26.4 Acid-Base Balance,https://open.oregonstate.education/aandp/chapter/26-4-acid-base-balance/,"Chloride ions are important in neutralizing positive ion charges in the body. If chloride is lost, the body uses bicarbonate ions in place of the lost chloride ions. Thus, lost chloride results in an increased reabsorption of bicarbonate by the renal system.",True,Renal Regulation of Acid-Base Balance,,,,
+bd27d976-2857-4598-acf7-41473c322fcf,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"The body contains a large variety of ions, or electrolytes, which perform a variety of functions. Some ions assist in the transmission of electrical impulses along cell membranes in neurons and muscles. Other ions help to stabilize protein structures in enzymes. Still others aid in releasing hormones from endocrine glands. All of the ions in plasma contribute to the osmotic balance that controls the movement of water between cells and their environment.",True,Renal Regulation of Acid-Base Balance,,,,
+14fa0ce1-2020-4083-ba27-bba4e7052f51,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Electrolytes in living systems include sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium, copper, zinc, iron, manganese, molybdenum, copper, and chromium. In terms of body functioning, six electrolytes are most important: sodium, potassium, chloride, bicarbonate, calcium, and phosphate.",True,Renal Regulation of Acid-Base Balance,,,,
+ba53b693-8b4c-4530-a4b8-d7c8edf878b9,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,Roles of Electrolytes,False,Roles of Electrolytes,,,,
+bc71ab37-e283-4a02-ba15-3a361e7bb2c0,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"These six ions aid in nerve excitability, endocrine secretion, membrane permeability, buffering body fluids, and controlling the movement of fluids between compartments. These ions enter the body through the digestive tract. More than 90 percent of the calcium and phosphate that enters the body is incorporated into bones and teeth, with bone serving as a mineral reserve for these ions. In the event that calcium and phosphate are needed for other functions, bone tissue can be broken down to supply the blood and other tissues with these minerals. Phosphate is a normal constituent of nucleic acids; hence, blood levels of phosphate will increase whenever nucleic acids are broken down.",True,Roles of Electrolytes,,,,
+12e118fc-d9ae-4651-a449-bb843a0c1430,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Excretion of ions occurs mainly through the kidneys, with lesser amounts lost in sweat and in feces. Excessive sweating may cause a significant loss, especially of sodium and chloride. Severe vomiting or diarrhea will cause a loss of chloride and bicarbonate ions. Adjustments in respiratory and renal functions allow the body to regulate the levels of these ions in the ECF.",True,Roles of Electrolytes,,,,
+a4abd367-12a5-416b-b45d-5f619462c7b9,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Table 26.1 lists the reference values for blood plasma, cerebrospinal fluid (CSF), and urine for the six ions addressed in this section. In a clinical setting, sodium, potassium, and chloride are typically analyzed in a routine urine sample. In contrast, calcium and phosphate analysis requires a collection of urine across a 24-hour period, because the output of these ions can vary considerably over the course of a day. Urine values reflect the rates of excretion of these ions. Bicarbonate is the one ion that is not normally excreted in urine; instead, it is conserved by the kidneys for use in the body’s buffering systems.",True,Roles of Electrolytes,,,,
+ec081ec0-b73f-499a-91b1-e51883cabd51,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,Regulation of Sodium and Potassium,False,Regulation of Sodium and Potassium,,,,
+e09a13db-eec9-40d3-9851-b0caef593490,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Sodium is reabsorbed from the renal filtrate, and potassium is excreted into the filtrate in the renal collecting tubule. The control of this exchange is governed principally by two hormones—aldosterone and angiotensin II.",True,Regulation of Sodium and Potassium,,,,
+010f2d2c-7d00-475d-b68d-363ade2645bb,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,Regulation of Calcium and Phosphate,False,Regulation of Calcium and Phosphate,,,,
+60b8141e-489e-4203-82cc-864adb6f7ea0,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Calcium and phosphate are both regulated through the actions of three hormones: parathyroid hormone (PTH), dihydroxyvitamin D (calcitriol), and calcitonin. All three are released or synthesized in response to the blood levels of calcium.",True,Regulation of Calcium and Phosphate,,,,
+231267fa-648c-4d62-89c7-7efa191f7e3a,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"PTH is released from the parathyroid gland in response to a decrease in the concentration of blood calcium. The hormone activates osteoclasts to break down bone matrix and release inorganic calcium-phosphate salts. PTH also increases the gastrointestinal absorption of dietary calcium by converting vitamin D into dihydroxyvitamin D (calcitriol), an active form of vitamin D that intestinal epithelial cells require to absorb calcium.",True,Regulation of Calcium and Phosphate,,,,
+73805318-ecfd-4e5e-8af8-5058784bc007,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,PTH raises blood calcium levels by inhibiting the loss of calcium through the kidneys. PTH also increases the loss of phosphate through the kidneys.,True,Regulation of Calcium and Phosphate,,,,
+3f5f4074-3abb-4838-b1ce-c94829f59443,https://open.oregonstate.education/aandp/,26.3 Electrolyte Balance,https://open.oregonstate.education/aandp/chapter/26-3-electrolyte-balance/,"Calcitonin is released from the thyroid gland in response to elevated blood levels of calcium. The hormone increases the activity of osteoblasts, which remove calcium from the blood and incorporate calcium into the bony matrix.",True,Regulation of Calcium and Phosphate,,,,
+603a76bd-3fd2-45fa-96f7-b60dd5f1d304,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"On a typical day, the average adult will take in about 2500 mL (almost 3 quarts) of aqueous fluids. Although most of the intake comes through the digestive tract, about 230 mL (8 ounces) per day is generated metabolically, in the last steps of aerobic respiration. Additionally, each day about the same volume (2500 mL) of water leaves the body by different routes; most of this lost water is removed as urine. The kidneys also can adjust blood volume though mechanisms that draw water out of the filtrate and urine. The kidneys can regulate water levels in the body; they conserve water if you are dehydrated, and they can make urine more dilute to expel excess water if necessary. Water is lost through the skin through evaporation from the skin surface without overt sweating and from air expelled from the lungs. This type of water loss is called insensible water loss because a person is usually unaware of it.",True,Regulation of Calcium and Phosphate,,,,
+4801a828-57fa-48ac-9aaa-7036ff3c627d,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,Regulation of Water Intake,False,Regulation of Water Intake,,,,
+7b366118-4642-4e10-9ae7-7bafaeeb42b2,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Osmolality is the ratio of solutes in a solution to a volume of solvent in a solution. Plasma osmolality is thus the ratio of solutes to water in blood plasma. A person’s plasma osmolality value reflects his or her state of hydration. A healthy body maintains plasma osmolality within a narrow range, by employing several mechanisms that regulate both water intake and output.",True,Regulation of Water Intake,,,,
+f3236012-7154-4cd8-a302-659c199e78d7,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Drinking water is considered voluntary. So how is water intake regulated by the body? Consider someone who is experiencing dehydration, a net loss of water that results in insufficient water in blood and other tissues. The water that leaves the body, as exhaled air, sweat, or urine, is ultimately extracted from blood plasma. As the blood becomes more concentrated, the thirst response—a sequence of physiological processes—is triggered (Figure 26.2.1). Osmoreceptors are sensory receptors in the thirst center in the hypothalamus that monitor the concentration of solutes (osmolality) of the blood. If blood osmolality increases above its ideal value, the hypothalamus transmits signals that result in a conscious awareness of thirst. The person should (and normally does) respond by drinking water. The hypothalamus of a dehydrated person also releases antidiuretic hormone (ADH) through the posterior pituitary gland. ADH signals the kidneys to recover water from urine, effectively diluting the blood plasma. To conserve water, the hypothalamus of a dehydrated person also sends signals via the sympathetic nervous system to the salivary glands in the mouth. The signals result in a decrease in watery, serous output (and an increase in stickier, thicker mucus output). These changes in secretions result in a “dry mouth” and the sensation of thirst.",True,Regulation of Water Intake,Figure 26.2.1,26.2 Water Balance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2708_Flowchart_of_Thirst_Response-01.jpg,Figure 26.2.1 – A Flowchart Showing the Thirst Response: The thirst response begins when osmoreceptors detect a decrease in water levels in the blood.
+b1c734fd-d701-4cec-9db1-1258b6670e9a,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Decreased blood volume resulting from water loss has two additional effects. First, baroreceptors, blood-pressure receptors in the arch of the aorta and the carotid arteries in the neck, detect a decrease in blood pressure that results from decreased blood volume. The heart is ultimately signaled to increase its rate and/or strength of contractions to compensate for the lowered blood pressure.",True,Regulation of Water Intake,,,,
+30295370-6e27-49b8-8e26-19eb18df25d9,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Second, the kidneys have a renin-angiotensin hormonal system that increases the production of the active form of the hormone angiotensin II, which helps stimulate thirst, but also stimulates the release of the hormone aldosterone from the adrenal glands. Aldosterone increases the reabsorption of sodium in the distal tubules of the nephrons in the kidneys, and water follows this reabsorbed sodium back into the blood. Circulating angiotensin II can also stimulate the hypothalamus to release ADH.",True,Regulation of Water Intake,,,,
+efbcf8d8-d02e-418b-955b-cb911a8c5050,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"If adequate fluids are not consumed, dehydration results and a person’s body contains too little water to function correctly. A person who repeatedly vomits or who has diarrhea may become dehydrated, and infants, because their body mass is so low, can become dangerously dehydrated very quickly. Endurance athletes such as distance runners often become dehydrated during long races. Dehydration can be a medical emergency, and a dehydrated person may lose consciousness, become comatose, or die, if his or her body is not rehydrated quickly.",True,Regulation of Water Intake,,,,
+4d3cfcae-bfba-4f85-99d8-ef54df3c2c98,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,Regulation of Water Output,False,Regulation of Water Output,,,,
+97ca311c-5769-4f5a-961d-2ec956c948e3,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Water loss from the body occurs predominantly through the renal system. A person produces an average of 1.5 liters (1.6 quarts) of urine per day. Although the volume of urine varies in response to hydration levels, there is a minimum volume of urine production required for proper bodily functions. The kidney excretes 100 to 1200 milliosmoles of solutes per day to rid the body of a variety of excess salts and other water-soluble chemical wastes, most notably creatinine, urea, and uric acid. Failure to produce the minimum volume of urine means that metabolic wastes cannot be effectively removed from the body, a situation that can impair organ function. The minimum level of urine production necessary to maintain normal function is about 0.47 liters (0.5 quarts) per day.",True,Regulation of Water Output,,,,
+63fcdcbe-c0c1-4fe2-88e4-71008fdfbbac,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"The kidneys also must make adjustments in the event of ingestion of too much fluid. Diuresis, which is the production of urine in excess of normal levels, begins about 30 minutes after drinking a large quantity of fluid. Diuresis reaches a peak after about 1 hour, and normal urine production is reestablished after about 3 hours.",True,Regulation of Water Output,,,,
+6af3704e-4994-4294-b73e-94dd8c7ca84b,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,Role of ADH,False,Role of ADH,,,,
+5d4caa65-f79c-4a0a-8fcf-a14d2a6711a1,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"Antidiuretic hormone (ADH), also known as vasopressin, controls the amount of water reabsorbed from the collecting ducts and tubules in the kidney. This hormone is produced in the hypothalamus and is delivered to the posterior pituitary for storage and release (Figure 26.2.2). When the osmoreceptors in the hypothalamus detect an increase in the concentration of blood plasma, the hypothalamus signals the release of ADH from the posterior pituitary into the blood.",True,Role of ADH,Figure 26.2.2,26.2 Water Balance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2709_ADH.jpg,"Figure 26.2.2 – Antidiuretic Hormone (ADH): ADH is produced in the hypothalamus and released by the posterior pituitary gland. It causes the kidneys to retain water, constricts arterioles in the peripheral circulation, and affects some social behaviors in mammals."
+c3a554a9-6dd0-4b6a-a77b-0bb8ca98fbeb,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"ADH has two major effects. It constricts the arterioles in the peripheral circulation, which reduces the flow of blood to the extremities and thereby increases the blood supply to the core of the body. ADH also causes the epithelial cells that line the renal collecting tubules to move water channel proteins, called aquaporins, from the interior of the cells to the apical surface, where these proteins are inserted into the cell membrane (Figure 26.2.3). The result is an increase in the water permeability of these cells and, thus, a large increase in water passage from the urine through the walls of the collecting tubules, leading to more reabsorption of water into the bloodstream. When the blood plasma becomes less concentrated and the level of ADH decreases, aquaporins are removed from collecting tubule cell membranes, and the passage of water out of urine and into the blood decreases.",True,Role of ADH,Figure 26.2.3,26.2 Water Balance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2710_Aquaporins-01.jpg,"Figure 26.2.3 – Aquaporins: The binding of ADH to receptors on the cells of the collecting tubule results in aquaporins being inserted into the plasma membrane, shown in the lower cell. This dramatically increases the flow of water out of the tubule and into the bloodstream."
+add7750d-5bbd-4147-8d07-810e94d61321,https://open.oregonstate.education/aandp/,26.2 Water Balance,https://open.oregonstate.education/aandp/chapter/26-2-water-balance/,"A diuretic is a compound that increases urine output and therefore decreases water conservation by the body. Diuretics are used to treat hypertension, congestive heart failure, and fluid retention associated with menstruation. Alcohol acts as a diuretic by inhibiting the release of ADH. Additionally, caffeine, when consumed in high concentrations, acts as a diuretic.",True,Role of ADH,,,,
+76fad33e-a95b-4f1c-9606-274f802b1dde,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, an electrolyte is referred to as a mineral dissociated from a salt that carries an electrical charge (an ion). For instance, sodium ions (Na+) and chloride ions (Cl–) are often referred to as electrolytes.",True,Role of ADH,,,,
+3a96951f-46bf-441b-83a2-5801f164841b,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration to regions of lower concentration, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function.",True,Role of ADH,,,,
+67302f65-3d80-4aea-bd63-52f651340631,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,Body Water Content,False,Body Water Content,,,,
+c80686d8-21b8-49b3-9c2e-bedd54b6c955,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Human beings are mostly water, ranging from about 75 percent of body mass in infants to about 50–60 percent in adult men and women, to as low as 45 percent in old age. The percent of body water changes with development, because the proportions of the body given over to each organ and to muscles, fat, bone, and other tissues change from infancy to adulthood (Figure 26.1.1). Your brain and kidneys have the highest proportions of water, which composes 80–85 percent of their masses. In contrast, teeth have the lowest proportion of water, at 8–10 percent.",True,Body Water Content,Figure 26.1.1,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2701_Water_Content_in_the_Body-01.jpg,"Figure 26.1.1 – Water Content of the Body’s Organs and Tissues: Water content varies in different body organs and tissues, from as little as 8 percent in the teeth to as much as 85 percent in the brain."
+56509782-da45-4abb-9e3a-5f58cf8af71c,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,Fluid Compartments,False,Fluid Compartments,,,,
+52b0d7ba-fe3c-40bb-8e5a-262497d1dae7,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Body fluids can be discussed in terms of their specific fluid compartment, a location that is largely separate from another compartment by some form of a physical barrier. The intracellular fluid (ICF) compartment is the system that includes all fluid enclosed in cells by their plasma membranes. Extracellular fluid (ECF) surrounds all cells in the body. Extracellular fluid has two primary constituents: the fluid component of the blood (called plasma) and the interstitial fluid (IF) that surrounds all cells not in the blood (Figure 26.1.2).",True,Fluid Compartments,Figure 26.1.2,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2702_Fluid_Compartments_ICF_ECF.jpg,Figure 26.1.2 – Fluid Compartments in the Human Body: The intracellular fluid (ICF) is the fluid within cells. The interstitial fluid (IF) is part of the extracellular fluid (ECF) between the cells. Blood plasma is the second part of the ECF. Materials travel between cells and the plasma in capillaries through the IF.
+62f00794-0ebc-441c-b083-fd23089adb01,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,Composition of Body Fluids,False,Composition of Body Fluids,,,,
+c258196a-0dd3-4a83-99a3-c4453a0514be,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"The compositions of the two components of the ECF—plasma and IF—are more similar to each other than either is to the ICF (Figure 26.1.4). Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein. The IF has high concentrations of sodium, chloride, and bicarbonate, but a relatively lower concentration of protein. In contrast, the ICF has elevated amounts of potassium, phosphate, magnesium, and protein. Overall, the ICF contains high concentrations of potassium and phosphate (HPO42−HPO42−), whereas both plasma and the ECF contain high concentrations of sodium and chloride.",True,Composition of Body Fluids,Figure 26.1.4,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2704_Concentration_of_Elements_in_Body_Fluids.jpg,"Figure 26.1.4 – The Concentrations of Different Elements in Key Bodily Fluids: The graph shows the composition of the ICF, IF, and plasma. The compositions of plasma and IF are similar to one another but are quite different from the composition of the ICF."
+a2448dab-0473-4aec-aa6e-684b5921afa6,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Most body fluids are neutral in charge. Thus, cations, or positively charged ions, and anions, or negatively charged ions, are balanced in fluids. As seen in the previous graph, sodium (Na+) ions and chloride (Cl–) ions are concentrated in the ECF of the body, whereas potassium (K+) ions are concentrated inside cells. Although sodium and potassium can “leak” through “pores” into and out of cells, respectively, the high levels of potassium and low levels of sodium in the ICF are maintained by sodium-potassium pumps in the cell membranes. These pumps use the energy supplied by ATP to pump sodium out of the cell and potassium into the cell (Figure 26.1.5).",True,Composition of Body Fluids,Figure 26.1.5,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2705_Sodium_Potassium_Pump.jpg,Figure 26.1.5 – The Sodium-Potassium Pump: The sodium-potassium pump is powered by ATP to transfer sodium out of the cytoplasm and into the ECF. The pump also transfers potassium out of the ECF and into the cytoplasm. (credit: modification of work by Mariana Ruiz Villarreal)
+d2f8f6c2-699e-4411-b03a-299ce4882bbc,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,Fluid Movement between Compartments,False,Fluid Movement between Compartments,,,,
+9614dfc8-7b1e-4a8b-a0eb-665b3951711f,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Hydrostatic pressure, the force exerted by a fluid against a wall, causes movement of fluid between compartments. The hydrostatic pressure of blood is the pressure exerted by blood against the walls of the blood vessels by the pumping action of the heart. In capillaries, hydrostatic pressure (also known as capillary blood pressure) is higher than the opposing “colloid osmotic pressure” in blood—a “constant” pressure primarily produced by circulating albumin—at the arteriolar end of the capillary (Figure 26.1.6). This pressure forces plasma and nutrients out of the capillaries and into surrounding tissues. Fluid and the cellular wastes in the tissues enter the capillaries at the venule end, where the hydrostatic pressure is less than the osmotic pressure in the vessel. Filtration pressure squeezes fluid from the plasma in the blood to the IF surrounding the tissue cells. The surplus fluid in the interstitial space that is not returned directly back to the capillaries is drained from tissues by the lymphatic system, and then re-enters the vascular system at the subclavian veins.",True,Fluid Movement between Compartments,Figure 26.1.6,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2108_Capillary_Exchange.jpg,Figure 26.1.6 – Capillary Exchange: Net filtration occurs near the arterial end of the capillary since capillary hydrostatic pressure (CHP) is greater than blood colloidal osmotic pressure (BCOP). There is no net movement of fluid near the midpoint of the capillary since CHP = BCOP. Net reabsorption occurs near the venous end of the capillary since BCOP is greater than CHP.
+e55773c2-4d8d-4a2d-aa12-9abf358fd841,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Hydrostatic pressure is especially important in governing the movement of water in the nephrons of the kidneys to ensure proper filtering of the blood to form urine. As hydrostatic pressure in the kidneys increases, the amount of water leaving the capillaries also increases, and more urine filtrate is formed. If hydrostatic pressure in the kidneys drops too low, as can happen in dehydration, the functions of the kidneys will be impaired, and less nitrogenous wastes will be removed from the bloodstream. Extreme dehydration can result in kidney failure.",True,Fluid Movement between Compartments,,,,
+29069c64-40e0-499a-845a-109d1eddb380,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Fluid also moves between compartments along an osmotic gradient. Recall that an osmotic gradient is produced by the difference in concentration of all solutes on either side of a semi-permeable membrane. The magnitude of the osmotic gradient is proportional to the difference in the concentration of solutes on one side of the cell membrane to that on the other side. Water will move by osmosis from the side where its concentration is high (and the concentration of solute is low) to the side of the membrane where its concentration is low (and the concentration of solute is high). In the body, water moves by osmosis from plasma to the IF (and the reverse) and from the IF to the ICF (and the reverse). In the body, water moves constantly into and out of fluid compartments as conditions change in different parts of the body.",True,Fluid Movement between Compartments,,,,
+a4e30243-cf2f-45dc-846d-dd4f5a55f813,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"For example, if you are sweating, you will lose water through your skin. Sweating depletes your tissues of water and increases the solute concentration in those tissues. As this happens, water diffuses from your blood into sweat glands and surrounding skin tissues that have become dehydrated because of the osmotic gradient. Additionally, as water leaves the blood, it is replaced by the water in other tissues throughout your body that are not dehydrated. If this continues, dehydration spreads throughout the body. When a dehydrated person drinks water and rehydrates, the water is redistributed by the same gradient, but in the opposite direction, replenishing water in all of the tissues.",True,Fluid Movement between Compartments,,,,
+97c2d80c-f892-4442-b994-69ee8acba5d0,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,Solute Movement between Compartments,False,Solute Movement between Compartments,,,,
+139a179a-f213-49e4-b6e1-3d8dd0398e43,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"The movement of some solutes between compartments is active, which consumes energy and is an active transport process, whereas the movement of other solutes is passive, which does not require energy. Active transport allows cells to move a specific substance against its concentration gradient through a membrane protein, requiring energy in the form of ATP. For example, the sodium-potassium pump employs active transport to pump sodium out of cells and potassium into cells, with both substances moving against their concentration gradients.",True,Solute Movement between Compartments,,,,
+c3a22990-644c-4e7d-9d7c-60d65710c0d4,https://open.oregonstate.education/aandp/,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/aandp/chapter/26-1-body-fluids-and-fluid-compartments/,"Passive transport of a molecule or ion depends on its ability to pass through the membrane, as well as the existence of a concentration gradient that allows the molecules to diffuse from an area of higher concentration to an area of lower concentration. Some molecules, like gases, lipids, and water itself (which also utilizes water channels in the membrane called aquaporins), slip fairly easily through the cell membrane; others, including polar molecules like glucose, amino acids, and ions do not. Some of these molecules enter and leave cells using facilitated transport, whereby the molecules move down a concentration gradient through specific protein channels in the membrane. This process does not require energy. For example, glucose is transferred into cells by glucose transporters that use facilitated transport (Figure 26.1.7).",True,Solute Movement between Compartments,Figure 26.1.7,26.1 Body Fluids and Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2706_Facilitated_Diffusion.jpg,Figure 26.1.7 – Facilitated Diffusion: Glucose molecules use facilitated diffusion to move down a concentration gradient through the carrier protein channels in the membrane. (credit: modification of work by Mariana Ruiz Villarreal)
+340c3162-153f-469c-816b-1b05eec97ce3,https://open.oregonstate.education/aandp/,26.0 Introduction,https://open.oregonstate.education/aandp/chapter/26-0-introduction/,"Homeostasis, or the maintenance of constant conditions in the body, is a fundamental property of all living things. In the human body, the substances that participate in chemical reactions must remain within narrows ranges of concentration. Too much or too little of a single substance can disrupt your bodily functions. Because metabolism relies on reactions that are all interconnected, any disruption might affect multiple organs or even organ systems. Water is the most ubiquitous substance in the chemical reactions of life. The interactions of various aqueous solutions—solutions in which water is the solvent—are continuously monitored and adjusted by a large suite of interconnected feedback systems in your body. Understanding the ways in which the body maintains these critical balances is key to understanding good health.",True,Solute Movement between Compartments,,,,
+402d43b1-a21c-495a-be65-2fdd5d5818f7,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"All systems of the body are interrelated. A change in one system may affect all other systems in the body, with mild to devastating effects. A failure of urinary continence can be embarrassing and inconvenient, but is not life threatening. The loss of other urinary functions may prove fatal. A failure to synthesize vitamin D is one such example.",True,Solute Movement between Compartments,,,,
+53f2fe74-f388-4184-ae16-313a035c804c,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Vitamin D Synthesis,False,Vitamin D Synthesis,,,,
+b3c26c39-504c-4734-9542-397320b795e0,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"In order for vitamin D to become active, it must undergo a hydroxylation reaction in the kidney, that is, an –OH group must be added to calcidiol to make calcitriol (1,25-dihydroxycholecalciferol). Activated vitamin D is important for absorption of Ca++ in the digestive tract, its reabsorption in the kidney, and the maintenance of normal serum concentrations of Ca++ and phosphate. Calcium is vitally important in bone health, muscle contraction, hormone secretion, and neurotransmitter release. Inadequate Ca++ leads to disorders like osteoporosis and osteomalacia in adults and rickets in children. Deficits may also result in problems with cell proliferation, neuromuscular function, blood clotting, and the inflammatory response. Recent research has confirmed that vitamin D receptors are present in most, if not all, cells of the body, reflecting the systemic importance of vitamin D. Many scientists have suggested it be referred to as a hormone rather than a vitamin.",True,Vitamin D Synthesis,,,,
+11b28122-bfae-49f3-9f89-0bd8fb4cd761,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Erythropoiesis,False,Erythropoiesis,,,,
+89b036d7-37e0-4219-bbf9-af016a71adb9,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"Erythropoetin (EPO) is a hormone produced by the kidney that stimulates the formation of red blood cells in the bone marrow. The kidney produces 85 percent of circulating EPO; the liver, the remainder. If you move to a higher altitude, the partial pressure of oxygen is lower, meaning there is less pressure to push oxygen across the alveolar membrane and into the red blood cell. One way the body compensates is to manufacture more red blood cells by increasing EPO production. If you start an aerobic exercise program, your tissues will need more oxygen to cope, and the kidney will respond with more EPO. If erythrocytes are lost due to severe or prolonged bleeding, or under produced due to disease or severe malnutrition, the kidneys come to the rescue by producing more EPO. Renal failure (loss of EPO production) is associated with anemia, which makes it difficult for the body to cope with increased oxygen demands or to supply oxygen adequately even under normal conditions. Anemia diminishes performance and can be life threatening.",True,Erythropoiesis,,,,
+2117c3c2-0215-4927-a6b3-6035fe0a9383,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Blood Pressure Regulation,False,Blood Pressure Regulation,,,,
+e99cae02-7857-43ea-83b5-7d735b71a615,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"Due to osmosis, water follows where Na+ leads. In other words, “water follows salt.” Much of the water the kidneys recover from the filtrate follows the reabsorption of Na+. ADH stimulation of aquaporin channels allows for regulation of water recovery in the collecting ducts. Normally, all of the glucose is recovered, but loss of glucose control (diabetes mellitus) may result in an osmotic diuresis severe enough to produce severe dehydration and death. A loss of renal function means a loss of effective vascular volume control, leading to hypotension (low blood pressure) or hypertension (high blood pressure), which can lead to stroke, heart attack, and aneurysm formation.",True,Blood Pressure Regulation,,,,
+788fb609-c304-4be9-b817-71a9d666ed9f,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin–angiotensin–aldosterone system (see Chapter 25 Figure 25.4.2). The liver synthesizes and secretes the inactive precursor angiotensinogen. When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II (Figure 25.9.1). The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. angiotensin II also stimulates the adrenal cortex to release the steroid hormone aldosterone, which results in renal reabsorption of Na+ and its associated osmotic recovery of water. The reabsorption of Na+ helps to raise and maintain blood pressure over a longer term.",True,Blood Pressure Regulation,Figure 25.4.2,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2626_Renin_Aldosterone_Angiotensin.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.
+ac85c119-895b-4fce-8074-72365d91db72,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Regulation of Osmolarity,False,Regulation of Osmolarity,,,,
+0d927029-cf17-4fb5-a793-56817f1fe33b,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"Blood pressure and osmolarity are regulated in a similar fashion. Severe hypo-osmolarity can cause problems like lysis (rupture) of blood cells or widespread edema, which is due to a solute imbalance. Inadequate solute concentration (such as protein) in the plasma results in water moving toward an area of greater solute concentration, in this case, the interstitial space and cell cytoplasm. If the kidney glomeruli are damaged by an autoimmune illness, large quantities of protein may be lost in the urine. The resultant drop in serum osmolarity leads to widespread edema that, if severe, may lead to damaging or fatal brain swelling. Severe hypertonic conditions may arise with severe dehydration from lack of water intake, severe vomiting, or uncontrolled diarrhea. When the kidney is unable to recover sufficient water from the forming urine, the consequences may be severe (lethargy, confusion, muscle cramps, and finally, death) .",True,Regulation of Osmolarity,,,,
+8fabe16f-ce45-4987-a877-74527e26427c,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Recovery of Electrolytes,False,Recovery of Electrolytes,,,,
+abb1308e-4ba6-4fb1-a5d4-a115e29fd590,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"Sodium, calcium, and potassium must be closely regulated. The role of Na+ and Ca++ homeostasis has been discussed at length. Failure of K+ regulation can have serious consequences on nerve conduction, skeletal muscle function, and most significantly, on cardiac muscle contraction and rhythm.",True,Recovery of Electrolytes,,,,
+30b26639-decc-4eef-afac-79dbbd6e3509,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,pH Regulation,False,pH Regulation,,,,
+4f14b03d-e59c-443a-9afc-8d21a6885089,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,"Recall that enzymes lose their three-dimensional conformation and, therefore, their function if the pH is too acidic or basic. This loss of conformation may be a consequence of the breaking of hydrogen bonds. Move the pH away from the optimum for a specific enzyme and you may severely hamper its function throughout the body, including hormone binding, central nervous system signaling, or myocardial contraction. Proper kidney function is essential for pH homeostasis.",True,pH Regulation,,,,
+4e638cba-baae-425b-b59b-c8619c9c9690,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Everyday Connection,False,Everyday Connection,,,,
+a6b54e48-65a3-49c2-8385-62a90531ccd8,https://open.oregonstate.education/aandp/,25.9 The Urinary System and Homeostasis,https://open.oregonstate.education/aandp/chapter/25-9-the-urinary-system-and-homeostasis/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+3bfa8c9e-bc49-49f2-969d-dbaa744c0e61,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,Describe how the kidney modifies filtrate to influence urine production,False,Describe how the kidney modifies filtrate to influence urine production,,,,
+0c7d998c-3916-4d88-afed-53909b57c003,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,"Urine is the end product once the filtrate has been fully manipulated by the nephrons. Until the filtrate passes through the renal papilla into the minor calyx, it can be affected by nephron processes. This is how kidneys produce anywhere from .4 L of urine/day to as much as 20L urine/day, all while balancing plasma composition and excreting potential toxins in the urine.",True,Describe how the kidney modifies filtrate to influence urine production,,,,
+f00abf42-a84c-44eb-8947-864597089642,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,"The two kidneys filter your entire blood volume many times each day to remove wastes as urine. Characteristics of urine can be variable (Table 25.1) depending on water intake and losses, nutrient intake, and other factors described in this chapter, though cells, proteins and blood are not normally found in the urine. Some of the characteristics such as color and odor are rough descriptors of your state of hydration. For example, if you exercise or work outside, and sweat a great deal, your urine will turn darker and produce a slight odor. Alternatively, a well hydrated person will have light or clear colored urine with little odor (Figure 25.8.1).",True,Describe how the kidney modifies filtrate to influence urine production,Figure 25.8.1,25.8 Urine Transport and Elimination,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2601_Urine_Color_Chart.jpg,Figure 25.8.1 Urine Color can change due to degree of hydration.
+4222e657-3ad6-4f2a-86f0-71fbb2833c19,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,Ureters,False,Ureters,,,,
+6cf3f17f-020d-4f6a-a23b-27802b7d98e7,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,Bladder,False,Bladder,,,,
+24c4650c-94d7-4fa4-a3f0-45286a3527c1,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,Urethra,False,Urethra,,,,
+2ed5d2e9-de73-4743-8f76-c670b2ec0990,https://open.oregonstate.education/aandp/,25.8 Urine Transport and Elimination,https://open.oregonstate.education/aandp/chapter/25-8-urine-transport-and-elimination/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+2432fb10-8781-4f42-a4c6-1c77afe51533,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"The major hormones influencing total body water are ADH, aldosterone, and ANH. Circumstances that lead to fluid depletion in the body include blood loss and dehydration. Homeostasis requires that volume and osmolarity be preserved. Blood volume is important in maintaining sufficient blood pressure, and there are nonrenal mechanisms involved in its preservation, including vasoconstriction, which can act within seconds of a drop in pressure. Thirst mechanisms are also activated to promote the consumption of water lost through respiration, evaporation, or urination. Hormonal mechanisms are activated to recover volume while maintaining a normal osmotic environment. These mechanisms act principally on the kidney.",True,Answers for Critical Thinking Questions,,,,
+72a6bd59-5415-4650-adea-4b13620cb10a,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Volume-sensing Mechanisms,False,Volume-sensing Mechanisms,,,,
+d64f3f93-b98b-44a7-a05b-f93355e34660,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"The body cannot directly measure blood volume, but blood pressure can be measured. Blood pressure often reflects blood volume and is measured by baroreceptors in the aorta and carotid sinuses. When blood pressure increases, baroreceptors send more frequent action potentials to the central nervous system, leading to widespread vasodilation. Included in this vasodilation are the afferent arterioles supplying the glomerulus, resulting in increased GFR, and water loss by the kidneys. If pressure decreases, fewer action potentials travel to the central nervous system, resulting in more sympathetic stimulation-producing vasoconstriction, which will result in decreased filtration and GFR, and water loss.",True,Volume-sensing Mechanisms,,,,
+c505fb25-aa41-4f32-bfe7-3adce50a11f0,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Decreased blood pressure is also sensed by the granular cells in the afferent arteriole of the JGA. In response, the enzyme renin is released. You saw earlier in the chapter that renin activity leads to an almost immediate rise in blood pressure as activated angiotensin II produces vasoconstriction. The rise in pressure is sustained by the aldosterone effects initiated by angiotensin II; this includes an increase in Na+ retention and water volume. As an aside, late in the menstrual cycle, progesterone has a modest influence on water retention. Due to its structural similarity to aldosterone, progesterone binds to the aldosterone receptor in the collecting duct of the kidney, causing the same, albeit weaker, effect on Na+ and water retention.",True,Volume-sensing Mechanisms,,,,
+31821790-9b0f-45d0-9e31-4d73f9d92ced,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Cardiomyocytes of the atria also respond to greater stretch (as blood pressure rises) by secreting ANH. ANH opposes the action of aldosterone by inhibiting the recovery of Na+ by the DCT and collecting ducts. More Na+ is lost, and as water follows, total blood volume and pressure decline. In low-pressure states, ANH does not seem to have much effect.",True,Volume-sensing Mechanisms,,,,
+7d1537fe-d772-4243-abc1-6f7bc2002eb9,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"ADH is also called vasopressin. Early researchers found that in cases of unusually high secretion of ADH, the hormone caused vasoconstriction (vasopressor activity, hence the name). Only later were its antidiuretic properties identified. Synthetic ADH is still used occasionally to stem life-threatening esophagus bleeding in alcoholics.",True,Volume-sensing Mechanisms,,,,
+d65417a7-ef18-4449-a0f2-734af6e7757c,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"When blood volume drops 5–10 percent, causing a decrease in blood pressure, there is a rapid and significant increase in ADH release from the posterior pituitary. Immediate vasoconstriction to increase blood pressure is the result. ADH also causes activation of aquaporin channels in the collecting ducts to affect the recovery of water to help restore vascular volume.",True,Volume-sensing Mechanisms,,,,
+2e6b2ec4-cf8a-42f9-a92c-f9b7d26daa4a,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Diuretics and Fluid Volume,False,Diuretics and Fluid Volume,,,,
+7d993858-3354-4f3e-ad64-55ea4295cf9a,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"A diuretic is a compound that increases urine volume. Three familiar drinks contain diuretic compounds: coffee, tea, and alcohol. The caffeine in coffee and tea works by promoting vasodilation in the nephron, which increases GFR. Alcohol increases GFR by inhibiting ADH release from the posterior pituitary, resulting in less water recovery by the collecting duct. In cases of high blood pressure, diuretics may be prescribed to reduce blood volume and, thereby, reduce blood pressure. The most frequently prescribed anti-hypertensive diuretic is hydrochlorothiazide. It inhibits the Na+/ Cl– symporter in the DCT and collecting duct. The result is a loss of Na+ with water following passively by osmosis.",True,Diuretics and Fluid Volume,,,,
+dbff1fcd-4b01-40b7-88ea-3a7ccf3d743a,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Osmotic diuretics promote water loss by osmosis. An example is the indigestible sugar mannitol, which is most often administered to reduce brain swelling after head injury. However, it is not the only sugar that can produce a diuretic effect. In cases of poorly controlled diabetes mellitus, glucose levels exceed the capacity of the tubular glucose symporters, resulting in glucose in the urine. The unrecovered glucose becomes a powerful osmotic diuretic. Classically, in the days before glucose could be detected in the blood and urine, clinicians identified diabetes mellitus by the three Ps: polyuria (diuresis), polydipsia (increased thirst), and polyphagia (increased hunger).",True,Diuretics and Fluid Volume,,,,
+6734918d-a691-4520-ad56-1dd8c3beea39,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Regulation of Extracellular Na+,False,Regulation of Extracellular Na+,,,,
+79e0ed86-7a44-4f7a-9dc3-22e7b0458a9c,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Sodium has a very strong osmotic effect and attracts water. It plays a larger role in the osmolarity of the plasma than any other circulating component of the blood. If there is too much Na+ present, either due to poor control or excess dietary consumption, a series of metabolic problems ensue. There is an increase in total volume of water, which leads to hypertension (high blood pressure). Over a long period, this increases the risk of serious complications such as heart attacks, strokes, and aneurysms. It can also contribute to system-wide edema (swelling).",True,Regulation of Extracellular Na+,,,,
+034162d8-3379-4067-99bd-02650fd2733c,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Mechanisms for regulating Na+ concentration include the renin–angiotensin–aldosterone system and ADH (see Chapter 25 Figure Figure 25.4.2). Aldosterone stimulates the uptake of Na+ on the apical cell membrane of cells in the DCT and collecting ducts, whereas ADH helps to regulate Na+ concentration indirectly by regulating the reabsorption of water.",True,Regulation of Extracellular Na+,Figure 25.4.2,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2626_Renin_Aldosterone_Angiotensin.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.
+4f87ebd5-9060-45f9-b8e0-a39c98a39120,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Regulation of Extracellular K+,False,Regulation of Extracellular K+,,,,
+a8800ea1-bca7-46c4-b8bd-55373bce8e5c,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Potassium is present in a 30-fold greater concentration inside the cell than outside the cell. A generalization can be made that K+ and Na+ concentrations will move in opposite directions. When more Na+ is reabsorbed, more K+ is secreted; when less Na+ is reabsorbed (leading to excretion by the kidney), more K+ is retained. When aldosterone causes a recovery of Na+ in the nephron, a negative electrical gradient is created that promotes the secretion of K+ and Cl– into the lumen.",True,Regulation of Extracellular K+,,,,
+51baa3d9-1171-4118-8323-d87e92dd3701,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Regulation of Cl–,False,Regulation of Cl–,,,,
+3b1c2315-0a6c-46d8-ae4c-bab7be45536c,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Chloride is important in acid–base balance in the extracellular space and has other functions, such as in the stomach, where it combines with hydrogen ions in the stomach lumen to form hydrochloric acid, aiding digestion. Its close association with Na+ in the extracellular environment makes it the dominant anion of this compartment, and its regulation closely mirrors that of Na+.",True,Regulation of Cl–,,,,
+5a6f1293-f9d5-48f5-837a-c62d2a70b270,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Regulation of Ca++ and Phosphate,False,Regulation of Ca++ and Phosphate,,,,
+8524e994-b10c-45f3-bca8-6810ffd383bc,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"The parathyroid glands monitor and respond to circulating levels of Ca++ in the blood. When levels drop too low, parathyroid hormone (PTH) is released to stimulate the DCT to reabsorb Ca++ from the forming urine. When levels are adequate or high, less PTH is released and more Ca++ remains in the forming urine to be lost. Phosphate levels move in the opposite direction. When Ca++ levels are low, PTH inhibits reabsorption of phosphate (PO3–) causing its loss in the urine which decreases the phosphate in the blood. The retention of phosphate would result in the formation of calcium phosphate in the plasma, reducing circulating Ca++ levels. By ridding the blood of phosphate, blood Ca++ levels rise. PTH also stimulates the renal conversion of calcidiol into calcitriol, the active form of vitamin D. Calcitriol then stimulates the intestines to absorb more Ca++ from the diet.",True,Regulation of Ca++ and Phosphate,,,,
+4f403e4f-7eaa-406d-9e28-07d08cbd9d3f,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Regulation of H+, Bicarbonate, and pH",False,"Regulation of H+, Bicarbonate, and pH",,,,
+fecb5b75-dd97-4cc7-b19b-d1cf73f7821b,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"The acid–base homeostasis of the body is a function of chemical buffers and physiologic buffering provided by the lungs and kidneys. Buffers, especially proteins, HCO3−, and ammonia have a very large capacity to absorb or release H+ as needed to resist a change in pH. They can act within fractions of a second. The lungs can rid the body of excess acid very rapidly (seconds to minutes) through the conversion of HCO3– into CO2, which is then exhaled. It is rapid but has limited capacity in the face of a significant acid challenge. The kidneys can rid the body of both acid and base. The renal capacity is large but slow (minutes to hours). The cells of the PCT actively secrete H+ into the forming urine as Na+ is reabsorbed. The body rids itself of excess H+ and raises blood pH. In the collecting ducts, the apical surfaces of intercalated cells have proton pumps that actively secrete H+ into the luminal, forming urine to remove it from the body.",True,"Regulation of H+, Bicarbonate, and pH",,,,
+092d3916-ab46-4ba8-ba15-2dd3177c9dcb,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"As hydrogen ions are pumped into the forming urine, it is buffered by bicarbonate (HCO3–), H2PO4– (dihydrogen phosphate ion), or ammonia (forming NH4+, ammonium ion). Urine pH typically varies in a normal range from 4.5 to 8.0.",True,"Regulation of H+, Bicarbonate, and pH",,,,
+42cf2721-557c-46a5-8cc3-e47f20ceb6d3,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Regulation of Nitrogen Wastes,False,Regulation of Nitrogen Wastes,,,,
+7af4b12b-37e3-4ab1-aca4-4476d5b6cfca,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Nitrogen wastes are produced by the breakdown of proteins during normal metabolism. Proteins are broken down into amino acids, which in turn are deaminated by having their nitrogen groups removed. Deamination converts the amino (NH2) groups into ammonia (NH3), ammonium ion (NH4+), urea, or uric acid (Figure 25.7.1). Ammonia is extremely toxic, so most of it is very rapidly converted into urea in the liver. Human urinary wastes typically contain primarily urea with small amounts of ammonium and very little uric acid.",True,Regulation of Nitrogen Wastes,Figure 25.7.1,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2627_Nitrogen_Wastes.jpg,Figure 25.7.1 Nitrogen Wastes.
+f5ba1246-b2ac-4aef-879d-ec1e7e538e7d,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,Elimination of Drugs and Hormones,False,Elimination of Drugs and Hormones,,,,
+5ea3779e-eed6-4a90-a1d5-a762adfc1b04,https://open.oregonstate.education/aandp/,25.7 Physiology of Urine Formation: Regulation of Fluid Volume and Composition,https://open.oregonstate.education/aandp/chapter/25-7-physiology-of-urine-formation-regulation-of-fluid-volume-and-composition/,"Water-soluble drugs may be excreted in the urine and are influenced by one or all of the following processes: glomerular filtration, tubular secretion, or tubular reabsorption. Drugs that are structurally small can be filtered by the glomerulus with the filtrate. Large drug molecules such as heparin or those that are bound to plasma proteins cannot be filtered and are not readily eliminated. Some drugs can be eliminated by carrier proteins that enable secretion of the drug into the tubule lumen. There are specific carriers that eliminate basic (such as dopamine or histamine) or acidic drugs (such as penicillin or indomethacin). As is the case with other substances, drugs may be both filtered and reabsorbed passively along a concentration gradient.",True,Elimination of Drugs and Hormones,,,,
+5474272e-1046-4fb8-81b1-4bfb31ff7862,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"The structure of the loop of Henle and associated peritubular capillary create a countercurrent multiplier system (Figure 25.6.1). The countercurrent term comes from the fact that the descending and ascending loops are next to each other and their fluid flows in opposite directions (countercurrent). The multiplier term is due to the action of solute pumps that increase (multiply) the concentrations of urea and Na+ deep in the medulla, as described next.",True,Elimination of Drugs and Hormones,Figure 25.6.1,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2621_Loop_of_Henle_Countercurrent_Multiplier_System.jpg,Figure 25.6.1 Countercurrent Multiplier System.
+18c74f0c-19f9-4ec2-b923-1e5063140221,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"The presence of aquaporin channels in the descending loop allows prodigious quantities of water to leave the loop and enter the hyperosmolar interstitium of the pyramid, where it is returned to the circulation by the vasa recta. As the loop turns to become the ascending loop, there is an absence of aquaporin channels, so water cannot leave the loop. However, in the basal membrane of cells of the thick ascending loop, ATPase pumps actively remove Na+ from the cell into the interstitial space. A Na+/K+/2Cl– symporter in the apical membrane passively allows these ions to enter the cell cytoplasm from the lumen of the loop down a concentration gradient created by the pump. This mechanism works to dilute the fluid of the ascending loop ultimately to approximately 50–100 mOsmol/L.",True,Elimination of Drugs and Hormones,,,,
+f82bc4fe-ba50-4778-8dd9-ee267396027f,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"At the same time that water is freely diffusing out of the descending loop through aquaporin channels into the interstitial spaces of the medulla, urea freely diffuses into the lumen of the descending loop as it descends deeper into the medulla, much of it to be reabsorbed from the filtrate when it reaches the collecting duct. In addition, collecting ducts have urea pumps that actively pump urea into the interstitial spaces. This results in the recovery of Na+ to the circulation via the vasa recta and creates a high osmolar environment in the depths of the medulla. Thus, the movement of Na+ and urea into the interstitial spaces by these mechanisms creates the hyperosmotic environment in the depths of the medulla. The net result of this countercurrent multiplier system is to recover both water and Na+ in the circulation.",True,Elimination of Drugs and Hormones,,,,
+5c973816-6b1e-4f41-8665-72299e5417ef,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"At the transition from the DCT to the collecting duct, about 20 percent of the original water is still present and about 10 percent of the sodium. If no other mechanism for water reabsorption existed, about 20–25 liters of urine would be produced. Now consider what is happening in the adjacent capillaries, the vasa recta. They are recovering both solutes and water at a rate that preserves the countercurrent multiplier system. In general, blood flows slowly in capillaries to allow time for exchange of nutrients and wastes. In the vasa recta particularly, this rate of flow is important for two additional reasons. The flow must be slow to allow blood cells to lose and regain water without either crenating or bursting. Second, a rapid flow would remove too much Na+ and urea, destroying the osmolar gradient that is necessary for the recovery of solutes and water. Thus, by flowing slowly to preserve the countercurrent mechanism, as the vasa recta descend, Na+ and urea are freely able to enter the capillary, while water freely leaves; as they ascend, Na+ and urea are secreted into the surrounding medulla, while water reenters and is removed.",True,Elimination of Drugs and Hormones,,,,
+478d042d-f2e5-4dce-abf7-a4d4b65d3615,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,Hormonal Influence on Reabsorption of Water,False,Hormonal Influence on Reabsorption of Water,,,,
+b89d9342-ca50-479d-bfc5-782d6d436c86,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"The renal medulla has a concentration gradient with a low osmolarity superficially and a high osmolarity at its deepest point. The kidneys have expended a large amount of cellular energy to create this gradient, but what do the nephrons do with this gradient? In the presence of hormones, the kidney is able to concentrate the filtrate to be 20 times more concentrated than the glomerular plasma and PCT filtrate.",True,Hormonal Influence on Reabsorption of Water,,,,
+507bbad2-0a5a-4e41-9140-24c8d903d9ec,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"The process of concentrating the filtrate occurs in the DCT and collecting ducts. Recall that the DCT and collecting ducts are lined with simple cuboidal epithelium with receptors for aldosterone and ADH, respectively. Solutes move across the membranes of the cells of the DCT and collecting ducts, which contain two distinct cell types, principal cells and intercalated cells. A principal cell possesses channels for the recovery or loss of sodium and potassium. An intercalated cell secretes or absorbs acid or bicarbonate. As in other portions of the nephron, there is an array of micromachines (pumps and channels) on display in the membranes of these cells.",True,Hormonal Influence on Reabsorption of Water,,,,
+aa2510af-0b8f-4d42-843e-eed0cf89ff26,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"Regulation of urine volume and osmolarity are major functions of the collecting ducts. By varying the amount of water that is recovered, the collecting ducts play a major role in maintaining the body’s normal osmolarity. If the blood becomes hyperosmotic, the collecting ducts recover more water to dilute the blood; if the blood becomes hyposmotic, the collecting ducts recover less of the water, leading to concentration of the blood. Another way of saying this is: If plasma osmolarity rises, more water is recovered and urine volume decreases; if plasma osmolarity decreases, less water is recovered and urine volume increases. This function is regulated by the posterior pituitary hormone ADH (vasopressin). With mild dehydration, plasma osmolarity rises slightly. This increase is detected by osmoreceptors in the hypothalamus, which stimulates the release of ADH from the posterior pituitary. If plasma osmolarity decreases slightly, the opposite occurs.",True,Hormonal Influence on Reabsorption of Water,,,,
+b3cfa8b5-5231-4d58-b222-e43779ca67f7,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"When stimulated by ADH, the principal cells of the collecting duct will insert aquaporin channels proteins into their apical membranes. Recall that aquaporins allow water to pass from the duct lumen across the lipid-rich, hydrophobic cell membranes to travel through the cells and into the interstitial spaces where the water will be recovered by the vasa recta. As the ducts descend through the medulla, the osmolarity surrounding them increases (due to the countercurrent mechanisms described above). If aquaporin water channels are present, water will be osmotically pulled from the collecting duct into the surrounding interstitial space and into the peritubular capillaries. This process allows for the recovery of large amounts of water from the filtrate back into the blood, which produces a more concentrated urine. If less ADH is secreted, fewer aquaporin channels are inserted and less water is recovered, resulting in dilute urine. By altering the number of aquaporin channels, the volume of water recovered or lost is altered. This, in turn, regulates the blood osmolarity, blood pressure, and osmolarity of the urine.",True,Hormonal Influence on Reabsorption of Water,,,,
+cf882bab-b9c1-468c-b61c-f344e7deb99f,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"As Na+ is pumped from the filtrate, water is passively recaptured for the circulation; this preservation of vascular volume is critically important for the maintenance of a normal blood pressure. Aldosterone is secreted by the adrenal cortex in response to angiotensin II stimulation. As an extremely potent vasoconstrictor, angiotensin II functions immediately to increase blood pressure. By also stimulating aldosterone production, it provides a longer-lasting mechanism to support blood pressure by maintaining vascular volume (water recovery).",True,Hormonal Influence on Reabsorption of Water,,,,
+57f6f2a5-7060-4083-9250-7278ee54e817,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,"In addition to receptors for ADH, principal cells have receptors for the steroid hormone aldosterone. While ADH is primarily involved in the regulation of water recovery, aldosterone regulates Na+ recovery. Aldosterone stimulates principal cells to manufacture luminal Na+ and K+ channels as well as Na+/K+ ATPase pumps on the basal membrane of the cells of the DCT and collecting duct. When aldosterone output increases, more Na+ is recovered from the filtrate and water follows the Na+ passively. The movement of Na+ out of the lumen of the collecting duct creates a negative charge that promotes the movement of Cl– out of the lumen into the interstitial space by a paracellular route across tight junctions. Peritubular capillaries (or vasa recta) receive the solutes and water, returning them to the circulation. As the pump recovers Na+ for the body, it is also pumping K+ into the filtrate, since the pump moves K+ in the opposite direction.",True,Hormonal Influence on Reabsorption of Water,,,,
+22912985-39fb-45d1-9fa0-3dd8a2d7d3b2,https://open.oregonstate.education/aandp/,25.6 Physiology of Urine Formation: Medullary Concentration Gradient,https://open.oregonstate.education/aandp/chapter/25-6-physiology-of-urine-formation-medullary-concentration-gradient/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+1a7bcd02-09d3-4f84-be6d-e2a31ad33e26,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"With up to 180 liters per day passing through the nephrons of the kidney, it is quite obvious that most of that fluid and its contents must be reabsorbed. Recall that substances that need to be removd from the body but were not yet filtered, can be secreted. This reabsorption occurs in the PCT, loop of Henle, DCT, and the collecting ducts while the majority of secretion occurs in the PCT and DCT (Table 25.5 and Figure 25.5.1). Various portions of the nephron differ in their capacity to reabsorb water and specific solutes. While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT. About 10 percent (about 18 L) reaches the collecting ducts. The collecting ducts, under the influence of ADH, can recover almost all of the water passing through them, in cases of dehydration, or almost none of the water, in cases of over-hydration.",True,Answers for Critical Thinking Questions,Figure 25.5.1,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2618_Nephron_Secretion_Reabsorption.jpg,Figure 25.5.1 Locations of Secretion and Reabsorption in the Nephron.
+626262ab-9ccc-4695-a13a-c08a6bb28a00,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Mechanisms of Recovery,False,Mechanisms of Recovery,,,,
+554f5f7f-b1a1-4c6a-8c9f-8e6ecd3c5baa,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Mechanisms by which substances move across membranes for reabsorption or secretion include active transport, diffusion, facilitated diffusion, secondary active transport, and osmosis. These were discussed in an earlier chapter, and you may wish to review them.",True,Mechanisms of Recovery,,,,
+aea3959b-6ed4-47a8-b59c-9dc3950c75a2,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Active transport utilizes energy, usually the energy found in a phosphate bond of ATP, to move a substance across a membrane from a low to a high concentration. It is very specific and must have an appropriately shaped receptor for the substance to be transported. An example would be the active transport of Na+ out of a cell and K+ into a cell by the Na+/K+ pump. Both ions are moved in opposite directions from a lower to a higher concentration.",True,Mechanisms of Recovery,,,,
+277a639f-9fc9-4a9b-8ddf-89131153c70f,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Simple diffusion moves a substance from a higher to a lower concentration down its concentration gradient. It requires no energy and only needs to be soluble.,True,Mechanisms of Recovery,,,,
+f56e842b-3830-473b-851b-8126e91a2e79,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Facilitated diffusion is similar to diffusion in that it moves a substance down its concentration gradient. The difference is that it requires specific membrane receptors or channel proteins for movement. The movement of glucose and, in certain situations, Na+ ions, is an example of facilitated diffusion. In some cases of facilitated diffusion, two different substances share the same channel protein port; these mechanisms are described by the terms symport and antiport.",True,Mechanisms of Recovery,,,,
+c91b7f4b-4f09-47ee-8391-75c958171619,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Symport mechanisms move two or more substances in the same direction at the same time, whereas antiport mechanisms move two or more substances in opposite directions across the cell membrane. Both mechanisms may utilize concentration gradients maintained by ATP pumps. This is a mechanism described by the term “secondary active transport.” For example, a Na+ ATPase pump on the basilar membrane of a cell may constantly pump Na+ out of a cell, maintaining a strong electrochemical gradient. On the opposite (apical) surface, a Na+/glucose symport protein channel assists both Na+ and glucose into the cell as Na+ moves down the concentration gradient created by the basilar Na+ ATPase pumps. The glucose molecule then diffuses across the basal membrane by facilitated diffusion into the interstitial space and from there into peritubular capillaries.",True,Mechanisms of Recovery,,,,
+c47463a9-f896-4fcf-b701-b980a4dff121,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Most of the Ca++, Na+, glucose, and amino acids must be reabsorbed by the nephron to maintain homeostatic plasma concentrations. Other substances, such as urea, K+, ammonia (NH3), creatinine, and some drugs are secreted into the filtrate as waste products. Acid–base balance is maintained through actions of the lungs and kidneys: The lungs rid the body of H+, whereas the kidneys secrete or reabsorb H+ and HCO3– (Table 25.6). In the case of urea, about 50 percent is passively reabsorbed by the PCT. More is recovered by in the collecting ducts as needed. ADH induces the insertion of urea transporters and aquaporin channel proteins.",True,Mechanisms of Recovery,,,,
+f9095521-82c4-4d85-ae29-fd9e46f2c6d1,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Reabsorption in the Proximal Convoluted Tubule,False,Reabsorption in the Proximal Convoluted Tubule,,,,
+e2bce7f3-70d4-438f-819c-b5609e6c559a,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"The renal corpuscle filters the blood to create a filtrate that still contains many important molecules that the body needs to reclaim. The PCT reclaims more of these than any other portion of the nephron. The cells of the PCT have two surfaces: apical faces the lumen of the tubule and is in contact with the filtrate. The basal surface of the PCT cell faces the interstitial space near the peritubular capillary. Sodium is actively pumped by the PCT cells into the interstitial space and diffuses down its concentration gradient into the peritubular capillary. As it does so, water follows passively by osmosis. This is called obligatory water reabsorption, because water is “obliged” to follow the Na+ (Figure 25.5.2). Filtered amino acids and glucose move with sodium using specific membrane transport proteins (symports), accounting for 100% of reabsorption of these molecules in healthy individuals. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. The numbers and particular types of pumps and channels vary between the apical and basilar surfaces (Table 25.7) as well as the directionality of movement. Some molecules do not require cellular transport proteins but instead move between adjacent cell membranes (paracellular) across the tubule and back into the blood.",True,Reabsorption in the Proximal Convoluted Tubule,Figure 25.5.2,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2619_Substances_Reabsorbed_And_Secreted_By_The_PCT.jpg,Figure 25.5.2 Substances Reabsorbed and Secreted by the PCT.
+5c0d74cb-3a7f-4b6b-8028-5f99f1d1bb7b,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm) like that seen with diabetes mellitus. Fifty percent of Cl– and variable quantities of HCO3–, Ca++, Mg++, and HPO42− are also recovered in the PCT. The significant recovery of solutes from the PCT lumen to the interstitial space creates an osmotic gradient that promotes water recovery.",True,Reabsorption in the Proximal Convoluted Tubule,,,,
+30b8c5ec-8a34-4eac-bddf-9ab727547c7e,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"About 67 percent of the water, Na+, and K+ entering the nephron is reabsorbed in the PCT and returned to the circulation. Almost 100 percent of glucose, amino acids, and other organic substances such as vitamins are normally recovered here. Some glucose may appear in the urine if circulating glucose levels are high enough that all the glucose transporters in the PCT are saturated, so that their capacity to move glucose is exceeded (transport maximum, or Tm). In men, the maximum amount of glucose that can be recovered is about 375 mg/min, whereas in women, it is about 300 mg/min. This recovery rate translates to an arterial concentration of about 200 mg/dL. Though an exceptionally high sugar intake might cause sugar to appear briefly in the urine, the appearance of glycosuria usually points to type I or II diabetes mellitus. The transport of glucose from the lumen of the PCT to the interstitial space is similar to the way it is absorbed by the small intestine. Both glucose and Na+ bind simultaneously to the same symport proteins on the apical surface of the cell to be transported in the same direction, toward the interstitial space. Sodium moves down its electrochemical and concentration gradient into the cell and takes glucose with it. Na+ is then actively pumped out of the cell at the basal surface of the cell into the interstitial space. Glucose leaves the cell to enter the interstitial space by facilitated diffusion. The energy to move glucose comes from the Na+/K+ ATPase that pumps Na+ out of the cell on the basal surface. Fifty percent of Cl– and variable quantities of Ca++, Mg++, and HPO42− are also recovered in the PCT.",True,Reabsorption in the Proximal Convoluted Tubule,,,,
+6278ea47-9527-4a70-8196-b083c1e9a4cd,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Recovery of bicarbonate (HCO3–) is vital to the maintenance of acid–base balance, since it is a very powerful and fast-acting buffer. An important enzyme is used to catalyze this mechanism: carbonic anhydrase (CA). This same enzyme and reaction is used in red blood cells in the transportation of CO2, in the stomach to produce hydrochloric acid, and in the pancreas to produce HCO3– to buffer acidic chyme from the stomach. In the kidney, most of the CA is located within the cell, but a small amount is bound to the brush border of the membrane on the apical surface of the cell. In the lumen of the PCT, HCO3– combines with hydrogen ions to form carbonic acid (H2CO3). This is enzymatically catalyzed into CO2 and water, which diffuse across the apical membrane into the cell. Water can move osmotically across the lipid bilayer membrane due to the presence of aquaporin water channels. Inside the cell, the reverse reaction occurs to produce bicarbonate ions (HCO3–). These bicarbonate ions are cotransported with Na+ across the basal membrane to the interstitial space around the PCT (Figure 25.5.3). At the same time this is occurring, a Na+/H+ antiporter excretes H+ into the lumen, while it recovers Na+. Note how the hydrogen ion is recycled so that bicarbonate can be recovered. Also, note that a Na+ gradient is created by the Na+/K+ pump.",True,Reabsorption in the Proximal Convoluted Tubule,Figure 25.5.3,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2620_Reabsorption_of_Bicarbonate_from_the_PCT.jpg,Figure 25.5.3 Reabsorption of Bicarbonate from the PCT.
+314f3a8d-e5b5-4641-bad3-a15bab6e13f9,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Reabsorption in the Loop of Henle,False,Reabsorption in the Loop of Henle,,,,
+dce152b5-8736-4fe8-8c8b-4b2b178fbc65,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"The loop of Henle consists of two sections: thick and thin descending and thin and thick ascending sections. The loops of cortical nephrons do not extend into the renal medulla very far, if at all. Juxtamedullary nephrons have loops that extend variable distances, some very deep into the medulla. The descending and ascending portions of the loop are highly specialized to enable recovery of the remaining Na+ and water that were filtered by the glomerulus but not yet reabsorbed. As the filtrate moves through the loop, its osmolarity will change from iso-osmotic with blood (about 278–300 mOsmol/kg) to first a very hypertonic solution of about 1200 mOsmol/kg and then a very hypotonic solution of about 100 mOsmol/kg. These changes are accomplished by osmosis in the descending limb and active transport of salt in the ascending limb. Solutes and water recovered from these loops are returned to the circulation by way of the peritubular capillaries (cortical nephron) or vasa recta (juxtamedullary nephron).",True,Reabsorption in the Loop of Henle,,,,
+fd5b77c4-de68-46e4-b54b-3a0732ad8007,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Reabsorption in the Distal Convoluted Tubule and Collecting Ducts,False,Reabsorption in the Distal Convoluted Tubule and Collecting Ducts,,,,
+24b76051-117e-4245-b32e-f5863263cfed,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Approximately 80 percent of filtered water has been recovered by the time the dilute filtrate enters the DCT. The DCT will recover another 10–15 percent before the filtrate enters the collecting ducts. Under hormonal action, additional water and solutes can be reabsorbed into the peritubular capillaries and returned to the circulation.",True,Reabsorption in the Distal Convoluted Tubule and Collecting Ducts,,,,
+91af6734-b9a7-4f00-9c0d-9dc070eed217,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Cells of the DCT also recover Ca++ from the filtrate. Receptors for parathyroid hormone (PTH) are found in DCT cells and when bound to PTH, induce the insertion of calcium channels on their luminal surface. The channels enhance Ca++ recovery from the forming urine. In addition, as Na+ is pumped out of the cell, the resulting electrochemical gradient attracts Ca++ into the cell. Finally, calcitriol (1,25 dihydroxyvitamin D, the active form of vitamin D) is very important for calcium recovery. It induces the production of calcium-binding proteins that transport Ca++ into the cell. These binding proteins are also important for the movement of calcium inside the cell and aid in exocytosis of calcium across the basolateral membrane. Any Ca++ not reabsorbed at this point is lost in the urine.",True,Reabsorption in the Distal Convoluted Tubule and Collecting Ducts,,,,
+1b2275b4-92ae-4d28-888f-2ada80051747,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Tubular Secretion,False,Tubular Secretion,,,,
+ec148879-7646-443e-b281-2b29996c4f6c,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,"Tubular secretion occurs mostly in the PCT and DCT where unfiltered substances are moved from the peritubular capillary into the lumen of the tubule. Secretion usually removes substances that are too large to be filtered (ex: antibiotics, toxins) or those that are in excess in the blood (ex: H+, K+).",True,Tubular Secretion,,,,
+a4caaf26-08b8-41be-b53a-460db536b65a,https://open.oregonstate.education/aandp/,25.5 Physiology of Urine Formation: Tubular Reabsorption and Secretion,https://open.oregonstate.education/aandp/chapter/25-5-physiology-of-urine-formation-tubular-reabsorption-and-secretion/,Tubular Reabsorption and Secretion to Control pH,False,Tubular Reabsorption and Secretion to Control pH,,,,
+61c91c28-8dbf-4450-b2ec-d69e5b324769,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Glomerular Filtration,False,Glomerular Filtration,,,,
+9358d784-9708-4c62-9738-c5cc1b022311,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"Filtrate is produced by the glomerulus when the hydrostatic pressure produced by the heart pushes water and solutes through the filtration membrane. Glomerular filtration is a passive process as cellular energy is not used at the filtration membrane to produce filtrate. Recall that the filtration membrane lies between the blood in the glomerulus and the filtrate in the Bowman’s (glomerular) capsule and this filtration membrane is highly fenestrated allowing the passage of small molecules such as water, sodium, glucose, etc.",True,Glomerular Filtration,,,,
+8f5d4eeb-1f53-4ced-a405-7d431288950e,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"The volume of filtrate formed by both kidneys per minute is termed glomerular filtration rate (GFR). Approximately 20% of your cardiac output is filtered by your kidneys per minute under resting conditions. The work of the kidneys produces about 125 mL/min filtrate in men (range of 90 to 140 mL/min) and 105 mL/min filtrate in women (range of 80 to 125 mL/min). This amount equates to a volume of about 180 L/day in men and 150 L/day in women. However, 99% of this filtrate is returned to the circulation through reabsorption resulting in only about 1–2 liters of urine per day.",True,Glomerular Filtration,,,,
+5faa8ef0-15d8-4922-8d8c-6ccaa6b71124,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"GFR is influenced by multiple factors, like those seen at tissue capillary beds (see chapter 19). Recall that filtration occurs as pressure forces fluid and solutes through a semipermeable barrier with the solute movement constrained by particle size. Hydrostatic pressure is the pressure produced by a fluid against a surface. The blood inside the glomerulus creates glomerular hydrostatic pressure which forces fluid out of the glomerulus into the glomerular capsule. The fluid in the glomerular capsule creates pressure pushing fluid out of the glomerular capsule back into the glomerulus, opposing the glomerular hydrostatic pressure. This is the capsular hydrostatic pressure. These fluids exert pressures in opposing directions. Net fluid movement will be in the direction of the lower pressure. However, the concentration of the solutes in the fluids affects net movement of fluid as well.",True,Glomerular Filtration,,,,
+fa84698d-2ff2-4866-a16c-57c15bf38df2,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Water moves across a membrane from areas of high water concentration (low dissolved solute concentration) to areas of low water concentration (high dissolved solute concentration) through the process of osmosis. The concentration of plasma solutes in the glomerulus is greater than the concentration of the filtrate in the glomerular capsule since the filtration membrane limits the size of particles crossing the membrane. Most proteins cannot pass into the filtrate resulting in water’s movement out of the capsule towards the glomerulus. This pressure acting to draw water into the glomerulus is called blood colloid osmotic pressure. The absence of proteins in the glomerular space (the lumen within the glomerular capsule) results in a capsular osmotic pressure near zero.,True,Glomerular Filtration,,,,
+adcdc713-1db0-4220-9d47-24b9394b0eed,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"Glomerular filtration occurs when glomerular (blood) hydrostatic pressure exceeds the hydrostatic pressure of the glomerular capsule and the blood colloid osmotic pressure. The sum of all of the influences, both osmotic and hydrostatic, results in a net filtration pressure (NFP). Glomerular hydrostatic pressure is typically about 55 mmHg pushing fluid into the glomerular capsule. This outward pressure is countered by a typical capsular hydrostatic pressure of about 15 mmHg and a blood colloid osmotic pressure of 30 mmHg. To calculate the value of NFP:",True,Glomerular Filtration,,,,
+fa2ad3f6-bbfb-4f18-84f4-7f5b0718fd04,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,NFP = Glomerular blood hydrostatic pressure (GBHP) – [capsular hydrostatic pressure (CHP) + blood colloid osmotic pressure (BCOP)] = 10 mm Hg,True,Glomerular Filtration,,,,
+02d25208-ecaa-400d-ba68-f51787617c09,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,That is: NFP = GBHP – [CHP + BCOP] = 10 mm Hg,True,Glomerular Filtration,,,,
+96a0d48f-81e4-445f-9c67-9978d5f445b8,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Or: NFP = 55 – [15 + 30] = 10 mm Hg (Figure 25.4.1).,True,Glomerular Filtration,Figure 25.4.1,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2617_Net_Filtration_Pressure_revised-e1568240504781.png,Figure 25.4.1 – Net Filtration Pressure: The NFP is the sum of osmotic and hydrostatic pressures.
+664e6c0b-b26c-472a-8115-77f7b4b71761,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"A proper concentration of solutes in the blood is important in maintaining osmotic pressure both in the glomerulus and systemically. There are disorders in which too much protein passes through the filtration slits into the kidney filtrate. This excess protein in the filtrate leads to a deficiency of circulating plasma proteins. Together, blood colloid osmotic pressure decreases, resulting in an increase in urine volume potentially causing dehydration.",True,Glomerular Filtration,,,,
+3d338015-c49a-4511-9b25-1f6c1c8b3c3f,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"As you can see, there is a low net pressure across the filtration membrane. Intuitively, you should realize that minor changes in osmolarity of the blood or changes in capillary blood pressure result in major changes in the amount of filtrate formed at any given point in time. The kidney is able to cope with a wide range of blood pressures. In large part, this is due to the autoregulatory nature of smooth muscle. When you stretch it, it contracts. Thus, when blood pressure goes up, smooth muscle in the afferent arterioles contracts to limit any increase in blood flow and filtration rate. When blood pressure drops, the same capillaries relax to maintain blood flow and filtration rate. The net result is a relatively steady flow of blood into the glomerulus and a relatively steady filtration rate in spite of significant systemic blood pressure changes. Mean arterial blood pressure is calculated by adding 1/3 of the difference between the systolic and diastolic pressures to the diastolic pressure. Therefore, if the blood pressure is 110/80, the difference between systolic and diastolic pressure is 30. One third of this is 10, and when you add this to the diastolic pressure of 80, you arrive at a calculated mean arterial pressure of 90 mm Hg. Therefore, if you use mean arterial pressure for the GBHP in the formula for calculating NFP, you can determine that as long as mean arterial pressure is above approximately 60 mm Hg, the pressure will be adequate to maintain glomerular filtration. Blood pressures below this level will impair renal function and cause systemic disorders that are severe enough to threaten survival. This condition is called shock.",True,Glomerular Filtration,,,,
+9c81a925-e997-4f02-a9ab-6489ec14d2b4,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"It is vital that the flow of blood through the kidney be at a suitable rate to allow for filtration and yet not too fast to overwhelm the reabsorbing potential of the nephron tubule. This rate determines how much solute is retained or discarded, how much water is retained or discarded, and ultimately, the osmolarity of blood and the blood pressure of the body.",True,Glomerular Filtration,,,,
+10bef629-f227-4e61-a75b-203840d704a9,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Regulation of GFR,False,Regulation of GFR,,,,
+4ed397a2-9d6f-422c-99bd-66a01a3ccf2c,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"Glomerular filtration has to be carefully and thoroughly controlled because the simple act of filtrate production can have huge impacts on body fluid homeostasis and systemic blood pressure. Due to these two very distinct physiological needs, the body employs two very different mechanisms to regulate GFR. The kidney can control itself locally through intrinsic controls, also called renal autoregulation. These intrinsic control mechanisms maintain filtrate production so that the body can maintain fluid, electrolyte, and acid-base balance and also remove wastes and toxins from the body. There are also control mechanisms that originate outside of the kidney, the nervous and endocrine systems, and are called extrinsic controls. The nervous system and hormones released by the endocrine systems function to control systemic blood pressure by increasing or decreasing GFR to change systemic blood pressure by changing the fluid lost from the body.",True,Regulation of GFR,,,,
+95a00522-6687-4fe8-b81f-5503e83626c5,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"The kidneys are very effective at regulating the rate of blood flow over a wide range of blood pressures. Your blood pressure will decrease when you are relaxed or sleeping. It will increase when exercising. Yet, despite these changes, the filtration rate through the kidney will change very little. The kidney’s ability to autoregulate can maintain GFR with a MAP of as low as 80 mm Hg to as high as 180 mm Hg. This is due to two internal autoregulatory mechanisms that operate without outside influence: the myogenic mechanism and the tubuloglomerular feedback mechanism.",True,Regulation of GFR,,,,
+0aec96ba-e7b4-4e46-8640-8008273858ad,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"The extrinsic control mechanisms have an effect on GFR, but their primary function is to maintain systemic blood pressure. While the intrinsic controls functioned to specifically control GFR at the level of the kidneys, the neural and hormonal controls have a broader scope and function to meet the whole body’s needs, not just the needs of the kidneys.",True,Regulation of GFR,,,,
+18ae9b40-c40e-4537-9465-80d7f868e8e9,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"The kidneys are innervated by the sympathetic neurons of the autonomic nervous system via the celiac plexus and splanchnic nerves. Reduction of sympathetic stimulation results in vasodilation and increased blood flow through the kidneys during resting conditions. When the frequency of action potentials increases, the arteriolar smooth muscle constricts (vasoconstriction), resulting in diminished glomerular flow, so less filtration occurs. Under conditions of stress, sympathetic nervous activity increases, resulting in the direct vasoconstriction of afferent arterioles (norepinephrine effect) as well as stimulation of the adrenal medulla. The adrenal medulla, in turn, produces a generalized vasoconstriction through the release of epinephrine. This includes vasoconstriction of the afferent arterioles, further reducing the volume of blood flowing through the kidneys. This process redirects blood to other organs with more immediate needs. Under severe stress, such as significant blood loss, the sympathetic nervous system kicks into high gear to keep the blood routed to essential organs and keep the body alive. The strong vasoconstriction required to maintain systemic blood pressure under these severe conditions significantly reduces blood flow to the kidneys and can be damaging to the kidney tissues. If blood pressure falls, the sympathetic nerves will also stimulate the release of renin which we will discuss next.",True,Regulation of GFR,,,,
+365e5856-7e33-4384-9cd9-d823d09cb028,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"Recall that renin is an enzyme that is produced by the granular cells of the afferent arteriole at the JGA. It enzymatically converts angiotensinogen (made by the liver, freely circulating) into angiotensin I. Its release is stimulated by paracrine signals from the JGA in response to decreased extracellular fluid volume.",True,Regulation of GFR,,,,
+921aac27-2d7f-45ca-89f9-69cbe1391cec,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Angiotensin-converting enzyme (ACE) enzymatically converts inactive angiotensin I into active angiotensin II. ACE is not a hormone but it is functionally important in regulating systemic blood pressure and kidney function. It is produced in the lungs but binds to the surfaces of endothelial cells in the afferent arterioles and glomerulus. ACE is important in increasing blood pressure and this is why people with high blood pressure are sometimes prescribed ACE inhibitors to lower their blood pressure.,True,Regulation of GFR,,,,
+eafe0a74-48be-4cd3-99d7-53f8150472f3,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,"Angiotensin II is a potent vasoconstrictor that plays an immediate role in the regulation of blood pressure. It acts systemically to cause vasoconstriction as well as constriction of both the afferent and efferent arterioles of the glomerulus. Under the influence of Angiotensin II, the efferent arteriole constricts more strongly than the afferent arteriole, increasing GFR. In instances of blood loss or dehydration, Angiotensin II reduces both GFR and renal blood flow, thereby limiting fluid loss and preserving blood volume. Its release is usually stimulated by decreases in blood pressure, and so the preservation of adequate blood pressure is its primary role.",True,Regulation of GFR,,,,
+748cad85-2a71-4348-b09c-fc2648753a8a,https://open.oregonstate.education/aandp/,25.4 Physiology of Urine Formation: Glomerular Filtration,https://open.oregonstate.education/aandp/chapter/25-4-physiology-of-urine-formation-glomerular-filtration/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+610adc61-f5b4-49b5-b918-93c994a25eb3,https://open.oregonstate.education/aandp/,25.3 Physiology of Urine Formation: Overview,https://open.oregonstate.education/aandp/chapter/25-3-physiology-of-urine-formation-overview/,"Having reviewed the anatomy and microanatomy of the urinary system, now is the time to focus on the physiology. Recall that the glomerulus produce a simple filtrate of the blood and the remainder of the nephron works to modify the filtrate into urine. You will discover that different parts of the nephron utilize three specific processes to produce urine: filtration, reabsorption, and secretion. You will learn how each of these processes works and where they occur along the nephron and collecting ducts. The physiologic goal is to modify the composition of the plasma and, in doing so, produce the waste product urine.",True,Answers for Critical Thinking Questions,,,,
+0e9dafa2-edd5-4690-8747-5eaabe461aaf,https://open.oregonstate.education/aandp/,25.3 Physiology of Urine Formation: Overview,https://open.oregonstate.education/aandp/chapter/25-3-physiology-of-urine-formation-overview/,"Glomerular filtration occurs as blood passes into the glomerulus producing a plasma-like filtrate (minus proteins) that gets captured by the Bowman’s (glomerular) capsule and funneled into the renal tubule. This filtrate produced then becomes highly modified along its route through the nephron by the following processes, finally producing urine at the end of the collecting duct.",True,Answers for Critical Thinking Questions,,,,
+88198aff-edd3-4544-9455-a2de3d3d35ca,https://open.oregonstate.education/aandp/,25.3 Physiology of Urine Formation: Overview,https://open.oregonstate.education/aandp/chapter/25-3-physiology-of-urine-formation-overview/,"As the filtrate travels along the length of the nephron, the cells lining the tubule selectively, and often actively, take substances from the filtrate and move them out of the tubule into the blood. Recall that the glomerulus is simply a filter and anything suspended in the plasma that can fit through the holes in the filtration membrane can end up in the filtrate. This includes very physiologically important molecules such as water, sodium, chloride, and bicarbonate (along with many others) as well as molecules that the digestive system used a lot of energy to absorb, such as glucose and amino acids. These molecules would be lost in the urine if not reclaimed by the tubule cells. These cells are so efficient that they can reclaim all of the glucose and amino acids and up to 99% of the water and important ions lost due to glomerular filtration. The filtrate that is not reasbsorbed becomes urine at the base of the collecting duct.",True,Answers for Critical Thinking Questions,,,,
+066b23c9-a978-4fbf-b10b-493ea6dd7838,https://open.oregonstate.education/aandp/,25.2 Microscopic Anatomy of the Kidney: Anatomy of the Nephron,https://open.oregonstate.education/aandp/chapter/25-2-microscopic-anatomy-of-the-kidney-anatomy-of-the-nephron/,"Nephrons are the “functional units” of the kidney; they cleanse the blood of toxins and balance the constituents of the circulation to homeostatic set points through the processes of filtration, reabsorption, and secretion. The nephrons also function to control blood pressure (via production of renin), red blood cell production (via the hormone erythropoetin), and calcium absorption (via conversion of calcidiol into calcitriol, the active form of vitamin D).",True,Answers for Critical Thinking Questions,,,,
+7fa3f4f9-12df-4f9b-b6b4-eece6453245c,https://open.oregonstate.education/aandp/,25.2 Microscopic Anatomy of the Kidney: Anatomy of the Nephron,https://open.oregonstate.education/aandp/chapter/25-2-microscopic-anatomy-of-the-kidney-anatomy-of-the-nephron/,Microanatomy of the Nephron,False,Microanatomy of the Nephron,,,,
+abe0fcb1-4087-45b7-bd9e-876c9474d3ef,https://open.oregonstate.education/aandp/,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/aandp/chapter/25-1-internal-and-external-anatomy-of-the-kidney/,Describe the macroscopic and microscopic anatomy of the kidney.,False,Describe the macroscopic and microscopic anatomy of the kidney.,,,,
+e62fa6df-a279-46d2-97f8-07e584d774c8,https://open.oregonstate.education/aandp/,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/aandp/chapter/25-1-internal-and-external-anatomy-of-the-kidney/,External Anatomy,False,External Anatomy,,,,
+002892cc-d47e-48ff-91d8-233e0f086deb,https://open.oregonstate.education/aandp/,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/aandp/chapter/25-1-internal-and-external-anatomy-of-the-kidney/,"The paired kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs. The left kidney is located at about the T12 to L3 vertebrae, whereas the right is lower due to slight displacement by the liver. Upper portions of the kidneys are somewhat protected by the eleventh and twelfth ribs (Figure 25.1.1). Each kidney weighs about 125–175 g in males and 115–155 g in females. They are about 11–14 cm in length, 6 cm wide, and 4 cm thick, and are directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them. This capsule is covered by a shock-absorbing layer of adipose tissue called the renal fat pad, which in turn is encompassed by a tough renal fascia. The fascia and, to a lesser extent, the overlying peritoneum serve to firmly anchor the kidneys to the posterior abdominal wall in a retroperitoneal position.",True,External Anatomy,Figure 25.1.1,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2608_Kidney_Position_in_Abdomen_revised-e1568240294915.png,Figure 25.1.1 – Kidneys: The kidneys are slightly protected by the ribs and are surrounded by fat for protection. On the superior aspect of each kidney is an adrenal gland.
+a92150a2-8243-4a97-aebf-3c8a50c2899c,https://open.oregonstate.education/aandp/,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/aandp/chapter/25-1-internal-and-external-anatomy-of-the-kidney/,"A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal medulla (Figure 25.1.2). In the medulla, 5-8 renal pyramids are separated by connective tissue renal columns. Each pyramid creates urine and terminates into a renal papilla. Each renal papilla drains into a collecting pool called a minor calyx; several minor calyces connect to form a major calyx; all major calyces connect to the single renal pelvis which connects to the ureter.",True,External Anatomy,Figure 25.1.2,25.1 Internal and External Anatomy of the Kidney,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2610_The_Kidney_revised.png,Figure 25.1.2 Left Kidney.
+e1bbd5b1-445c-4a0e-926e-cf75a0a6694b,https://open.oregonstate.education/aandp/,25.0 Introduction,https://open.oregonstate.education/aandp/chapter/25-0-introduction/,"The urinary system has many roles including cleansing the blood and ridding the body of wastes. However, there are additional, equally important functions played by the system including regulation of pH, blood pressure, concentration of red blood cells, and production of vitamin D. If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on the body. The urinary system, controlled by the nervous system, also stores urine until a convenient time for disposal and then provides the anatomical structures to transport this waste liquid to the outside of the body.",True,External Anatomy,,,,
+b5cf5ce6-c49a-4fb4-88f2-20929ad2e020,https://open.oregonstate.education/aandp/,25.0 Introduction,https://open.oregonstate.education/aandp/chapter/25-0-introduction/,"The urinary system consists of paired kidneys which produce filter blood to produce urine. Urine moves through the ureters to the urinary bladder where it is stored until it is released. When released, urine travels through the urethra to the outside world.",True,External Anatomy,,,,
+12ce598b-f51a-4cb0-a903-6a08d31bd434,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"The carbohydrates, lipids, and proteins in the foods you eat are used for energy to power molecular, cellular, and organ system activities. Importantly, the energy is stored primarily as fats. The quantity and quality of food that is ingested, digested, and absorbed affects the amount of fat that is stored as excess calories. Diet—both what you eat and how much you eat—has a dramatic impact on your health. Eating too much or too little food can lead to serious medical issues, including cardiovascular disease, cancer, anorexia, and diabetes, among others. Combine an unhealthy diet with unhealthy environmental conditions, such as smoking, and the potential medical complications increase significantly.",True,External Anatomy,,,,
+ef55f3b8-56cb-434f-85a6-dd503c395e18,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,Food and Metabolism,False,Food and Metabolism,,,,
+647943a6-06c1-4863-bfc8-23e1fd17c750,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"The amount of energy that is needed or ingested per day is measured in calories. The nutritional Calorie (C) is the amount of heat it takes to raise 1 kg (1000 g) of water by 1 °C. This is different from the calorie (c) used in the physical sciences, which is the amount of heat it takes to raise 1 g of water by 1 °C. When we refer to “calorie,” we are referring to the nutritional Calorie.",True,Food and Metabolism,,,,
+ca504579-9ae3-44ea-bba5-09042c59aa95,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"On average, a person needs 1500 to 2000 calories per day to sustain (or carry out) daily activities. The total number of calories needed by one person is dependent on their body mass, age, height, gender, activity level, and the amount of exercise per day. If exercise is regular part of one’s day, more calories are required. As a rule, people underestimate the number of calories ingested and overestimate the amount they burn through exercise. This can lead to ingestion of too many calories per day. The accumulation of an extra 3500 calories adds one pound of weight. If an excess of 200 calories per day is ingested, one extra pound of body weight will be gained every 18 days. At that rate, an extra 20 pounds can be gained over the course of a year. Of course, this increase in calories could be offset by increased exercise. Running or jogging one mile burns almost 100 calories.",True,Food and Metabolism,,,,
+9bb36344-3d40-43e9-90fe-18f8aa49ac01,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"The type of food ingested also affects the body’s metabolic rate. Processing of carbohydrates requires less energy than processing of proteins. In fact, the breakdown of carbohydrates requires the least amount of energy, whereas the processing of proteins demands the most energy. In general, the amount of calories ingested and the amount of calories burned determines the overall weight. To lose weight, the number of calories burned per day must exceed the number ingested. Calories are in almost everything you ingest, so when considering calorie intake, beverages must also be considered.",True,Food and Metabolism,,,,
+5c2091a1-e8ca-4012-a00d-a054e8fdd3c0,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"To help provide guidelines regarding the types and quantities of food that should be eaten every day, the USDA has updated their food guidelines from MyPyramid to MyPlate. They have put the recommended elements of a healthy meal into the context of a place setting of food. MyPlate categorizes food into the standard six food groups: fruits, vegetables, grains, protein foods, dairy, and oils. The accompanying website gives clear recommendations regarding quantity and type of each food that you should consume each day, as well as identifying which foods belong in each category. The accompanying graphic (Figure 24.7.1) gives a clear visual with general recommendations for a healthy and balanced meal. The guidelines recommend to “Make half your plate fruits and vegetables.” The other half is grains and protein, with a slightly higher quantity of grains than protein. Dairy products are represented by a drink, but the quantity can be applied to other dairy products as well.",True,Food and Metabolism,Figure 24.7.1,24.7 Nutrition and Diet,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2524_MyPlate.jpg,Figure 24.7.1 – MyPlate: The U.S. Department of Agriculture developed food guidelines called MyPlate to help demonstrate how to maintain a healthy lifestyle.
+8e8f5550-dce5-4993-ae47-0bd5e6fb88a1,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"ChooseMyPlate.gov provides extensive online resources for planning a healthy diet and lifestyle, including offering weight management tips and recommendations for physical activity. It also includes the SuperTracker, a web-based application to help you analyze your own diet and physical activity.",True,Food and Metabolism,,,,
+cde2c471-a322-4dbe-b902-77527d80c944,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,body mass index (BMI),False,body mass index (BMI),,,,
+55efe265-ded3-4985-b31e-379d63fd218c,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,Vitamins,False,Vitamins,,,,
+e9ef98fd-acf9-4893-bb67-7b29fe6cee3a,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"Vitamins are organic compounds found in foods and are a necessary part of the biochemical reactions in the body. They are involved in a number of processes, including mineral and bone metabolism, and cell and tissue growth, and they act as cofactors for energy metabolism. The B vitamins play the largest role of any vitamins in metabolism (Table 24.3 and Table 24.4).",True,Vitamins,,,,
+c5736730-f6aa-4e5f-af6d-7b6aa5c27669,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"You get most of your vitamins through your diet, although some can be formed from the precursors absorbed during digestion. For example, the body synthesizes vitamin A from the β-carotene in orange vegetables like carrots and sweet potatoes. Vitamins are either fat-soluble or water-soluble. Fat-soluble vitamins A, D, E, and K, are absorbed through the intestinal tract with lipids in chylomicrons. Vitamin D is also synthesized in the skin through exposure to sunlight. Because they are carried in lipids, fat-soluble vitamins can accumulate in the lipids stored in the body. If excess vitamins are retained in the lipid stores in the body, hypervitaminosis can result.",True,Vitamins,,,,
+bf26b37a-cca4-4205-8478-29770ca7e8f8,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"Water-soluble vitamins, including the eight B vitamins and vitamin C, are absorbed with water in the gastrointestinal tract. These vitamins move easily through bodily fluids, which are water based, so they are not stored in the body. Excess water-soluble vitamins are usually excreted in the urine. Therefore, hypervitaminosis of water-soluble vitamins rarely occurs, except with an excess of vitamin supplements.",True,Vitamins,,,,
+8579ae9c-75c2-4877-8fd6-835bafa4a52a,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,Minerals,False,Minerals,,,,
+9d529932-30f3-49bc-9e15-58f85916316e,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"Minerals in food are inorganic compounds that work with other nutrients to ensure the body functions properly. Minerals cannot be made in the body; they come from the diet. The amount of minerals in the body is small—only 4 percent of the total body mass—and most of that consists of the minerals that the body requires in moderate quantities: potassium, sodium, calcium, phosphorus, magnesium, and chloride.",True,Minerals,,,,
+ed14b65e-e0a6-48a1-9fd5-d3d18dcd8fe3,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"The most common minerals in the body are calcium and phosphorous, both of which are stored in the skeleton and necessary for the hardening of bones. Most minerals are ionized, and their ionic forms are used in physiological processes throughout the body. Sodium and chloride ions are electrolytes in the blood and extracellular tissues, and iron ions are critical to the formation of hemoglobin. Many minerals are used as cofactors and coenzymes in metabolic processes. There are additional trace minerals that are still important to the body’s functions, but their required quantities are much lower.",True,Minerals,,,,
+62b7e3ac-3d25-43bf-bcdf-47f42f334b23,https://open.oregonstate.education/aandp/,24.7 Nutrition and Diet,https://open.oregonstate.education/aandp/chapter/24-7-nutrition-and-diet/,"Like vitamins, minerals can be consumed in toxic quantities (although it is rare). A healthy diet includes most of the minerals your body requires, so supplements and processed foods can add potentially toxic levels of minerals. Table 24.5 and Table 24.6 provide a summary of minerals and their function in the body.",True,Minerals,,,,
+954e27da-fec9-49a4-88db-77822e27d7e8,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"The body tightly regulates the body temperature through a process called thermoregulation, in which the body can maintain its temperature within certain boundaries, even when the surrounding temperature is very different. The core temperature of the body remains steady at around 36.5–37.5 °C (or 97.7–99.5 °F). In the process of ATP production by cells throughout the body, approximately 60 percent of the energy produced is in the form of heat used to maintain body temperature. Thermoregulation is an example of negative feedback.",True,Minerals,,,,
+22bf97a3-dd19-47b3-944f-930a0fbd6405,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"The hypothalamus in the brain is the master switch that works as a thermostat to regulate the body’s core temperature (Figure 24.6.1). If the temperature is too high, the hypothalamus can initiate several processes to lower it. These include increasing the circulation of the blood to the surface of the body to allow for the dissipation of heat through the skin and initiation of sweating to allow evaporation of water on the skin to cool its surface. Conversely, if the temperature falls below the set core temperature, the hypothalamus can initiate shivering to generate heat. The body uses more energy and generates more heat. In addition, thyroid hormone will stimulate more energy use and heat production by cells throughout the body. An environment is said to be thermoneutral when the body does not expend or release energy to maintain its core temperature. For a naked human, this is an ambient air temperature of around 84 °F. If the temperature is higher, for example, when wearing clothes, the body compensates with cooling mechanisms. The body loses heat through the mechanisms of heat exchange.",True,Minerals,Figure 24.6.1,24.6 Energy and Heat Balance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2523_The-Hypothalamus_Controls_Thermoregulation-608x1024-1.jpg,Figure 24.6.1 – Hypothalamus Controls Thermoregulation: The hypothalamus controls thermoregulation.
+e5c05bab-4b2e-40b3-943a-250a988a07a9,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,Mechanisms of Heat Exchange,False,Mechanisms of Heat Exchange,,,,
+ee4894f3-34a4-4f79-bb40-60921c87f4b4,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"When the environment is not thermoneutral, the body uses four mechanisms of heat exchange to maintain homeostasis: conduction, convection, radiation, and evaporation. Each of these mechanisms relies on the property of heat to flow from a higher concentration to a lower concentration; therefore, each of the mechanisms of heat exchange varies in rate according to the temperature and conditions of the environment.",True,Mechanisms of Heat Exchange,,,,
+145df463-3dbe-4ce5-9228-3abad3ba7fe9,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"Conduction is the transfer of heat by two objects that are in direct contact with one another. It occurs when the skin comes in contact with a cold or warm object. For example, when holding a glass of ice water, the heat from your skin will warm the glass and in turn melt the ice. Alternatively, on a cold day, you might warm up by wrapping your cold hands around a hot mug of coffee. Only about 3 percent of the body’s heat is lost through conduction.",True,Mechanisms of Heat Exchange,,,,
+e8e3734d-42a1-4980-b018-c72e8e393b77,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"Convection is the transfer of heat to the air surrounding the skin. The warmed air rises away from the body and is replaced by cooler air that is subsequently heated. Convection can also occur in water. When the water temperature is lower than the body’s temperature, the body loses heat by warming the water closest to the skin, which moves away to be replaced by cooler water. The convection currents created by the temperature changes continue to draw heat away from the body more quickly than the body can replace it, resulting in hypothermia. About 15 percent of the body’s heat is lost through convection.",True,Mechanisms of Heat Exchange,,,,
+5b5899a4-85ba-4d93-b1d8-ee6c463b3a0c,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"Radiation is the transfer of heat via infrared waves. This occurs between any two objects when their temperatures differ. A radiator can warm a room via radiant heat. On a sunny day, the radiation from the sun warms the skin. The same principle works from the body to the environment. About 60 percent of the heat lost by the body is lost through radiation.",True,Mechanisms of Heat Exchange,,,,
+90d838cf-4010-4b8a-b429-77c13aaae90e,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"Evaporation is the transfer of heat by the evaporation of water. Because it takes a great deal of energy for a water molecule to change from a liquid to a gas, evaporating water (in the form of sweat) takes with it a great deal of energy from the skin. However, the rate at which evaporation occurs depends on relative humidity—more sweat evaporates in lower humidity environments. Sweating is the primary means of cooling the body during exercise, whereas at rest, about 20 percent of the heat lost by the body occurs through evaporation.",True,Mechanisms of Heat Exchange,,,,
+9fbaaccf-6e4e-485d-8703-2d25231d4dd5,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,Metabolic Rate,False,Metabolic Rate,,,,
+f6ab4504-31d7-48c3-b5ed-cdd270b82966,https://open.oregonstate.education/aandp/,24.6 Energy and Heat Balance,https://open.oregonstate.education/aandp/chapter/24-6-energy-and-heat-balance/,"The metabolic rate is the amount of energy consumed minus the amount of energy expended by the body. The basal metabolic rate (BMR) describes the amount of daily energy expended by humans at rest, in a neutrally temperate environment, while in the postabsorptive state. It measures how much energy the body needs for normal, basic, daily activity. About 70 percent of all daily energy expenditure comes from the basic functions of the organs in the body. Another 20 percent comes from physical activity, and the remaining 10 percent is necessary for body thermoregulation or temperature control. This rate will be higher if a person is more active or has more lean body mass. As you age, the BMR generally decreases as the percentage of less lean muscle mass decreases.",True,Metabolic Rate,,,,
+56cb3f58-a3c3-4783-bbb1-c3bf6ab34bf4,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"You eat periodically throughout the day; however, your organs, especially the brain, need a continuous supply of glucose. How does the body meet this constant demand for energy? Your body processes the food you eat both to use immediately and, importantly, to store as energy for later demands. If there were no method in place to store excess energy, you would need to eat constantly in order to meet energy demands. Distinct mechanisms are in place to facilitate energy storage, and to make stored energy available during times of fasting and starvation.",True,Metabolic Rate,,,,
+e14fb871-6296-4e71-9d3e-8a26d0d1bc30,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,The Absorptive State,False,The Absorptive State,,,,
+94d1f0ee-4190-45dc-8c34-2e1f4be4206b,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"The absorptive state, or the fed state, occurs after a meal when your body is digesting the food and absorbing the nutrients (anabolism exceeds catabolism). Digestion begins the moment you put food into your mouth, as the food is broken down into its constituent parts to be absorbed through the intestine. The digestion of carbohydrates begins in the mouth, whereas the digestion of proteins and fats begins in the stomach and small intestine. The constituent parts of these carbohydrates, fats, and proteins are transported across the intestinal wall and enter the bloodstream (sugars and amino acids) or the lymphatic system (fats). From the intestines, these systems transport them to the liver, adipose tissue, or muscle cells that will process and use, or store, the energy.",True,The Absorptive State,,,,
+64bb5a93-1f73-4b86-91bb-73f8a6fead39,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"Depending on the amounts and types of nutrients ingested, the absorptive state can linger for up to 4 hours. The ingestion of food and the rise of glucose concentrations in the bloodstream stimulate pancreatic beta cells to release insulin into the bloodstream, where it initiates the absorption of blood glucose by liver hepatocytes, and by adipose and muscle cells. Once inside these cells, glucose is immediately converted into glucose-6-phosphate. By doing this, a concentration gradient is established where glucose levels are higher in the blood than in the cells. This allows for glucose to continue moving from the blood to the cells where it is needed. Insulin also stimulates the storage of glucose as glycogen in the liver and muscle cells where it can be used for later energy needs of the body. Insulin also promotes the synthesis of protein in muscle. As you will see, muscle protein can be catabolized and used as fuel in times of starvation.",True,The Absorptive State,,,,
+be0fe9f2-85ec-4e4e-ad6c-8744f401c488,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"If energy is exerted shortly after eating, the dietary fats and sugars that were just ingested will be processed and used immediately for energy. If not, the excess glucose is stored as glycogen in the liver and muscle cells, or as fat in adipose tissue; excess dietary fat is also stored as triglycerides in adipose tissues.",True,The Absorptive State,,,,
+6a01f26c-aabd-4d29-955d-62d0dbf6b576,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,Figure 24.5.1 summarizes the metabolic processes occurring in the body during the absorptive state.,True,The Absorptive State,Figure 24.5.1,24.5 Metabolic States of the Body,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2521_The_Absorptive_Stage-scaled.jpg,"Figure 24.5.1 – Absorptive State: During the absorptive state, the body digests food and absorbs the nutrients into cells."
+f58450b9-0c0c-4558-8cc8-568924212f58,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,The Postabsorptive State,False,The Postabsorptive State,,,,
+062d9e61-f1dc-4fd4-8378-5af645f70006,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"The postabsorptive state, or the fasting state, occurs when the food has been digested, absorbed, and stored. You commonly fast overnight, but skipping meals during the day puts your body in the postabsorptive state as well. During this state, the body must rely initially on stored glycogen. Glucose levels in the blood begin to drop as it is absorbed and used by the cells. In response to the decrease in glucose, insulin levels also drop. Glycogen and triglyceride storage slows. However, due to the demands of the tissues and organs, blood glucose levels must be maintained in the normal range of 80–120 mg/dL. In response to a drop in blood glucose concentration, the hormone glucagon is released from the alpha cells of the pancreas. Glucagon acts upon the liver cells, where it inhibits the synthesis of glycogen and stimulates the breakdown of stored glycogen back into glucose. This glucose is released from the liver to be used by the peripheral tissues and the brain. As a result, blood glucose levels begin to rise. Gluconeogenesis will also begin in the liver to replace the glucose that has been used by the peripheral tissues.",True,The Postabsorptive State,,,,
+79322182-c101-48c5-ad99-8666d655b1c6,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"After ingestion of food, fats and proteins are processed as described previously; however, the glucose processing changes a bit. The peripheral tissues preferentially absorb glucose. The liver, which normally absorbs and processes glucose, will not do so after a prolonged fast. The gluconeogenesis that has been ongoing in the liver will continue after fasting to replace the glycogen stores that were depleted in the liver. After these stores have been replenished, excess glucose that is absorbed by the liver will be converted into triglycerides and fatty acids for long-term storage. Figure 24.5.2 summarizes the metabolic processes occurring in the body during the postabsorptive state.",True,The Postabsorptive State,Figure 24.5.2,24.5 Metabolic States of the Body,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2522_The_Postabsorptive_Stage-scaled.jpg,"Figure 24.5.2 – Postabsorptive State: During the postabsorptive state, the body must rely on stored glycogen for energy, breaking down glycogen in the cells and releasing it to cell (muscle) or the body (liver)."
+4a26aee4-8dee-4979-9885-f603a142d773,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,Starvation,False,Starvation,,,,
+46979334-fe5d-4d41-9837-40fd6b8173f8,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells (see Chapter 24.1 Figure 24.1.1). Because glucose levels are very low during starvation, glycolysis will shut off in cells that can use alternative fuels. For example, muscles will switch from using glucose to fatty acids as fuel. As previously explained, fatty acids can be converted into acetyl CoA and processed through the Krebs cycle to make ATP. Pyruvate, lactate, and alanine from muscle cells are not converted into acetyl CoA and used in the Krebs cycle, but are exported to the liver to be used in the synthesis of glucose. As starvation continues, and more glucose is needed, glycerol from fatty acids can be liberated and used as a source for gluconeogenesis.",True,Starvation,Figure 24.1.1,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2501_The_Structure_of_ATP_Molecules.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions."
+907c469c-aa0c-4f01-a867-a0f97fa86629,https://open.oregonstate.education/aandp/,24.5 Metabolic States of the Body,https://open.oregonstate.education/aandp/chapter/24-5-metabolic-states-of-the-body/,"After several days of starvation, ketone bodies become the major source of fuel for the heart and other organs. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. This prevents the continued breakdown of proteins that serve as carbon sources for gluconeogenesis. Once these stores are fully depleted, proteins from muscles are released and broken down for glucose synthesis. Overall survival is dependent on the amount of fat and protein stored in the body.",True,Starvation,,,,
+48726f29-6477-423e-830b-d49780e7b9ef,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"Much of the body is made of protein, and these proteins take on a myriad of forms. They represent cell signaling receptors, signaling molecules, structural members, enzymes, intracellular trafficking components, extracellular matrix scaffolds, ion pumps, ion channels, oxygen and CO2 transporters (hemoglobin). That is not even the complete list! There is protein in bones (collagen), muscles, and tendons; the hemoglobin that transports oxygen; and enzymes that catalyze all biochemical reactions. Protein is also used for growth and repair. Amid all these necessary functions, proteins also hold the potential to serve as a metabolic fuel source. Proteins are not stored for later use, so excess proteins must be converted into glucose or triglycerides, and used to supply energy or build energy reserves. Although the body can synthesize proteins from amino acids, food is an important source of those amino acids, especially because humans cannot synthesize all of the 20 amino acids used to build proteins.",True,Starvation,,,,
+0fc23cb1-d75a-4329-966b-5dedd44ee9e3,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"The digestion of proteins begins in the stomach. When protein-rich foods enter the stomach, they are greeted by a mixture of the enzyme pepsin and hydrochloric acid (HCl; 0.5 percent). The latter produces an environmental pH of 1.5–3.5 that denatures proteins within food. Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. When the food-gastric juice mixture (chyme) enters the small intestine, the pancreas releases sodium bicarbonate to neutralize the HCl. This helps to protect the lining of the intestine. The small intestine also releases digestive hormones, including secretin and CCK, which stimulate digestive processes to break down the proteins further. Secretin also stimulates the pancreas to release sodium bicarbonate. The pancreas releases most of the digestive enzymes, including the proteases trypsin, chymotrypsin, carboxypeptidase, and elastase, which aid protein digestion. Together, all of these enzymes break complex proteins into smaller individual amino acids (Figure 24.4.1), which are then transported across the intestinal mucosa to be used to create new proteins, or to be converted into fats or acetyl CoA and used in the Krebs cycle.",True,Starvation,Figure 24.4.1,24.4 Protein Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2517_Protein-Digesting_EnzymesN.jpg,"Figure 24.4.1 – Digestive Enzymes and Hormones: Enzymes in the stomach and small intestine break down proteins into amino acids. HCl in the stomach aids in proteolysis by denaturing proteins, and hormones secreted by intestinal cells direct the digestive processes."
+9cb34cb2-9701-4310-add8-01e3265350b8,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"In order to avoid breaking down the proteins that make up the pancreas and small intestine, pancreatic enzymes are released as inactive proenzymes that are only activated in the small intestine. In the pancreas, vesicles store trypsin, chymotrypsin, and carboxypeptidase as trypsinogen, chymotrypsinogen, and procarboxypeptidase. Once released into the small intestine, an enzyme found in the wall of the small intestine, called enterokinase, binds to trypsinogen and converts it into its active form, trypsin. Trypsin then binds to chymotrypsinogen and procarboxypeptidase to convert it into the active chymotrypsin and carboxypeptidase. Trypsin, chymotrypsin, and carboxypeptidase break down large proteins into smaller peptides, a process called proteolysis. These smaller peptides are catabolized into their constituent amino acids by the brush border enzymes, aminopeptidase and dipeptidase. The free amino acids are then transported across the apical surface of the intestinal mucosa in a process that is mediated by secondary active transport using sodium-amino acid transporters. These transporters bind sodium and then bind the amino acid to transport it across the membrane. At the basal surface of the mucosal cells, the sodium and amino acid are released. The sodium can be reused in the transporter, whereas the amino acids are transferred into the bloodstream to be transported to the liver and cells throughout the body for protein synthesis.",True,Starvation,,,,
+7a8e720a-8b68-48db-bbf1-1e87cd0581e2,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"Freely available amino acids are used to create proteins. If amino acids exist in excess, the body has no capacity or mechanism for their storage; thus, they are converted into glucose or ketones, or they are decomposed. Amino acid decomposition results in hydrocarbons and nitrogenous waste. However, high concentrations of nitrogen are toxic as they produce ammonium ions. The urea cycle processes nitrogen and facilitates its excretion from the body.",True,Starvation,,,,
+6f0c4ca7-e2ee-493f-af02-4fce94dc97c3,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,Urea Cycle,False,Urea Cycle,,,,
+0412ecb6-ba81-4c74-a548-9a7c1b38e114,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated.",True,Urea Cycle,,,,
+d97a7269-f28f-4082-b370-16285284110d,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.4.2).",True,Urea Cycle,Figure 24.4.2,24.4 Protein Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2518_Urea_Cycle-scaled.jpg,"Figure 24.4.2 – Urea Cycle: Nitrogen is transaminated, creating ammonia and intermediates of the Krebs cycle. Ammonia is processed in the urea cycle to produce urea that is eliminated through the kidneys."
+e20e84d7-bbea-4d2e-9db6-1f6e32fe5240,https://open.oregonstate.education/aandp/,24.4 Protein Metabolism,https://open.oregonstate.education/aandp/chapter/24-4-protein-metabolism/,"Amino acids can also be used as a source of energy, especially in times of starvation. Because the processing of amino acids results in the creation of metabolic intermediates, including pyruvate, acetyl CoA, acetoacyl CoA, oxaloacetate, and α-ketoglutarate, amino acids can serve as a source of energy production through the Krebs cycle (Figure 24.4.3). Figure 24.4.4 summarizes the pathways of catabolism and anabolism for carbohydrates, lipids, and proteins.",True,Urea Cycle,Figure 24.4.3,24.4 Protein Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2519_Energy_From_Amino_Acids.jpg,Figure 24.4.3 – Energy from Amino Acids: Amino acids can be broken down into precursors for glycolysis or the Krebs cycle. Amino acids (in bold) can enter the cycle through more than one pathway.
+01ad7802-248d-48a3-a381-509fb7d64007,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors (Figure 24.3.1). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids.",True,Urea Cycle,Figure 24.3.1,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2511_A_Triglyceride_Molecule_a_Is_Broken_Down_Into_Monoglycerides_b.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).
+b920dc76-e609-484f-88bb-60df13f1243f,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Lipid metabolism begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule (see Figure 24.3.1b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant.",True,Urea Cycle,Figure 24.3.1,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2511_A_Triglyceride_Molecule_a_Is_Broken_Down_Into_Monoglycerides_b.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).
+26f87c4e-8cb9-465d-b9dd-c63fa285d74b,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Once the bile salts have emulsified the triglycerides, the pancreatic lipases down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons (Figure 24.3.2). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylomicrons are transported to the circulatory system. Once in the circulation, they can either go to the liver or be stored in fat cells (adipocytes) that comprise adipose (fat) tissue found throughout the body.",True,Urea Cycle,Figure 24.3.2,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2512_Chylomicrons_Contain_Triglycerides_Cholesterol_Molecules_and_Other_Lipids.jpg,"Figure 24.3.2 – Chylomicrons: Chylomicrons contain triglycerides, cholesterol molecules, and other apolipoproteins (protein molecules). They function to carry these water-insoluble molecules from the intestine, through the lymphatic system, and into the bloodstream, which carries the lipids to adipose tissue for storage."
+890d3fb2-8c34-4933-9535-9e93396e8fb7,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,Lipolysis,False,Lipolysis,,,,
+386fb610-4721-43c8-bdad-b689630a2cf9,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"To obtain energy from fat, triglycerides must first be broken down by hydrolysis into their two principal components, fatty acids and glycerol. This process, called lipolysis, takes place in the cytoplasm. The resulting fatty acids are oxidized by β-oxidation into acetyl CoA, which is used by the Krebs cycle. The glycerol that is released from triglycerides after lipolysis directly enters the glycolysis pathway as DHAP. Because one triglyceride molecule yields three fatty acid molecules with as much as 16 or more carbons in each one, fat molecules yield more energy than carbohydrates and are an important source of energy for the human body. Triglycerides yield more than twice the energy per unit mass when compared to carbohydrates and proteins. Therefore, when glucose levels are low, triglycerides can be converted into acetyl CoA molecules and used to generate ATP through aerobic respiration.",True,Lipolysis,,,,
+20f4138c-ebaf-4436-8a8f-64f9da67147c,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"The breakdown of fatty acids, called fatty acid oxidation or beta (β)-oxidation, begins in the cytoplasm, where fatty acids are converted into fatty acyl CoA molecules. This fatty acyl CoA combines with carnitine to create a fatty acyl carnitine molecule, which helps to transport the fatty acid across the mitochondrial membrane. Once inside the mitochondrial matrix, the fatty acyl carnitine molecule is converted back into fatty acyl CoA and then into acetyl CoA (Figure 24.3.3). The newly formed acetyl CoA enters the Krebs cycle and is used to produce ATP in the same way as acetyl CoA derived from pyruvate.",True,Lipolysis,Figure 24.3.3,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2513_The_Breakdown_of_Fatty_Acids-scaled.jpg,"Figure 24.3.3 – Breakdown of Fatty Acids: During fatty acid oxidation, triglycerides can be broken down into acetyl CoA molecules and used for energy when glucose levels are low."
+e54361ee-8f14-47c8-9cb5-4caea21af21e,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,Ketogenesis,False,Ketogenesis,,,,
+6d4940c3-d491-4302-ae2d-a98cbc2749fe,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"If excessive acetyl CoA is created from the oxidation of fatty acids and the Krebs cycle is overloaded and cannot handle it, the acetyl CoA is diverted to create ketone bodies. These ketone bodies can serve as a fuel source if glucose levels are too low in the body. Ketones serve as fuel in times of prolonged starvation or when patients suffer from uncontrolled diabetes and cannot utilize most of the circulating glucose. In both cases, fat stores are liberated to generate energy through the Krebs cycle and will generate ketone bodies when too much acetyl CoA accumulates.",True,Ketogenesis,,,,
+3837e37d-bbfa-4b8e-b8b6-95af7d47f4e0,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"In this ketone synthesis reaction, excess acetyl CoA is converted into hydroxymethylglutaryl CoA (HMG CoA). HMG CoA is a precursor of cholesterol and is an intermediate that is subsequently converted into β-hydroxybutyrate, the primary ketone body in the blood (Figure 24.3.4).",True,Ketogenesis,Figure 24.3.4,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2514_Ketogenesis.jpg,"Figure 24.3.4 – Ketogenesis: Excess acetyl CoA is diverted from the Krebs cycle to the ketogenesis pathway. This reaction occurs in the mitochondria of liver cells. The result is the production of β-hydroxybutyrate, the primary ketone body found in the blood."
+8517224d-59a1-48db-9b93-cfb95ca97341,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,Ketone Body Oxidation,False,Ketone Body Oxidation,,,,
+159e8d45-9b9c-4084-8164-b9f88ccadd1c,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Organs that have classically been thought to be dependent solely on glucose, such as the brain, can actually use ketones as an alternative energy source. This keeps the brain functioning when glucose is limited. When ketones are produced faster than they can be used, they can be broken down into CO2 and acetone. The acetone is removed by exhalation. One symptom of ketogenesis is that the patient’s breath smells sweet like alcohol. This effect provides one way of telling if a diabetic is properly controlling the disease. The carbon dioxide produced can acidify the blood, leading to diabetic ketoacidosis, a dangerous condition in diabetics.",True,Ketone Body Oxidation,,,,
+d2071756-ed36-4df1-b2fe-5463b2ea55fd,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Ketones oxidize to produce energy for the brain. beta (β)-hydroxybutyrate is oxidized to acetoacetate and NADH is released. An HS-CoA molecule is added to acetoacetate, forming acetoacetyl CoA. The carbon within the acetoacetyl CoA that is not bonded to the CoA then detaches, splitting the molecule in two. This carbon then attaches to another free HS-CoA, resulting in two acetyl CoA molecules. These two acetyl CoA molecules are then processed through the Krebs cycle to generate energy (Figure 24.3.5).",True,Ketone Body Oxidation,Figure 24.3.5,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2515_Ketone_Oxidation.jpg,"Figure 24.3.5 – Ketone Oxidation: When glucose is limited, ketone bodies can be oxidized to produce acetyl CoA to be used in the Krebs cycle to generate energy."
+3c0b7dc0-fa32-4b66-b912-8c34d7f41952,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,Lipogenesis,False,Lipogenesis,,,,
+24c5e97c-72e8-4218-a07d-d2dc1efaa725,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"When glucose levels are plentiful, the excess acetyl CoA generated by glycolysis can be converted into fatty acids, triglycerides, cholesterol, steroids, and bile salts. This process, called lipogenesis, creates lipids (fat) from the acetyl CoA and takes place in the cytoplasm of adipocytes (fat cells) and hepatocytes (liver cells). When you eat more glucose or carbohydrates than your body needs, your system uses acetyl CoA to turn the excess into fat. Although there are several metabolic sources of acetyl CoA, it is most commonly derived from glycolysis. Acetyl CoA availability is significant, because it initiates lipogenesis. Lipogenesis begins with acetyl CoA and advances by the subsequent addition of two carbon atoms from another acetyl CoA; this process is repeated until fatty acids are the appropriate length. Because this is a bond-creating anabolic process, ATP is consumed. However, the creation of triglycerides and lipids is an efficient way of storing the energy available in carbohydrates. Triglycerides and lipids, both high-energy molecules, are stored in adipose tissue until they are needed.",True,Lipogenesis,,,,
+8a199751-3180-45d0-a5b7-b2647f721571,https://open.oregonstate.education/aandp/,24.3 Lipid Metabolism,https://open.oregonstate.education/aandp/chapter/24-3-lipid-metabolism/,"Although lipogenesis occurs in the cytoplasm, the necessary acetyl CoA is created in the mitochondria and cannot be transported across the mitochondrial membrane. To solve this problem, pyruvate is converted into both oxaloacetate and acetyl CoA. Two different enzymes are required for these conversions. Oxaloacetate forms via the action of pyruvate carboxylase, whereas the action of pyruvate dehydrogenase creates acetyl CoA. Oxaloacetate and acetyl CoA combine to form citrate, which can cross the mitochondrial membrane and enter the cytoplasm. In the cytoplasm, citrate is converted back into oxaloacetate and acetyl CoA. Oxaloacetate is converted into malate and then into pyruvate. Pyruvate crosses back across the mitochondrial membrane to wait for the next cycle of lipogenesis. The acetyl CoA is converted into malonyl CoA that is used to synthesize fatty acids. Figure 24.3.6 summarizes the pathways of lipid metabolism.",True,Lipogenesis,Figure 24.3.6,24.3 Lipid Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2516_Lipid_Metabolism.jpg,Figure 24.3.6 – Lipid Metabolism: Lipids may follow one of several pathways during metabolism. Glycerol and fatty acids follow different pathways.
+6aa0f074-8169-4164-a441-67f2520ce809,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen atoms. The family of carbohydrates includes both simple and complex sugars. Glucose and fructose are examples of simple sugars, and starch, glycogen, and cellulose are all examples of complex sugars. The complex sugars are also called polysaccharides and are made of multiple monosaccharide molecules. Polysaccharides serve as energy storage (e.g., starch and glycogen) and as structural components (e.g., chitin in insects and cellulose in plants).",True,Lipogenesis,,,,
+1b4d6f86-9f98-4bc9-90ed-db5b6006ac38,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"During digestion, carbohydrates are broken down into simple, soluble sugars that can be transported across the intestinal wall into the circulatory system to be transported throughout the body. Carbohydrate digestion begins in the mouth with the action of salivary amylase on starches, continues in the duodenum with the action of pancreatic amylase, and ends with monosaccharides being absorbed across the epithelium of the small intestine. Once the absorbed monosaccharides are transported to the tissues, the process of cellular respiration begins (Figure 24.2.1). The goal of cellular respiration is to produce ATP for use by the body to power physiological processes. To start the process, a glucose molecule will get modified to two pyruvate molecules in the metabolic pathway called glycolysis. When oxygen is available, the pyruvate molecules will then be converted to acetyl CoA which enters the mitochondria and enters the citric acid cycle. Both glycolysis and the citric acid cycle produce a small amount of ATP (2 ATP per pathway), but the majority of the ATP produced by aerobic metabolism is achieved when the products of glyolysis and the citric acid, NADH and FADH2, carry their electrons to the electron transport chain. The electron transport chain transfers electrons through electron carriers, ultimately to oxygen in a process called oxidative phosphorylaton. This final process of cellular respiration harnesses the energy delivered by NADH and FADH2 to drive ATP synthase to produce 34 ATP per glucose. This first section will focus first on glycolysis, a process where the monosaccharide glucose is oxidized, releasing the energy stored in its bonds to produce ATP.",True,Lipogenesis,Figure 24.2.1,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2503_Cellular_Respiration.jpg,"Figure 24.2.1 – Cellular Respiration: Cellular respiration oxidizes glucose molecules through glycolysis, the Krebs cycle, and oxidative phosphorylation to produce ATP."
+7d361344-bc12-4811-acb8-63f3197e4e15,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,Glycolysis,False,Glycolysis,,,,
+bc08bdd7-b014-49c8-90c9-20025c93c7f3,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Glucose is the body’s most readily available source of energy. After digestive processes break polysaccharides down into monosaccharides, including glucose, the monosaccharides are transported across the wall of the small intestine and into the circulatory system, which transports them to the liver. In the liver, hepatocytes either pass the glucose on through the circulatory system or store excess glucose as glycogen. Cells in the body take up the circulating glucose in response to insulin and, through a series of reactions called glycolysis, transfer some of the energy in glucose to ADP to form ATP (Figure 24.2.2). The last step in glycolysis produces the product pyruvate.",True,Glycolysis,Figure 24.2.2,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2504_Glycosis_Overview-scaled.jpg,"Figure 24.2.2 – Glycolysis Overview: During the energy-consuming phase of glycolysis, two ATPs are consumed, transferring two phosphates to the glucose molecule. The glucose molecule then splits into two three-carbon compounds, each containing a phosphate. During the second phase, an additional phosphate is added to each of the three-carbon compounds. The energy for this endergonic reaction is provided by the removal (oxidation) of two electrons from each three-carbon compound. During the energy-releasing phase, the phosphates are removed from both three-carbon compounds and used to produce four ATP molecules."
+a22e42d6-c450-47bf-a8bd-042ee25bb924,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Glycolysis begins with the phosphorylation of glucose by hexokinase to form glucose-6-phosphate. This step uses one ATP, which is the donor of the phosphate group. Under the action of phosphofructokinase, glucose-6-phosphate is converted into fructose-6-phosphate. At this point, a second ATP donates its phosphate group, forming fructose-1,6-bisphosphate. This six-carbon sugar is split to form two phosphorylated three-carbon molecules, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate, which are both converted into glyceraldehyde-3-phosphate. The glyceraldehyde-3-phosphate is further phosphorylated with groups donated by dihydrogen phosphate present in the cell to form the three-carbon molecule 1,3-bisphosphoglycerate. The energy of this reaction comes from the oxidation of (removal of electrons from) glyceraldehyde-3-phosphate. In a series of reactions leading to pyruvate, the two phosphate groups are then transferred to two ADPs to form two ATPs. Thus, glycolysis uses two ATPs but generates four ATPs, yielding a net gain of two ATPs and two molecules of pyruvate. In the presence of oxygen, pyruvate continues on to the Krebs cycle (also called the citric acid cycle or tricarboxylic acid cycle (TCA), where additional energy is extracted and passed on.",True,Glycolysis,,,,
+04d405b1-c78e-4bf0-bc66-a5f1e486b068,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Glycolysis can be divided into two phases: energy consuming (also called chemical priming) and energy yielding. The first phase is the energy-consuming phase, so it requires two ATP molecules to start the reaction for each molecule of glucose. However, the end of the reaction produces four ATPs, resulting in a net gain of two ATP energy molecules.",True,Glycolysis,,,,
+3a83e0a9-5eac-4954-b304-58fc4f134be0,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,Glycolysis can be expressed as the following equation:,False,Glycolysis can be expressed as the following equation:,,,,
+1b3e49e8-fc16-4328-9e9f-5d681acf2067,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"This equation states that glucose, in combination with ATP (the energy source), NAD+ (a coenzyme that serves as an electron acceptor), and inorganic phosphate, breaks down into two pyruvate molecules, generating four ATP molecules—for a net yield of two ATP—and two energy-containing NADH coenzymes. The NADH that is produced in this process will be used later to produce ATP in the mitochondria. Importantly, by the end of this process, one glucose molecule generates two pyruvate molecules, two high-energy ATP molecules, and two electron-carrying NADH molecules.",True,Glycolysis can be expressed as the following equation:,,,,
+5eba726d-1430-4117-a971-ae1e4725a651,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The following discussions of glycolysis include the enzymes responsible for the reactions. When glucose enters a cell, the enzyme hexokinase (or glucokinase, in the liver) rapidly adds a phosphate to convert it into glucose-6-phosphate. A kinase is a type of enzyme that adds a phosphate molecule to a substrate (in this case, glucose, but it can be true of other molecules also). This conversion step requires one ATP and essentially traps the glucose in the cell, preventing it from passing back through the plasma membrane, thus allowing glycolysis to proceed. It also functions to maintain a concentration gradient with higher glucose levels in the blood than in the tissues. By establishing this concentration gradient, the glucose in the blood will be able to flow from an area of high concentration (the blood) into an area of low concentration (the tissues) to be either used or stored. Hexokinase is found in nearly every tissue in the body. Glucokinase, on the other hand, is expressed in tissues that are active when blood glucose levels are high, such as the liver. Hexokinase has a higher affinity for glucose than glucokinase and therefore is able to convert glucose at a faster rate than glucokinase. This is important when levels of glucose are very low in the body, as it allows glucose to travel preferentially to those tissues that require it more.",True,Glycolysis can be expressed as the following equation:,,,,
+72daa74f-2354-4e7d-9ec5-768ad7906b43,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"In the next step of the first phase of glycolysis, the enzyme glucose-6-phosphate isomerase converts glucose-6-phosphate into fructose-6-phosphate. Like glucose, fructose is also a six carbon-containing sugar. The enzyme phosphofructokinase-1 then adds one more phosphate to convert fructose-6-phosphate into fructose-1-6-bisphosphate, another six-carbon sugar, using another ATP molecule. Aldolase then breaks down this fructose-1-6-bisphosphate into two three-carbon molecules, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. The triosephosphate isomerase enzyme then converts dihydroxyacetone phosphate into a second glyceraldehyde-3-phosphate molecule. Therefore, by the end of this chemical-priming or energy-consuming phase, one glucose molecule is broken down into two glyceraldehyde-3-phosphate molecules.",True,Glycolysis can be expressed as the following equation:,,,,
+a8762967-a190-4c09-b1d3-eeb4a859dddb,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The second phase of glycolysis, the energy-yielding phase, creates the energy that is the product of glycolysis. Glyceraldehyde-3-phosphate dehydrogenase converts each three-carbon glyceraldehyde-3-phosphate produced during the energy-consuming phase into 1,3-bisphosphoglycerate. This reaction releases an electron that is then picked up by NAD+ to create an NADH molecule. NADH is a high-energy molecule, like ATP, but unlike ATP, it is not used as energy currency by the cell. Because there are two glyceraldehyde-3-phosphate molecules, two NADH molecules are synthesized during this step. Each 1,3-bisphosphoglycerate is subsequently dephosphorylated (i.e., a phosphate is removed) by phosphoglycerate kinase into 3-phosphoglycerate. Each phosphate released in this reaction can convert one molecule of ADP into one high-energy ATP molecule, resulting in a gain of two ATP molecules.",True,Glycolysis can be expressed as the following equation:,,,,
+44be8396-75c0-4201-839f-4f5b9431e78d,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,The enzyme phosphoglycerate mutase then converts the 3-phosphoglycerate molecules into 2-phosphoglycerate. The enolase enzyme then acts upon the 2-phosphoglycerate molecules to convert them into phosphoenolpyruvate molecules. The last step of glycolysis involves the dephosphorylation of the two phosphoenolpyruvate molecules by pyruvate kinase to create two pyruvate molecules and two ATP molecules.,True,Glycolysis can be expressed as the following equation:,,,,
+f1e6a9cc-9161-48e8-947b-652949ffc5d1,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"In summary, one glucose molecule breaks down into two pyruvate molecules, and creates two net ATP molecules and two NADH molecules by glycolysis. Therefore, glycolysis generates energy for the cell and creates pyruvate molecules that can be processed further through the aerobic Krebs cycle (also called the citric acid cycle or tricarboxylic acid cycle); converted into lactic acid or alcohol (in yeast) by fermentation; or used later for the synthesis of glucose through gluconeogenesis.",True,Glycolysis can be expressed as the following equation:,,,,
+1431446b-ec16-47d5-87ad-efc76170e5b7,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,False,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,,,,
+b25ad104-5b60-41bb-a4ef-a7383ef8e1ae,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The pyruvate molecules generated during glycolysis are transported across the mitochondrial membrane into the inner mitochondrial matrix, where they are metabolized by enzymes in a pathway called the Krebs cycle (Figure 24.2.4). The Krebs cycle is also commonly called the citric acid cycle or the tricarboxylic acid (TCA) cycle. During the Krebs cycle, high-energy molecules, including ATP, NADH, and FADH2, are created. NADH and FADH2 then pass electrons through the electron transport chain in the mitochondria to generate more ATP molecules.",True,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,Figure 24.2.4,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2507_The_Krebs_Cycle.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules."
+747822ad-89f4-43c0-b6df-1ac631c84a65,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The three-carbon pyruvate molecule generated during glycolysis moves from the cytoplasm into the mitochondrial matrix, where it is converted by the enzyme pyruvate dehydrogenase into a two-carbon acetyl coenzyme A (acetyl CoA) molecule. This reaction is an oxidative decarboxylation reaction. It converts the three-carbon pyruvate into a two-carbon acetyl CoA molecule, releasing carbon dioxide and transferring two electrons that combine with NAD+ to form NADH. Acetyl CoA enters the Krebs cycle by combining with a four-carbon molecule, oxaloacetate, to form the six-carbon molecule citrate, or citric acid, at the same time releasing the coenzyme A molecule.",True,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,,,,
+2673bafb-84ac-415e-98db-e3e08594f7e8,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The six-carbon citrate molecule is systematically converted to a five-carbon molecule and then a four-carbon molecule, ending with oxaloacetate, the beginning of the cycle. Along the way, each citrate molecule will produce one ATP, one FADH2, and three NADH. The FADH2 and NADH will enter the oxidative phosphorylation system located in the inner mitochondrial membrane. In addition, the Krebs cycle supplies the starting materials to process and break down proteins and fats.",True,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,,,,
+3f7582ea-f269-4c12-800a-dbb7b2f63f66,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"To start the Krebs cycle, citrate synthase combines acetyl CoA and oxaloacetate to form a six-carbon citrate molecule; CoA is subsequently released and can combine with another pyruvate molecule to begin the cycle again. The aconitase enzyme converts citrate into isocitrate. In two successive steps of oxidative decarboxylation, two molecules of CO2 and two NADH molecules are produced when isocitrate dehydrogenase converts isocitrate into the five-carbon α-ketoglutarate, which is then catalyzed and converted into the four-carbon succinyl CoA by α-ketoglutarate dehydrogenase. The enzyme succinyl CoA dehydrogenase then converts succinyl CoA into succinate and forms the high-energy molecule GTP, which transfers its energy to ADP to produce ATP. Succinate dehydrogenase then converts succinate into fumarate, forming a molecule of FADH2. Fumarase then converts fumarate into malate, which malate dehydrogenase then converts back into oxaloacetate while reducing NAD+ to NADH. Oxaloacetate is then ready to combine with the next acetyl CoA to start the Krebs cycle again (see Figure 24.2.4). For each turn of the cycle, three NADH, one ATP (through GTP), and one FADH2 are created. Each carbon of pyruvate is converted into CO2, which is released as a byproduct of oxidative (aerobic) respiration.",True,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,Figure 24.2.4,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2507_The_Krebs_Cycle.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules."
+fd919cb5-4115-4c42-9c13-f47e6163b787,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,Oxidative Phosphorylation and the Electron Transport Chain,False,Oxidative Phosphorylation and the Electron Transport Chain,,,,
+c74ffc00-7aec-42ae-ab88-c562a2437d5d,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The electron transport chain (ETC) uses the NADH and FADH2 produced by the Krebs cycle to generate ATP. Electrons from NADH and FADH2 are transferred through protein complexes embedded in the inner mitochondrial membrane by a series of enzymatic reactions. The electron transport chain consists of a series of four enzyme complexes (Complex I – Complex IV) and two coenzymes (ubiquinone and Cytochrome c), which act as electron carriers and proton pumps used to transfer H+ ions into the space between the inner and outer mitochondrial membranes (Figure 24.2.5). The ETC couples the transfer of electrons between a donor (like NADH) and an electron acceptor (like O2) with the transfer of protons (H+ ions) across the inner mitochondrial membrane, enabling the process of oxidative phosphorylation. In the presence of oxygen, energy is passed, stepwise, through the electron carriers to collect gradually the energy needed to attach a phosphate to ADP and produce ATP. The role of molecular oxygen, O2, is as the terminal electron acceptor for the ETC. This means that once the electrons have passed through the entire ETC, they must be passed to another, separate molecule. These electrons, O2, and H+ ions from the matrix combine to form new water molecules. This is the basis for your need to breathe in oxygen. Without oxygen, electron flow through the ETC ceases.",True,Oxidative Phosphorylation and the Electron Transport Chain,Figure 24.2.5,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2508_The_Electron_Transport_Chain.jpg,Figure 24.2.5 – Electron Transport Chain: The electron transport chain is a series of electron carriers and ion pumps that are used to pump H+ ions out of the inner mitochondrial matrix.
+debe9ce5-6f9f-492b-a7d1-c81a2fcf8dee,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"The electrons released from NADH and FADH2 are passed along the chain by each of the carriers, which are reduced when they receive the electron and oxidized when passing it on to the next carrier. Each of these reactions releases a small amount of energy, which is used to pump H+ ions across the inner membrane. The accumulation of these protons in the space between the membranes creates a proton gradient with respect to the mitochondrial matrix.",True,Oxidative Phosphorylation and the Electron Transport Chain,,,,
+94f9b4ef-ae7d-4cfd-8ac2-112ccb5f342a,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Also embedded in the inner mitochondrial membrane is an amazing protein pore complex called ATP synthase. Effectively, it is a turbine that is powered by the flow of H+ ions across the inner membrane down a gradient and into the mitochondrial matrix. As the H+ ions traverse the complex, the shaft of the complex rotates. This rotation enables other portions of ATP synthase to encourage ADP and Pi to create ATP. In accounting for the total number of ATP produced per glucose molecule through aerobic respiration, it is important to remember the following points:",True,Oxidative Phosphorylation and the Electron Transport Chain,,,,
+c2a14cf6-30a6-4d80-9aa5-98ca28ebf97e,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Therefore, for every glucose molecule that enters aerobic respiration, a net total of 36 ATPs are produced (Figure 24.2.6).",True,Oxidative Phosphorylation and the Electron Transport Chain,Figure 24.2.6,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2509_Carbohydrate_Metabolism-scaled.jpg,"Figure 24.2.6 – Carbohydrate Metabolism: Carbohydrate metabolism involves glycolysis, the Krebs cycle, and the electron transport chain."
+fe99d784-418c-447d-b155-e74ab5873726,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,Gluconeogenesis,False,Gluconeogenesis,,,,
+15456db4-f990-41c5-9980-bb5c0b1d88d4,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Gluconeogenesis is the synthesis of new glucose molecules from pyruvate, lactate, glycerol, or the amino acids alanine or glutamine. This process takes place primarily in the liver during periods of low glucose, that is, under conditions of fasting, starvation, and low carbohydrate diets. So, the question can be raised as to why the body would create something it has just spent a fair amount of effort to break down? Certain key organs, including the brain, can use only glucose as an energy source; therefore, it is essential that the body maintain a minimum blood glucose concentration. When the blood glucose concentration falls below that certain point, new glucose is synthesized by the liver to raise the blood concentration to normal.",True,Gluconeogenesis,,,,
+ae5c9c26-fbd0-4345-a08c-14b677d357cd,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"Gluconeogenesis is not simply the reverse of glycolysis. There are some important differences (Figure 24.2.7). Pyruvate is a common starting material for gluconeogenesis. First, the pyruvate is converted into oxaloacetate. Oxaloacetate then serves as a substrate for the enzyme phosphoenolpyruvate carboxykinase (PEPCK), which transforms oxaloacetate into phosphoenolpyruvate (PEP). From this step, gluconeogenesis is nearly the reverse of glycolysis. PEP is converted back into 2-phosphoglycerate, which is converted into 3-phosphoglycerate. Then, 3-phosphoglycerate is converted into 1,3 bisphosphoglycerate and then into glyceraldehyde-3-phosphate. Two molecules of glyceraldehyde-3-phosphate then combine to form fructose-1-6-bisphosphate, which is converted into fructose 6-phosphate and then into glucose-6-phosphate. Finally, a series of reactions generates glucose itself. In gluconeogenesis (as compared to glycolysis), the enzyme hexokinase is replaced by glucose-6-phosphatase, and the enzyme phosphofructokinase-1 is replaced by fructose-1,6-bisphosphatase. This helps the cell to regulate glycolysis and gluconeogenesis independently of each other.",True,Gluconeogenesis,Figure 24.2.7,,,
+82df9b29-e5d8-4df4-bf29-977dc2f4e37a,https://open.oregonstate.education/aandp/,24.2 Carbohydrate Metabolism,https://open.oregonstate.education/aandp/chapter/24-2-carbohydrate-metabolism/,"As will be discussed as part of lipolysis, fats can be broken down into glycerol, which can be phosphorylated to form dihydroxyacetone phosphate or DHAP. DHAP can either enter the glycolytic pathway or be used by the liver as a substrate for gluconeogenesis.",True,Gluconeogenesis,,,,
+81884056-b3e0-479c-8310-6ebc2d5f7436,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Metabolic processes are constantly taking place in the body. Metabolism is the sum of all of the chemical reactions that are involved in catabolism and anabolism. The reactions governing the breakdown of food to obtain energy are called catabolic reactions. Conversely, anabolic reactions use the energy produced by catabolic reactions to synthesize larger molecules from smaller ones, such as when the body forms proteins by stringing together amino acids. Both sets of reactions are critical to maintaining life.",True,Gluconeogenesis,,,,
+68c583cf-20ea-4572-9dcc-be7a2923ad62,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Because catabolic reactions produce energy and anabolic reactions use energy, ideally, energy usage would balance the energy produced. If the net energy change is positive (catabolic reactions release more energy than the anabolic reactions use), then the body stores the excess energy by building fat molecules for long-term storage. On the other hand, if the net energy change is negative (catabolic reactions release less energy than anabolic reactions use), the body uses stored energy to compensate for the deficiency of energy released by catabolism.",True,Gluconeogenesis,,,,
+cca98760-4ab9-4b31-9703-de7b5d59c781,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,Catabolic Reactions,False,Catabolic Reactions,,,,
+1b0ae55b-89fe-475e-94c6-7f8396ca1699,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Catabolic reactions break down large organic molecules into smaller molecules, releasing the energy contained in the chemical bonds. These energy releases (conversions) are not 100 percent efficient. The amount of energy released is less than the total amount contained in the molecule. Approximately 40 percent of energy yielded from catabolic reactions is directly transferred to the high-energy molecule adenosine triphosphate (ATP). ATP, the energy currency of cells, can be used immediately to power molecular machines that support cell, tissue, and organ function. This includes building new tissue and repairing damaged tissue. ATP can also be stored to fulfill future energy demands. The remaining 60 percent of the energy released from catabolic reactions is given off as heat, which tissues and body fluids absorb.",True,Catabolic Reactions,,,,
+d71df0fd-28e1-438f-a26a-f2bc7103bb0d,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Structurally, ATP molecules consist of an adenine, a ribose, and three phosphate groups (Figure 24.1.1). The chemical bond between the second and third phosphate groups, termed a high-energy bond, represents the greatest source of energy in a cell. It is the first bond that catabolic enzymes break when cells require energy to do work. The products of this reaction are a molecule of adenosine diphosphate (ADP) and a lone phosphate group (Pi). ATP, ADP, and Pi are constantly being cycled through reactions that build ATP and store energy, and reactions that break down ATP and release energy.",True,Catabolic Reactions,Figure 24.1.1,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2501_The_Structure_of_ATP_Molecules.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions."
+65d8da7c-500a-4380-bc4c-603f1877bce2,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"The energy from ATP drives all bodily functions, such as contracting muscles, maintaining the electrical potential of nerve cells, and absorbing food in the gastrointestinal tract. The metabolic reactions that produce ATP come from various sources (Figure 24.1.2).",True,Catabolic Reactions,Figure 24.1.2,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2502_Catabolic_Reactions.jpg,"Figure 24.1.2 – Sources of ATP: During catabolic reactions, proteins are broken down into amino acids, lipids are broken down into fatty acids, and polysaccharides are broken down into monosaccharides. These building blocks are then used for the synthesis of molecules in anabolic reactions."
+d3a7a739-0cc6-4f09-bd7f-3c13ac821758,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Of the four major macromolecular groups (carbohydrates, lipids, proteins, and nucleic acids) that are processed by digestion, carbohydrates are considered the most common source of energy to fuel the body. They take the form of either complex carbohydrates, polysaccharides like starch and glycogen, or simple sugars (monosaccharides) like glucose and fructose. Sugar catabolism breaks polysaccharides down into their individual monosaccharides. Among the monosaccharides, glucose is the most common fuel for ATP production in cells, and as such, there are a number of endocrine control mechanisms to regulate glucose concentration in the bloodstream. Excess glucose is either stored as an energy reserve in the liver and skeletal muscles as the complex polymer glycogen, or it is converted into fat (triglyceride) in adipose cells (adipocytes).",True,Catabolic Reactions,,,,
+5849f685-335f-41d5-ad90-ed18b01d1612,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Among the lipids (fats), triglycerides are most often used for energy via a metabolic process called β-oxidation. About one-half of excess fat is stored in adipocytes that accumulate in the subcutaneous tissue under the skin, whereas the rest is stored in adipocytes in other tissues and organs.",True,Catabolic Reactions,,,,
+5852e9a6-25cc-4c50-9697-41df37f4c123,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Proteins, which are polymers, can be broken down into their monomers, individual amino acids. Amino acids can be used as building blocks of new proteins or broken down further for the production of ATP. When one is chronically starving, this use of amino acids for energy production can lead to a wasting away of the body, as more and more proteins are broken down.",True,Catabolic Reactions,,,,
+2f9273c5-0e7a-4071-b038-925e92d9ab0e,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Nucleic acids are present in most of the foods you eat. During digestion, nucleic acids including DNA and various RNAs are broken down into their constituent nucleotides. These nucleotides are readily absorbed and transported throughout the body to be used by individual cells during nucleic acid metabolism.",True,Catabolic Reactions,,,,
+a625e093-5c85-4d80-ad10-454cf4eb405c,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,Anabolic Reactions,False,Anabolic Reactions,,,,
+d70cc584-f3fe-4ca5-ac00-a6a52cd8fc5e,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"In contrast to catabolic reactions, anabolic reactions involve the joining of smaller molecules into larger ones. Anabolic reactions combine monosaccharides to form polysaccharides, fatty acids to form triglycerides, amino acids to form proteins, and nucleotides to form nucleic acids. These processes require energy in the form of ATP molecules generated by catabolic reactions. Anabolic reactions, also called biosynthesis reactions, create new molecules that form new cells and tissues, and revitalize organs.",True,Anabolic Reactions,,,,
+b0bb80f4-c412-49bb-a631-a38120f15cb3,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,Hormonal Regulation of Metabolism,False,Hormonal Regulation of Metabolism,,,,
+558f5689-5b17-45ae-9fd4-2ebcc7c311b2,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Catabolic and anabolic hormones in the body help regulate metabolic processes. Catabolic hormones stimulate the breakdown of molecules and the production of energy. These include cortisol, glucagon, adrenaline/epinephrine, and cytokines. All of these hormones are mobilized at specific times to meet the needs of the body. Anabolic hormones are required for the synthesis of molecules and include growth hormone, insulin-like growth factor, insulin, testosterone, and estrogen. Table 24.1 summarizes the function of each of the catabolic hormones and Table 24.2 summarizes the functions of the anabolic hormones.",True,Hormonal Regulation of Metabolism,,,,
+e90955b0-9c8e-4a94-9e6b-1666a8569bd6,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,Oxidation-Reduction Reactions,False,Oxidation-Reduction Reactions,,,,
+31d904c2-c8d4-40f8-bd7f-79f201fc9c98,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"The chemical reactions underlying metabolism involve the transfer of electrons from one compound to another by processes catalyzed by enzymes. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a hydrogen atom, in the form of a hydrogen ion (H+) and an electron, breaking the molecule into smaller parts. The loss of an electron, or oxidation, releases a small amount of energy; both the electron and the energy are then passed to another molecule in the process of reduction, or the gaining of an electron. These two reactions always happen together in an oxidation-reduction reaction (also called a redox reaction)—when an electron is passed between molecules, the donor is oxidized and the recipient is reduced. Oxidation-reduction reactions often happen in a series, so that a molecule that is reduced is subsequently oxidized, passing on not only the electron it just received but also the energy it received. As the series of reactions progresses, energy accumulates that is used to combine Pi and ADP to form ATP, the high-energy molecule that the body uses for fuel.",True,Oxidation-Reduction Reactions,,,,
+73c8f638-b2d9-4e03-a7e1-edb6894915f3,https://open.oregonstate.education/aandp/,24.1 Overview of Metabolic Reactions,https://open.oregonstate.education/aandp/chapter/24-1-overview-of-metabolic-reactions/,"Oxidation-reduction reactions are catalyzed by enzymes that trigger the removal of hydrogen atoms. Coenzymes work with enzymes and accept hydrogen atoms. The two most common coenzymes of oxidation-reduction reactions are nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). Their respective reduced coenzymes are NADH and FADH2, which are energy-containing molecules used to transfer energy during the creation of ATP.",True,Oxidation-Reduction Reactions,,,,
+cffb5033-7853-4566-a487-1545455c6043,https://open.oregonstate.education/aandp/,24.0 Introduction,https://open.oregonstate.education/aandp/chapter/24-0-introduction/,"Eating is essential to life. Many of us look to eating as not only a necessity, but also a pleasure. You may have been told since childhood to start the day with a good breakfast to give you the energy to get through most of the day. You most likely have heard about the importance of a balanced diet, with plenty of fruits and vegetables. But what does this all mean to your body and the physiological processes it carries out each day? You need to absorb a range of nutrients so that your cells have the building blocks for metabolic processes that release the energy for the cells to carry out their daily jobs, to manufacture new proteins, cells, and body parts, and to recycle materials in the cell.",True,Oxidation-Reduction Reactions,,,,
+76ffb395-b78d-4614-aeeb-0716b9e47079,https://open.oregonstate.education/aandp/,24.0 Introduction,https://open.oregonstate.education/aandp/chapter/24-0-introduction/,"This chapter will take you through some of the chemical reactions essential to life, the sum of which is referred to as metabolism. The focus of these discussions will be anabolic (building up) reactions and catabolic (breaking down) reactions. You will examine the various chemical reactions that are important to sustain life, including why you must have oxygen, how mitochondria transfer energy, and the importance of certain “metabolic” hormones and vitamins.",True,Oxidation-Reduction Reactions,,,,
+9d2a0c22-c38a-493e-a508-459c6a49ffcd,https://open.oregonstate.education/aandp/,24.0 Introduction,https://open.oregonstate.education/aandp/chapter/24-0-introduction/,"Metabolism varies, depending on age, gender, activity level, fuel consumption, and lean body mass. Your own metabolic rate fluctuates throughout life. By modifying your diet and exercise regimen, you can increase both lean body mass and metabolic rate. Factors affecting metabolism also play important roles in controlling muscle mass. Aging is known to decrease the metabolic rate by as much as 5 percent per year. Additionally, because men tend have more lean muscle mass then women, their basal metabolic rate (metabolic rate at rest) is higher; therefore, men tend to burn more calories than women do. Lastly, an individual’s inherent metabolic rate is a function of the proteins and enzymes derived from their genetic background. Thus, your genes play a big role in your metabolism. Nonetheless, each person’s body engages in the same overall metabolic processes.",True,Oxidation-Reduction Reactions,,,,
+8bcdca8e-fede-4532-831b-3807650d7c5b,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"As you have learned, the process of mechanical digestion is relatively simple. It involves the physical breakdown of food but does not alter its chemical makeup. Chemical digestion, on the other hand, is a complex process that reduces food into its chemical building blocks, which are then absorbed to nourish the cells of the body (Figure 23.7.1). In this section, you will look more closely at the processes of chemical digestion and absorption.",True,Oxidation-Reduction Reactions,Figure 23.7.1,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2426_Mechanical_and_Chemical_DigestionN.jpg,Figure 23.7.1 – Digestion and Absorption: Digestion begins in the mouth and continues as food travels through the small intestine. Most absorption occurs in the small intestine.
+0b1cfb85-5a8d-41e6-acad-a01265831fc0,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Chemical Digestion,False,Chemical Digestion,,,,
+8eb5c646-d159-463f-ba10-062ff7ffa589,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Large food molecules (for example, proteins, lipids, nucleic acids, and starches) must be broken down into subunits that are small enough to be absorbed by the lining of the alimentary canal. This is accomplished by enzymes through hydrolysis. The many enzymes involved in chemical digestion are summarized in Table 23.8.",True,Chemical Digestion,,,,
+2c6c43f4-90cf-4d04-8210-f807b2c4d323,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Carbohydrate Digestion,False,Carbohydrate Digestion,,,,
+8469032a-167f-4235-8208-c0d800a5fd50,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The average American diet is about 50 percent carbohydrates, which may be classified according to the number of monomers they contain of simple sugars (monosaccharides and disaccharides) and/or complex sugars (polysaccharides). Glucose, galactose, and fructose are the three monosaccharides that are commonly consumed and are readily absorbed. Your digestive system is also able to break down the disaccharide sucrose (regular table sugar: glucose + fructose), lactose (milk sugar: glucose + galactose), and maltose (grain sugar: glucose + glucose), and the polysaccharides glycogen and starch (chains of monosaccharides). Your bodies do not produce enzymes that can break down most fibrous polysaccharides, such as cellulose. While indigestible polysaccharides do not provide any nutritional value, they do provide dietary fiber, which helps propel food through the alimentary canal.",True,Carbohydrate Digestion,,,,
+fc5dbdcd-5909-4b50-bcb4-d3cb81ba6c56,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,The chemical digestion of starches begins in the mouth and has been reviewed above.,True,Carbohydrate Digestion,,,,
+eea843c6-37b6-4293-a28b-aa4a658a1878,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"In the small intestine, pancreatic amylase does the ‘heavy lifting’ for starch and carbohydrate digestion (Figure 23.7.2). After amylases break down starch into smaller fragments, the brush border enzyme α-dextrinase starts working on α-dextrin, breaking off one glucose unit at a time. Three brush border enzymes hydrolyze sucrose, lactose, and maltose into monosaccharides. Sucrase splits sucrose into one molecule of fructose and one molecule of glucose; maltase breaks down maltose and maltotriose into two and three glucose molecules, respectively; and lactase breaks down lactose into one molecule of glucose and one molecule of galactose. Insufficient lactase can lead to lactose intolerance.",True,Carbohydrate Digestion,Figure 23.7.2,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2427_Carbon_Digestion.jpg,Figure 23.7.2 – Carbohydrate Digestion Flow Chart: Carbohydrates are broken down into their monomers in a series of steps.
+0eeb2380-adc1-49f4-b479-ad2632a301e4,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Protein Digestion,False,Protein Digestion,,,,
+2b217221-bdc2-41a6-a111-f60ca0f2725a,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Proteins are polymers composed of amino acids linked by peptide bonds to form long chains. Digestion reduces them to their constituent amino acids. You usually consume about 15 to 20 percent of your total calorie intake as protein.,True,Protein Digestion,,,,
+e82f9977-e36b-4b98-b982-e860dacce8ef,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The digestion of protein starts in the stomach, where HCl denatures the proteins and then pepsin begins to break them down into smaller polypeptides, which then travel to the small intestine (Figure 23.7.3). Chemical digestion in the small intestine is continued by pancreatic enzymes, including trypsin, chymotrypsin and carboxypeptidase, each of which act on specific bonds in amino acid sequences. At the same time, the cells of the brush border secrete enzymes such as aminopeptidase and dipeptidase, which further break down peptide chains. This results in molecules small enough to enter the bloodstream (Figure 23.7.4).",True,Protein Digestion,Figure 23.7.3,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2429_Digestion_of_Proteins_Physiology.jpg,Figure 23.7.3 – Digestion of Protein: The digestion of protein begins in the stomach and is completed in the small intestine.
+099cc3da-3ba7-44cc-96fc-340335574b4d,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Lipid Digestion,False,Lipid Digestion,,,,
+1bdd1f94-849c-460c-944b-3f56a2f9c92e,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"A healthy diet limits lipid intake to 35 percent of total calorie intake. The most common dietary lipids are triglycerides, which are made up of a glycerol molecule bound to three fatty acid chains. Small amounts of dietary cholesterol and phospholipids are also consumed.",True,Lipid Digestion,,,,
+40dd7bdb-7f96-4453-9425-31ba79ba6e1a,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The three lipases responsible for lipid digestion are lingual lipase, gastric lipase, and pancreatic lipase. However, because the pancreas is the only consequential source of lipase, virtually all lipid digestion occurs in the small intestine. Pancreatic lipase breaks down each triglyceride into two free fatty acids and a monoglyceride. The fatty acids include both short-chain (less than 10 to 12 carbons) and long-chain fatty acids.",True,Lipid Digestion,,,,
+34d5ca8c-c714-4d15-8153-0e19394ed3e2,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Nucleic Acid Digestion,False,Nucleic Acid Digestion,,,,
+9f1b5b67-c08d-4448-97cb-febf5ea8ac26,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The nucleic acids DNA and RNA are found in most of the foods you eat. Two types of pancreatic nuclease are responsible for their digestion: deoxyribonuclease, which digests DNA, and ribonuclease, which digests RNA. The nucleotides produced by this digestion are further broken down by two intestinal brush border enzymes (nucleosidase and phosphatase) into pentoses, phosphates, and nitrogenous bases, which can be absorbed through the alimentary canal wall. The large food molecules that must be broken down into subunits are summarized Table 23.9",True,Nucleic Acid Digestion,,,,
+32660759-411a-4168-8d34-cbbae32b36f0,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Absorption,False,Absorption,,,,
+ecf2aa5d-15b6-492e-b62d-c1e3dad7df3e,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi. The absorptive capacity of the alimentary canal is almost endless. Each day, the alimentary canal processes up to 10 liters of food, liquids, and GI secretions, yet less than one liter enters the large intestine. Almost all ingested food, 80 percent of electrolytes, and 90 percent of water are absorbed in the small intestine. Although the entire small intestine is involved in the absorption of water and lipids, most absorption of carbohydrates and proteins occurs in the jejunum. Notably, bile salts and vitamin B12 are absorbed in the terminal ileum. By the time chyme passes from the ileum into the large intestine, it is essentially indigestible food residue (mainly plant fibers like cellulose), some water, and millions of bacteria (Figure 23.7.5).",True,Absorption,Figure 23.7.5,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2430_Digestive_Secretions_Absorption_of_WaterN.jpg,"Figure 23.7.5 – Digestive Secretions and Absorption of Water: Absorption is a complex process, in which nutrients from digested food are harvested."
+50d5fb56-081d-4439-990a-9422cc08edcb,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Absorption can occur through five mechanisms: (1) active transport, (2) passive diffusion, (3) facilitated diffusion, (4) co-transport (or secondary active transport), and (5) endocytosis. As you will recall from Chapter 3, active transport refers to the movement of a substance across a cell membrane going from an area of lower concentration to an area of higher concentration (up the concentration gradient). In this type of transport, proteins within the cell membrane act as “pumps,” using cellular energy (ATP) to move the substance. Passive diffusion refers to the movement of substances from an area of higher concentration to an area of lower concentration, while facilitated diffusion refers to the movement of substances from an area of higher to an area of lower concentration using a carrier protein in the cell membrane. Co-transport uses the movement of one molecule through the membrane from higher to lower concentration to power the movement of another from lower to higher. Finally, endocytosis is a transportation process in which the cell membrane engulfs material. It requires energy, generally in the form of ATP.",True,Absorption,,,,
+a8b5c722-ec8b-49b7-a888-123d095e9354,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Because the cell’s plasma membrane is made up of hydrophobic phospholipids, water-soluble nutrients must use transport molecules embedded in the membrane to enter cells. Moreover, substances cannot pass between the epithelial cells of the intestinal mucosa because these cells are bound together by tight junctions. Thus, substances can only enter blood capillaries by passing through the apical surfaces of epithelial cells and into the interstitial fluid. Water-soluble nutrients enter the capillary blood in the villi and travel to the liver via the hepatic portal vein.",True,Absorption,,,,
+7c4c3030-df7e-42de-a6c5-dc8040e3064c,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"In contrast to the water-soluble nutrients, lipid-soluble nutrients can diffuse through the plasma membrane. Once inside the cell, they are packaged for transport via the base of the cell and then enter the lacteals of the villi to be transported by lymphatic vessels to the systemic circulation via the thoracic duct. The absorption of most nutrients through the mucosa of the intestinal villi requires active transport fueled by ATP. The routes of absorption for each food category are summarized in Table 23.10.",True,Absorption,,,,
+f51026a1-60b2-4274-8d91-37c0da670388,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Carbohydrate Absorption,False,Carbohydrate Absorption,,,,
+382dab98-18ca-4e89-8a79-12f9b8b0de20,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"All carbohydrates are absorbed in the form of monosaccharides. The small intestine is highly efficient at this, absorbing monosaccharides at an estimated rate of 120 grams per hour. All normally digested dietary carbohydrates are absorbed; indigestible fibers are eliminated in the feces. The monosaccharides glucose and galactose are transported into the epithelial cells by common protein carriers via secondary active transport (that is, co-transport with sodium ions). The monosaccharides leave these cells via facilitated diffusion and enter the capillaries through intercellular clefts. The monosaccharide fructose (which is in fruit) is absorbed and transported by facilitated diffusion alone. The monosaccharides combine with the transport proteins immediately after the disaccharides are broken down.",True,Carbohydrate Absorption,,,,
+afc93540-9200-4ae9-937d-2b94e8a675de,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Protein Absorption,False,Protein Absorption,,,,
+e5cdee89-3815-4414-8b33-5123bd95d76a,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Secondary active transport mechanisms, primarily in the duodenum and jejunum, absorb most proteins as their breakdown products, amino acids. These mechanisms are conceptually identical to the absorptive processes involved in monosaccharide absorption. Almost all (95 to 98 percent) protein is digested and absorbed in the small intestine. The type of carrier that transports an amino acid varies. Most carriers are linked to the active transport of sodium. Short chains of two amino acids (dipeptides) or three amino acids (tripeptides) are also transported actively. However, after they enter the absorptive epithelial cells, they are broken down into their amino acids before leaving the cell and entering the capillary blood via facilitated diffusion.",True,Protein Absorption,,,,
+bfdfb91b-e747-45e4-958b-aa279bcee773,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Lipid Absorption,False,Lipid Absorption,,,,
+0c6d08c5-3230-42a2-80ea-326c1765c6a1,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"About 95 percent of lipids are absorbed in the small intestine. Bile salts not only speed up lipid digestion, they are also essential to the absorption of the end products of lipid digestion. Short-chain fatty acids are relatively water soluble and can enter the absorptive cells (enterocytes) directly. Despite being hydrophobic, the small size of short-chain fatty acids enables them to be absorbed by enterocytes via simple diffusion, and then take the same path as monosaccharides and amino acids into the blood capillary of a villus.",True,Lipid Absorption,,,,
+64bebc18-ae7f-4a31-a376-a274f3425d5a,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The large and hydrophobic long-chain fatty acids and monoacylglycerides are not so easily suspended in the watery intestinal chyme. However, bile salts and lecithin resolve this issue by enclosing them in a micelle, which is a tiny sphere with polar (hydrophilic) ends facing the watery environment and hydrophobic tails turned to the interior, creating a receptive environment for the long-chain fatty acids. The core also includes cholesterol and fat-soluble vitamins. Without micelles, lipids would sit on the surface of chyme and never come in contact with the absorptive surfaces of the epithelial cells. Micelles can easily squeeze between microvilli and get very near the luminal cell surface. At this point, lipid substances exit the micelle and are absorbed via simple diffusion.",True,Lipid Absorption,,,,
+1fb2dda4-d6de-403b-8ad4-2b1dcbe84b44,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The free fatty acids and monoacylglycerides that enter the epithelial cells are reincorporated into triglycerides. The triglycerides are mixed with phospholipids and cholesterol, and surrounded with a protein coat. This new complex, called a chylomicron, is a water-soluble lipoprotein. After being processed by the Golgi apparatus, chylomicrons are released from the cell (Figure 23.7.6). Too big to pass through the basement membranes of blood capillaries, chylomicrons instead enter the large pores of lacteals. The lacteals come together to form the lymphatic vessels. The chylomicrons are transported in the lymphatic vessels and empty through the thoracic duct into the subclavian vein of the circulatory system. Once in the bloodstream, the enzyme lipoprotein lipase breaks down the triglycerides of the chylomicrons into free fatty acids and glycerol. These breakdown products then pass through capillary walls to be used for energy by cells or stored in adipose tissue as fat. Liver cells combine the remaining chylomicron remnants with proteins, forming lipoproteins that transport cholesterol in the blood.",True,Lipid Absorption,Figure 23.7.6,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2431_Lipid_Absorption.jpg,"Figure 23.7.6 – Lipid Absorption: Unlike amino acids and simple sugars, lipids are transformed as they are absorbed through epithelial cells."
+d363b17b-c21c-4f62-99a7-4e2f8a243602,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Nucleic Acid Absorption,False,Nucleic Acid Absorption,,,,
+4bd98d6a-3d18-4768-87bf-86a0dcf5a035,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The products of nucleic acid digestion—pentose sugars, nitrogenous bases, and phosphate ions—are transported by carriers across the villus epithelium via active transport. These products then enter the bloodstream.",True,Nucleic Acid Absorption,,,,
+30ce3055-6813-4b43-8ec3-7505329de6e6,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Mineral Absorption,False,Mineral Absorption,,,,
+a5076aaf-59e3-4d85-acbd-e9fcf9ad030f,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The electrolytes absorbed by the small intestine are from both GI secretions and ingested foods. Since electrolytes dissociate into ions in water, most are absorbed via active transport throughout the entire small intestine. During absorption, co-transport mechanisms result in the accumulation of sodium ions inside the cells, whereas anti-port mechanisms reduce the potassium ion concentration inside the cells. To restore the sodium-potassium gradient across the cell membrane, a sodium-potassium pump requiring ATP pumps sodium out and potassium in.",True,Mineral Absorption,,,,
+e74d9e94-1ec5-49db-88da-db081bde62d3,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"In general, all minerals that enter the intestine are absorbed, whether you need them or not. Iron and calcium are exceptions; they are absorbed in the duodenum in amounts that meet the body’s current requirements, as follows:",True,Mineral Absorption,,,,
+b99e29ce-eec6-4be7-9829-d5989d51b3df,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Iron—The ionic iron needed for the production of hemoglobin is absorbed into mucosal cells via active transport. Once inside mucosal cells, ionic iron binds to the protein ferritin, creating iron-ferritin complexes that store iron until needed. When the body has enough iron, most of the stored iron is lost when worn-out epithelial cells slough off. When the body needs iron because, for example, it is lost during acute or chronic bleeding, there is increased uptake of iron from the intestine and accelerated release of iron into the bloodstream. Since women experience significant iron loss during menstruation, they have around four times as many iron transport proteins in their intestinal epithelial cells as do men.",True,Mineral Absorption,,,,
+4bc7d7c0-4cd5-4180-b88f-a07e9e897418,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Calcium—Blood levels of ionic calcium determine the absorption of dietary calcium. When blood levels of ionic calcium drop, parathyroid hormone (PTH) secreted by the parathyroid glands stimulates the release of calcium ions from bone matrices and increases the reabsorption of calcium by the kidneys. PTH also upregulates the activation of vitamin D in the kidney, which then facilitates intestinal calcium ion absorption.",True,Mineral Absorption,,,,
+11065ea0-eaba-4c38-9b46-365be54a5901,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Vitamin Absorption,False,Vitamin Absorption,,,,
+968f4fb0-ea83-45af-a017-69af08c47fe1,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"The small intestine absorbs the vitamins that occur naturally in food and supplements. Fat-soluble vitamins (A, D, E, and K) are absorbed along with dietary lipids in micelles via simple diffusion. This is why you are advised to eat some fatty foods when you take fat-soluble vitamin supplements. Most water-soluble vitamins (including most B vitamins and vitamin C) also are absorbed by simple diffusion. An exception is vitamin B12, which is a very large molecule. Intrinsic factor secreted in the stomach binds to vitamin B12, preventing its digestion and creating a complex that binds to mucosal receptors in the terminal ileum, where it is taken up by endocytosis.",True,Vitamin Absorption,,,,
+2284f1dd-ae80-4296-ab3b-50fb2669f560,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,Water Absorption,False,Water Absorption,,,,
+9d8f41e2-ab61-47e7-9498-64f7685bdbe7,https://open.oregonstate.education/aandp/,23.7 Chemical Digestion and Absorption: A Closer Look,https://open.oregonstate.education/aandp/chapter/23-7-chemical-digestion-and-absorption-a-closer-look/,"Each day, about nine liters of fluid enter the small intestine. About 2.3 liters are ingested in foods and beverages, and the rest is from GI secretions. About 90 percent of this water is absorbed in the small intestine. Water absorption is driven by the concentration gradient of the water: The concentration of water is higher in chyme than it is in epithelial cells. Thus, water moves down its concentration gradient from the chyme into cells. As noted earlier, much of the remaining water is then absorbed in the colon.",True,Water Absorption,,,,
+928036d2-6c22-4423-8d93-26498d805269,https://open.oregonstate.education/aandp/,23.6 The Small and Large Intestines,https://open.oregonstate.education/aandp/chapter/23-6-the-small-and-large-intestines/,"The word intestine is derived from a Latin root meaning “internal,” and indeed, the two organs together nearly fill the interior of the abdominal cavity. In addition, called the small and large bowel, or colloquially the “guts,” they constitute the greatest mass and length of the alimentary canal and, with the exception of ingestion, perform all digestive system functions.",True,Water Absorption,,,,
+8f11d6af-5535-4c65-b15c-e8681a0356d7,https://open.oregonstate.education/aandp/,23.6 The Small and Large Intestines,https://open.oregonstate.education/aandp/chapter/23-6-the-small-and-large-intestines/,The Small Intestine,False,The Small Intestine,,,,
+99c670e4-6aaa-40ce-8140-e4148835546f,https://open.oregonstate.education/aandp/,23.6 The Small and Large Intestines,https://open.oregonstate.education/aandp/chapter/23-6-the-small-and-large-intestines/,"Chyme released from the stomach enters the small intestine, which is the primary digestive organ in the body. Not only is this where most digestion occurs, it is also where practically all absorption occurs. The longest part of the alimentary canal, the small intestine is about 3.05 meters (10 feet) long in a living person (but about twice as long in a cadaver due to the loss of muscle tone). Since this makes it about five times longer than the large intestine, you might wonder why it is called “small.” In fact, its name derives from its relatively smaller diameter of only about 2.54 cm (1 in), compared with 7.62 cm (3 in) for the large intestine. As we’ll see shortly, in addition to its length, the folds and projections of the lining of the small intestine work to give it an enormous surface area, which is approximately 200 m2, more than 100 times the surface area of your skin. This large surface area is necessary for complex processes of digestion and absorption that occur within it.",True,The Small Intestine,,,,
+112fe0b6-cb2e-415d-9959-0f968cbb12cb,https://open.oregonstate.education/aandp/,23.6 The Small and Large Intestines,https://open.oregonstate.education/aandp/chapter/23-6-the-small-and-large-intestines/,The Large Intestine,False,The Large Intestine,,,,
+1226475b-ed13-4bbc-aaf9-4dffbb027f67,https://open.oregonstate.education/aandp/,23.6 The Small and Large Intestines,https://open.oregonstate.education/aandp/chapter/23-6-the-small-and-large-intestines/,"The large intestine is the terminal part of the alimentary canal. The primary function of this organ is to finish absorption of nutrients and water, synthesize certain vitamins, as well as to form, store, and eliminate feces from the body.",True,The Large Intestine,,,,
+bd8ea296-82a2-4b00-b9e0-cc353620747d,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"Chemical digestion in the small intestine relies on the activities of three accessory digestive organs: the liver, pancreas, and gallbladder (Figure 23.5.1). The digestive role of the liver is to produce bile and export it to the duodenum. The gallbladder primarily stores, concentrates, and releases bile. The pancreas produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum.",True,The Large Intestine,Figure 23.5.1,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2422_Accessory_Organs.jpg,"Figure 23.5.1 – Accessory Organs: The liver, pancreas, and gallbladder are considered accessory digestive organs, but their roles in the digestive system are vital."
+2e4a039f-7887-40b3-bef3-47c6f307aa95,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,The Liver,False,The Liver,,,,
+0710b319-a783-44bb-a0e4-2a47df70b9bd,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The liver is the largest gland in the body, weighing about three pounds in an adult. It is also one of the most important organs. In addition to being an accessory digestive organ, it plays a number of roles in metabolism and regulation. The liver lies inferior to the diaphragm in the right upper quadrant of the abdominal cavity and receives protection from the surrounding ribs.",True,The Liver,,,,
+650d3de9-7974-4780-849a-5f65c2738586,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The liver is divided into two primary lobes: a large right lobe and a much smaller left lobe. In the right lobe, some anatomists also identify an inferior quadrate lobe and a posterior caudate lobe, which are defined by internal features. The liver is connected to the abdominal wall and diaphragm by five peritoneal folds referred to as ligaments. These are the falciform ligament, the coronary ligament, two lateral ligaments, and the ligamentum teres hepatis. The falciform ligament and ligamentum teres hepatis are actually remnants of the umbilical vein, and separate the right and left lobes anteriorly. The lesser omentum tethers the liver to the lesser curvature of the stomach.",True,The Liver,,,,
+4e160623-2f0e-42f8-abcc-656c0134652a,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The porta hepatis (“gate to the liver”) is where the hepatic artery and hepatic portal vein enter the liver. These two vessels, along with the common hepatic duct, run behind the lateral border of the lesser omentum on the way to their destinations. As shown in Figure 23.5.2, the hepatic artery delivers oxygenated blood from the heart to the liver. The hepatic portal vein delivers partially deoxygenated blood containing nutrients absorbed from the small intestine and actually supplies more oxygen to the liver than do the much smaller hepatic arteries. In addition to nutrients, drugs and toxins are also absorbed. After processing the bloodborne nutrients and toxins, the liver releases nutrients needed by other cells back into the blood, which drains into the central vein and then through the hepatic vein to the inferior vena cava. With this hepatic portal circulation, all blood from the alimentary canal passes through the liver. This largely explains why the liver is the most common site for the metastasis of cancers that originate in the alimentary canal.",True,The Liver,Figure 23.5.2,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2423_Microscopic_Anatomy_of_Liver.jpg,Figure 23.5.2 – Microscopic Anatomy of the Liver: The liver is organized into repeating structures called lobules made up of hepatocytes. The liver receives oxygenated blood from the hepatic artery and nutrient-rich deoxygenated blood from the hepatic portal vein and drain the bile formed by the hepatocytes into the bile duct.
+4072932a-8f36-47cd-9e55-e1a6acda9f66,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,The Pancreas,False,The Pancreas,,,,
+ebeefd9e-0d3f-4976-82db-3e2e4870711d,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The soft, oblong, glandular pancreas lies transversely in the retroperitoneum behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen. It is a curious mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions (Figure 23.5.3).",True,The Pancreas,Figure 23.5.3,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2424_Exocrine_and_Endocrine_Pancreas.jpg,"Figure 23.5.3 – Exocrine and Endocrine Pancreas: The pancreas has a head, a body, and a tail. It delivers pancreatic juice to the duodenum through the pancreatic duct."
+d3cc7eca-d65c-42ed-a211-a2aa72e7d3d5,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The exocrine part of the pancreas arises as little grape-like cell clusters, each called an acinus (plural = acini), located at the terminal ends of pancreatic ducts. These acinar cells secrete enzyme-rich pancreatic juice into tiny merging ducts that form two dominant ducts. The larger duct fuses with the common bile duct (carrying bile from the liver and gallbladder) just before entering the duodenum via a common opening (the hepatopancreatic ampulla). The smooth muscle sphincter of the hepatopancreatic ampulla controls the release of pancreatic juice and bile into the small intestine. The second and smaller pancreatic duct, the accessory duct (duct of Santorini), runs from the pancreas directly into the duodenum, approximately 1 inch above the hepatopancreatic ampulla. When present, it is a persistent remnant of pancreatic development.",True,The Pancreas,,,,
+05703c0b-c686-484d-b96d-0a9cfce3a2ab,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"Scattered through the sea of exocrine acini are small islands of endocrine cells, the islets of Langerhans. These vital cells produce the hormones pancreatic polypeptide, insulin, glucagon, and somatostatin.",True,The Pancreas,,,,
+de5471e0-f387-46a8-ab46-a94b3d737b8b,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,The Gallbladder,False,The Gallbladder,,,,
+9fd704ae-913b-4b28-80b2-5a73c5a0c626,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The gallbladder is 8–10 cm (~3–4 in) long and is nested in a shallow area on the posterior aspect of the right lobe of the liver. It is divided into three regions. The fundus is the widest portion and tapers medially into the body, which in turn narrows to become the neck. The neck angles slightly superiorly as it approaches the hepatic duct. The cystic duct is 1–2 cm (less than 1 in) long and turns inferiorly as it bridges the neck and hepatic duct.",True,The Gallbladder,,,,
+f933d02f-9b2b-428f-94e8-0dea40bf6f47,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"The simple columnar epithelium of the gallbladder mucosa is organized in rugae, similar to those of the stomach. There is no submucosa in the gallbladder wall. The wall’s middle, muscular coat is made of smooth muscle fibers. When these fibers contract, the gallbladder’s contents are ejected through the cystic duct and into the bile duct (Figure 23.5.4). Visceral peritoneum reflected from the liver capsule holds the gallbladder against the liver and forms the outer coat of the gallbladder. The gallbladder’s mucosa absorbs water and ions from bile, concentrating it by up to 10-fold.",True,The Gallbladder,Figure 23.5.4,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2425_Gallbladder.jpg,"Figure 23.5.4 – Gallbladder: The gallbladder stores and concentrates bile, and releases it into the two-way cystic duct when it is needed by the small intestine."
+714c8c1d-0c11-40c6-bc60-afdbd954c88a,https://open.oregonstate.education/aandp/,"23.5 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder",https://open.oregonstate.education/aandp/chapter/23-5-accessory-organs-in-digestion-the-liver-pancreas-and-gallbladder/,"This gall bladder stores, concentrates, and, when stimulated, propels the bile into the duodenum via the common bile duct. When fatty chyme enters the duodenum, CCK is released which causes the smooth muscle of the gall bladder to contract. Also, stimulation of the gall bladder by the vagus nerve and stimulate muscle contraction. Both CCK and vagal stimulation cause the gall bladder to release the stored bile into the duodenum to emulsify the lipids present in the chyme.",True,The Gallbladder,,,,
+425fff51-c92a-4f06-9ff3-8bbc07c3149d,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Although a minimal amount of digestion occurs in the mouth, chemical digestion really gets underway in the stomach, primarily as the initial site of protein digestion. An expansion of the alimentary canal that lies immediately inferior to the esophagus, the stomach links the esophagus to the first part of the small intestine (the duodenum) and is relatively fixed in place at its esophageal and duodenal ends. In between, however, it can be a highly active structure, contracting and continually changing position and size. These contractions provide mechanical assistance to digestion. The empty stomach is only about the size of your fist, but can stretch to hold as much as 4 liters of food and fluid, or more than 75 times its empty volume, and then return to its resting size when empty. Although you might think that the size of a person’s stomach is related to how much food that individual consumes, body weight does not correlate with stomach size. Rather, when you eat greater quantities of food—such as at holiday dinner—you stretch the stomach more than when you eat less.",True,The Gallbladder,,,,
+0429fe01-5976-46fa-9629-61859e6d0893,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Popular culture tends to refer to the stomach as the location where all digestion takes place. Of course, this is not true. An important function of the stomach is to serve as a temporary holding chamber. You can ingest a meal far more quickly than it can be digested and absorbed by the small intestine. Thus, the stomach holds food and parses only small amounts into the small intestine at a time. Foods are not processed in the order they are eaten; rather, they are mixed together with digestive juices in the stomach until they are converted into chyme, which is released into the small intestine.",True,The Gallbladder,,,,
+ce80e02a-9ad2-4c0b-9103-d8b19b8e8071,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"As you will see in the sections that follow, the stomach plays several important roles in chemical digestion, including the continued digestion of carbohydrates until salivary amylase is inactivated by stomach acid, and the initial digestion of proteins and triglycerides. Little if any absorption occurs in the stomach, with the exception of lipid soluble substances such as alcohol and aspirin.",True,The Gallbladder,,,,
+e5beb4d8-bba6-441f-a056-06d1eb23c35c,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Structure,False,Structure,,,,
+68bd869a-b396-4c36-b21e-986f1eb39540,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"There are four main regions in the stomach: the cardia, fundus, body, and pylorus (Figure 23.4.1). The cardia (or cardiac region) is the point where the esophagus connects to the stomach and through which food passes into the stomach. Located inferior to the diaphragm, above and to the left of the cardia, is the dome-shaped fundus. Below the fundus is the body, the main part of the stomach. The funnel-shaped pylorus connects the stomach to the duodenum. The wider end of the funnel, the pyloric antrum, connects to the body of the stomach. The narrower end is called the pyloric canal, which connects to the duodenum. The smooth muscle pyloric sphincter is located at this latter point of connection and controls stomach emptying. In the absence of food, the stomach deflates inward, and its mucosa and submucosa fall into large folds called  rugae.",True,Structure,Figure 23.4.1,23.4 The Stomach,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2414_Stomach.jpg,"Figure 23.4.1 – Stomach: The stomach has four major regions: the cardia, fundus, body, and pylorus. The addition of an inner oblique smooth muscle layer gives the muscularis the ability to vigorously churn and mix food."
+b8c5a5dd-de3a-4e48-8556-a84c156e5ce9,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The convex lateral surface of the stomach is called the greater curvature; the concave medial border is the lesser curvature. The stomach is held in place by the lesser omentum, which extends from the liver to the lesser curvature, and the greater omentum, which runs from the greater curvature to the posterior abdominal wall.",True,Structure,,,,
+89f73be9-3601-4022-b888-3eb41c63736a,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Histology,False,Histology,,,,
+a4e36078-7841-41b3-acea-c348412050b0,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The wall of the stomach is made of the same four layers as most of the rest of the alimentary canal, but with adaptations to the mucosa and muscularis for the unique functions of this organ. In addition to the typical circular and longitudinal smooth muscle layers, the muscularis has an inner oblique smooth muscle layer (Figure 23.4.2). As a result, in addition to moving food through the canal, the stomach can vigorously churn food, mechanically breaking it down into smaller particles.",True,Histology,Figure 23.4.2,23.4 The Stomach,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2415_Histology_of_StomachN.jpg,"Figure 23.4.2 – Histology of the Stomach: The stomach wall is adapted for the functions of the stomach. In the epithelium, gastric pits lead to gastric glands that secrete gastric juice. The gastric glands (one gland is shown enlarged on the right) contain different types of cells that secrete a variety of enzymes, including hydrochloride acid, which activates the protein-digesting enzyme pepsin."
+74964477-aa22-4d7f-8ebf-6238c4e9afc0,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The stomach mucosa’s epithelial lining consists only of surface mucus cells, which secrete a protective coat of alkaline mucus. A vast number of gastric pits dot the surface of the epithelium, giving it the appearance of a well-used pincushion, and mark the entry to each gastric gland, which secretes a complex digestive fluid referred to as gastric juice.",True,Histology,,,,
+89e0d179-2b93-4d7a-a45e-7e3bef9a606c,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Although the walls of the gastric pits are made up primarily of mucus cells, the gastric glands are made up of different types of cells. The glands of the cardia and pylorus are composed primarily of mucus-secreting cells. Cells that make up the pyloric antrum secrete mucus and a number of hormones, including the majority of the stimulatory hormone, gastrin. The much larger glands of the fundus and body of the stomach, the site of most chemical digestion, produce most of the gastric secretions. These glands are made up of a variety of secretory cells. These include parietal cells, chief cells, mucous neck cells, and enteroendocrine cells.",True,Histology,,,,
+5fa42fba-d76e-4dcf-82f4-38bd69b14e0b,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Parietal cells—Located primarily in the middle region of the gastric glands are parietal cells, which are among the most highly differentiated of the body’s epithelial cells. These relatively large cells produce both hydrochloric acid (HCl) and intrinsic factor. HCl is responsible for the high acidity (pH 1.5 to 3.5) of the stomach contents and is needed to activate the protein-digesting enzyme, pepsin. The acidity also kills much of the bacteria you ingest with food and helps to denature proteins, making them more available for enzymatic digestion. Intrinsic factor is a glycoprotein necessary for the absorption of vitamin B12 in the small intestine.",True,Histology,,,,
+636df4f7-d4db-445a-b2dd-dda177342fab,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Chief cells—Located primarily in the basal regions of gastric glands are chief cells, which secrete pepsinogen, the inactive proenzyme form of pepsin. HCl is necessary for the conversion of pepsinogen to pepsin.",True,Histology,,,,
+34d92fe8-8ff9-4a67-863c-2504661ad6b9,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Mucous neck cells—Gastric glands in the upper part of the stomach contain mucous neck cells that secrete alkaline mucus that is similary to the mucus secreted by the cells of the surface epithelium.,True,Histology,,,,
+d1887fa2-9ef9-4068-b6c6-7ef1c3de3bed,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"Enteroendocrine cells—Finally, enteroendocrine cells found in the gastric glands secrete various hormones into the interstitial fluid of the lamina propria. These include gastrin, which is released mainly by enteroendocrine G cells.",True,Histology,,,,
+d5ba8c10-dc6e-4818-8beb-cf3375fcf5d7,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Table 23.6 describes the digestive functions of important hormones secreted by the stomach.,True,Histology,,,,
+a686234e-b2e4-47c8-86e1-aa6a63ffcd8d,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Gastric Secretion,False,Gastric Secretion,,,,
+a4e565af-937b-4ec5-9604-c95465946543,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The secretion of gastric juice is controlled by both nerves and hormones. Stimuli in the brain, stomach, and small intestine activate or inhibit gastric juice production. This is why the three phases of gastric secretion are called the cephalic, gastric, and intestinal phases (Figure 23.4.3). However, once gastric secretion begins, all three phases can occur simultaneously.",True,Gastric Secretion,Figure 23.4.3,23.4 The Stomach,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2416_Three_Phases_Gastric_Secretion.jpg,"Figure 23.4.3 – The Three Phases of Gastric Secretion: Gastric secretion occurs in three phases: cephalic, gastric, and intestinal. During each phase, the secretion of gastric juice can be stimulated or inhibited. EDITOR’S NOTE: Each place where figure says “Stimulates stomach secretory activity,” describe what that activity is and how much it is activated. In the section on the cephalic phase it could say something like: secretion of HCl and pepsin. In the section on the gastric phase it could say something like: increased secretion of HCl and pepsin and increased gastric motility. Etc."
+ba4045cc-6ed1-4d23-85cd-d5ea1a2f0b80,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The cephalic phase (reflex phase) of gastric secretion, which is relatively brief, takes place before food enters the stomach. The smell, taste, sight, or thought of food triggers this phase. For example, when you bring a piece of sushi to your lips, impulses from receptors in your taste buds or the nose are relayed to your brain, which returns signals that increase gastric secretion to prepare your stomach for digestion. This enhanced secretion is a conditioned reflex, meaning it occurs only if you like or want a particular food. Depression and loss of appetite can suppress the cephalic reflex.",True,Gastric Secretion,,,,
+9a6dd7ab-8eaa-4f3c-9d3b-4a02997e633d,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The gastric phase of secretion lasts 3 to 4 hours, and is set in motion by local neural and hormonal mechanisms triggered by the entry of food into the stomach. For example, when your sushi reaches the stomach, it creates distention that activates the stretch receptors. This stimulates parasympathetic neurons to release acetylcholine, which then provokes increased secretion of gastric juice. Partially digested proteins, caffeine, and rising pH stimulate the release of gastrin from enteroendocrine G cells, which in turn induces parietal cells to increase their production of HCl, which is needed to create an acidic environment for the conversion of pepsinogen to pepsin, and protein digestion. Additionally, the release of gastrin activates vigorous smooth muscle contractions. However, it should be noted that the stomach does have a natural means of avoiding excessive acid secretion and potential heartburn. Whenever pH levels drop too low, cells in the stomach react by suspending HCl secretion and increasing mucous secretions.",True,Gastric Secretion,,,,
+13e381ca-9fb3-4717-986a-068f69dd3187,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The intestinal phase of gastric secretion has both excitatory and inhibitory elements. The duodenum has a major role in regulating the stomach and its emptying. When partially digested food fills the duodenum, intestinal mucosal cells release a hormone called intestinal (enteric) gastrin, which further excites gastric juice secretion. This stimulatory activity is brief, however, because when the intestine distends with chyme, the enterogastric reflex inhibits secretion. One of the effects of this reflex is to close the pyloric sphincter, which blocks additional chyme from entering the duodenum. In addition to the enterogastric reflex, several hormones such as cholecystokinin (CCK) and secretin are released by the enteroendocrine cells of the duodenum when fatty, acidic, or carbohydrate rich chyme enters the duodenum. CCK and secretin enter the blood and travel to the stomach inhibiting the production of HCl and pepsin as well as inhibiting gastric motility allowing time for the duodenum to break down the chyme.",True,Gastric Secretion,,,,
+d1a7cd63-fff7-4053-bc0f-9cfb9fc8af5f,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,The Mucosal Barrier,False,The Mucosal Barrier,,,,
+03a3cea2-864d-474f-a3a4-9e216b300868,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The mucosa of the stomach is exposed to the highly corrosive acidity of gastric juice. Gastric enzymes that can digest protein can also digest the stomach itself. The stomach is protected from self-digestion by the mucosal barrier. This barrier has several components. First, the stomach wall is covered by a thick coating of bicarbonate-rich mucus. This mucus forms a physical barrier, and its bicarbonate ions neutralize acid. Second, the epithelial cells of the stomach’s mucosa meet at tight junctions, which block gastric juice from penetrating the underlying tissue layers. Finally, stem cells located where gastric glands join the gastric pits quickly replace damaged epithelial mucosal cells, when the epithelial cells are shed. In fact, the surface epithelium of the stomach is completely replaced every 3 to 6 days.",True,The Mucosal Barrier,,,,
+785c7ff4-6573-40b2-b2d6-9d0310710d7c,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,Digestive Functions of the Stomach,False,Digestive Functions of the Stomach,,,,
+bf570386-c1aa-416a-8dba-03c3e1094182,https://open.oregonstate.education/aandp/,23.4 The Stomach,https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/,"The stomach participates in virtually all the digestive activities with the exception of ingestion and defecation. Although almost all absorption takes place in the small intestine, the stomach does absorb some nonpolar substances, such as alcohol and aspirin.",True,Digestive Functions of the Stomach,,,,
+a5fc4fe7-894f-4194-8929-f47fb3d2c1c0,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"In this section, you will examine the anatomy and functions of the three main organs of the upper alimentary canal—the mouth, pharynx, and esophagus—as well as three associated accessory organs—the tongue, salivary glands, and teeth.",True,Digestive Functions of the Stomach,,,,
+af4180ae-29f1-431c-8dde-f02e245f8b20,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Mouth,False,The Mouth,,,,
+cf3e0ed7-aaa0-4d0b-93ed-1dca144426d4,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or buccal cavity). The structures of the mouth are illustrated in Figure 23.3.1.",True,The Mouth,Figure 23.3.1,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2406_Structures_of_the_Mouth.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth."
+55dade2e-ce68-4a4e-93b3-d1f6a5e25d9b,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"At the entrance to the mouth are the lips, or labia (singular = labium). Their outer covering is skin, which transitions to a mucous membrane in the mouth proper. Lips are very vascular with only a thin layer of keratinized epithelium and therefore they look red due to the red blood cell color showing through the thin, transparent epithelium. They have a huge representation on the cerebral cortex, which probably explains the human fascination with kissing! The lips cover the orbicularis oris muscle, which regulates what comes in and goes out of the mouth. The labial frenulum is a midline fold of mucous membrane that attaches the inner surface of each lip to the gum. The cheeks make up the oral cavity’s sidewalls. While their outer covering is skin, their inner covering is mucous membrane. This membrane is made up of non-keratinized, stratified squamous epithelium. Between the skin and mucous membranes are connective tissue and buccinator muscles. The next time you eat some food, notice how the buccinator muscles in your cheeks and the orbicularis oris muscle in your lips contract, helping you keep the food from falling out of your mouth. Additionally, notice how these muscles work when you are speaking.",True,The Mouth,,,,
+a5eb0072-b458-424e-857d-cf36b0b3a208,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The pocket-like part of the mouth that is framed on the inside by the gums and teeth, and on the outside by the cheeks and lips is called the oral vestibule. Moving farther into the mouth, the opening between the oral cavity and throat (oropharynx) is called the fauces (like the kitchen “faucet”). The main open area of the mouth, or oral cavity proper, runs from the gums and teeth to the fauces.",True,The Mouth,,,,
+2e665ef4-d0f0-4363-abcd-2ccefa0dbb02,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"When you are chewing, you do not find it difficult to breathe simultaneously. The next time you have food in your mouth, notice how the arched shape of the roof of your mouth allows you to handle both digestion and respiration at the same time. This arch is called the palate. The anterior region of the palate serves as a wall (or septum) between the oral and nasal cavities as well as a rigid shelf against which the tongue can push food. It is created by the maxillary and palatine bones of the skull and, given its bony structure, is known as the hard palate. If you run your tongue along the roof of your mouth, you’ll notice that the hard palate ends in the posterior oral cavity, and the tissue becomes fleshier. This part of the palate, known as the soft palate, is composed mainly of skeletal muscle. You can therefore manipulate, subconsciously, the soft palate—for instance, to yawn, swallow, or sing (see Figure 23.3.1).",True,The Mouth,Figure 23.3.1,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2406_Structures_of_the_Mouth.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth."
+a389905c-f734-45ba-a7da-7e1114b2f475,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"A fleshy bead of tissue called the uvula drops down from the center of the posterior edge of the soft palate. Although some have suggested that the uvula is a vestigial organ, it serves an important purpose. When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity. Unfortunately, it can also contribute to the sound produced by snoring. Two muscular folds extend downward from the soft palate, on either side of the uvula. Toward the front, the palatoglossal arch lies next to the base of the tongue; behind it, the palatopharyngeal arch forms the superior and lateral margins of the fauces. Between these two arches are the palatine tonsils, clusters of lymphoid tissue that protect the pharynx. The lingual tonsils are located at the base of the tongue.",True,The Mouth,,,,
+3f5aa277-d344-4205-859c-05c4609ad55a,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Tongue,False,The Tongue,,,,
+e97300ff-4a5e-40c6-872c-1b3121559e37,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Perhaps you have heard it said that the tongue is the strongest muscle in the body. Those who stake this claim cite its strength proportionate to its size. Although it is difficult to quantify the relative strength of different muscles, it remains indisputable that the tongue is a workhorse, facilitating ingestion, mechanical digestion, chemical digestion (lingual lipase), sensation (of taste, texture, and temperature of food), swallowing, and vocalization.",True,The Tongue,,,,
+145b4c00-1e05-45bb-b79f-adb937738727,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The tongue is attached to the mandible, the styloid processes of the temporal bones, and the hyoid bone. The hyoid is unique in that it only distantly/indirectly articulates with other bones. The tongue is positioned over the floor of the oral cavity. A medial septum extends the entire length of the tongue, dividing it into symmetrical halves.",True,The Tongue,,,,
+002aa59b-67e7-46e7-ab0b-ea3452632b57,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Beneath its mucous membrane covering, each half of the tongue is composed of the same number and type of intrinsic and extrinsic skeletal muscles. The intrinsic muscles (those within the tongue) are the longitudinalis inferior, longitudinalis superior, transversus linguae, and verticalis linguae muscles. These allow you to change the size and shape of your tongue, as well as to stick it out, if you wish. Having such a flexible tongue facilitates both swallowing and speech.",True,The Tongue,,,,
+ec8199b1-fe42-47dd-860f-7650f89fb749,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"As you learned in your study of the muscular system, the extrinsic muscles of the tongue are the mylohyoid, hyoglossus, styloglossus, and genioglossus muscles. These muscles originate outside the tongue and insert into connective tissues within the tongue. The mylohyoid is responsible for raising the tongue, the hyoglossus pulls it down and back, the styloglossus pulls it up and back, and the genioglossus pulls it forward. Working in concert, these muscles perform three important digestive functions in the mouth: (1) position food for optimal chewing, (2) gather food into a bolus (rounded mass), and (3) position food so it can be swallowed.",True,The Tongue,,,,
+8703c972-8143-4f96-b9ae-4d3611d1fa01,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The top and sides of the tongue are studded with papillae, extensions of lamina propria of the mucosa, which are covered in stratified squamous epithelium (Figure 23.3.2). Fungiform papillae, which are mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear of the tongue and smaller on the tip and sides. Circumvallate papillae are much fewer in number, only 8 to 12, and lie in a row along the posterior portion of the tongue anterior to the lingual tonsil. In contrast, filiform papillae are long and thin. Fungiform and circumvallate papillae contain taste buds, and filiform papillae have touch receptors that help the tongue move food around in the mouth. The filiform papillae create an abrasive surface that performs mechanically, much like a cat’s rough tongue that is used for grooming. Lingual glands in the lamina propria of the tongue secrete mucus and a watery serous fluid that contains the enzyme lingual lipase, which plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach. A fold of mucous membrane on the underside of the tongue, the lingual frenulum, tethers the tongue to the floor of the mouth. People with the congenital anomaly ankyloglossia, also known by the non-medical term “tongue tie,” have a lingual frenulum that is too short or otherwise malformed. Severe ankyloglossia can impair speech and must be corrected with surgery.",True,The Tongue,Figure 23.3.2,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2407_Tongue.jpg,Figure 23.3.2 – Tongue: This superior view of the tongue shows the locations and types of lingual papillae.
+0a245bfb-8d51-4fab-bc07-6cafe4a676e0,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Salivary Glands,False,The Salivary Glands,,,,
+b12d677d-8c00-4f57-bea1-8aac82df4ca6,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Many small salivary glands are housed within the mucous membranes of the mouth and tongue. These minor exocrine glands are constantly secreting saliva, either directly into the oral cavity or indirectly through ducts, even while you sleep. In fact, an average of 1 to 1.5 liters of saliva is secreted each day. Usually just enough saliva is present to moisten the mouth and teeth. Secretion increases when you eat, because saliva is essential to moisten food and initiate the chemical breakdown of carbohydrates. Small amounts of saliva are also secreted by the labial glands in the lips. In addition, the buccal glands in the cheeks, palatal glands in the palate, and lingual glands in the tongue help ensure that all areas of the mouth are supplied with adequate saliva.",True,The Salivary Glands,,,,
+4a5d4f34-48da-44b4-aa62-d0cb35e46b42,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Teeth,False,The Teeth,,,,
+c1eda848-e956-48a2-bccb-6f3ad00f7fff,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The teeth, or dentes (singular = dens), are organs similar to bones that you use to tear, grind, and otherwise mechanically break down food.",True,The Teeth,,,,
+c4bc58ae-d88f-402e-99d6-c4d95eee1d06,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Pharynx,False,The Pharynx,,,,
+675f530d-0ee3-4d10-9d2d-7ea6ccad0b4e,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The pharynx (throat) is involved in both digestion and respiration. It receives food and air from the mouth, and air from the nasal cavities. When food enters the pharynx, involuntary muscle contractions close off the air passageways.",True,The Pharynx,,,,
+1f8a07a6-b298-4e71-b2a2-f5a22d928f5d,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"A short tube of skeletal muscle lined with a mucous membrane, the pharynx runs from the posterior oral and nasal cavities to the opening of the esophagus and larynx. It has three subdivisions. The most superior, the nasopharynx, is involved only in breathing and speech. The other two subdivisions, the oropharynx and the laryngopharynx, are used for both breathing and digestion. The oropharynx begins inferior to the nasopharynx and is continuous below with the laryngopharynx (Figure 23.3.6). The inferior border of the laryngopharynx connects to the esophagus, whereas the anterior portion connects to the larynx, allowing air to flow into the bronchial tree.",True,The Pharynx,Figure 23.3.6,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2411_Pharynx.jpg,Figure 23.3.6 – Pharynx: The pharynx runs from the nostrils to the esophagus and the larynx.
+833d84b8-fdd3-4a27-a401-5c201005f237,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Histologically, the wall of the oropharynx is similar to that of the oral cavity. The mucosa includes a stratified squamous epithelium that is endowed with mucus-producing glands. During swallowing, the elevator skeletal muscles of the pharynx contract, raising and expanding the pharynx to receive the bolus of food. Once received, these muscles relax and the constrictor muscles of the pharynx contract, forcing the bolus into the esophagus and initiating peristalsis.",True,The Pharynx,,,,
+717b58ee-2b1d-4591-b6d4-f0fe1475cdd5,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Usually during swallowing, the soft palate and uvula rise reflexively to close off the entrance to the nasopharynx. At the same time, the larynx is pulled superiorly and the cartilaginous epiglottis, its most superior structure, folds inferiorly, covering the glottis (the opening to the larynx); this process effectively blocks access to the trachea and bronchi. When the food “goes down the wrong way,” it goes into the trachea. When food enters the trachea, the reaction is to cough, which usually forces the food up and out of the trachea, and back into the pharynx.",True,The Pharynx,,,,
+149813db-9df8-45fa-8d7f-d830d689a282,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,The Esophagus,False,The Esophagus,,,,
+8ed2bf48-da3a-4889-97e8-04adcd297886,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The esophagus is a muscular tube that connects the pharynx to the stomach. It is approximately 25.4 cm (10 in) in length, located posterior to the trachea, and remains in a collapsed form when not engaged in swallowing. As you can see in Figure 23.3.7, the esophagus runs a mainly straight route through the mediastinum of the thorax. To enter the abdomen, the esophagus penetrates the diaphragm through an opening called the esophageal hiatus.",True,The Esophagus,Figure 23.3.7,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2412_The_Esophagus.jpg,Figure 23.3.7 – Esophagus: The upper esophageal sphincter controls the movement of food from the pharynx to the esophagus. The lower esophageal sphincter controls the movement of food from the esophagus to the stomach.
+44bd9dcf-eed0-4446-9b79-c3db1526b1dd,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,Deglutition,False,Deglutition,,,,
+1d328887-f4dc-4233-9dcb-f059f274aeda,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Deglutition is another word for swallowing—the movement of food from the mouth to the stomach. The entire process takes about 4 to 8 seconds for solid or semisolid food, and about 1 second for very soft food and liquids. Although this sounds quick and effortless, deglutition is, in fact, a complex process that involves both the skeletal muscle of the tongue and the muscles of the pharynx and esophagus. It is aided by the presence of mucus and saliva. There are three stages in deglutition: the voluntary phase, the pharyngeal phase, and the esophageal phase (Figure 23.3.8). The autonomic nervous system controls the latter two phases.",True,Deglutition,Figure 23.3.8,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2413_Deglutition_revised.png,Figure 23.3.8 – Deglutition: Deglutition includes the voluntary phase and two involuntary phases: the pharyngeal phase and the esophageal phase.
+f89a2600-5384-4a20-891c-23684b085cdc,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Parotid gland saliva is watery with little mucus but a lot of amylase, which allows it to mix freely with food during mastication and begin the digestion of carbohydrates. In contrast, sublingual gland saliva has a lot of mucus with the least amount of amylase of all the salivary glands. The high mucus content serves to lubricate the food for swallowing.",True,Deglutition,,,,
+f1ec99f6-2051-4260-b1e6-8c5a6240ad0a,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"The incisors. Since these teeth are used for tearing off pieces of food during ingestion, the player will need to ingest foods that have already been cut into bite-sized pieces until the broken teeth are replaced.",True,Deglutition,,,,
+e035dfdd-54ea-4518-b170-6812a5e1ec28,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"If the lower esophageal sphincter does not close completely, the stomach’s acidic contents can back up into the esophagus, a phenomenon known as GERD.",True,Deglutition,,,,
+d8446994-fd83-4754-af13-4b9f4151f49f,https://open.oregonstate.education/aandp/,"23.3 The Mouth, Pharynx, and Esophagus",https://open.oregonstate.education/aandp/chapter/23-3-the-mouth-pharynx-and-esophagus/,"Peristalsis moves the bolus down the esophagus and toward the stomach. Esophageal glands secrete mucus that lubricates the bolus and reduces friction. When the bolus nears the stomach, the lower esophageal sphincter relaxes, allowing the bolus to pass into the stomach.",True,Deglutition,,,,
+b2f90e57-1d84-4d2d-9e5e-4f35971ce7c1,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,The digestive system uses mechanical and chemical activities to break food down into absorbable substances during its journey through the digestive system. Table 23.3 provides an overview of the basic functions of the digestive organs.,True,Deglutition,,,,
+34876f8c-8d3f-4a9f-b936-bed7a313ec7f,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,Digestive Processes,False,Digestive Processes,,,,
+40059ada-dc1b-4397-913d-05cb46665af2,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"The processes of digestion include six activities: ingestion, propulsion, mechanical or physical digestion, chemical digestion, absorption, and defecation.",True,Digestive Processes,,,,
+de5586e4-4690-456c-b95d-3103b7d198bf,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"The first of these processes, ingestion, refers to the entry of food into the alimentary canal through the mouth. There, the food is chewed and mixed with saliva, which contains enzymes that begin breaking down the carbohydrates in the food plus some lipid digestion via lingual lipase. Chewing increases the surface area of the food and allows an appropriately sized bolus to be produced.",True,Digestive Processes,,,,
+c99c61f3-6927-4afe-8476-f9b291b60971,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"Food leaves the mouth when the tongue and pharyngeal muscles propel it into the esophagus. This act of swallowing, the last voluntary act until defecation, is an example of propulsion, which refers to the movement of food through the digestive tract. It includes both the voluntary process of swallowing and the involuntary process of peristalsis. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along (Figure 23.2.1). These waves also play a role in mixing food with digestive juices. Peristalsis is so powerful that foods and liquids you swallow enter your stomach even if you are standing on your head.",True,Digestive Processes,Figure 23.2.1,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2404_PeristalsisN.jpg,Figure 23.2.1 – Peristalsis: Peristalsis moves food through the digestive tract with alternating waves of muscle contraction and relaxation.
+ba0f1158-5dc9-49ba-953f-230cb9011b26,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"Digestion includes both mechanical and chemical processes. Mechanical digestion is a purely physical process that does not change the chemical nature of the food. Instead, it makes the food smaller to increase both surface area and mobility. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with saliva. Although there may be a tendency to think that mechanical digestion is limited to the first steps of the digestive process, it occurs after the food leaves the mouth, as well. The mechanical churning of food in the stomach serves to further break it apart and expose more of its surface area to digestive juices, creating an acidic “soup” called chyme. Segmentation, which occurs mainly in the small intestine, consists of localized contractions of circular muscle of the muscularis layer of the alimentary canal. These contractions isolate small sections of the intestine, moving their contents back and forth while continuously subdividing, breaking up, and mixing the contents. By moving food back and forth in the intestinal lumen, segmentation mixes food with digestive juices and facilitates absorption.",True,Digestive Processes,,,,
+db810bab-139a-4e0b-9253-42fcbf696b4f,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"In chemical digestion, starting in the mouth, digestive secretions break down complex food molecules into their chemical building blocks (for example, proteins into separate amino acids). These secretions vary in composition, but typically contain water, various enzymes, acids, and salts. The process is completed in the small intestine.",True,Digestive Processes,,,,
+26cd0057-ef6a-47df-aab0-9b07d5a95d18,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"Food that has been broken down is of no value to the body unless it enters the bloodstream and its nutrients are put to work. This occurs through the process of absorption, which takes place primarily within the small intestine. There, most nutrients are absorbed from the lumen of the alimentary canal into the bloodstream through the epithelial cells that make up the mucosa. Lipids are absorbed into lacteals and are transported via the lymphatic vessels to the bloodstream (the subclavian veins near the heart). The details of these processes will be discussed later.",True,Digestive Processes,,,,
+914dc44b-571c-4612-804b-9212ab8ac1d8,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"In defecation, the final step in digestion, undigested materials are removed from the body as feces.",True,Digestive Processes,,,,
+46b5fe96-7dd8-4d56-8fa5-dc45365edc56,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"In some cases, a single organ is in charge of a digestive process. For example, ingestion occurs only in the mouth and defecation only in the anus. However, most digestive processes involve the interaction of several organs and occur gradually as food moves through the alimentary canal (Figure 23.2.2).",True,Digestive Processes,Figure 23.2.2,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2405_Digestive_Process.jpg,"Figure 23.2.2 – Digestive Processes: The digestive processes are ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation."
+03ff3e7e-99f7-43f1-8800-aba411106de4,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"Some chemical digestion occurs in the mouth. Some absorption can occur in the mouth and stomach, for example, alcohol and aspirin.",True,Digestive Processes,,,,
+6ff77fa0-9b7c-4a74-a477-f809cf9c8b1b,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,Regulatory Mechanisms,False,Regulatory Mechanisms,,,,
+5db7d62e-7ba0-47bd-bcc8-dfab38e4bd88,https://open.oregonstate.education/aandp/,23.2 Digestive System Processes and Regulation,https://open.oregonstate.education/aandp/chapter/23-2-digestive-system-processes-and-regulation/,"Neural and endocrine regulatory mechanisms work to maintain the optimal conditions in the lumen needed for digestion and absorption. These regulatory mechanisms, which stimulate digestive activity through mechanical and chemical activity, are controlled both extrinsically and intrinsically.",True,Regulatory Mechanisms,,,,
+b38cc90c-46eb-472e-9efe-c8b376dace71,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process (Figure 23.1.1).",True,Regulatory Mechanisms,Figure 23.1.1,23.1 Overview of the Digestive System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2401_Components_of_the_Digestive_System_revised-e1568240853144.png,Figure 23.1.1 – Components of the Digestive System: All digestive organs play integral roles in the life-sustaining process of digestion.
+fed48418-0c90-40e5-9fc9-3aaffa197bca,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"As is the case with all body systems, the digestive system does not work in isolation; it functions cooperatively with the other systems of the body. Consider for example, the interrelationship between the digestive and cardiovascular systems. Arteries supply the digestive organs with oxygen and processed nutrients, and veins drain the digestive tract. These intestinal veins, constituting the hepatic portal system, are unique in that they do not return blood directly to the heart. Rather, this blood is diverted to the liver where its nutrients are off-loaded for processing before blood completes its circuit back to the heart. At the same time, the digestive system provides nutrients to the heart muscle and vascular tissue to support their functioning. The interrelationship of the digestive and endocrine systems is also critical. Hormones secreted by several endocrine glands, as well as endocrine cells of the pancreas, the stomach, and the small intestine, contribute to the control of digestion and nutrient metabolism. In turn, the digestive system provides the nutrients to fuel endocrine function. Table 23.1 gives a quick glimpse at how these other systems contribute to the functioning of the digestive system.",True,Regulatory Mechanisms,,,,
+09680460-46ce-443c-9f7d-583506f159b3,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,Digestive System Organs,False,Digestive System Organs,,,,
+a213e050-7078-45e2-8bab-797b85b26317,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The easiest way to understand the digestive system is to divide its organs into two main categories. The first group is the organs that make up the alimentary canal. Accessory digestive organs comprise the second group and are critical for orchestrating the breakdown of food and the assimilation of its nutrients into the body. Accessory digestive organs, despite their name, are critical to the function of the digestive system.",True,Digestive System Organs,,,,
+5ff9cc30-1bc1-4c00-bdfe-95e4149dade0,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,Histology of the Alimentary Canal,False,Histology of the Alimentary Canal,,,,
+e51eb039-bc24-4ec8-b43d-7a508a9925c3,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Throughout its length, the alimentary tract is composed of the same four tissue layers; the details of their structural arrangements vary to fit their specific functions. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2).",True,Histology of the Alimentary Canal,Figure 23.1.2,23.1 Overview of the Digestive System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2402_Layers_of_the_Gastrointestinal_Tract.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa."
+419c8372-8eaf-4649-b1f4-a9be7fbea21d,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The mucosa is referred to as a mucous membrane, because mucus production is a characteristic feature of gut epithelium. The membrane consists of epithelium, which is in direct contact with ingested food, and the lamina propria, a layer of connective tissue analogous to the dermis. In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosa (not to be confused with the muscularis layer, described below).",True,Histology of the Alimentary Canal,,,,
+615e75f5-5dc2-4371-9a8d-37474183fc5e,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Epithelium—In the mouth, pharynx, esophagus, and anal canal, the epithelium is primarily a non-keratinized, stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. Interspersed among its epithelial cells are goblet cells, which secrete mucus and fluid into the lumen, and enteroendocrine cells, which secrete hormones into the interstitial spaces between cells. Epithelial cells have a very brief lifespan, averaging from only a couple of days (in the mouth) to about a week (in the gut). This process of rapid renewal helps preserve the health of the alimentary canal, despite the wear and tear resulting from continued contact with foodstuffs.",True,Histology of the Alimentary Canal,,,,
+7a0511f7-f95a-4377-8747-4c782a568c85,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Lamina propria—In addition to loose connective tissue, the lamina propria contains numerous blood and lymphatic vessels that transport nutrients absorbed through the alimentary canal to other parts of the body. The lamina propria also serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT). These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyer’s patches. When you consider that the alimentary canal is exposed to foodborne bacteria and other foreign matter, it is not hard to appreciate why the immune system has evolved a means of defending against the pathogens encountered within it.",True,Histology of the Alimentary Canal,,,,
+b720673d-c68a-4ae4-bf26-bc5a19030843,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Muscularis mucosa—This thin layer of smooth muscle is in a constant state of tension, pulling the mucosa of the stomach and small intestine into undulating folds. These folds dramatically increase the surface area available for digestion and absorption.",True,Histology of the Alimentary Canal,,,,
+6f1cd849-13b5-40a3-a9af-42f843531729,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"As its name implies, the submucosa lies immediately beneath the mucosa. A broad layer of dense connective tissue, it connects the overlying mucosa to the underlying muscularis. It includes blood and lymphatic vessels (which transport absorbed nutrients), and a scattering of submucosal glands that release digestive secretions. Additionally, it serves as a conduit for a dense branching network of nerves, the submucosal plexus, which functions as described below.",True,Histology of the Alimentary Canal,,,,
+f8269a06-9fb4-433e-84f2-a0e208eebda5,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The third layer of the alimentary canal is the muscalaris (also called the muscularis externa). The muscularis in the small intestine is made up of a double layer of smooth muscle: an inner circular layer and an outer longitudinal layer. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal. In the most proximal and distal regions of the alimentary canal, including the mouth, pharynx, anterior part of the esophagus, and external anal sphincter, the muscularis is made up of skeletal muscle, which gives you voluntary control over swallowing and defecation. The basic two-layer structure found in the small intestine is modified in the organs proximal and distal to it. The stomach is equipped for its churning function by the addition of a third layer, the oblique muscle. While the colon has two layers like the small intestine, its longitudinal layer is segregated into three narrow parallel bands, the tenia coli, which make it look like a series of pouches rather than a simple tube.",True,Histology of the Alimentary Canal,,,,
+d9023a82-6b63-4461-8dae-d85dcaf2b5a3,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The serosa is the portion of the alimentary canal superficial to the muscularis. Present only in the region of the alimentary canal within the abdominal cavity, it consists of a layer of visceral peritoneum overlying a layer of loose connective tissue. Instead of serosa, the mouth, pharynx, and esophagus have a dense sheath of collagen fibers called the adventitia. These tissues serve to hold the alimentary canal in place near the ventral surface of the vertebral column.",True,Histology of the Alimentary Canal,,,,
+947eb33f-4d2a-4353-8078-13c4b1ec1e0c,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,Nerve Supply,False,Nerve Supply,,,,
+b43c85fa-90a5-451b-a2a5-fc56d8dc8bee,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"As soon as food enters the mouth, it is detected by receptors that send impulses along the sensory neurons of cranial nerves. Without these nerves, not only would your food be without taste, but you would also be unable to feel either the food or the structures of your mouth, and you would be unable to avoid biting yourself as you chew, an action enabled by the motor branches of cranial nerves.",True,Nerve Supply,,,,
+9212f6b9-ee8e-4f91-8a6d-c427c8452631,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Intrinsic innervation of much of the alimentary canal is provided by the enteric nervous system, which runs from the esophagus to the anus, and contains approximately 100 million motor, sensory, and interneurons (unique to this system compared to all other parts of the peripheral nervous system). These enteric neurons are grouped into two plexuses. The myenteric plexus (plexus of Auerbach) lies in the muscularis layer of the alimentary canal and is responsible for motility, especially the rhythm and force of the contractions of the muscularis. The submucosal plexus (plexus of Meissner) lies in the submucosal layer and is responsible for regulating digestive secretions and reacting to the presence of food (see Figure 23.1.2).",True,Nerve Supply,Figure 23.1.2,23.1 Overview of the Digestive System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2402_Layers_of_the_Gastrointestinal_Tract.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa."
+beaae40a-878b-4028-a3a0-48b3c95e933c,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Extrinsic innervations of the alimentary canal are provided by the autonomic nervous system, which includes both sympathetic and parasympathetic nerves. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. In contrast, parasympathetic activation (the rest-and-digest response) increases GI secretion and motility by stimulating neurons of the enteric nervous system.",True,Nerve Supply,,,,
+4415a77c-932d-4ceb-a2bf-65a3bf4d4389,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,Blood Supply,False,Blood Supply,,,,
+db907aef-0a8e-4623-84c7-b0d0d8f89107,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The blood vessels serving the digestive system have two functions. They transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen. Lipids are absorbed via lacteals, tiny structures of the lymphatic system. The blood vessels’ second function is to supply the organs of the alimentary canal with the nutrients and oxygen needed to drive their cellular processes.",True,Blood Supply,,,,
+1a618ac1-1eaf-4e06-9140-6e5fb5d24edf,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"Specifically, the more anterior parts of the alimentary canal are supplied with blood by arteries branching off the aortic arch and thoracic aorta. Below this point, the alimentary canal is supplied with blood by arteries branching from the abdominal aorta. The celiac trunk services the liver, stomach, and duodenum, whereas the superior and inferior mesenteric arteries supply blood to the remaining small and large intestines.",True,Blood Supply,,,,
+c0d8819b-b096-4ee4-b670-8704313ee02c,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The veins that collect nutrient-rich blood from the small intestine (where most absorption occurs) empty into the hepatic portal system. This venous network takes the blood into the liver where the nutrients are either processed or stored for later use. Only then does the blood drained from the alimentary canal viscera circulate back to the heart. To appreciate just how demanding the digestive process is on the cardiovascular system, consider that while you are “resting and digesting,” about one-fourth of the blood pumped with each heartbeat enters arteries serving the intestines.",True,Blood Supply,,,,
+da487474-4cf2-4a66-8dad-827571c4b107,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,The Peritoneum,False,The Peritoneum,,,,
+cef33a08-3c23-4acf-a670-968cb492c0a8,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The digestive organs within the abdominal cavity are held in place by the peritoneum, a broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue. It is composed of two different regions: the parietal peritoneum, which lines the abdominal wall, and the visceral peritoneum, which envelopes the abdominal organs (Figure 23.1.3). The peritoneal cavity is the space bounded by the visceral and parietal peritoneal surfaces. A few milliliters of watery fluid act as a lubricant to minimize friction between the serosal surfaces of the peritoneum.",True,The Peritoneum,Figure 23.1.3,23.1 Overview of the Digestive System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2403_The_PeritoneumN.jpg,"Figure 23.1.3 – The Peritoneum: A cross-section of the abdomen shows the relationship between abdominal organs and the peritoneum (darker lines). EDITOR’S NOTE: Please add an anterior and sagittal image showing the mesentery, mesocolon, greater omentum, and lesser omentum."
+aa4fa40b-8a1d-47c8-94c8-392844e21e03,https://open.oregonstate.education/aandp/,23.1 Overview of the Digestive System,https://open.oregonstate.education/aandp/chapter/23-1-overview-of-the-digestive-system/,"The visceral peritoneum includes multiple large folds that envelope various abdominal organs, holding them to the dorsal surface of the body wall. Within these folds are blood vessels, lymphatic vessels, and nerves that innervate the organs with which they are in contact, supplying their adjacent organs. The five major peritoneal folds are described in Table 23.2. An important one of these folds is the mesentery which attaches the small intestine to the body wall allowing for blood vessels, nerves, and lymphatic vessels to have a secure structure to travel through on their way to and from the small intestine. The mesocolon is the portion of the mesentery serving the colon and is considered part of the larger mesentery organ. Note that during fetal development, certain digestive structures, including the first portion of the small intestine (called the duodenum), the pancreas, and portions of the large intestine (the ascending and descending colon, and the rectum) remain completely or partially posterior to the peritoneum. Thus, the location of these organs is described as retroperitoneal.",True,The Peritoneum,,,,
+534c606f-c19b-4879-a89f-594821705f7e,https://open.oregonstate.education/aandp/,23.0 Introduction,https://open.oregonstate.education/aandp/chapter/23-0-introduction/,"The digestive system is continually at work, yet people seldom appreciate the complex tasks it performs in a choreographed biologic symphony. Consider what happens when you eat an apple. Of course, you enjoy the apple’s taste as you chew it, but in the hours that follow, unless something goes amiss and you get a stomachache, you don’t notice that your digestive system is working. You may be taking a walk or studying or sleeping, having forgotten all about the apple, but your stomach and intestines are busy digesting it and absorbing its vitamins and other nutrients. By the time any waste material is excreted, the body has appropriated all it can use from the apple. In short, whether you pay attention or not, the organs of the digestive system perform their specific functions, allowing you to use the food you eat to keep you going. This chapter examines the structure and functions of these organs, and explores the mechanics and chemistry of the digestive processes.",True,The Peritoneum,,,,
+db8ff036-5884-4279-ae75-5d992647c603,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,"Development of the respiratory system begins early in the fetus. It is a complex process that includes many structures, most of which arise from the endoderm. Towards the end of development, the fetus can be observed making breathing movements. Until birth, however, the mother provides all of the oxygen to the fetus as well as removes all of the fetal carbon dioxide via the placenta.",True,The Peritoneum,,,,
+a5ddb9e2-52a9-497e-9f6d-2aacacd2b2c6,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,Time Line,False,Time Line,,,,
+23d2f848-9c5e-44bb-a1c0-4823d4cdee80,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,"The development of the respiratory system begins at about week 4 of gestation. By week 28, enough alveoli have matured that a baby born prematurely at this time can usually breathe on its own. The respiratory system, however, is not fully developed until early childhood, when a full complement of mature alveoli is present.",True,Time Line,,,,
+45c3c3e6-2589-493a-a65d-a7d4d2934dab,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,Fetal “Breathing”,False,Fetal “Breathing”,,,,
+ececf9ec-74c3-4ffc-8865-614921e09ab6,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,"Although the function of fetal breathing movements is not entirely clear, they can be observed starting at 20–21 weeks of development. Fetal breathing movements involve muscle contractions that cause the inhalation of amniotic fluid and exhalation of the same fluid, with pulmonary surfactant and mucus. Fetal breathing movements are not continuous and may include periods of frequent movements and periods of no movements. Maternal factors can influence the frequency of breathing movements. For example, high blood glucose levels, called hyperglycemia, can boost the number of breathing movements. Conversely, low blood glucose levels, called hypoglycemia, can reduce the number of fetal breathing movements. Tobacco use is also known to lower fetal breathing rates. Fetal breathing may help tone the muscles in preparation for breathing movements once the fetus is born. It may also help the alveoli to form and mature. Fetal breathing movements are considered a sign of robust health.",True,Fetal “Breathing”,,,,
+7c8c9a7d-d620-4894-b9fe-fd94dd6a85b3,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,Birth,False,Birth,,,,
+717a7e99-8ce9-49cd-996a-3a67260142eb,https://open.oregonstate.education/aandp/,22.7 Embryonic Development of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-7-embryonic-development-of-the-respiratory-system/,"Prior to birth, the lungs are filled with amniotic fluid, mucus, and surfactant. As the fetus is squeezed through the birth canal, the fetal thoracic cavity is compressed, expelling much of this fluid. Some fluid remains, however, but is rapidly absorbed by the body shortly after birth. The first inhalation occurs within 10 seconds after birth and not only serves as the first inspiration, but also acts to inflate the lungs. Pulmonary surfactant is critical for inflation to occur, as it reduces the surface tension of the alveoli. Preterm birth around 26 weeks frequently results in severe respiratory distress, although with current medical advancements, some babies may survive. Prior to 26 weeks, sufficient pulmonary surfactant is not produced, and the surfaces for gas exchange have not formed adequately; therefore, survival is low.",True,Birth,,,,
+b5f06283-2843-4959-9b32-c201e3458f63,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"At rest, the respiratory system performs its functions at a constant, rhythmic pace, as regulated by the respiratory centers of the brain. At this pace, ventilation provides sufficient oxygen to all the tissues of the body. However, there are times that the respiratory system must alter the pace of its functions in order to accommodate the oxygen demands of the body.",True,Birth,,,,
+7c28ef2c-d69d-4470-95a9-4ee94c316a5f,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,Hyperpnea,False,Hyperpnea,,,,
+84f5b8ea-9949-4ec8-87e3-ef5890332e97,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"Hyperpnea is an increased depth and rate of ventilation to meet an increase in oxygen demand as might be seen in exercise or disease, particularly diseases that target the respiratory or digestive tracts. This does not significantly alter blood oxygen or carbon dioxide levels, but merely increases the depth and rate of ventilation to meet the demand of the cells. In contrast, hyperventilation is an increased ventilation rate that is independent of the cellular oxygen needs and leads to abnormally low blood carbon dioxide levels and high (alkaline) blood pH.",True,Hyperpnea,,,,
+2ae008d0-00cc-4d35-bdfa-015d4404f19c,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"Interestingly, exercise does not cause hyperpnea as one might think. Muscles that perform work during exercise do increase their demand for oxygen, stimulating an increase in ventilation. However, hyperpnea during exercise appears to occur before a drop in oxygen levels within the muscles can occur. Therefore, hyperpnea must be driven by other mechanisms, either instead of or in addition to a drop in oxygen levels. The exact mechanisms behind exercise hyperpnea are not well understood, and some hypotheses are somewhat controversial. However, in addition to low oxygen, high carbon dioxide, and low pH levels, there appears to be a complex interplay of factors related to the nervous system and the respiratory centers of the brain.",True,Hyperpnea,,,,
+d0236b73-cff2-4490-8214-7058fbac5c70,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"First, a conscious decision to partake in exercise, or another form of physical exertion, results in a psychological stimulus that may trigger the respiratory centers of the brain to increase ventilation. In addition, the respiratory centers of the brain may be stimulated through the activation of motor neurons that innervate muscle groups that are involved in the physical activity. Finally, physical exertion stimulates proprioceptors, which are receptors located within the muscles, joints, and tendons, which sense movement and stretching; proprioceptors thus create a stimulus that may also trigger the respiratory centers of the brain. These neural factors are consistent with the sudden increase in ventilation that is observed immediately as exercise begins. Because the respiratory centers are stimulated by psychological, motor neuron, and proprioceptor inputs throughout exercise, the fact that there is also a sudden decrease in ventilation immediately after the exercise ends when these neural stimuli cease, further supports the idea that they are involved in triggering the changes of ventilation.",True,Hyperpnea,,,,
+75c2a0f9-4c0f-4d58-afb3-8b280f67bd65,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,High Altitude Effects,False,High Altitude Effects,,,,
+ab1047d8-5abc-473d-9bdd-baa911c2ccef,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"An increase in altitude results in a decrease in atmospheric pressure. Although the proportion of oxygen relative to gases in the atmosphere remains at 21 percent, its partial pressure decreases (Table 22.4). As a result, it is more difficult for a body to achieve the same level of oxygen saturation at high altitude than at low altitude, due to lower atmospheric pressure. In fact, hemoglobin saturation is lower at high altitudes compared to hemoglobin saturation at sea level. For example, hemoglobin saturation is about 67 percent at 19,000 feet above sea level, whereas it reaches about 98 percent at sea level.",True,High Altitude Effects,,,,
+4e3b3f56-3760-4167-b71d-6a796149555e,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"As you recall, partial pressure is extremely important in determining how much gas can cross the respiratory membrane and enter the blood of the pulmonary capillaries. A lower partial pressure of oxygen means that there is a smaller difference in partial pressures between the alveoli and the blood, so less oxygen crosses the respiratory membrane. As a result, fewer oxygen molecules are bound by hemoglobin. Despite this, the tissues of the body still receive a sufficient amount of oxygen during rest at high altitudes. This is due to two major mechanisms. First, the number of oxygen molecules that enter the tissue from the blood is nearly equal between sea level and high altitudes. At sea level, hemoglobin saturation is higher, but only a quarter of the oxygen molecules are actually released into the tissue. At high altitudes, a greater proportion of molecules of oxygen are released into the tissues. Secondly, at high altitudes, a greater amount of BPG is produced by erythrocytes, which enhances the dissociation of oxygen from hemoglobin. Physical exertion, such as skiing or hiking, can lead to altitude sickness due to the low amount of oxygen reserves in the blood at high altitudes. At sea level, there is a large amount of oxygen reserve in venous blood (even though venous blood is thought of as “deoxygenated”) from which the muscles can draw during physical exertion. Because the oxygen saturation is much lower at higher altitudes, this venous reserve is small, resulting in pathological symptoms of low blood oxygen levels. You may have heard that it is important to drink more water when traveling at higher altitudes than you are accustomed to. This is because your body will increase micturition (urination) at high altitudes to counteract the effects of lower oxygen levels. By removing fluids, blood plasma levels drop but not the total number of erythrocytes. In this way, the overall concentration of erythrocytes in the blood increases, which helps tissues obtain the oxygen they need.",True,High Altitude Effects,,,,
+420fb1ec-445e-43f8-8e69-0c9eac76e08d,https://open.oregonstate.education/aandp/,22.6 Modifications in Respiratory Functions,https://open.oregonstate.education/aandp/chapter/22-6-modifications-in-respiratory-functions/,"Acute mountain sickness (AMS), or altitude sickness, is a condition that results from acute exposure to high altitudes due to a low partial pressure of oxygen at high altitudes. AMS typically can occur at 2400 meters (8000 feet) above sea level. AMS is a result of low blood oxygen levels, as the body has acute difficulty adjusting to the low partial pressure of oxygen. In serious cases, AMS can cause pulmonary or cerebral edema. Symptoms of AMS include nausea, vomiting, fatigue, lightheadedness, drowsiness, feeling disoriented, increased pulse, and nosebleeds. The only treatment for AMS is descending to a lower altitude; however, pharmacologic treatments and supplemental oxygen can improve symptoms. AMS can be prevented by slowly ascending to the desired altitude, allowing the body to acclimate, as well as maintaining proper hydration.",True,High Altitude Effects,,,,
+f882e941-6c9f-4ef2-9115-d5d478578826,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,"The other major activity in the lungs is the process of respiration, the process of gas exchange. The function of respiration is to provide oxygen for use by body cells during cellular respiration and to eliminate carbon dioxide, a waste product of cellular respiration, from the body. In order for the exchange of oxygen and carbon dioxide to occur, both gases must be transported between the external and internal respiration sites. Although carbon dioxide is more soluble than oxygen in blood, both gases require a specialized transport system for the majority of the gas molecules to be moved between the lungs and other tissues.",True,High Altitude Effects,,,,
+1b708fd7-f9da-4493-a269-26846a24c922,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,Oxygen Transport in the Blood,False,Oxygen Transport in the Blood,,,,
+a640bc7d-a55b-4d00-8f6f-29ec9b0cca37,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,"Even though oxygen is transported via the blood, you may recall that oxygen is not very soluble in liquids. A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Erythrocytes contain a metalloprotein, hemoglobin, which serves to bind oxygen molecules to the erythrocyte (Figure 22.5.1). Heme is the portion of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing Heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product, oxyhemoglobin (Hb–O2), which is formed when oxygen binds to hemoglobin. Oxyhemoglobin is a bright red-colored molecule that contributes to the bright red color of oxygenated blood.",True,Oxygen Transport in the Blood,Figure 22.5.1,22.5 Transport of Gases,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2322_Fig_23.22-a.jpg,"Figure 22.5.1 – Erythrocyte and Hemoglobin: Hemoglobin consists of four subunits, each of which contains one molecule of iron."
+69b21a62-3d24-454c-8451-2e23b095092e,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,"In this formula, Hb represents reduced hemoglobin, that is, hemoglobin that does not have oxygen bound to it. There are multiple factors involved in how readily heme binds to and dissociates from oxygen, which will be discussed in the subsequent sections.",True,Oxygen Transport in the Blood,,,,
+d9762f30-60b0-4651-9ad9-333f7ee3d2bb,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,Carbon Dioxide Transport in the Blood,False,Carbon Dioxide Transport in the Blood,,,,
+66bce94f-8c0a-4634-9c16-aad8fcd453c8,https://open.oregonstate.education/aandp/,22.5 Transport of Gases,https://open.oregonstate.education/aandp/chapter/22-5-transport-of-gases/,"Carbon dioxide is transported by three major mechanisms. The first mechanism of carbon dioxide transport is by blood plasma, as some carbon dioxide molecules dissolve in the blood. The second mechanism is transport in the form of bicarbonate (HCO3–), which also dissolves in plasma. The third mechanism of carbon dioxide transport is similar to the transport of oxygen by erythrocytes (Figure 22.5.4).",True,Carbon Dioxide Transport in the Blood,Figure 22.5.4,22.5 Transport of Gases,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2325_Carbon_Dioxide_Transport.jpg,"Figure 22.5.4 – Carbon Dioxide Transport: Carbon dioxide is transported by three different methods: (a) in erythrocytes; (b) after forming carbonic acid (H2CO3 ), which is dissolved in plasma; (c) and in plasma."
+0c44030f-5e03-48bb-a052-73155c9dd9d5,https://open.oregonstate.education/aandp/,22.4 Gas Exchange,https://open.oregonstate.education/aandp/chapter/22-4-gas-exchange/,"The purpose of the respiratory system is to perform gas exchange. Pulmonary ventilation provides air to the alveoli for this gas exchange process. At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.",True,Carbon Dioxide Transport in the Blood,,,,
+bcf33b25-760b-4458-aee2-4d2a1210b59c,https://open.oregonstate.education/aandp/,22.4 Gas Exchange,https://open.oregonstate.education/aandp/chapter/22-4-gas-exchange/,Gas Exchange,False,Gas Exchange,,,,
+e1c9104e-2953-4f66-8d0e-76b52e4bfde6,https://open.oregonstate.education/aandp/,22.4 Gas Exchange,https://open.oregonstate.education/aandp/chapter/22-4-gas-exchange/,"In order to understand the mechanisms of gas exchange in the lung, it is important to understand the underlying principles of gases and their behavior. In addition to Boyle’s law, several other gas laws help to describe the behavior of gases.",True,Gas Exchange,,,,
+ec30236b-a924-4edc-8c68-ea51a954e300,https://open.oregonstate.education/aandp/,22.4 Gas Exchange,https://open.oregonstate.education/aandp/chapter/22-4-gas-exchange/,Gas Exchange,False,Gas Exchange,,,,
+a3604b31-c13b-4059-b80e-93fc40b60331,https://open.oregonstate.education/aandp/,22.4 Gas Exchange,https://open.oregonstate.education/aandp/chapter/22-4-gas-exchange/,"Gas exchange occurs at two sites in the body: in the lungs, where oxygen is picked up and carbon dioxide is released at the respiratory membrane, and at the tissues, where oxygen is released and carbon dioxide is picked up. External respiration is the exchange of gases with the external environment, and occurs in the alveoli of the lungs. Internal respiration is the exchange of gases with the internal environment, and occurs in the tissues. The actual exchange of gases occurs due to simple diffusion. Energy is not required to move oxygen or carbon dioxide across membranes. Instead, these gases follow pressure gradients that allow them to diffuse. The anatomy of the lung maximizes the diffusion of gases: The respiratory membrane is highly permeable to gases; the respiratory and blood capillary membranes are very thin; and there is a large surface area throughout the lungs.",True,Gas Exchange,,,,
+d4b4526b-0200-48fd-a4e1-d760ffc81fd0,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"Pulmonary ventilation is the act of breathing, which can be described as the movement of air into and out of the lungs. The major mechanisms that drive pulmonary ventilation are atmospheric pressure (Patm); the air pressure within the alveoli, called alveolar pressure (Palv); and the pressure within the pleural cavity, called intrapleural pressure (Pip).",True,Gas Exchange,,,,
+9f6d376f-1d49-4917-ae9f-83a4a6803596,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,Mechanisms of Breathing,False,Mechanisms of Breathing,,,,
+620b6fba-ba91-495d-8e7b-22e0fa83d0cd,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"The alveolar and intrapleural pressures are dependent on certain physical features of the lung. However, the ability to breathe—to have air enter the lungs during inspiration and air leave the lungs during expiration—is dependent on the air pressure of the atmosphere and the air pressure within the lungs.",True,Mechanisms of Breathing,,,,
+e012477f-5870-44aa-a662-fc852411a39d,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,Pulmonary Ventilation,False,Pulmonary Ventilation,,,,
+fc2b2bc3-c3fa-4621-9b51-46132ef6d8c7,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"The difference in pressures drives pulmonary ventilation because air flows down a pressure gradient, that is, air flows from an area of higher pressure to an area of lower pressure. Air flows into the lungs largely due to a difference in pressure; atmospheric pressure is greater than intra-alveolar pressure, and intra-alveolar pressure is greater than intrapleural pressure. Air flows out of the lungs during expiration based on the same principle; pressure within the lungs becomes greater than the atmospheric pressure.",True,Pulmonary Ventilation,,,,
+93566d34-1c6d-4e26-9da5-454210281ed3,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"Pulmonary ventilation comprises two major steps: inspiration and expiration. Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs (Figure 22.3.3). A respiratory cycle is one sequence of inspiration and expiration. In general, two muscle groups are used during normal inspiration: the diaphragm and the external intercostal muscles. Additional muscles can be used if a bigger breath is required. When the diaphragm contracts, it moves inferiorly toward the abdominal cavity, creating a larger thoracic cavity and more space for the lungs. Contraction of the external intercostal muscles moves the ribs upward and outward, causing the rib cage to expand, which increases the volume of the thoracic cavity. Due to the adhesive force of the pleural fluid, the expansion of the thoracic cavity forces the lungs to stretch and expand as well. This increase in volume leads to a decrease in intra-alveolar pressure, creating a pressure lower than atmospheric pressure. As a result, a pressure gradient is created that drives air into the lungs.",True,Pulmonary Ventilation,Figure 22.3.3,22.3 The Process of Breathing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2316_Inspiration_and_Expiration.jpg,"Figure 22.3.3 – Inspiration and Expiration: Inspiration and expiration occur due to the expansion and contraction of the thoracic cavity, respectively."
+e50c3793-f51f-4611-afdf-1397a9712946,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"The process of normal expiration is passive, meaning that energy is not required to push air out of the lungs. Instead, the elasticity of the lung tissue causes the lung to recoil, as the diaphragm and intercostal muscles relax following inspiration. In turn, the thoracic cavity and lungs decrease in volume, causing an increase in interpulmonary pressure. The interpulmonary pressure rises above atmospheric pressure, creating a pressure gradient that causes air to leave the lungs.",True,Pulmonary Ventilation,,,,
+efcb7e14-2457-4a80-a988-f65446e74487,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"There are different types, or modes, of breathing that require a slightly different process to allow inspiration and expiration. Quiet breathing, also known as eupnea, is a mode of breathing that occurs at rest and does not require the cognitive thought of the individual. During quiet breathing, the diaphragm and external intercostals must contract.",True,Pulmonary Ventilation,,,,
+8f13c1a1-c535-4ed1-b922-421616c75267,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"A deep breath, called diaphragmatic breathing, requires the diaphragm to contract. As the diaphragm relaxes, air passively leaves the lungs. A shallow breath, called costal breathing, requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs.",True,Pulmonary Ventilation,,,,
+02806de7-fafc-4f47-ae2e-850f599de454,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"In contrast, forced breathing, also known as hyperpnea, is a mode of breathing that can occur during exercise or actions that require the active manipulation of breathing, such as singing. During forced breathing, inspiration and expiration both occur due to muscle contractions. In addition to the contraction of the diaphragm and intercostal muscles, other accessory muscles must also contract. During forced inspiration, muscles of the neck, including the scalenes, contract and lift the thoracic wall, increasing lung volume. During forced expiration, accessory muscles of the abdomen, including the obliques, contract, forcing abdominal organs upward against the diaphragm. This helps to push the diaphragm further into the thorax, pushing more air out. In addition, accessory muscles (primarily the internal intercostals) help to compress the rib cage, which also reduces the volume of the thoracic cavity.",True,Pulmonary Ventilation,,,,
+c7d2ea0c-b3ff-4dc8-a22c-2f52b2decffb,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,Respiratory Volumes and Capacities,False,Respiratory Volumes and Capacities,,,,
+c555c2d7-9885-4226-a304-1dcd756209b0,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22.3.4). Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for men. Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration. This is the extra volume that can be brought into the lungs during a forced inspiration. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible. The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22.3.5).",True,Respiratory Volumes and Capacities,Figure 22.3.4,22.3 The Process of Breathing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2317_Spirometry_and_Respiratory_Volumes.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.
+4418d1f4-b796-4700-9681-80ad3497f01a,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"Respiratory capacity is the combination of two or more selected volumes, which further describes the amount of air in the lungs during a given time. For example, total lung capacity (TLC) is the sum of all of the lung volumes (TV, ERV, IRV, and RV), which represents the total amount of air a person can hold in the lungs after a forceful inhalation. TLC is about 6000 mL air for men, and about 4200 mL for women. Vital capacity (VC) is the amount of air a person can move into or out of his or her lungs, and is the sum of all of the volumes except residual volume (TV, ERV, and IRV), which is between 4000 and 5000 milliliters. Inspiratory capacity (IC) is the maximum amount of air that can be inhaled past a normal tidal expiration, is the sum of the tidal volume and inspiratory reserve volume. On the other hand, the functional residual capacity (FRC) is the amount of air that remains in the lung after a normal tidal expiration; it is the sum of expiratory reserve volume and residual volume (see Figure 22.3.4).",True,Respiratory Volumes and Capacities,Figure 22.3.4,22.3 The Process of Breathing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2317_Spirometry_and_Respiratory_Volumes.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.
+32c77cd5-629f-40cc-ad20-d5debee0add3,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"In addition to the air that creates respiratory volumes, the respiratory system also contains anatomical dead space, which is air that is present in the airway that never reaches the alveoli and therefore never participates in gas exchange. Alveolar dead space involves air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow. Total dead space is the anatomical dead space and alveolar dead space together, and represents all of the air in the respiratory system that is not being used in the gas exchange process.",True,Respiratory Volumes and Capacities,,,,
+ce5660d5-fb6c-4f71-9760-33b48b2b733d,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,Respiratory Rate and Control of Ventilation,False,Respiratory Rate and Control of Ventilation,,,,
+7a56e2db-3d44-468a-a9fa-b7f8260c3c8f,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"Breathing usually occurs without thought, although at times you can consciously control it, such as when you swim under water, sing a song, or blow bubbles. The respiratory rate is the total number of breaths, or respiratory cycles, that occur each minute. Respiratory rate can be an important indicator of disease, as the rate may increase or decrease during an illness or in a disease condition. The respiratory rate is controlled by the respiratory center located within the medulla oblongata in the brain, which responds primarily to changes in carbon dioxide, oxygen, and pH levels in the blood.",True,Respiratory Rate and Control of Ventilation,,,,
+21921387-c503-494b-9770-3f0a286e0b42,https://open.oregonstate.education/aandp/,22.3 The Process of Breathing,https://open.oregonstate.education/aandp/chapter/22-3-the-process-of-breathing/,"The normal respiratory rate of a child decreases from birth to adolescence. A child under 1 year of age has a normal respiratory rate between 30 and 60 breaths per minute, but by the time a child is about 10 years old, the normal rate is closer to 18 to 30. By adolescence, the normal respiratory rate is similar to that of adults, 12 to 18 breaths per minute.",True,Respiratory Rate and Control of Ventilation,,,,
+87eeee03-92e6-4aeb-ae9e-061940b0744b,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"A major organ of the respiratory system, each lung houses structures of both the conducting and respiratory zones. The main function of the lungs is to perform the exchange of oxygen and carbon dioxide with air from the atmosphere. To this end, the lungs exchange respiratory gases across a very large epithelial surface area—about 70 square meters—that is highly permeable to gases.",True,Respiratory Rate and Control of Ventilation,,,,
+9675c7eb-fed3-4739-9e23-3d7ac5508744,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,Gross Anatomy of the Lungs,False,Gross Anatomy of the Lungs,,,,
+61c2f229-1c42-4a12-95fb-29d9eabb5ba5,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"The lungs are pyramid-shaped, paired organs that are connected to the trachea by the right and left bronchi; on the inferior surface, the lungs are bordered by the diaphragm. The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity. The lungs are enclosed by the pleurae, which are attached to the mediastinum. The right lung is shorter and wider than the left lung, and the left lung occupies a smaller volume than the right. The cardiac notch is an indentation on the surface of the left lung, and it allows space for the heart (Figure 22.2.1). The apex of the lung is the superior region, whereas the base is the opposite region near the diaphragm. The costal surface of the lung borders the ribs. The mediastinal surface faces the midline.",True,Gross Anatomy of the Lungs,Figure 22.2.1,22.2 The Lungs,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2312_Gross_Anatomy_of_the_Lungs.jpg,Figure 22.2.1 Gross Anatomy of the Lungs.
+d6cb9dc5-0026-4faa-b538-d0d85f87a6de,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"Each lung is composed of smaller units called lobes. Fissures separate these lobes from each other. The right lung consists of three lobes: the superior, middle, and inferior lobes. The left lung consists of two lobes: the superior and inferior lobes. A bronchopulmonary segment is a division of a lobe, and each lobe houses multiple bronchopulmonary segments. Each segment receives air from its own tertiary bronchus and is supplied with blood by its own artery. Some diseases of the lungs typically affect one or more bronchopulmonary segments, and in some cases, the diseased segments can be surgically removed with little influence on neighboring segments. A pulmonary lobule is a subdivision formed as the bronchi branch into bronchioles. Each lobule receives its own large bronchiole that has multiple branches. An interlobular septum is a wall, composed of connective tissue, which separates lobules from one another.",True,Gross Anatomy of the Lungs,,,,
+b21aa59d-527d-4912-835f-1bd83af07a9d,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,Blood Supply and Nervous Innervation of the Lungs,False,Blood Supply and Nervous Innervation of the Lungs,,,,
+6ec038ca-545e-4c37-a298-d478066f33d4,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"The blood supply of the lungs plays an important role in gas exchange and serves as a transport system for gases throughout the body. In addition, innervation by the both the parasympathetic and sympathetic nervous systems provides an important level of control through dilation and constriction of the airway.",True,Blood Supply and Nervous Innervation of the Lungs,,,,
+15eff0b1-b31e-4555-adb6-2845d0a9a1a3,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,Pleura of the Lungs,False,Pleura of the Lungs,,,,
+7e8691f6-86cc-4b5b-aaef-cc87ecee4e0f,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"Each lung is enclosed within a cavity that is surrounded by the pleura. The pleura (plural = pleurae) is a serous membrane that surrounds the lung. The right and left pleurae, which enclose the right and left lungs, respectively, are separated by the mediastinum. The pleurae consist of two layers. The visceral pleura is the layer that is superficial to the lungs, and extends into and lines the lung fissures (Figure 22.2.2). In contrast, the parietal pleura is the outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The visceral and parietal pleurae connect to each other at the hilum. The pleural cavity is the space between the visceral and parietal layers.",True,Pleura of the Lungs,Figure 22.2.2,22.2 The Lungs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2313_The_Lung_Pleurea.jpg,Figure 22.2.2 Parietal and Visceral Pleurae of the Lungs.
+cf415e07-eee1-4022-b124-f24bb13f2b0d,https://open.oregonstate.education/aandp/,22.2 The Lungs,https://open.oregonstate.education/aandp/chapter/22-2-the-lungs/,"The pleurae perform two major functions: They produce pleural fluid and create cavities that separate the major organs. Pleural fluid is secreted by mesothelial cells from both pleural layers and acts to lubricate their surfaces. This lubrication reduces friction between the two layers to prevent trauma during breathing, and creates surface tension that helps maintain the position of the lungs against the thoracic wall. This adhesive characteristic of the pleural fluid causes the lungs to enlarge when the thoracic wall expands during ventilation, allowing the lungs to fill with air. The pleurae also create a division between major organs that prevents interference due to the movement of the organs, while preventing the spread of infection.",True,Pleura of the Lungs,,,,
+92650709-902a-4da9-842e-bba61bd8500f,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,"The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to maintain acid-base balance. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing (Figure 22.1.1).",True,Pleura of the Lungs,Figure 22.1.1,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2301_Major_Respiratory_Organs.jpg,Figure 22.1.1 – Major Respiratory Structures: The major respiratory structures span the nasal cavity to the diaphragm.
+3c5b3ebb-327e-4558-bc22-2784b05a67f5,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,"Functionally, the respiratory system can be divided into a conducting zone and a respiratory zone. The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. The gas exchange occurs in the respiratory zone.",True,Pleura of the Lungs,,,,
+a104ff1c-d2f1-4461-9d2f-a405999ac68e,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,Conducting Zone,False,Conducting Zone,,,,
+20b3ef53-bebc-4774-912f-acec5f4b9580,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,"The major functions of the conducting zone are to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air. Several structures within the conducting zone perform other functions as well. The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens.",True,Conducting Zone,,,,
+1522001d-5134-4710-9435-a5b5ae0c8b91,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,Respiratory Zone,False,Respiratory Zone,,,,
+9096842f-f5e9-45ab-9170-185b498566f5,https://open.oregonstate.education/aandp/,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/aandp/chapter/22-1-organs-and-structures-of-the-respiratory-system/,"In contrast to the conducting zone, the respiratory zone includes structures that are directly involved in gas exchange. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole (Figure 22.1.9), which then leads to an alveolar duct, opening into a cluster of alveoli.",True,Respiratory Zone,Figure 22.1.9,22.1 Organs and Structures of the Respiratory System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2309_The_Respiratory_Zone.jpg,"Figure 22.1.9 – Respiratory Zone: Bronchioles lead to alveolar sacs in the respiratory zone, where gas exchange occurs."
+43ab76bd-12db-456c-b5b5-696f39abb9f4,https://open.oregonstate.education/aandp/,22.0 Introduction,https://open.oregonstate.education/aandp/chapter/22-0-introduction/,"Hold your breath. Really! See how long you can hold your breath as you continue reading…How long can you do it? Chances are you are feeling uncomfortable already. A typical human cannot survive without breathing for more than 3 minutes, and even if you wanted to hold your breath longer, your autonomic nervous system would take control. This is because every cell in the body needs to run the oxidative stages of cellular respiration, the process by which energy is produced in the form of adenosine triphosphate (ATP). For oxidative phosphorylation to occur, oxygen is used as a reactant and carbon dioxide is released as a waste product. You may be surprised to learn that although oxygen is a critical need for cells, it is actually the accumulation of carbon dioxide that primarily drives your need to breathe. Carbon dioxide is exhaled and oxygen is inhaled through the respiratory system, which includes muscles to move air into and out of the lungs, passageways through which air moves, and microscopic gas exchange surfaces covered by capillaries. The circulatory system transports gases from the lungs to tissues throughout the body and vice versa. A variety of diseases can affect the respiratory system, such as asthma, emphysema, chronic obstruction pulmonary disorder (COPD), and lung cancer. All of these conditions affect the gas exchange process and result in labored breathing and other difficulties.",True,Respiratory Zone,,,,
+05e5b04f-206a-4614-b5b0-f17b14f77ac2,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"The immune responses to transplanted organs and to cancer cells are both important medical issues. With the use of tissue typing and anti-rejection drugs, transplantation of organs and the control of the anti-transplant immune response have made huge strides in the past 50 years. Today, these procedures are commonplace. Tissue typing is the determination of MHC molecules in the tissue to be transplanted to better match the donor to the recipient. The immune response to cancer, on the other hand, has been more difficult to understand and control. Although it is clear that the immune system can recognize some cancers and control them, others seem to be resistant to immune mechanisms.",True,Respiratory Zone,,,,
+0eeb9525-790e-4651-b733-0a498074e682,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,The Rh Factor,False,The Rh Factor,,,,
+521e348f-e4e0-40f1-88f4-9f38b4724d4e,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"Red blood cells can be typed based on their surface antigens. ABO blood type, in which individuals are type A, B, AB, or O according to their genetics, is one example. A separate antigen system seen on red blood cells is the Rh antigen. When someone is “A positive” for example, the positive refers to the presence of the Rh antigen, whereas someone who is “A negative” would lack this molecule.",True,The Rh Factor,,,,
+1af60fc7-ab69-4e51-acf7-ac86c3568f2a,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"An interesting consequence of Rh factor expression is seen in erythroblastosis fetalis, a hemolytic disease of the newborn (Figure 21.7.1). This disease occurs when mothers negative for Rh antigen have multiple Rh-positive children. During the birth of a first Rh-positive child, the mother makes a primary anti-Rh antibody response to the fetal blood cells that enter the maternal bloodstream. If the mother has a second Rh-positive child, IgG antibodies against Rh-positive blood mounted during this secondary response cross the placenta and attack the fetal blood, causing anemia. This is a consequence of the fact that the fetus is not genetically identical to the mother, and thus the mother is capable of mounting an immune response against it. This disease is treated with antibodies specific for Rh factor. These are given to the mother during the subsequent births, destroying any fetal blood that might enter her system and preventing the immune response.",True,The Rh Factor,Figure 21.7.1,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2230_Erythroblastosis_Fetalis.jpg,"Figure 21.7.1 – Erythroblastosis Fetalis: Erythroblastosis fetalis (hemolytic disease of the newborn) is the result of an immune response in an Rh-negative mother who has multiple children with an Rh-positive father. During the first birth, fetal blood enters the mother’s circulatory system, and anti-Rh antibodies are made. During the gestation of the second child, these antibodies cross the placenta and attack the blood of the fetus. The treatment for this disease is to give the mother anti-Rh antibodies (RhoGAM) during the first pregnancy to destroy Rh-positive fetal red blood cells from entering her system and causing the anti-Rh antibody response in the first place."
+c727dbf7-6cf2-4f60-bd26-689b70b11d58,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,Tissue Transplantation,False,Tissue Transplantation,,,,
+f6f84d77-9237-47d9-89bd-a4579120df2d,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"Tissue transplantation is more complicated than blood transfusions because of two characteristics of MHC molecules. These molecules are the major cause of transplant rejection (hence the name “histocompatibility”). MHC polygeny refers to the multiple MHC proteins on cells, and MHC polymorphism refers to the multiple alleles for each individual MHC locus. Thus, there are many alleles in the human population that can be expressed (Table 21.8 and Table 21.9). When a donor organ expresses MHC molecules that are different from the recipient, the latter will often mount a cytotoxic T cell response to the organ and reject it. Histologically, if a biopsy of a transplanted organ exhibits massive infiltration of T lymphocytes within the first weeks after transplant, it is a sign that the transplant is likely to fail. The response is a classical, and very specific, primary T cell immune response. As far as medicine is concerned, the immune response in this scenario does the patient no good at all and causes significant harm.",True,Tissue Transplantation,,,,
+c41f5f0d-72da-476c-a3e1-8f4babec8545,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"Immunosuppressive drugs such as cyclosporine A have made transplants more successful, but matching the MHC molecules is still key. In humans, there are six MHC molecules that show the most polymorphisms, three class I molecules (A, B, and C) and three class II molecules called DP, DQ, and DR. A successful transplant usually requires a match between at least 3–4 of these molecules, with more matches associated with greater success. Family members, since they share a similar genetic background, are much more likely to share MHC molecules than unrelated individuals do. In fact, due to the extensive polymorphisms in these MHC molecules, unrelated donors are found only through a worldwide database. The system is not foolproof however, as there are not enough individuals in the system to provide the organs necessary to treat all patients needing them.",True,Tissue Transplantation,,,,
+5a7bc392-c910-4009-a9e8-b15b3cd98e6e,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"One disease of transplantation occurs with bone marrow transplants, which are used to treat various diseases, including SCID and leukemia. Because the bone marrow cells being transplanted contain lymphocytes capable of mounting an immune response, and because the recipient’s immune response has been destroyed before receiving the transplant, the donor cells may attack the recipient tissues, causing graft-versus-host disease. Symptoms of this disease, which usually include a rash and damage to the liver and mucosa, are variable, and attempts have been made to moderate the disease by first removing mature T cells from the donor bone marrow before transplanting it.",True,Tissue Transplantation,,,,
+57623556-2753-49e6-a60c-9107f5bb30cd,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,Immune Responses Against Cancer,False,Immune Responses Against Cancer,,,,
+397a0647-10e8-4931-a9ff-2175c7c07934,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"It is clear that with some cancers, for example Kaposi’s sarcoma, a healthy immune system does a good job at controlling them (Figure 21.7.2). This disease, which is caused by the human herpesvirus, is almost never observed in individuals with strong immune systems, such as the young and immunocompetent. Other examples of cancers caused by viruses include liver cancer caused by the hepatitis B virus and cervical cancer caused by the human papilloma virus. As these last two viruses have vaccines available for them, getting vaccinated can help prevent these two types of cancer by stimulating the immune response.",True,Immune Responses Against Cancer,Figure 21.7.2,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2231_Kaposis_Sacroma_Lesions.jpg,Figure 21.7.2 Karposi’s Sarcoma Lesions. (credit: National Cancer Institute)
+8a1a5576-8909-4ad9-a2c3-a2670b4e57a4,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"On the other hand, as cancer cells are often able to divide and mutate rapidly, they may escape the immune response, just as certain pathogens such as HIV do. There are three stages in the immune response to many cancers: elimination, equilibrium, and escape. Elimination occurs when the immune response first develops toward tumor-specific antigens specific to the cancer and actively kills most cancer cells, followed by a period of controlled equilibrium during which the remaining cancer cells are held in check. Unfortunately, many cancers mutate, so they no longer express any specific antigens for the immune system to respond to, and a subpopulation of cancer cells escapes the immune response, continuing the disease process.",True,Immune Responses Against Cancer,,,,
+a1e862cc-96fc-4bd4-8976-ab354cb1e101,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"This fact has led to extensive research in trying to develop ways to enhance the early immune response to completely eliminate the early cancer and thus prevent a later escape. One method that has shown some success is the use of cancer vaccines, which differ from viral and bacterial vaccines in that they are directed against the cells of one’s own body. Treated cancer cells are injected into cancer patients to enhance their anti-cancer immune response and thereby prolong survival. The immune system has the capability to detect these cancer cells and proliferate faster than the cancer cells do, overwhelming the cancer in a similar way as they do for viruses. Cancer vaccines have been developed for malignant melanoma, a highly fatal skin cancer, and renal (kidney) cell carcinoma. These vaccines are still in the development stages, but some positive and encouraging results have been obtained clinically.",True,Immune Responses Against Cancer,,,,
+ef6af9a6-8ab8-4d8b-9384-56cf63fe9439,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"It is tempting to focus on the complexity of the immune system and the problems it causes as a negative. The upside to immunity, however, is so much greater: The benefit of staying alive far outweighs the negatives caused when the system does sometimes go awry. Working on “autopilot,” the immune system helps to maintain your health and kill pathogens. The only time you really miss the immune response is when it is not being effective and illness results, or, as in the extreme case of HIV disease, the immune system is gone completely.",True,Immune Responses Against Cancer,,,,
+0708744f-e05c-4d70-ac2d-b5751cd97c50,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"At one time, it was assumed that all types of stress reduced all aspects of the immune response, but the last few decades of research have painted a different picture. First, most short-term stress does not impair the immune system in healthy individuals enough to lead to a greater incidence of diseases. However, older individuals and those with suppressed immune responses due to disease or immunosuppressive drugs may respond even to short-term stressors by getting sicker more often. It has been found that short-term stress diverts the body’s resources towards enhancing innate immune responses, which have the ability to act fast and would seem to help the body prepare better for possible infections associated with the trauma that may result from a fight-or-flight exchange. The diverting of resources away from the adaptive immune response, however, causes its own share of problems in fighting disease.",True,Immune Responses Against Cancer,,,,
+f405fcb4-15fb-4199-b004-7501deed66da,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,"Chronic stress, unlike short-term stress, may inhibit immune responses even in otherwise healthy adults. The suppression of both innate and adaptive immune responses is clearly associated with increases in some diseases, as seen when individuals lose a spouse or have other long-term stresses, such as taking care of a spouse with a fatal disease or dementia. The new science of psychoneuroimmunology, while still in its relative infancy, has great potential to make exciting advances in our understanding of how the nervous, endocrine, and immune systems have evolved together and communicate with each other.",True,Immune Responses Against Cancer,,,,
+17196fb4-3e95-4f02-a892-a0f6fef15937,https://open.oregonstate.education/aandp/,21.7 Transplantation and Cancer Immunology,https://open.oregonstate.education/aandp/chapter/21-7-transplantation-and-cancer-immunology/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+14552618-fe9e-43db-9389-3e93f577e75c,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"This section is about how the immune system goes wrong. When it goes haywire, and becomes too weak or too strong, it leads to a state of disease. The factors that maintain immunological homeostasis are complex and incompletely understood.",True,Answers for Critical Thinking Questions,,,,
+9a181dd5-c282-44d9-9dc0-48b5f89fc157,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,Immunodeficiencies,False,Immunodeficiencies,,,,
+6b485244-a359-4d93-8f47-675fc7c6254d,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"As you have seen, the immune system is quite complex. It has many pathways using many cell types and signals. Because it is so complex, there are many ways for it to go wrong. Inherited immunodeficiencies arise from gene mutations that affect specific components of the immune response. There are also acquired immunodeficiencies with potentially devastating effects on the immune system, such as HIV.",True,Immunodeficiencies,,,,
+0188c02c-87e5-4135-90fa-0500661ee46a,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,Hypersensitivities,False,Hypersensitivities,,,,
+3fb7cb07-dc85-4fcc-b821-aac90ef43b26,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"The word “hypersensitivity” simply means sensitive beyond normal levels of activation. Allergies and inflammatory responses to nonpathogenic environmental substances have been observed since the dawn of history. Hypersensitivity is a medical term describing symptoms that are now known to be caused by unrelated mechanisms of immunity. Still, it is useful for this discussion to use the four types of hypersensitivities as a guide to understand these mechanisms (Figure 21.6.1).",True,Hypersensitivities,Figure 21.6.1,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2228_Immune_Hypersensitivity_new-scaled.jpg,"Figure 21.6.1 – Immune Hypersensitivity: Components of the immune system cause four types of hypersensitivity. Notice that types I–III are B cell mediated, whereas type IV hypersensitivity is exclusively a T cell phenomenon."
+d34d877a-9b6f-405d-87a1-0d0846575aa8,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,Autoimmune Responses,False,Autoimmune Responses,,,,
+fe715004-25db-470c-a211-cf0a5dd6e63b,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"The worst cases of the immune system over-reacting are autoimmune diseases. Somehow, tolerance breaks down and the immune systems in individuals with these diseases begin to attack their own bodies, causing significant damage. The trigger for these diseases is, more often than not, unknown, and the treatments are usually based on resolving the symptoms using immunosuppressive and anti-inflammatory drugs such as steroids. These diseases can be localized and crippling, as in rheumatoid arthritis, or diffuse in the body with multiple symptoms that differ in different individuals, as is the case with systemic lupus erythematosus (Figure 21.6.2).",True,Autoimmune Responses,Figure 21.6.2,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2229_Autoimmune_Disorders_Rheumatoid_Arthritis_and_Lupus.jpg,Figure 21.6.2 – Autoimmune Disorders: Rheumatoid Arthritis and Lupus. (a) Extensive damage to the right hand of a rheumatoid arthritis sufferer is shown in the x-ray. (b) The diagram shows a variety of possible symptoms of systemic lupus erythematosus.
+d0cafc68-ab9f-4dd7-bdbf-e2e7d809ac0b,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"Environmental triggers seem to play large roles in autoimmune responses. One explanation for the breakdown of tolerance is that, after certain bacterial infections, an immune response to a component of the bacterium cross-reacts with a self-antigen. This mechanism is seen in rheumatic fever, a result of infection with Streptococcus bacteria, which causes strep throat. The antibodies to this pathogen’s M protein cross-react with an antigenic component of heart myosin, a major contractile protein of the heart that is critical to its normal function. The antibody binds to these molecules and activates complement proteins, causing damage to the heart, especially to the heart valves. On the other hand, some theories propose that having multiple common infectious diseases actually prevents autoimmune responses. The fact that autoimmune diseases are rare in countries that have a high incidence of infectious diseases supports this idea, another example of the hygiene hypothesis discussed earlier in this chapter.",True,Autoimmune Responses,,,,
+4f866bd9-bb0d-4472-a5e2-0837d0209a60,https://open.oregonstate.education/aandp/,21.6 Diseases Associated with Depressed or Overactive Immune Responses,https://open.oregonstate.education/aandp/chapter/21-6-diseases-associated-with-depressed-or-overactive-immune-responses/,"There are genetic factors in autoimmune diseases as well. Some diseases are associated with the MHC genes that an individual expresses. The reason for this association is likely because if one’s MHC molecules are not able to present a certain self-antigen, then that particular autoimmune disease cannot occur. Overall, there are more than 80 different autoimmune diseases, which are a significant health problem in the elderly. Table 21.7 lists several of the most common autoimmune diseases, the antigens that are targeted, and the segment of the adaptive immune response that causes the damage.",True,Autoimmune Responses,,,,
+909bdcc6-c5af-4207-9623-99e1e16ddc97,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Explain the development of immunological competence,False,Explain the development of immunological competence,,,,
+d1c93589-0b82-490d-83f2-42f40fe80a93,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Describe the mucosal immune response,False,Describe the mucosal immune response,,,,
+ef0b4b09-715e-464b-b656-9a72ac780b8e,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,"Discuss immune responses against bacterial, viral, fungal, and animal pathogens",False,"Discuss immune responses against bacterial, viral, fungal, and animal pathogens",,,,
+9c6ee626-8aac-4ccf-95fc-1db791d6a4e4,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Describe different ways pathogens evade immune responses,False,Describe different ways pathogens evade immune responses,,,,
+74cd108c-5f87-460c-b915-205e38b0271d,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Defenses against Bacteria and Fungi,False,Defenses against Bacteria and Fungi,,,,
+54d22fff-7149-4733-9057-6286933b0129,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Defenses against Parasites,False,Defenses against Parasites,,,,
+144eecb9-a799-4316-9769-6063a98f46ca,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Defenses against Viruses,False,Defenses against Viruses,,,,
+4ccfe584-2911-44c7-a345-1346af92ab46,https://open.oregonstate.education/aandp/,21.5 The Immune Response against Pathogens,https://open.oregonstate.education/aandp/chapter/21-5-the-immune-response-against-pathogens/,Evasion of the Immune System by Pathogens,False,Evasion of the Immune System by Pathogens,,,,
+0d53848e-5395-474f-b2f4-be706a9a1fb3,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Antibodies were the first component of the adaptive immune response to be characterized by scientists working on the immune system. It was already known that individuals who survived a bacterial infection were immune to re-infection with the same pathogen. Early microbiologists took serum from an immune patient and mixed it with a fresh culture of the same type of bacteria, then observed the bacteria under a microscope. The bacteria became clumped in a process called agglutination. When a different bacterial species was used, the agglutination did not happen. Thus, there was something in the serum of immune individuals that could specifically bind to and agglutinate bacteria.",True,Evasion of the Immune System by Pathogens,,,,
+90fe1754-4d70-40e6-aec7-20e5648c2ec2,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Scientists now know the cause of the agglutination is an antibody molecule, also called an immunoglobulin. What is an antibody? An antibody protein is essentially a secreted form of a B cell receptor. (In fact, surface immunoglobulin is another name for the B cell receptor.) Not surprisingly, the same genes encode both the secreted antibodies and the surface immunoglobulins. One minor difference in the way these proteins are synthesized distinguishes a naïve B cell with antibody on its surface from an antibody-secreting plasma cell with no antibodies on its surface. The antibodies of the plasma cell have the exact same antigen-binding site and specificity as their B cell precursors.",True,Evasion of the Immune System by Pathogens,,,,
+2cb00ecc-6356-406f-b416-0b9bf323241f,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"There are five different classes of antibody found in humans: IgM, IgD, IgG, IgA, and IgE. Each of these has specific functions in the immune response, so by learning about them, researchers can learn about the great variety of antibody functions critical to many adaptive immune responses.",True,Evasion of the Immune System by Pathogens,,,,
+6bc8b12c-4be7-4f56-b775-a9e0951b7100,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"B cells do not recognize antigen in the complex fashion of T cells. B cells can recognize native, unprocessed antigen and do not require the participation of MHC molecules and antigen-presenting cells.",True,Evasion of the Immune System by Pathogens,,,,
+338ce92e-febd-4d78-af61-9504ec69ece9,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,B Cell Differentiation and Activation,False,B Cell Differentiation and Activation,,,,
+2ae74d6e-ecac-4b04-a3e8-2cf669058a89,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"B cells differentiate in the bone marrow. During the process of maturation, up to 100 trillion different clones of B cells are generated, which is similar to the diversity of antigen receptors seen in T cells.",True,B Cell Differentiation and Activation,,,,
+bb8fdcc4-ce6f-4dd0-a124-648d8a7a2c40,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"B cell differentiation and the development of tolerance are not quite as well understood as it is in T cells. Central tolerance is the destruction or inactivation of B cells that recognize self-antigens in the bone marrow, and its role is critical and well established. In the process of clonal deletion, immature B cells that bind strongly to self-antigens expressed on tissues are signaled to commit suicide by apoptosis, removing them from the population. In the process of clonal anergy, however, B cells exposed to soluble antigen in the bone marrow are not physically deleted, but become unable to function.",True,B Cell Differentiation and Activation,,,,
+7d753a1e-cb3e-443b-bca7-3d6df4e56382,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Another mechanism called peripheral tolerance is a direct result of T cell tolerance. In peripheral tolerance, functional, mature B cells leave the bone marrow but have yet to be exposed to self-antigen. Most protein antigens require signals from helper T cells (Th2) to proceed to make antibody. When a B cell binds to a self-antigen but receives no signals from a nearby Th2 cell to produce antibody, the cell is signaled to undergo apoptosis and is destroyed. This is yet another example of the control that T cells have over the adaptive immune response.",True,B Cell Differentiation and Activation,,,,
+ecdd2501-9658-4f62-851c-e6c20d7a882e,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"After B cells are activated by their binding to antigen, they differentiate into plasma cells. Plasma cells often leave the secondary lymphoid organs, where the response is generated, and migrate back to the bone marrow, where the whole differentiation process started. After secreting antibodies for a specific period, they die, as most of their energy is devoted to making antibodies and not to maintaining themselves. Thus, plasma cells are said to be terminally differentiated.",True,B Cell Differentiation and Activation,,,,
+a7c34592-6537-4ae0-b2aa-6f9d6e8f082b,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"The final B cell of interest is the memory B cell, which results from the clonal expansion of an activated B cell. Memory B cells function in a way similar to memory T cells. They lead to a stronger and faster secondary response when compared to the primary response, as illustrated below.",True,B Cell Differentiation and Activation,,,,
+327eeb7b-ed0f-483c-9979-c6e7b624bbb1,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,Antibody Structure,False,Antibody Structure,,,,
+8d1baa6e-1051-4339-abfa-00a49afee517,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Antibodies are glycoproteins consisting of two types of polypeptide chains with attached carbohydrates. The heavy chain and the light chain are the two polypeptides that form the antibody. The main differences between the classes of antibodies are in the differences between their heavy chains, but as you shall see, the light chains have an important role, forming part of the antigen-binding site on the antibody molecules.",True,Antibody Structure,,,,
+9f969308-538c-42c1-8910-231ac8d78e4f,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,Active versus Passive Immunity,False,Active versus Passive Immunity,,,,
+aa12427e-dcba-498a-9038-b950172fac82,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Immunity to pathogens, and the ability to control pathogen growth so that damage to the tissues of the body is limited, can be acquired by (1) the active development of an immune response in the infected individual or (2) the passive transfer of immune components from an immune individual to a nonimmune one. Both active and passive immunity have examples in the natural world and as part of medicine.",True,Active versus Passive Immunity,,,,
+7ff157ac-0355-4391-830c-f2b5151c5bc4,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Active immunity is the resistance to pathogens acquired during an adaptive immune response within an individual (Table 21.6). Naturally acquired active immunity, the response to a pathogen, is the focus of this chapter. Artificially acquired active immunity involves the use of vaccines. A vaccine is a killed or weakened pathogen or its components that, when administered to a healthy individual, leads to the development of immunological memory (a weakened primary immune response) without causing much in the way of symptoms. Thus, with the use of vaccines, one can avoid the damage from disease that results from the first exposure to the pathogen, yet reap the benefits of protection from immunological memory. The advent of vaccines was one of the major medical advances of the twentieth century and led to the eradication of smallpox and the control of many infectious diseases, including polio, measles, and whooping cough.",True,Active versus Passive Immunity,,,,
+5e1b838b-8370-48d5-9ffa-17910327051b,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"Passive immunity arises from the transfer of antibodies to an individual without requiring them to mount their own active immune response. Naturally acquired passive immunity is seen during fetal development. IgG is transferred from the maternal circulation to the fetus via the placenta, protecting the fetus from infection and protecting the newborn for the first few months of its life. As already stated, a newborn benefits from the IgA antibodies it obtains from milk during breastfeeding. The fetus and newborn thus benefit from the immunological memory of the mother to the pathogens to which she has been exposed. In medicine, artificially acquired passive immunity usually involves injections of immunoglobulins, taken from animals previously exposed to a specific pathogen. This treatment is a fast-acting method of temporarily protecting an individual who was possibly exposed to a pathogen. The downside to both types of passive immunity is the lack of the development of immunological memory. Once the antibodies are transferred, they are effective for only a limited time before they degrade.",True,Active versus Passive Immunity,,,,
+851442ea-bfb5-43a3-9dbe-9881e7dddaf7,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,T cell-dependent versus T cell-independent Antigens,False,T cell-dependent versus T cell-independent Antigens,,,,
+b79678a3-f7b4-434a-ab53-20dcc2ff668a,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"As discussed previously, Th2 cells secrete cytokines that drive the production of antibodies in a B cell, responding to complex antigens such as those made by proteins. On the other hand, some antigens are T cell independent. A T cell-independent antigen usually is in the form of repeated carbohydrate moieties found on the cell walls of bacteria. Each antibody on the B cell surface has two binding sites, and the repeated nature of T cell-independent antigen leads to crosslinking of the surface antibodies on the B cell. The crosslinking is enough to activate it in the absence of T cell cytokines.",True,T cell-dependent versus T cell-independent Antigens,,,,
+6d05cfe6-98ee-46f1-823d-9475b2eba651,https://open.oregonstate.education/aandp/,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/aandp/chapter/21-4-the-adaptive-immune-response-b-lymphocytes-and-antibodies/,"A T cell-dependent antigen, on the other hand, usually is not repeated to the same degree on the pathogen and thus does not crosslink surface antibody with the same efficiency. To elicit a response to such antigens, the B and T cells must come close together (Figure 21.4.5). The B cell must receive two signals to become activated. Its surface immunoglobulin must recognize native antigen. Some of this antigen is internalized, processed, and presented to the Th2 cells on a class II MHC molecule. The T cell then binds using its antigen receptor and is activated to secrete cytokines that diffuse to the B cell, finally activating it completely. Thus, the B cell receives signals from both its surface antibody and the T cell via its cytokines, and acts as a professional antigen-presenting cell in the process.",True,T cell-dependent versus T cell-independent Antigens,Figure 21.4.5,21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2224_T_and_B_Cell_Binding.jpg,"Figure 21.4.5 – T and B Cell Binding: To elicit a response to a T cell-dependent antigen, the B and T cells must come close together. To become fully activated, the B cell must receive two signals from the native antigen and the T cell’s cytokines."
+6a39eb4c-60e2-4f74-9b58-e41b3f10a725,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Innate immune responses (and early induced responses) are in many cases ineffective at completely controlling pathogen growth. However, they slow pathogen growth and allow time for the adaptive immune response to strengthen and either control or eliminate the pathogen. The innate immune system also sends signals to the cells of the adaptive immune system, guiding them in how to attack the pathogen. Thus, these are the two important arms of the immune response.",True,T cell-dependent versus T cell-independent Antigens,,,,
+388aba2e-bdd7-4d8e-825f-e993baad75b9,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,The Benefits of the Adaptive Immune Response,False,The Benefits of the Adaptive Immune Response,,,,
+b7db8a56-fb4b-4dba-8c32-a1e1cc2d5f02,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"The specificity of the adaptive immune response—its ability to specifically recognize and make a response against a wide variety of pathogens—is its great strength. Antigens, the small chemical groups often associated with pathogens, are recognized by receptors on the surface of B and T lymphocytes. The adaptive immune response to these antigens is so versatile that it can respond to nearly any pathogen. This increase in specificity comes because the adaptive immune response has a unique way to develop as many as 1011, or 100 trillion, different receptors to recognize nearly every conceivable pathogen. How could so many different types of antibodies be encoded? And what about the many specificities of T cells? There is not nearly enough DNA in a cell to have a separate gene for each specificity. The mechanism was finally worked out in the 1970s and 1980s using the new tools of molecular genetics",True,The Benefits of the Adaptive Immune Response,,,,
+7deb2406-4451-49cd-8ce7-0d0383dc51ee,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,T Cell-Mediated Immune Responses,False,T Cell-Mediated Immune Responses,,,,
+657b0e2c-3139-421b-9d55-6b908f715c9f,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"The primary cells that control the adaptive immune response are the lymphocytes, the T and B cells. T cells are particularly important, as they not only control a multitude of immune responses directly, but also control B cell immune responses in many cases as well. Thus, many of the decisions about how to attack a pathogen are made at the T cell level, and knowledge of their functional types is crucial to understanding the functioning and regulation of adaptive immune responses as a whole.",True,T Cell-Mediated Immune Responses,,,,
+b9c47509-f15d-48fa-bc82-3dfab3fad601,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,T lymphocytes recognize antigens based on a two-chain protein receptor. The most common and important of these are the alpha-beta T cell receptors (Figure 21.3.1).,True,T Cell-Mediated Immune Responses,Figure 21.3.1,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2215_Alpha-Beta_T_Cell_Receptor.jpg,"Figure 21.3.1 – Alpha-beta T Cell Receptor: Notice the constant and variable regions of each chain, anchored by the transmembrane region."
+5edcf582-4349-4d1c-aa41-fe5e4c0ce297,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"There are two chains in the T cell receptor, and each chain consists of two domains. The variable region domain is furthest away from the T cell membrane and is so named because its amino acid sequence varies between receptors. In contrast, the constant region domain has less variation. The differences in the amino acid sequences of the variable domains are the molecular basis of the diversity of antigens the receptor can recognize. Thus, the antigen-binding site of the receptor consists of the terminal ends of both receptor chains, and the amino acid sequences of those two areas combine to determine its antigenic specificity. Each T cell produces only one type of receptor and thus is specific for a single particular antigen.",True,T Cell-Mediated Immune Responses,,,,
+ea8dd9bd-2daf-4b12-a3ab-39d482e651d1,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,Antigens,False,Antigens,,,,
+e5c3bf77-723c-4754-8ebb-baaeb8d84d1e,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Antigens on pathogens are usually large and complex, and consist of many antigenic determinants. An antigenic determinant (epitope) is one of the small regions within an antigen to which a receptor can bind, and antigenic determinants are limited by the size of the receptor itself. They usually consist of six or fewer amino acid residues in a protein, or one or two sugar moieties in a carbohydrate antigen. Antigenic determinants on a carbohydrate antigen are usually less diverse than on a protein antigen. Carbohydrate antigens are found on bacterial cell walls and on red blood cells (the ABO blood group antigens). Protein antigens are complex because of the variety of three-dimensional shapes that proteins can assume, and are especially important for the immune responses to viruses and worm parasites. It is the interaction of the shape of the antigen and the complementary shape of the amino acids of the antigen-binding site that accounts for the chemical basis of specificity (Figure 21.3.2).",True,Antigens,Figure 21.3.2,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2214_Antigenic_Determinants.jpg,"Figure 21.3.2 – Antigenic Determinants: A typical protein antigen has multiple antigenic determinants, shown by the ability of T cells with three different specificities to bind to different parts of the same antigen."
+50616c0f-8e59-4c85-aa9f-052818d8a643,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,T Cell Development and Differentiation,False,T Cell Development and Differentiation,,,,
+45b7a359-cd5f-43a6-bad8-c639e5c39041,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"The process of eliminating T cells that might attack the cells of one’s own body is referred to as T cell tolerance. While thymocytes are in the cortex of the thymus, they are referred to as “double negatives,” meaning that they do not bear the CD4 or CD8 molecules that you can use to follow their pathways of differentiation (Figure 21.3.4). In the cortex of the thymus, they are exposed to cortical epithelial cells. In a process known as positive selection, double-negative thymocytes bind to the MHC molecules they observe on the thymic epithelia, and the MHC molecules of “self” are selected. This mechanism kills many thymocytes during T cell differentiation. In fact, only two percent of the thymocytes that enter the thymus leave it as mature, functional T cells.",True,T Cell Development and Differentiation,Figure 21.3.4,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2217_Differentiation_of_T_Cells_Within_the_Thymus.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.
+50a4fb71-65e2-42e9-b79e-a4037222e7b0,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Later, the cells become double positives that express both CD4 and CD8 markers and move from the cortex to the junction between the cortex and medulla. It is here that negative selection takes place. In negative selection, self-antigens are brought into the thymus from other parts of the body by professional antigen-presenting cells. The T cells that bind to these self-antigens are selected for negatively and are killed by apoptosis. In summary, the only T cells left are those that can bind to MHC molecules of the body with foreign antigens presented on their binding clefts, preventing an attack on one’s own body tissues, at least under normal circumstances. Tolerance can be broken, however, by the development of an autoimmune response, to be discussed later in this chapter.",True,T Cell Development and Differentiation,,,,
+afe8a533-6f65-4333-9d26-c4297fd27142,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"The cells that leave the thymus become single positives, expressing either CD4 or CD8, but not both (see Figure 21.3.4). The CD4+ T cells will bind to class II MHC and the CD8+ cells will bind to class I MHC. The discussion that follows explains the functions of these molecules and how they can be used to differentiate between the different T cell functional types.",True,T Cell Development and Differentiation,Figure 21.3.4,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2217_Differentiation_of_T_Cells_Within_the_Thymus.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.
+0f2cd2fc-22b7-49b3-8800-19cedf596c32,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,Mechanisms of T Cell-mediated Immune Responses,False,Mechanisms of T Cell-mediated Immune Responses,,,,
+408030f4-c427-4a1d-83a7-35c5a0b0dd11,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Mature T cells become activated by recognizing processed foreign antigen in association with a self-MHC molecule and begin dividing rapidly by mitosis. This proliferation of T cells is called clonal expansion and is necessary to make the immune response strong enough to effectively control a pathogen. How does the body select only those T cells that are needed against a specific pathogen? Again, the specificity of a T cell is based on the amino acid sequence and the three-dimensional shape of the antigen-binding site formed by the variable regions of the two chains of the T cell receptor (Figure 21.3.5). Clonal selection is the process of antigen binding only to those T cells that have receptors specific to that antigen. Each T cell that is activated has a specific receptor “hard-wired” into its DNA, and all of its progeny will have identical DNA and T cell receptors, forming clones of the original T cell.",True,Mechanisms of T Cell-mediated Immune Responses,Figure 21.3.5,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2218_Clonal_Selection_and_Expansion_of_T_Lymphocytes.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded."
+2989268a-4e6e-4132-bc2f-de0aa20ca8d1,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,Clonal Selection and Expansion,False,Clonal Selection and Expansion,,,,
+db783d22-3e77-4242-b8d7-1cbca32dff62,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"The clonal selection theory was proposed by Frank Burnet in the 1950s. However, the term clonal selection is not a complete description of the theory, as clonal expansion goes hand in glove with the selection process. The main tenet of the theory is that a typical individual has a multitude (1011) of different types of T cell clones based on their receptors. In this use, a clone is a group of lymphocytes that share the same antigen receptor. Each clone is necessarily present in the body in low numbers. Otherwise, the body would not have room for lymphocytes with so many specificities.",True,Clonal Selection and Expansion,,,,
+9d5bb4aa-e2b7-4454-aadc-5a9a96abfe86,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Only those clones of lymphocytes whose receptors are activated by the antigen are stimulated to proliferate. Keep in mind that most antigens have multiple antigenic determinants, so a T cell response to a typical antigen involves a polyclonal response. A polyclonal response is the stimulation of multiple T cell clones. Once activated, the selected clones increase in number and make many copies of each cell type, each clone with its unique receptor. By the time this process is complete, the body will have large numbers of specific lymphocytes available to fight the infection (see Figure 21.3.5).",True,Clonal Selection and Expansion,Figure 21.3.5,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2218_Clonal_Selection_and_Expansion_of_T_Lymphocytes.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded."
+196160bc-abf2-40b7-b65b-f59392308398,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,The Cellular Basis of Immunological Memory,False,The Cellular Basis of Immunological Memory,,,,
+d846a50b-1948-4b08-8e43-f7f018f9b2e5,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"As already discussed, one of the major features of an adaptive immune response is the development of immunological memory.",True,The Cellular Basis of Immunological Memory,,,,
+fc0dbc31-3441-4d6f-b46b-b873f59261e0,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"During a primary adaptive immune response, both memory T cells and effector T cells are generated. Memory T cells are long-lived and can even persist for a lifetime. Memory cells are primed to act rapidly. Thus, any subsequent exposure to the pathogen will elicit a very rapid T cell response. This rapid, secondary adaptive response generates large numbers of effector T cells so fast that the pathogen is often overwhelmed before it can cause any symptoms of disease. This is what is meant by immunity to a disease. The same pattern of primary and secondary immune responses occurs in B cells and the antibody response, as will be discussed later in the chapter.",True,The Cellular Basis of Immunological Memory,,,,
+92a14374-5c82-43ed-90c8-5206cd1017c3,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,T Cell Types and their Functions,False,T Cell Types and their Functions,,,,
+4b6dbf0b-001e-4155-8d97-3a7d1e34ae05,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"In the discussion of T cell development, you saw that mature T cells express either the CD4 marker or the CD8 marker, but not both. These markers are cell adhesion molecules that keep the T cell in close contact with the antigen-presenting cell by directly binding to the MHC molecule (to a different part of the molecule than does the antigen). Thus, T cells and antigen-presenting cells are held together in two ways: by CD4 or CD8 attaching to MHC and by the T cell receptor binding to antigen (Figure 21.3.6).",True,T Cell Types and their Functions,Figure 21.3.6,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2219_Pathogen_Presentation.jpg,"Figure 21.3.6 – Pathogen Presentation: (a) CD4 is associated with helper and regulatory T cells. An extracellular pathogen is processed and presented in the binding cleft of a class II MHC molecule, and this interaction is strengthened by the CD4 molecule. (b) CD8 is associated with cytotoxic T cells. An intracellular pathogen is presented by a class I MHC molecule, and CD8 interacts with it."
+fd6ef7d6-d470-4a76-8f02-441d801e1d81,https://open.oregonstate.education/aandp/,21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types,https://open.oregonstate.education/aandp/chapter/21-3-the-adaptive-immune-response-t-lymphocytes-and-their-functional-types/,"Although the correlation is not 100 percent, CD4-bearing T cells are associated with helper functions and CD8-bearing T cells are associated with cytotoxicity. These functional distinctions based on CD4 and CD8 markers are useful in defining the function of each type.",True,T Cell Types and their Functions,,,,
+3567e14b-5da8-44e4-a13a-d38e1e9e7123,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"The immune system can be divided into two overlapping mechanisms to destroy pathogens: the innate immune response, which is relatively rapid but nonspecific and thus not always effective, and the adaptive immune response, which is slower in its development during an initial infection with a pathogen, but is highly specific and effective at attacking a wide variety of pathogens (Figure 21.2.1).",True,T Cell Types and their Functions,Figure 21.2.1,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2211_Cooperation_Between_Innate_and_Immune_Responses.jpg,Figure 21.2.1 – Cooperation between Innate and Adaptive Immune Responses: The innate immune system enhances adaptive immune responses so they can be more effective
+2452b440-2a72-4feb-ba3c-9715ec613c45,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"Any discussion of the innate immune response usually begins with the physical barriers that prevent pathogens from entering the body, destroy them after they enter, or flush them out before they can establish themselves in the hospitable environment of the body’s soft tissues. Barrier defenses are part of the body’s most basic defense mechanisms. The barrier defenses are not a response to infections, but they are continuously working to protect against a broad range of pathogens.",True,T Cell Types and their Functions,,,,
+bce31ede-2cf9-4049-8501-7374d273e8e3,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"The different modes of barrier defenses are associated with the external surfaces of the body, where pathogens may try to enter (Table 21.2). The primary barrier to the entrance of microorganisms into the body is the skin. Not only is the skin covered with a layer of dead, keratinized epithelium that is too dry for bacteria in which to grow, but as these cells are continuously sloughed off from the skin, they carry bacteria and other pathogens with them. Additionally, sweat and other skin secretions may lower pH, contain toxic lipids, and physically wash microbes away.",True,T Cell Types and their Functions,,,,
+a30c6e31-7bcd-496b-a74d-b693e6b6dd1e,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"Another barrier is the saliva in the mouth, which is rich in lysozyme—an enzyme that destroys bacteria by digesting their cell walls. The acidic environment of the stomach, which is fatal to many pathogens, is also a barrier. Additionally, the mucus layer of the gastrointestinal tract, respiratory tract, reproductive tract, eyes, ears, and nose traps both microbes and debris, and facilitates their removal. In the case of the upper respiratory tract, ciliated epithelial cells move potentially contaminated mucus upwards to the mouth, where it is then swallowed into the digestive tract, ending up in the harsh acidic environment of the stomach. Considering how often you breathe compared to how often you eat or perform other activities that expose you to pathogens, it is not surprising that multiple barrier mechanisms have evolved to work in concert to protect this vital area.",True,T Cell Types and their Functions,,,,
+dc090f27-5d58-4f7c-8344-e1e00a4a1c42,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,Cells of the Innate Immune Response,False,Cells of the Innate Immune Response,,,,
+d00a7ef5-be48-470b-b7df-4f06c3cd59a4,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"A phagocyte is a cell that is able to surround and engulf a particle or cell, a process called phagocytosis. The phagocytes of the immune system engulf other particles or cells, either to clean an area of debris, old cells, or to kill pathogenic organisms such as bacteria. The phagocytes are the body’s fast acting, first line of immunological defense against organisms that have breached barrier defenses and have entered the vulnerable tissues of the body.",True,Cells of the Innate Immune Response,,,,
+5c169917-c7c7-45c6-a9b7-08c1b223c7b0,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,Recognition of Pathogens,False,Recognition of Pathogens,,,,
+bccb1d20-ebfb-4f7b-b747-ea04221bccc7,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"Cells of the innate immune response, the phagocytic cells, and the cytotoxic NK cells recognize patterns of pathogen-specific molecules, such as bacterial cell wall components or bacterial flagellar proteins, using pattern recognition receptors. A pattern recognition receptor (PRR) is a membrane-bound receptor that recognizes characteristic features of a pathogen and molecules released by stressed or damaged cells.",True,Recognition of Pathogens,,,,
+df12c9c1-6f68-4394-803f-5126e2be52bc,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"These receptors, which are thought to have evolved prior to the adaptive immune response, are present on the cell surface whether they are needed or not. Their variety, however, is limited by two factors. First, the fact that each receptor type must be encoded by a specific gene requires the cell to allocate most or all of its DNA to make receptors able to recognize all pathogens. Secondly, the variety of receptors is limited by the finite surface area of the cell membrane. Thus, the innate immune system must “get by” using only a limited number of receptors that are active against as wide a variety of pathogens as possible. This strategy is in stark contrast to the approach used by the adaptive immune system, which uses large numbers of different receptors, each highly specific to a particular pathogen.",True,Recognition of Pathogens,,,,
+ce943d97-b492-49c2-86d6-39db64d1841d,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"Should the cells of the innate immune system come into contact with a species of pathogen they recognize, the cell will bind to the pathogen and initiate phagocytosis (or cellular apoptosis in the case of an intracellular pathogen) in an effort to destroy the offending microbe. Receptors vary somewhat according to cell type, but they usually include receptors for bacterial components and for complement, discussed below.",True,Recognition of Pathogens,,,,
+cb8ce986-6f3c-45c8-a2a6-a19bd9e37568,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,Soluble Mediators of the Innate Immune Response,False,Soluble Mediators of the Innate Immune Response,,,,
+7898d8fa-4a4c-4c2c-93f9-af5f777ed77a,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"The previous discussions have alluded to chemical signals that can induce cells to change various physiological characteristics, such as the expression of a particular receptor. These soluble factors are secreted during innate or early induced responses, and later during adaptive immune responses.",True,Soluble Mediators of the Innate Immune Response,,,,
+332c7458-ba43-4ea9-8dd0-549eb6c8f02d,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,Inflammatory Response,False,Inflammatory Response,,,,
+3349a431-ac4d-4c48-8477-fb335ba81721,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"The hallmark of the innate immune response is inflammation. Inflammation is something everyone has experienced. Stub a toe, cut a finger, or do any activity that causes tissue damage and inflammation will result, with its four characteristics: heat, redness, pain, and swelling (“loss of function” is sometimes mentioned as a fifth characteristic). It is important to note that inflammation does not have to be initiated by an infection, but can also be caused by tissue injuries. The release of damaged cellular contents into the site of injury is enough to stimulate the response, even in the absence of breaks in physical barriers that would allow pathogens to enter (by hitting your thumb with a hammer, for example). The inflammatory reaction brings in phagocytic cells to the damaged area to clear cellular debris and to set the stage for wound repair (Figure 21.2.3).",True,Inflammatory Response,Figure 21.2.3,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2213_Inflammatory_Process.jpg,Figure 21.2.3 Inflammatory Response.
+b51546ad-c4a8-4fcb-9523-b5462b183ce0,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"This reaction also brings in the cells of the innate immune system, allowing them to get rid of the sources of a possible infection. Inflammation is part of a very basic form of immune response. The process not only brings fluid and cells into the site to destroy the pathogen and remove it and debris from the site, but also helps to isolate the site, limiting the spread of the pathogen. Acute inflammation is a short-term inflammatory response to an insult to the body. If the cause of the inflammation is not resolved, however, it can lead to chronic inflammation, which is associated with major tissue destruction and fibrosis. Chronic inflammation is ongoing inflammation. It can be caused by foreign bodies, persistent pathogens, and autoimmune diseases such as rheumatoid arthritis.",True,Inflammatory Response,,,,
+953ab45c-3d5c-4656-8e9d-2c8ce113c498,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,There are four important parts to the inflammatory response:,False,There are four important parts to the inflammatory response:,,,,
+dbf60adf-7cc5-4e93-ba73-ec091d632810,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,"Overall, inflammation is valuable for many reasons. Not only are the pathogens killed and debris removed, but the increase in vascular permeability encourages the entry of clotting factors, the first step towards wound repair. Inflammation also facilitates the transport of antigen to lymph nodes by dendritic cells for the development of the adaptive immune response.",True,There are four important parts to the inflammatory response:,,,,
+ec1c2890-1001-4f0a-9597-a9a2f0b0c93d,https://open.oregonstate.education/aandp/,21.2 Barrier Defenses and the Innate Immune Response,https://open.oregonstate.education/aandp/chapter/21-2-barrier-defenses-and-the-innate-immune-response/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+498f8f2a-b050-4166-abb5-9d065a244fdd,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"The immune system is the complex collection of cells and organs that destroys or neutralizes pathogens that would otherwise cause disease or death. The lymphatic system, for most people, is associated with the immune system to such a degree that the two systems are virtually indistinguishable. The lymphatic system is the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood. The swelling of lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels are but two examples of the many connections between these critical organ systems.",True,Answers for Critical Thinking Questions,,,,
+3c907266-d960-44ef-82aa-7940e4ab5ea1,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,Functions of the Lymphatic System,False,Functions of the Lymphatic System,,,,
+310720ae-074c-4c22-85af-8bc7b5f35b28,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"A major function of the lymphatic system is to drain body fluids and return them to the bloodstream. Blood pressure causes leakage of fluid from the capillaries, resulting in the accumulation of fluid in the interstitial space—that is, spaces between individual cells in the tissues. In humans, 20 liters of plasma is released into the interstitial space of the tissues each day due to capillary filtration. Once this filtrate is out of the bloodstream and in the tissue spaces, it is referred to as interstitial fluid. Of this, 17 liters is reabsorbed directly by the blood vessels. But what happens to the remaining three liters? This is where the lymphatic system comes into play. It drains the excess fluid and empties it back into the bloodstream via a series of vessels, trunks, and ducts. Lymph is the term used to describe interstitial fluid once it has entered the lymphatic system. When the lymphatic system is damaged in some way, such as by being blocked by cancer cells or destroyed by injury, protein-rich interstitial fluid accumulates (sometimes “backs up” from the lymph vessels) in the tissue spaces. This inappropriate accumulation of fluid referred to as lymphedema may lead to serious medical consequences.",True,Functions of the Lymphatic System,,,,
+8709402d-a2f6-421d-a838-a471f6f961f3,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"As the vertebrate immune system evolved, the network of lymphatic vessels became convenient avenues for transporting the cells of the immune system. Additionally, the transport of dietary lipids and fat-soluble vitamins absorbed in the gut uses this system.",True,Functions of the Lymphatic System,,,,
+534b63a7-e7cf-48d7-9750-38333775d23f,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"Cells of the immune system not only use lymphatic vessels to make their way from interstitial spaces back into the circulation, but they also use lymph nodes as major staging areas for the development of critical immune responses. A lymph node is one of the small, bean-shaped organs located throughout the lymphatic system.",True,Functions of the Lymphatic System,,,,
+ce58d77a-ce81-446c-b501-e21fe02bb9c3,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,Structure of the Lymphatic System,False,Structure of the Lymphatic System,,,,
+3b29af0e-ebb7-4bed-99c8-cfe1082503a5,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"The lymphatic vessels begin as open-ended capillaries, which feed into larger and larger lymphatic vessels, and eventually empty into the bloodstream by a series of ducts. Along the way, the lymph travels through the lymph nodes, which are commonly found near the groin, armpits, neck, chest, and abdomen. Humans have about 500–600 lymph nodes throughout the body (Figure 21.1.1).",True,Structure of the Lymphatic System,Figure 21.1.1,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2201_Anatomy_of_the_Lymphatic_System.jpg,Figure 21.1.1 – Anatomy of the Lymphatic System: Lymphatic vessels in the arms and legs convey lymph to the larger lymphatic vessels in the torso.
+bea393eb-1903-48e5-86c8-bd7a8636a1b6,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"A major distinction between the lymphatic and cardiovascular systems in humans is that lymph is not actively pumped by the heart, but is forced through the vessels by the movements of the body, the contraction of skeletal muscles during body movements, and breathing. One-way valves (semi-lunar valves) in lymphatic vessels keep the lymph moving toward the heart. Lymph flows from the lymphatic capillaries, through lymphatic vessels, and then is dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck.",True,Structure of the Lymphatic System,,,,
+16f5fd34-c5df-4f7f-a944-38446781b029,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,The Organization of Immune Function,False,The Organization of Immune Function,,,,
+1cfaf7fe-8e7f-4ca3-b180-18dfabbb532d,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"The immune system is a collection of barriers, cells, and soluble proteins that interact and communicate with each other in extraordinarily complex ways. The modern model of immune function is organized into three phases based on the timing of their effects. The three temporal phases consist of the following:",True,The Organization of Immune Function,,,,
+d25ed840-6c78-4058-b7bd-806c49e6bd9a,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"The cells of the blood, including all those involved in the immune response, arise in the bone marrow via various differentiation pathways from hematopoietic stem cells (Figure 21.1.4). In contrast with embryonic stem cells, hematopoietic stem cells are present throughout adulthood and allow for the continuous differentiation of blood cells to replace those lost to age or function. These cells can be divided into three classes based on function:",True,The Organization of Immune Function,Figure 21.1.4,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2204_The_Hematopoietic_System_of_the_Bone_Marrow_new.jpg,Figure 21.1.4 – Hematopoietic System of the Bone Marrow: All the cells of the immune response as well as of the blood arise by differentiation from hematopoietic stem cells. Platelets are cell fragments involved in the clotting of blood.
+fd7924fe-b638-401b-9036-4d776facdc8b,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"Lymphocytes: B Cells, T Cells, Plasma Cells, and Natural Killer Cells",True,The Organization of Immune Function,,,,
+9709cb71-5d6d-4dd8-9fdb-cc09231361f6,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"As stated above, lymphocytes are the primary cells of adaptive immune responses (Table 21.1). The two basic types of lymphocytes, B cells and T cells, are identical morphologically with a large central nucleus surrounded by a thin layer of cytoplasm. They are distinguished from each other by their surface protein markers as well as by the molecules they secrete. While B cells mature in red bone marrow and T cells mature in the thymus, they both initially develop from bone marrow. T cells migrate from bone marrow to the thymus gland where they further mature. B cells and T cells are found in many parts of the body, circulating in the bloodstream and lymph, and residing in secondary lymphoid organs, including the spleen and lymph nodes, which will be described later in this section. The human body contains approximately 1012 lymphocytes.",True,The Organization of Immune Function,,,,
+514dec43-6e39-4d06-ad94-4a1afc741fb2,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,Primary Lymphoid Organs and Lymphocyte Development,False,Primary Lymphoid Organs and Lymphocyte Development,,,,
+6ae495a7-4d99-4b6b-82cc-2411a9b051f9,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"Understanding the differentiation and development of B and T cells is critical to the understanding of the adaptive immune response. It is through this process that the body (ideally) learns to destroy only pathogens and leaves the body’s own cells relatively intact. The primary lymphoid organs are the bone marrow and thymus gland. The lymphoid organs are where lymphocytes mature, proliferate, and are selected, which enables them to attack pathogens without harming the cells of the body.",True,Primary Lymphoid Organs and Lymphocyte Development,,,,
+9edfc002-f929-4cef-920b-736da86254f3,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,Secondary Lymphoid Organs and their Roles in Active Immune Responses,False,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+d4dc1d30-4a0d-42be-9176-4381d0a9524b,https://open.oregonstate.education/aandp/,21.1 Anatomy of the Lymphatic and Immune Systems,https://open.oregonstate.education/aandp/chapter/21-1-anatomy-of-the-lymphatic-and-immune-systems/,"Lymphocytes develop and mature in the primary lymphoid organs, but they mount immune responses from the secondary lymphoid organs. A naïve lymphocyte is one that has left the primary organ and entered a secondary lymphoid organ. Naïve lymphocytes are fully functional immunologically, but have yet to encounter an antigen to respond to. In addition to circulating in the blood and lymph, lymphocytes concentrate in secondary lymphoid organs, which include the lymph nodes, spleen, and lymphoid nodules. All of these tissues have many features in common, including the following:",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+d4d4b87a-1cd9-45d2-b756-5bf6447ed43d,https://open.oregonstate.education/aandp/,21.0 Introduction,https://open.oregonstate.education/aandp/chapter/21-0-introduction/,"In June 1981, the Centers for Disease Control and Prevention (CDC), in Atlanta, Georgia, published a report of an unusual cluster of five patients in Los Angeles, California. All five were diagnosed with a rare pneumonia caused by a fungus called Pneumocystis jirovecii (formerly known as Pneumocystis carinii).",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+bdc1a13c-dfd5-408e-bc44-d92e5511a686,https://open.oregonstate.education/aandp/,21.0 Introduction,https://open.oregonstate.education/aandp/chapter/21-0-introduction/,"Why was this unusual? Although commonly found in the lungs of healthy individuals, this fungus is an opportunistic pathogen that causes disease in individuals with suppressed or underdeveloped immune systems. The very young, whose immune systems have yet to mature, and the elderly, whose immune systems have declined with age, are particularly susceptible. The five patients from LA, though, were between 29 and 36 years of age and should have been in the prime of their lives, immunologically speaking. What could be going on?",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+fbe437dd-37e7-45f2-b651-c7ce1dd2da49,https://open.oregonstate.education/aandp/,21.0 Introduction,https://open.oregonstate.education/aandp/chapter/21-0-introduction/,"A few days later, a cluster of eight cases was reported in New York City, also involving young patients, this time exhibiting a rare form of skin cancer known as Kaposi’s sarcoma. This cancer of the cells that line the blood and lymphatic vessels was previously observed as a relatively innocuous disease of the elderly. The disease that doctors saw in 1981 was frighteningly more severe, with multiple, fast-growing lesions that spread to all parts of the body, including the trunk and face. Could the immune systems of these young patients have been compromised in some way? Indeed, when they were tested, they exhibited extremely low numbers of a specific type of white blood cell in their bloodstreams, indicating that they had somehow lost a major part of the immune system.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+b653175f-b632-42d8-a71f-a8617d0a8206,https://open.oregonstate.education/aandp/,21.0 Introduction,https://open.oregonstate.education/aandp/chapter/21-0-introduction/,"Acquired immune deficiency syndrome, or AIDS, turned out to be a new disease caused by the previously unknown human immunodeficiency virus (HIV). Although nearly 100 percent fatal in those with active HIV infections in the early years, the development of anti-HIV drugs has transformed HIV infection into a chronic, manageable disease and not the certain death sentence it once was. One positive outcome resulting from the emergence of HIV disease was that the public’s attention became focused as never before on the importance of having a functional and healthy immune system.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+a7f8c62f-18e2-4be4-b9c6-7d7e7e0b05f6,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"In a developing embryo,the heart has developed enough by day 21 post-fertilization to begin beating. Circulation patterns are clearly established by the fourth week of embryonic life. It is critical to the survival of the developing human that the circulatory system forms early to supply the growing tissue with nutrients and gases, and to remove waste products. Blood cells and vessel production in structures outside the embryo proper called the yolk sac, chorion, and connecting stalk begin about 15 to 16 days following fertilization. Development of these circulatory elements within the embryo itself begins approximately 2 days later. You will learn more about the formation and function of these early structures when you study the chapter on development. During those first few weeks, blood vessels begin to form from the embryonic mesoderm. The precursor cells are known as hemangioblasts. These in turn differentiate into angioblasts, which give rise to the blood vessels and pluripotent stem cells, which differentiate into the formed elements of blood. (Seek additional content for more detail on fetal development and circulation.) Together, these cells form masses known as blood islands scattered throughout the embryonic disc. Spaces appear on the blood islands that develop into vessel lumens. The endothelial lining of the vessels arise from the angioblasts within these islands. Surrounding mesenchymal cells give rise to the smooth muscle and connective tissue layers of the vessels. While the vessels are developing, the pluripotent stem cells begin to form the blood.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+77c844ef-63c4-4434-b8f7-4956ae5de163,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"Vascular tubes also develop on the blood islands, and they eventually connect to one another as well as to the developing, tubular heart. Thus, the developmental pattern, rather than beginning from the formation of one central vessel and spreading outward, occurs in many regions simultaneously with vessels later joining together. This angiogenesis—the creation of new blood vessels from existing ones—continues as needed throughout life as we grow and develop.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+427a3fc0-7dc8-4a31-92c8-24439b4a0ea2,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,Blood vessel development often follows the same pattern as nerve development and travels to the same target tissues and organs. This occurs because the many factors directing growth of nerves also stimulate blood vessels to follow a similar pattern. Whether a given vessel develops into an artery or a vein is dependent upon local concentrations of signaling proteins.,True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+a811788b-c20c-424d-8119-60a14856d92e,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"As the embryo grows within the mother’s uterus, its requirements for nutrients and gas exchange also grow. The placenta—a circulatory organ unique to pregnancy—develops jointly from the embryo and uterine wall structures to fill this need. Emerging from the placenta is the umbilical vein, which carries oxygen-rich blood from the mother to the fetal inferior vena cava via the ductus venosus to the heart that pumps it into fetal circulation. Two umbilical arteries carry oxygen-depleted fetal blood, including wastes and carbon dioxide, to the placenta. Remnants of the umbilical arteries remain in the adult. (Seek additional content for more information on the role of the placenta in fetal circulation.)",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+a8c61662-70ce-4090-8a45-d8d45002e9f2,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"There are three major shunts—alternate paths for blood flow—found in the circulatory system of the fetus. Two of these shunts divert blood from the pulmonary to the systemic circuit, whereas the third connects the umbilical vein to the inferior vena cava. The first two shunts are critical during fetal life, when the lungs are compressed, filled with amniotic fluid, and nonfunctional, and gas exchange is provided by the placenta. These shunts close shortly after birth, however, when the newborn begins to breathe. The third shunt persists a bit longer but becomes nonfunctional once the umbilical cord is severed. The three shunts are as follows (Figure 20.6.1):",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,Figure 20.6.1,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2139_Fetal_Circulation.jpg,"Figure 20.6.1 – Fetal Shunts: The foramen ovale in the interatrial septum allows blood to flow from the right atrium to the left atrium. The ductus arteriosus is a temporary vessel, connecting the aorta to the pulmonary trunk. The ductus venosus links the umbilical vein to the inferior vena cava largely through the liver."
+e1b9b10a-8065-4e77-bbf6-bd29edac1695,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"The foramen ovale is an opening in the interatrial septum that allows blood to flow from the right atrium to the left atrium. A valve associated with this opening prevents backflow of blood during the fetal period. As the newborn begins to breathe and blood pressure in the atria increases, this shunt closes. The fossa ovalis remains in the interatrial septum after birth, marking the location of the former foramen ovale.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+ff464996-97f4-4f0d-9163-f5b32e1c887b,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"The ductus arteriosus is a short, muscular vessel that connects the pulmonary trunk to the aorta. Most of the blood pumped from the right ventricle into the pulmonary trunk is thereby diverted into the aorta. Only enough blood reaches the fetal lungs to maintain the developing lung tissue. When the newborn takes the first breath, pressure within the lungs drops dramatically, and both the lungs and the pulmonary vessels expand. As the amount of oxygen increases, the smooth muscles in the wall of the ductus arteriosus constrict, sealing off the passage. Eventually, the muscular and endothelial components of the ductus arteriosus degenerate, leaving only the connective tissue component of the ligamentum arteriosum.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+0bee3300-fc24-41c7-8d00-00c5bb95d695,https://open.oregonstate.education/aandp/,20.6 Development of Blood Vessels and Fetal Circulation,https://open.oregonstate.education/aandp/chapter/20-6-development-of-blood-vessels-and-fetal-circulation/,"The ductus venosus is a temporary blood vessel that branches from the umbilical vein, allowing much of the freshly oxygenated blood from the placenta—the organ of gas exchange between the mother and fetus—to bypass the fetal liver and go directly to the fetal heart. The ductus venosus closes slowly during the first weeks of infancy and degenerates to become the ligamentum venosum.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+9e8443eb-1715-4181-a62c-3ffb2d056281,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Virtually every cell, tissue, organ, and system in the body is impacted by the circulatory system. This includes the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. Figure 20.5.1 summarizes these relationships.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,Figure 20.5.1,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2141_CircSyst_vs_OtherSystemsN.jpg,Figure 20.5.1 Interaction of the Circulatory System with Other Body Systems
+0f806f4e-b87f-4a08-99cc-a79294270ad3,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"As you learn about the vessels of the systemic and pulmonary circuits, notice that many arteries and veins share the same names, parallel one another throughout the body, and are very similar on the right and left sides of the body. These pairs of vessels will be traced through only one side of the body. Where differences occur in branching patterns or when vessels are singular, this will be indicated. For example, you will find a pair of femoral arteries and a pair of femoral veins, with one vessel on each side of the body. In contrast, some vessels closer to the midline of the body, such as the aorta, are unique. Moreover, some superficial veins, such as the great saphenous vein in the femoral region, have no arterial counterpart. Another phenomenon that can make the study of vessels challenging is that names of vessels can change with location. Like a street that changes name as it passes through an intersection, an artery or vein can change names as it passes an anatomical landmark. For example, the left subclavian artery becomes the axillary artery as it passes through the body wall and into the axillary region, and then becomes the brachial artery as it flows from the axillary region into the upper arm (or brachium). You will also find examples of anastomoses where two blood vessels that previously branched reconnect. Anastomoses are especially common in veins, where they help maintain blood flow even when one vessel is blocked or narrowed, although there are some important ones in the arteries supplying the brain.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+732adedb-3fc1-49eb-9402-5ae01e7a1720,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"As you read about circular pathways, notice that there is an occasional, very large artery referred to as a trunk, a term indicating that the vessel gives rise to several smaller arteries. For example, the celiac trunk gives rise to the left gastric, common hepatic, and splenic arteries.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+b6b98e94-c865-45ba-b3be-afcd039c5131,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"As you study this section, imagine you are on a “Voyage of Discovery” similar to Lewis and Clark’s expedition in 1804–1806, which followed rivers and streams through unfamiliar territory, seeking a water route from the Atlantic to the Pacific Ocean. You might envision being inside a miniature boat, exploring the various branches of the circulatory system. This simple approach has proven effective for many students in mastering these major circulatory patterns. Another approach that works well for many students is to create simple line drawings similar to the ones provided, labeling each of the major vessels. It is beyond the scope of this text to name every vessel in the body. However, we will attempt to discuss the major pathways for blood and acquaint you with the major named arteries and veins in the body. Also, please keep in mind that individual variations in circulation patterns are not uncommon.",True,Secondary Lymphoid Organs and their Roles in Active Immune Responses,,,,
+fb2c9702-8fb2-459d-8482-ec6fa20f0ef1,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Pulmonary Circulation,False,Pulmonary Circulation,,,,
+9534f415-fb1f-40ef-abe3-0b7e88b8c450,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Recall that blood returning from the systemic circuit enters the right atrium (Figure 20.5.2) via the superior and inferior venae cavae and the coronary sinus, which drains the blood supply of the heart muscle. These vessels will be described more fully later in this section. This blood is relatively low in oxygen and relatively high in carbon dioxide, since much of the oxygen has been extracted for use by the tissues and the waste gas carbon dioxide was picked up to be transported to the lungs for elimination. From the right atrium, blood moves into the right ventricle, which pumps it to the lungs for gas exchange. This system of vessels is referred to as the pulmonary circuit.",True,Pulmonary Circulation,Figure 20.5.2,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+fadadb34-f49f-4b07-9c44-97cd50672bef,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The single vessel exiting the right ventricle is the pulmonary trunk. At the base of the pulmonary trunk is the pulmonary semilunar valve, which prevents backflow of blood into the right ventricle during ventricular diastole. As the pulmonary trunk reaches the superior surface of the heart, it curves posteriorly and rapidly bifurcates (divides) into two branches, a left and a right pulmonary artery. To prevent confusion between these vessels, it is important to refer to the vessel exiting the heart as the pulmonary trunk, rather than also calling it a pulmonary artery. The pulmonary arteries in turn branch many times within the lung, forming a series of smaller arteries and arterioles that eventually lead to the pulmonary capillaries. The pulmonary capillaries surround lung structures known as alveoli that are the sites of oxygen and carbon dioxide exchange.",True,Pulmonary Circulation,,,,
+4f0e12ff-1d08-4bd0-9bf4-226090a59960,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Once gas exchange is completed, oxygenated blood flows from the pulmonary capillaries into a series of pulmonary venules that eventually lead to a series of larger pulmonary veins. Four pulmonary veins, two on the left and two on the right, return blood to the left atrium. At this point, the pulmonary circuit is complete. Table 20.4 defines the major arteries and veins of the pulmonary circuit discussed in the text.",True,Pulmonary Circulation,,,,
+56f68318-5efa-40c7-8d9e-93a10073e0f1,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Overview of Systemic Arteries,False,Overview of Systemic Arteries,,,,
+7a6b1494-a4e7-402b-b61d-0e8592e29d7e,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Blood relatively high in oxygen concentration is returned from the pulmonary circuit to the left atrium via the four pulmonary veins. From the left atrium, blood moves into the left ventricle, which pumps blood into the aorta. The aorta and its branches—the systemic arteries—send blood to virtually every organ of the body (Figure 20.5.3).",True,Overview of Systemic Arteries,Figure 20.5.3,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2120_Major_Systemic_Artery.jpg,Figure 20.5.3 – Systemic Arteries: The major systemic arteries shown here deliver oxygenated blood throughout the body.
+3d3ace65-fa8b-43f8-8b69-595a56cf902b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,The Aorta,False,The Aorta,,,,
+f75f21eb-0d0a-4f11-afcc-b58d75a0bb1e,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The aorta is the largest artery in the body (Figure 20.5.4). It arises from the left ventricle and eventually descends to the abdominal region, where it bifurcates at the level of the fourth lumbar vertebra into the two common iliac arteries. The aorta consists of the ascending aorta, the aortic arch, and the descending aorta, which passes through the diaphragm and a landmark that divides into the superior thoracic and inferior abdominal components. Arteries originating from the aorta ultimately distribute blood to virtually all tissues of the body. At the base of the aorta is the aortic semilunar valve that prevents backflow of blood into the left ventricle while the heart is relaxing. After exiting the heart, the ascending aorta moves in a superior direction for approximately 5 cm and ends at the sternal angle. Following this ascent, it reverses direction, forming a graceful arc to the left, called the aortic arch. The aortic arch descends toward the inferior portions of the body and ends at the level of the intervertebral disk between the fourth and fifth thoracic vertebrae. Beyond this point, the descending aorta continues close to the bodies of the vertebrae and passes through an opening in the diaphragm known as the aortic hiatus. Superior to the diaphragm, the aorta is called the thoracic aorta, and inferior to the diaphragm, it is called the abdominal aorta. The abdominal aorta terminates when it bifurcates into the two common iliac arteries at the level of the fourth lumbar vertebra. See Figure 20.5.4 for an illustration of the ascending aorta, the aortic arch, and the initial segment of the descending aorta plus major branches; Table 20.5 summarizes the structures of the aorta.",True,The Aorta,Figure 20.5.4,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2121_Aorta.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions."
+37f6ac41-1ee0-49f4-b48c-d6d28f7ffc4f,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Coronary Circulation,False,Coronary Circulation,,,,
+a6f34745-61d0-40e4-a69f-42beb5122847,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The first vessels that branch from the ascending aorta are the paired coronary arteries (see Figure 20.5.4), which arise from two of the three sinuses in the ascending aorta just superior to the aortic semilunar valve. These sinuses contain the aortic baroreceptors and chemoreceptors critical to maintain cardiac function. The left coronary artery arises from the left posterior aortic sinus. The right coronary artery arises from the anterior aortic sinus. Normally, the right posterior aortic sinus does not give rise to a vessel.",True,Coronary Circulation,Figure 20.5.4,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2121_Aorta.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions."
+e7239930-574e-4dcb-9501-1e95aed19236,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The coronary arteries encircle the heart, forming a ring-like structure that divides into the next level of branches that supplies blood to the heart tissues. (Seek additional content for more detail on cardiac circulation.)",True,Coronary Circulation,,,,
+d2049374-d61a-436e-997b-7e09007746fc,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Aortic Arch Branches,False,Aortic Arch Branches,,,,
+71540d30-3c6a-4b2d-b58f-063abf28b254,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"There are three major branches of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian (literally “under the clavicle”) artery. As you would expect based upon proximity to the heart, each of these vessels is classified as an elastic artery.",True,Aortic Arch Branches,,,,
+74ca4cd9-836b-42e1-b99b-0bed8dcc002e,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,The brachiocephalic artery is located only on the right side of the body; there is no corresponding artery on the left. The brachiocephalic artery branches into the right subclavian artery and the right common carotid artery. The left subclavian and left common carotid arteries arise independently from the aortic arch but otherwise follow a similar pattern and distribution to the corresponding arteries on the right side (see Figure 20.5.2).,True,Aortic Arch Branches,Figure 20.5.2,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+8d6502df-45e6-4e43-89f6-9be49024bcc5,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Each subclavian artery supplies blood to the arms, chest, shoulders, back, and central nervous system. It then gives rise to three major branches: the internal thoracic artery, the vertebral artery, and the thyrocervical artery. The internal thoracic artery, or mammary artery, supplies blood to the thymus, the pericardium of the heart, and the anterior chest wall. The vertebral artery passes through the vertebral foramen in the cervical vertebrae and then through the foramen magnum into the cranial cavity to supply blood to the brain and spinal cord. The paired vertebral arteries join together to form the large basilar artery at the base of the medulla oblongata. This is an example of an anastomosis. The subclavian artery also gives rise to the thyrocervical artery that provides blood to the thyroid, the cervical region of the neck, and the upper back and shoulder.",True,Aortic Arch Branches,,,,
+f32f9637-71bb-4aab-abb0-d6e5ae1d11da,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The common carotid artery divides into internal and external carotid arteries. The right common carotid artery arises from the brachiocephalic artery and the left common carotid artery arises directly from the aortic arch. The external carotid artery supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx. These branches include the lingual, facial, occipital, maxillary, and superficial temporal arteries. The internal carotid artery initially forms an expansion known as the carotid sinus, containing the carotid baroreceptors and chemoreceptors. Like their counterparts in the aortic sinuses, the information provided by these receptors is critical to maintaining cardiovascular homeostasis (see Figure 20.5.2).",True,Aortic Arch Branches,Figure 20.5.2,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+b40b9f53-291f-47e3-adc0-2bc14a8c1c72,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The internal carotid arteries along with the vertebral arteries are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. Recall that blood flow to the brain is remarkably constant, with approximately 20 percent of blood flow directed to this organ at any given time. When blood flow is interrupted, even for just a few seconds, a transient ischemic attack (TIA), or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. In some cases, the damage may be permanent. Loss of blood flow for longer periods, typically between 3 and 4 minutes, will likely produce irreversible brain damage or a stroke, also called a cerebrovascular accident (CVA). The locations of the arteries in the brain not only provide blood flow to the brain tissue but also prevent interruption in the flow of blood. Both the carotid and vertebral arteries branch once they enter the cranial cavity, and some of these branches form a structure known as the arterial circle (or circle of Willis), an anastomosis that is remarkably like a traffic circle that sends off branches (in this case, arterial branches to the brain). As a rule, branches to the anterior portion of the cerebrum are normally fed by the internal carotid arteries; the remainder of the brain receives blood flow from branches associated with the vertebral arteries.",True,Aortic Arch Branches,,,,
+fef21dcb-882c-49fa-af65-370bae1aeb11,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The internal carotid artery continues through the carotid canal of the temporal bone and enters the base of the brain through the carotid foramen where it gives rise to several branches (Figure 20.5.5 and Figure 20.5.6). One of these branches is the anterior cerebral artery that supplies blood to the frontal lobe of the cerebrum. Another branch, the middle cerebral artery, supplies blood to the temporal and parietal lobes, which are the most common sites of CVAs. The ophthalmic artery, the third major branch, provides blood to the eyes.",True,Aortic Arch Branches,Figure 20.5.5,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2122_Common_Carotid_Artery.jpg,"Figure 20.5.5 – Arteries Supplying the Head and Neck: The common carotid artery gives rise to the external and internal carotid arteries. The external carotid artery remains superficial and gives rise to many arteries of the head. The internal carotid artery first forms the carotid sinus and then reaches the brain via the carotid canal and carotid foramen, emerging into the cranium via the foramen lacerum. The vertebral artery branches from the subclavian artery and passes through the transverse foramen in the cervical vertebrae, entering the base of the skull at the vertebral foramen. The subclavian artery continues toward the arm as the axillary artery."
+616cb18b-7157-47cd-8ff7-2815136bc36e,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The right and left anterior cerebral arteries join together to form an anastomosis called the anterior communicating artery. The initial segments of the anterior cerebral arteries and the anterior communicating artery form the anterior portion of the arterial circle. The posterior portion of the arterial circle is formed by a left and a right posterior communicating artery that branches from the posterior cerebral artery, which arises from the basilar artery. It provides blood to the posterior portion of the cerebrum and brain stem. The basilar artery is an anastomosis that begins at the junction of the two vertebral arteries and sends branches to the cerebellum and brain stem. It flows into the posterior cerebral arteries. Table 20.6 summarizes the aortic arch branches, including the major branches supplying the brain.",True,Aortic Arch Branches,,,,
+afa2e059-5236-4861-b3e4-d1b6a179f31d,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Thoracic Aorta and Major Branches,False,Thoracic Aorta and Major Branches,,,,
+f0e8e9c1-adb9-43a6-9541-cb3dbcf71427,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The thoracic aorta begins at the level of vertebra T5 and continues through to the diaphragm at the level of T12, initially traveling within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are collectively referred to as visceral branches and parietal branches (Figure 20.5.7). Those branches that supply blood primarily to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. Each bronchial artery (typically two on the left and one on the right) supplies systemic blood to the lungs and visceral pleura, in addition to the blood pumped to the lungs for oxygenation via the pulmonary circuit. The bronchial arteries follow the same path as the respiratory branches, beginning with the bronchi and ending with the bronchioles. There is considerable, but not total, intermingling of the systemic and pulmonary blood at anastomoses in the smaller branches of the lungs. This may sound incongruous—that is, the mixing of systemic arterial blood high in oxygen with the pulmonary arterial blood lower in oxygen—but the systemic vessels also deliver nutrients to the lung tissue just as they do elsewhere in the body. The mixed blood drains into typical pulmonary veins, whereas the bronchial artery branches remain separate and drain into bronchial veins described later. Each pericardial artery supplies blood to the pericardium, the esophageal artery provides blood to the esophagus, and the mediastinal artery provides blood to the mediastinum. The remaining thoracic aorta branches are collectively referred to as parietal branches or somatic branches, and include the intercostal and superior phrenic arteries. Each intercostal artery provides blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery provides blood to the superior surface of the diaphragm. Table 20.7 lists the arteries of the thoracic region.",True,Thoracic Aorta and Major Branches,Figure 20.5.7,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2124_Thoracic_Abdominal_Arteries.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.
+b59c0a4b-c7d3-48f9-a67b-5aa0e6b9a1ba,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Abdominal Aorta and Major Branches,False,Abdominal Aorta and Major Branches,,,,
+c2f0e198-a2ab-47dd-9fe6-48303185de99,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"After crossing through the diaphragm at the aortic hiatus, the thoracic aorta is called the abdominal aorta (see Figure 20.5.7). This vessel remains to the left of the vertebral column and is embedded in adipose tissue behind the peritoneal cavity. It formally ends at approximately the level of vertebra L4, where it bifurcates to form the common iliac arteries. Before this division, the abdominal aorta gives rise to several important branches. A single celiac trunk (artery) emerges and divides into the left gastric artery to supply blood to the stomach and esophagus, the splenic artery to supply blood to the spleen, and the common hepatic artery, which in turn gives rise to the hepatic artery proper to supply blood to the liver, the right gastric artery to supply blood to the stomach, the cystic artery to supply blood to the gall bladder, and several branches, one to supply blood to the duodenum and another to supply blood to the pancreas. Two additional single vessels arise from the abdominal aorta. These are the superior and inferior mesenteric arteries. The superior mesenteric artery arises approximately 2.5 cm after the celiac trunk and branches into several major vessels that supply blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine. The inferior mesenteric artery supplies blood to the distal segment of the large intestine, including the rectum. It arises approximately 5 cm superior to the common iliac arteries.",True,Abdominal Aorta and Major Branches,Figure 20.5.7,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2124_Thoracic_Abdominal_Arteries.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.
+50f418cc-fa11-4d05-8a30-4eeb58b5c90b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"In addition to these single branches, the abdominal aorta gives rise to several significant paired arteries along the way. These include the inferior phrenic arteries, the adrenal arteries, the renal arteries, the gonadal arteries, and the lumbar arteries. Each inferior phrenic artery is a counterpart of a superior phrenic artery and supplies blood to the inferior surface of the diaphragm. The adrenal artery supplies blood to the adrenal (suprarenal) glands and arises near the superior mesenteric artery. Each renal artery branches approximately 2.5 cm inferior to the superior mesenteric arteries and supplies a kidney. The right renal artery is longer than the left since the aorta lies to the left of the vertebral column and the vessel must travel a greater distance to reach its target. Renal arteries branch repeatedly to supply blood to the kidneys. Each gonadal artery supplies blood to the gonads, or reproductive organs, and is also described as either an ovarian artery or a testicular artery (internal spermatic), depending upon the sex of the individual. An ovarian artery supplies blood to an ovary, uterine (Fallopian) tube, and the uterus, and is located within the suspensory ligament of the uterus. It is considerably shorter than a testicular artery, which ultimately travels outside the body cavity to the testes, forming one component of the spermatic cord. The gonadal arteries arise inferior to the renal arteries and are generally retroperitoneal. The ovarian artery continues to the uterus where it forms an anastomosis with the uterine artery that supplies blood to the uterus. Both the uterine arteries and vaginal arteries, which distribute blood to the vagina, are branches of the internal iliac artery. The four paired lumbar arteries are the counterparts of the intercostal arteries and supply blood to the lumbar region, the abdominal wall, and the spinal cord. In some instances, a fifth pair of lumbar arteries emerges from the median sacral artery.",True,Abdominal Aorta and Major Branches,,,,
+6a603ab0-c8e1-4ac7-86ff-5c536ebae134,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The aorta divides at approximately the level of vertebra L4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries provide blood to the pelvic region and ultimately to the lower limbs. They split into external and internal iliac arteries approximately at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also provide blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs. Figure 20.5.8 shows the distribution of the major branches of the aorta into the thoracic and abdominal regions. Figure 20.5.9 shows the distribution of the major branches of the common iliac arteries. Table 20.8 summarizes the major branches of the abdominal aorta.",True,Abdominal Aorta and Major Branches,Figure 20.5.8,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2125_Thoracic_Abdominal_Arteries_Chart-scaled.jpg,Figure 20.5.8 – Major Branches of the Aorta: The flow chart summarizes the distribution of the major branches of the aorta into the thoracic and abdominal regions.
+c7583023-f291-4cff-9ff4-0330422c989b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Arteries Serving the Upper Limbs,False,Arteries Serving the Upper Limbs,,,,
+e04bc1b2-7aca-42c5-ba62-9f152c8e7a61,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"As the subclavian artery exits the thorax into the axillary region, it is renamed the axillary artery. Although it does branch and supply blood to the region near the head of the humerus (via the humeral circumflex arteries), the majority of the vessel continues into the upper arm, or brachium, and becomes the brachial artery (Figure 20.5.10). The brachial artery supplies blood to much of the brachial region and divides at the elbow into several smaller branches, including the deep brachial arteries, which provide blood to the posterior surface of the arm, and the ulnar collateral arteries, which supply blood to the region of the elbow. As the brachial artery approaches the coronoid fossa, it bifurcates into the radial and ulnar arteries, which continue into the forearm, or antebrachium. The radial artery and ulnar artery parallel their namesake bones, giving off smaller branches until they reach the wrist, or carpal region. At this level, they fuse to form the superficial and deep palmar arches that supply blood to the hand, as well as the digital arteries that supply blood to the digits. Figure 20.5.11 shows the distribution of systemic arteries from the heart into the upper limb. Table 20.9 summarizes the arteries serving the upper limbs.",True,Arteries Serving the Upper Limbs,Figure 20.5.10,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2127_Thoracic_Upper_Limb_Arteries.jpg,Figure 20.5.10 – Major Arteries Serving the Thorax and Upper Limb: The arteries that supply blood to the arms and hands are extensions of the subclavian arteries.
+56b142ac-905a-49ba-8af3-870354995a93,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Arteries Serving the Lower Limbs,False,Arteries Serving the Lower Limbs,,,,
+a3471d74-cf23-437c-816e-2534a1be2a3b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The external iliac artery exits the body cavity and enters the femoral region of the lower leg (Figure 20.5.12). As it passes through the body wall, it is renamed the femoral artery. It gives off several smaller branches as well as the lateral deep femoral artery that in turn gives rise to a lateral circumflex artery. These arteries supply blood to the deep muscles of the thigh as well as ventral and lateral regions of the integument. The femoral artery also gives rise to the genicular artery, which provides blood to the region of the knee. As the femoral artery passes posterior to the knee near the popliteal fossa, it is called the popliteal artery. The popliteal artery branches into the anterior and posterior tibial arteries.",True,Arteries Serving the Lower Limbs,Figure 20.5.12,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2129ab_Lower_Limb_Arteries_Anterior_Posterior.jpg,Figure 20.5.12 – Major Arteries Serving the Lower Limb: Major arteries serving the lower limb are shown in anterior and posterior views.
+2e3cdecf-aba9-4c3f-bbae-0a2ebf2d40d8,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The anterior tibial artery is located between the tibia and fibula, and supplies blood to the muscles and integument of the anterior tibial region. Upon reaching the tarsal region, it becomes the dorsalis pedis artery, which branches repeatedly and provides blood to the tarsal and dorsal regions of the foot. The posterior tibial artery provides blood to the muscles and integument on the posterior surface of the tibial region. The fibular or peroneal artery branches from the posterior tibial artery. It bifurcates and becomes the medial plantar artery and lateral plantar artery, providing blood to the plantar surfaces. There is an anastomosis with the dorsalis pedis artery, and the medial and lateral plantar arteries form two arches called the dorsal arch (also called the arcuate arch) and the plantar arch, which provide blood to the remainder of the foot and toes. Figure 20.5.13 shows the distribution of the major systemic arteries in the lower limb. Table 20.10 summarizes the major systemic arteries discussed in the text.",True,Arteries Serving the Lower Limbs,Figure 20.5.13,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2130_Lower_Limb_Arteries_Chart.jpg,Figure 20.5.13 – Systemic Arteries of the Lower Limb: The flow chart summarizes the distribution of the systemic arteries from the external iliac artery into the lower limb.
+eaa1b784-8b3d-4cc4-b142-3f0ef529f9a6,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Overview of Systemic Veins,False,Overview of Systemic Veins,,,,
+86d62c3e-1bf0-44cd-b4be-206e28c51439,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Systemic veins return blood to the right atrium. Since the blood has already passed through the systemic capillaries, it will be relatively low in oxygen concentration. In many cases, there will be veins draining organs and regions of the body with the same name as the arteries that supplied these regions and the two often parallel one another. This is often described as a “complementary” pattern. However, there is a great deal more variability in the venous circulation than normally occurs in the arteries. For the sake of brevity and clarity, this text will discuss only the most commonly encountered patterns. However, keep this variation in mind when you move from the classroom to clinical practice.",True,Overview of Systemic Veins,,,,
+2d325877-0ae8-4695-a328-5e433d2ccdbb,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"In both the neck and limb regions, there are often both superficial and deeper levels of veins. The deeper veins generally correspond to the complementary arteries. The superficial veins do not normally have direct arterial counterparts, but in addition to returning blood, they also make contributions to the maintenance of body temperature. When the ambient temperature is warm, more blood is diverted to the superficial veins where heat can be more easily dissipated to the environment. In colder weather, there is more constriction of the superficial veins and blood is diverted deeper where the body can retain more of the heat.",True,Overview of Systemic Veins,,,,
+9a3887eb-290e-4190-9e4e-e1842cd54c66,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The “Voyage of Discovery” analogy and stick drawings mentioned earlier remain valid techniques for the study of systemic veins, but veins present a more difficult challenge because there are numerous anastomoses and multiple branches. It is like following a river with many tributaries and channels, several of which interconnect. Tracing blood flow through arteries follows the current in the direction of blood flow, so that we move from the heart through the large arteries and into the smaller arteries to the capillaries. From the capillaries, we move into the smallest veins and follow the direction of blood flow into larger veins and back to the heart. Figure 20.5.14 outlines the path of the major systemic veins.",True,Overview of Systemic Veins,Figure 20.5.14,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2131_Major_Systematic_Veins.jpg,Figure 20.5.14 – Major Systemic Veins of the Body: The major systemic veins of the body are shown here in an anterior view.
+98cfaca8-b747-4c2e-80f1-e98aab13c761,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The right atrium receives all of the systemic venous return. Most of the blood flows into either the superior vena cava or inferior vena cava. If you draw an imaginary line at the level of the diaphragm, systemic venous circulation from above that line will generally flow into the superior vena cava; this includes blood from the head, neck, chest, shoulders, and upper limbs. The exception to this is that most venous blood flow from the coronary veins flows directly into the coronary sinus and from there directly into the right atrium. Beneath the diaphragm, systemic venous flow enters the inferior vena cava, that is, blood from the abdominal and pelvic regions and the lower limbs.",True,Overview of Systemic Veins,,,,
+59aec442-fa51-466f-94ea-7ff0186bd6c8,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,The Superior Vena Cava,False,The Superior Vena Cava,,,,
+2b8d552c-9209-45d9-bb04-4da5b0d8a7dc,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The superior vena cava drains most of the body superior to the diaphragm (Figure 20.5.15). On both the left and right sides, the subclavian vein forms when the axillary vein passes through the body wall from the axillary region. It fuses with the external and internal jugular veins from the head and neck to form the brachiocephalic vein. Each vertebral vein also flows into the brachiocephalic vein close to this fusion. These veins arise from the base of the brain and the cervical region of the spinal cord, and flow largely through the intervertebral foramina in the cervical vertebrae. They are the counterparts of the vertebral arteries. Each internal thoracic vein, also known as an internal mammary vein, drains the anterior surface of the chest wall and flows into the brachiocephalic vein.",True,The Superior Vena Cava,Figure 20.5.15,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2132_Thoracic_Abdominal_Veins.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava."
+48706185-8c5e-458e-bbc6-a0a3775c81db,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The remainder of the blood supply from the thorax drains into the azygos vein. Each intercostal vein drains muscles of the thoracic wall, each esophageal vein delivers blood from the inferior portions of the esophagus, each bronchial vein drains the systemic circulation from the lungs, and several smaller veins drain the mediastinal region. Bronchial veins carry approximately 13 percent of the blood that flows into the bronchial arteries; the remainder intermingles with the pulmonary circulation and returns to the heart via the pulmonary veins. These veins flow into the azygos vein, and with the smaller hemiazygos vein (hemi- = “half”) on the left of the vertebral column, drain blood from the thoracic region. The hemiazygos vein does not drain directly into the superior vena cava but enters the brachiocephalic vein via the superior intercostal vein.",True,The Superior Vena Cava,,,,
+bdc8105a-9b90-46d7-b230-588e57d3517b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The azygos vein passes through the diaphragm from the thoracic cavity on the right side of the vertebral column and begins in the lumbar region of the thoracic cavity. It flows into the superior vena cava at approximately the level of T2, making a significant contribution to the flow of blood. It combines with the two large left and right brachiocephalic veins to form the superior vena cava.",True,The Superior Vena Cava,,,,
+ea060d2b-bf29-4292-bf05-8a94357de234,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Table 20.11 summarizes the veins of the thoracic region that flow into the superior vena cava.,True,The Superior Vena Cava,,,,
+77740ead-f4b9-4e28-9565-723a7891278b,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Veins of the Head and Neck,False,Veins of the Head and Neck,,,,
+ad88eef5-4cfb-4ef5-be05-4422bc011739,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Blood from the brain and the superficial facial vein flow into each internal jugular vein (Figure 20.5.16). Blood from the more superficial portions of the head, scalp, and cranial regions, including the temporal vein and maxillary vein, flow into each external jugular vein. Although the external and internal jugular veins are separate vessels, there are anastomoses between them close to the thoracic region. Blood from the external jugular vein empties into the subclavian vein. Table 20.12 summarizes the major veins of the head and neck.",True,Veins of the Head and Neck,Figure 20.5.16,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2133_Head_and_Neck_Veins.jpg,"Figure 20.5.16 – Veins of the Head and Neck: This left lateral view shows the veins of the head and neck, including the intercranial sinuses."
+c08df2a5-3d87-490d-b70d-d0572fdcc785,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Venous Drainage of the Brain,False,Venous Drainage of the Brain,,,,
+70516f2f-d937-45df-83e8-2ed5f076e7ad,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Circulation to the brain is both critical and complex (see Table 20.16). Many smaller veins of the brain stem and the superficial veins of the cerebrum lead to larger vessels referred to as intracranial sinuses. These include the superior and inferior sagittal sinuses, straight sinus, cavernous sinuses, left and right sinuses, the petrosal sinuses, and the occipital sinuses. Ultimately, sinuses will lead back to either the inferior jugular vein or vertebral vein.",True,Venous Drainage of the Brain,,,,
+103ca093-cc44-4c42-bc1b-0e3ac0461aa9,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Most of the veins on the superior surface of the cerebrum flow into the largest of the sinuses, the superior sagittal sinus. It is located midsagittally between the meningeal and periosteal layers of the dura mater within the falx cerebri and, at first glance in images or models, can be mistaken for the subarachnoid space. Most reabsorption of cerebrospinal fluid occurs via the chorionic villi (arachnoid granulations) into the superior sagittal sinus. Blood from most of the smaller vessels originating from the inferior cerebral veins flows into the great cerebral vein and into the straight sinus. Other cerebral veins and those from the eye socket flow into the cavernous sinus, which flows into the petrosal sinus and then into the internal jugular vein. The occipital sinus, sagittal sinus, and straight sinuses all flow into the left and right transverse sinuses near the lambdoid suture. The transverse sinuses in turn flow into the sigmoid sinuses that pass through the jugular foramen and into the internal jugular vein. The internal jugular vein flows parallel to the common carotid artery and is more or less its counterpart. It empties into the brachiocephalic vein. The veins draining the cervical vertebrae and the posterior surface of the skull, including some blood from the occipital sinus, flow into the vertebral veins. These parallel the vertebral arteries and travel through the transverse foramina of the cervical vertebrae. The vertebral veins also flow into the brachiocephalic veins. Table 20.13 summarizes the major veins of the brain.",True,Venous Drainage of the Brain,,,,
+a444bed6-d76f-4f48-b9a9-1fac2eb62fb3,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Veins Draining the Upper Limbs,False,Veins Draining the Upper Limbs,,,,
+ee669d45-2e21-4189-91ce-5bcee5408ee6,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The digital veins in the fingers come together in the hand to form the palmar venous arches (Figure 20.5.17). From here, the veins come together to form the radial vein, the ulnar vein, and the median antebrachial vein. The radial vein and the ulnar vein parallel the bones of the forearm and join together at the antebrachium to form the brachial vein, a deep vein that flows into the axillary vein in the brachium.",True,Veins Draining the Upper Limbs,Figure 20.5.17,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2134_Thoracic_Upper_Limb_Veins.jpg,Figure 20.5.17 – Veins of the Upper Limb: This anterior view shows the veins that drain the upper limb.
+a3d8f78e-63a4-4636-8acd-0f3b5bcef490,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The median antebrachial vein parallels the ulnar vein, is more medial in location, and joins the basilic vein in the forearm. As the basilic vein reaches the antecubital region, it gives off a branch called the median cubital vein that crosses at an angle to join the cephalic vein. The median cubital vein is the most common site for drawing venous blood in humans. The basilic vein continues through the arm medially and superficially to the axillary vein.",True,Veins Draining the Upper Limbs,,,,
+386e2e76-7839-4145-8d06-18829bcc1396,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,The cephalic vein begins in the antebrachium and drains blood from the superficial surface of the arm into the axillary vein. It is extremely superficial and easily seen along the surface of the biceps brachii muscle in individuals with good muscle tone and in those without excessive subcutaneous adipose tissue in the arms.,True,Veins Draining the Upper Limbs,,,,
+52b81a42-97e3-4e39-ac70-b3f42c87a9dd,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The subscapular vein drains blood from the subscapular region and joins the cephalic vein to form the axillary vein. As it passes through the body wall and enters the thorax, the axillary vein becomes the subclavian vein.",True,Veins Draining the Upper Limbs,,,,
+42fba2cc-1059-4672-8ef5-8015b84641da,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Many of the larger veins of the thoracic and abdominal region and upper limb are further represented in the flow chart in Figure 20.5.18. Table 20.14 summarizes the veins of the upper limbs.,True,Veins Draining the Upper Limbs,Figure 20.5.18,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2135_Veins_Draining_into_Superior_Vena_Cava_Chart.jpg,Figure 20.5.18 – Veins Flowing into the Superior Vena Cava: The flow chart summarizes the distribution of the veins flowing into the superior vena cava.
+01f9d760-24fd-49d2-b561-3c5ff8a6570f,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,The Inferior Vena Cava,False,The Inferior Vena Cava,,,,
+35dc9b32-4dbc-4a68-8578-d3558ed6e087,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Other than the small amount of blood drained by the azygos and hemiazygos veins, most of the blood inferior to the diaphragm drains into the inferior vena cava before it is returned to the heart (see Figure 20.5.15). Lying just beneath the parietal peritoneum in the abdominal cavity, the inferior vena cava parallels the abdominal aorta, where it can receive blood from abdominal veins. The lumbar portions of the abdominal wall and spinal cord are drained by a series of lumbar veins, usually four on each side. The ascending lumbar veins drain into either the azygos vein on the right or the hemiazygos vein on the left, and return to the superior vena cava. The remaining lumbar veins drain directly into the inferior vena cava.",True,The Inferior Vena Cava,Figure 20.5.15,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2132_Thoracic_Abdominal_Veins.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava."
+e53da91e-ee4e-4815-84d9-dbbeaccb7bd8,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Blood supply from the kidneys flows into each renal vein, normally the largest veins entering the inferior vena cava. A number of other, smaller veins empty into the left renal vein. Each adrenal vein drains the adrenal or suprarenal glands located immediately superior to the kidneys. The right adrenal vein enters the inferior vena cava directly, whereas the left adrenal vein enters the left renal vein.",True,The Inferior Vena Cava,,,,
+2fed4871-1f8b-44b8-aa95-8ceea7f770b0,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"From the male reproductive organs, each testicular vein flows from the scrotum, forming a portion of the spermatic cord. Each ovarian vein drains an ovary in females. Each of these veins is generically called a gonadal vein. The right gonadal vein empties directly into the inferior vena cava, and the left gonadal vein empties into the left renal vein.",True,The Inferior Vena Cava,,,,
+688999fc-9efe-4dd1-a9c8-69d93c4db91f,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation. Figure 20.5.19 provides a flow chart of the veins flowing into the inferior vena cava. Table 20.15 summarizes the major veins of the abdominal region.",True,The Inferior Vena Cava,Figure 20.5.19,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2140_FlowChart_Veins_into_VenaCava.jpg,Figure 20.5.19 – Venous Flow into Inferior Vena Cava: The flow chart summarizes veins that deliver blood to the inferior vena cava.
+d8a9dd4e-896a-43f6-9b3c-a61cece55c29,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Veins Draining the Lower Limbs,False,Veins Draining the Lower Limbs,,,,
+78b92780-d75a-4089-8054-eaae96134dfc,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The superior surface of the foot drains into the digital veins, and the inferior surface drains into the plantar veins, which flow into a complex series of anastomoses in the feet and ankles, including the dorsal venous arch and the plantar venous arch (Figure 20.5.20). From the dorsal venous arch, blood supply drains into the anterior and posterior tibial veins. The anterior tibial vein drains the area near the tibialis anterior muscle and combines with the posterior tibial vein and the fibular vein to form the popliteal vein. The posterior tibial vein drains the posterior surface of the tibia and joins the popliteal vein. The fibular vein drains the muscles and integument in proximity to the fibula and also joins the popliteal vein. The small saphenous vein located on the lateral surface of the leg drains blood from the superficial regions of the lower leg and foot, and flows into to the popliteal vein. As the popliteal vein passes behind the knee in the popliteal region, it becomes the femoral vein. It is palpable in patients without excessive adipose tissue.",True,Veins Draining the Lower Limbs,Figure 20.5.20,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2136ab_Lower_Limb_Veins_Anterior_Posterior.jpg,Figure 20.5.20 – Major Veins Serving the Lower Limbs: Anterior and posterior views show the major veins that drain the lower limb into the inferior vena cava.
+502ed3d6-01c1-4507-9163-a378b3f060cd,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Close to the body wall, the great saphenous vein, the deep femoral vein, and the femoral circumflex vein drain into the femoral vein. The great saphenous vein is a prominent surface vessel located on the medial surface of the leg and thigh that collects blood from the superficial portions of these areas. The deep femoral vein, as the name suggests, drains blood from the deeper portions of the thigh. The femoral circumflex vein forms a loop around the femur just inferior to the trochanters and drains blood from the areas in proximity to the head and neck of the femur.",True,Veins Draining the Lower Limbs,,,,
+74cf82bc-891a-4751-990c-fb7c69619182,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"As the femoral vein penetrates the body wall from the femoral portion of the upper limb, it becomes the external iliac vein, a large vein that drains blood from the leg to the common iliac vein. The pelvic organs and integument drain into the internal iliac vein, which forms from several smaller veins in the region, including the umbilical veins that run on either side of the bladder. The external and internal iliac veins combine near the inferior portion of the sacroiliac joint to form the common iliac vein. In addition to blood supply from the external and internal iliac veins, the middle sacral vein drains the sacral region into the common iliac vein. Similar to the common iliac arteries, the common iliac veins come together at the level of L5 to form the inferior vena cava.",True,Veins Draining the Lower Limbs,,,,
+c8a385e1-af91-4456-9228-eb8e8f9b3cfa,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Figure 20.5.21 is a flow chart of veins flowing into the lower limb. Table 20.16 summarizes the major veins of the lower limbs.,True,Veins Draining the Lower Limbs,Figure 20.5.21,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2137_Lower_Limb_Veins_Chart.jpg,Figure 20.5.21 – Major Veins of the Lower Limb: The flow chart summarizes venous flow from the lower limb.
+03e74749-e316-4d0d-9434-c137ac263d33,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,Hepatic Portal System,False,Hepatic Portal System,,,,
+40cba48e-e75f-4d53-8fcf-203d632c7969,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The liver is a complex biochemical processing plant. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile; and disposes of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes (for example, materials produced by the spleen) travel to the liver for processing. They do so via the hepatic portal system (Figure 20.5.22). Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver, the hepatic sinusoids. You saw the only other portal system with the hypothalamic-hypophyseal portal vessel in the endocrine chapter.",True,Hepatic Portal System,Figure 20.5.22,20.5 Circulatory Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2138_Hepatic_Portal_Vein_System.jpg,"Figure 20.5.22 – Hepatic Portal System: The liver receives blood from the normal systemic circulation via the hepatic artery. It also receives and processes blood from other organs, delivered via the veins of the hepatic portal system. All blood exits the liver via the hepatic vein, which delivers the blood to the inferior vena cava. (Different colors are used to help distinguish among the different vessels in the system.)"
+d7d401ec-c4c1-4489-9953-33f11f419d0a,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"The hepatic portal system consists of the hepatic portal vein and the veins that drain into it. The hepatic portal vein itself is relatively short, beginning at the level of L2 with the confluence of the superior mesenteric and splenic veins. It also receives branches from the inferior mesenteric vein, plus the splenic veins and all their tributaries. The superior mesenteric vein receives blood from the small intestine, two-thirds of the large intestine, and the stomach. The inferior mesenteric vein drains the distal third of the large intestine, including the descending colon, the sigmoid colon, and the rectum. The splenic vein is formed from branches from the spleen, pancreas, and portions of the stomach, and the inferior mesenteric vein. After its formation, the hepatic portal vein also receives branches from the gastric veins of the stomach and cystic veins from the gall bladder. The hepatic portal vein delivers materials from these digestive and circulatory organs directly to the liver for processing.",True,Hepatic Portal System,,,,
+dedec192-3bb1-4f7e-bb79-7055d494aaf8,https://open.oregonstate.education/aandp/,20.5 Circulatory Pathways,https://open.oregonstate.education/aandp/chapter/20-5-circulatory-pathways/,"Because of the hepatic portal system, the liver receives its blood supply from two different sources: from normal systemic circulation via the hepatic artery and from the hepatic portal vein. The liver processes the blood from the portal system to remove certain wastes and excess nutrients, which are stored for later use. This processed blood, as well as the systemic blood that came from the hepatic artery, exits the liver via the right, left, and middle hepatic veins, and flows into the inferior vena cava. Overall systemic blood composition remains relatively stable, since the liver is able to metabolize the absorbed digestive components.",True,Hepatic Portal System,,,,
+a1363acb-e9a0-4c16-b215-9b2d3ab1a09f,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"In order to maintain homeostasis in the cardiovascular system and provide adequate blood to the tissues, blood flow must be redirected continually to the tissues as they become more active. In a very real sense, the cardiovascular system engages in resource allocation, because there is not enough blood flow to distribute blood equally to all tissues simultaneously. For example, when an individual is exercising, more blood will be directed to skeletal muscles, the heart, and the lungs. Following a meal, more blood is directed to the digestive system. Only the brain receives a more or less constant supply of blood whether you are active, resting, thinking, or engaged in any other activity.",True,Hepatic Portal System,,,,
+a5f4ecea-3873-4733-88af-4cca948e97c8,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Table 20.3 provides the distribution of systemic blood at rest and during exercise. Although most of the data appears logical, the values for the distribution of blood to the integument may seem surprising. During exercise, the body distributes more blood to the body surface where it can dissipate the excess heat generated by increased activity into the environment.",True,Hepatic Portal System,,,,
+e398dc76-0027-472d-b5ec-79a6863bef15,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Three homeostatic mechanisms ensure adequate blood flow, blood pressure, distribution, and ultimately perfusion: neural, endocrine, and autoregulatory mechanisms. They are summarized in Figure 20.4.1.",True,Hepatic Portal System,Figure 20.4.1,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2115_Vascular_Homeostasis_Flow_Art-1-scaled.jpg,"Figure 20.4.1 – Summary of Factors Maintaining Vascular Homeostasis: Adequate blood flow, blood pressure, distribution, and perfusion involve autoregulatory, neural, and endocrine mechanisms."
+e8d91ae5-c982-4660-bc72-87f29a43edab,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,Neural Regulation,False,Neural Regulation,,,,
+36546c0a-82d9-46cb-8426-768bdca529a4,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"The nervous system plays a critical role in the regulation of vascular homeostasis. The primary regulatory sites include the cardiovascular centers in the brain that control both cardiac and vascular functions. In addition, more generalized neural responses from the limbic system and the autonomic nervous system are factors.",True,Neural Regulation,,,,
+a9d431a1-fbe5-4af8-b2e0-d098daf8f43f,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,Endocrine Regulation,False,Endocrine Regulation,,,,
+be187dab-6a70-4862-8fa9-5fd2fe64a882,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Endocrine control over the cardiovascular system involves the catecholamines, epinephrine and norepinephrine, as well as several hormones that interact with the kidneys in the regulation of blood volume.",True,Endocrine Regulation,,,,
+0735671e-bb69-4ca1-86ae-ca9d765d13ee,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,Autoregulation of Perfusion,False,Autoregulation of Perfusion,,,,
+006f5212-1e47-4be0-8461-7c75b6864cb8,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"As the name would suggest, autoregulation mechanisms require neither specialized nervous stimulation nor endocrine control. Rather, these are local, self-regulatory mechanisms that allow each region of tissue to adjust its blood flow—and thus its perfusion. These local mechanisms include chemical signals and myogenic controls.",True,Autoregulation of Perfusion,,,,
+7320998a-62d4-4fc1-b995-a39fc39dae40,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,Effect of Exercise on Vascular Homeostasis,False,Effect of Exercise on Vascular Homeostasis,,,,
+e78e346b-b7cd-4591-8700-5b6599749708,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"The heart is a muscle and, like any muscle, it responds dramatically to exercise. For a healthy young adult, cardiac output (heart rate × stroke volume) increases in the nonathlete from approximately 5.0 liters (5.25 quarts) per minute to a maximum of about 20 liters (21 quarts) per minute. Accompanying this will be an increase in blood pressure from about 120/80 to 185/75. However, well-trained aerobic athletes can increase these values substantially. For these individuals, cardiac output soars from approximately 5.3 liters (5.57 quarts) per minute resting to more than 30 liters (31.5 quarts) per minute during maximal exercise. Along with this increase in cardiac output, blood pressure increases from 120/80 at rest to 200/90 at maximum values.",True,Effect of Exercise on Vascular Homeostasis,,,,
+526a6c55-23f3-49c9-91d8-ffb6ef725dc1,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"In addition to improved cardiac function, exercise increases the size and mass of the heart. The average weight of the heart for the nonathlete is about 300 g, whereas in an athlete it will increase to 500 g. This increase in size generally makes the heart stronger and more efficient at pumping blood, increasing both stroke volume and cardiac output.",True,Effect of Exercise on Vascular Homeostasis,,,,
+53ecd47e-5dea-4285-aa6a-3b4b8a7c4a33,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Tissue perfusion also increases as the body transitions from a resting state to light exercise and eventually to heavy exercise (see Figure 20.4.4). These changes result in selective vasodilation in the skeletal muscles, heart, lungs, liver, and integument. Simultaneously, vasoconstriction occurs in the vessels leading to the kidneys and most of the digestive and reproductive organs. The flow of blood to the brain remains largely unchanged whether at rest or exercising, since the vessels in the brain largely do not respond to regulatory stimuli, in most cases, because they lack the appropriate receptors.",True,Effect of Exercise on Vascular Homeostasis,Figure 20.4.4,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2143_Mechanism_Regulating_Arteries_and_Veins-1-scaled.jpg,Figure 20.4.4 Summary of Mechanisms Regulating Arteriole Smooth Muscle and Veins.
+68dbe977-212f-4ef9-930e-a090f875fdc0,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"As vasodilation occurs in selected vessels, resistance drops and more blood rushes into the organs they supply. This blood eventually returns to the venous system. Venous return is further enhanced by both the skeletal muscle and respiratory pumps. As blood returns to the heart more quickly, preload rises and the Frank-Starling principle tells us that contraction of the cardiac muscle in the atria and ventricles will be more forceful. Eventually, even the best-trained athletes will fatigue and must undergo a period of rest following exercise. Cardiac output and distribution of blood then return to normal.",True,Effect of Exercise on Vascular Homeostasis,,,,
+dc80fe33-7e8a-4b1c-8973-bbf77fb6a76e,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Regular exercise promotes cardiovascular health in a variety of ways. Because an athlete’s heart is larger than a nonathlete’s, stroke volume increases, so the athletic heart can deliver the same amount of blood as the nonathletic heart but with a lower heart rate. This increased efficiency allows the athlete to exercise for longer periods of time before muscles fatigue and places less stress on the heart. Exercise also lowers overall cholesterol levels by removing from the circulation a complex form of cholesterol, triglycerides, and proteins known as low-density lipoproteins (LDLs), which are widely associated with increased risk of cardiovascular disease. Although there is no way to remove deposits of plaque from the walls of arteries other than specialized surgery, exercise does promote the health of vessels by decreasing the rate of plaque formation and reducing blood pressure, so the heart does not have to generate as much force to overcome resistance.",True,Effect of Exercise on Vascular Homeostasis,,,,
+22c7632f-19e9-4e98-9ec7-a57a2d11aa03,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Generally as little as 30 minutes of noncontinuous exercise over the course of each day has beneficial effects and has been shown to lower the rate of heart attack by nearly 50 percent. While it is always advisable to follow a healthy diet, stop smoking, and lose weight, studies have clearly shown that fit, overweight people may actually be healthier overall than sedentary slender people. Thus, the benefits of moderate exercise are undeniable.",True,Effect of Exercise on Vascular Homeostasis,,,,
+39793081-4b87-4896-8f94-b2167059d6d0,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,Clinical Considerations in Vascular Homeostasis,False,Clinical Considerations in Vascular Homeostasis,,,,
+46b4c549-10a1-4740-8139-5aab36cce62e,https://open.oregonstate.education/aandp/,20.4 Homeostatic Regulation of the Vascular System,https://open.oregonstate.education/aandp/chapter/20-4-homeostatic-regulation-of-the-vascular-system/,"Any disorder that affects blood volume, vascular tone, or any other aspect of vascular functioning is likely to affect vascular homeostasis as well. That includes hypertension, hemorrhage, and shock.",True,Clinical Considerations in Vascular Homeostasis,,,,
+45b945f0-31c6-4ec9-8dbd-62a72e294879,https://open.oregonstate.education/aandp/,20.3 Capillary Exchange,https://open.oregonstate.education/aandp/chapter/20-3-capillary-exchange/,"The primary purpose of the cardiovascular system is to circulate gases, nutrients, wastes, and other substances to and from the cells of the body. Small molecules, such as gases, lipids, and lipid-soluble molecules, can diffuse directly through the membranes of the endothelial cells of the capillary wall. Glucose, amino acids, and ions—including sodium, potassium, calcium, and chloride—use transporters to move through specific channels in the membrane by facilitated diffusion. Glucose, ions, and larger molecules may also leave the blood through intercellular clefts. Larger molecules can pass through the pores of fenestrated capillaries, and even large plasma proteins can pass through the great gaps in the sinusoids. Some large proteins in blood plasma can move into and out of the endothelial cells packaged within vesicles by endocytosis and exocytosis. Water moves by osmosis.",True,Clinical Considerations in Vascular Homeostasis,,,,
+40f3aaa5-7c6f-4192-b175-828fd49de7fa,https://open.oregonstate.education/aandp/,20.3 Capillary Exchange,https://open.oregonstate.education/aandp/chapter/20-3-capillary-exchange/,Bulk Flow,False,Bulk Flow,,,,
+dfea5dc8-ef85-4938-ab2a-a9d421e219cb,https://open.oregonstate.education/aandp/,20.3 Capillary Exchange,https://open.oregonstate.education/aandp/chapter/20-3-capillary-exchange/,"The mass movement of fluids into and out of capillary beds requires a transport mechanism far more efficient than mere diffusion. This movement, often referred to as bulk flow, involves two pressure-driven mechanisms: Volumes of fluid move from an area of higher pressure in a capillary bed to an area of lower pressure in the tissues via filtration. In contrast, the movement of fluid from an area of higher pressure in the tissues into an area of lower pressure in the capillaries is reabsorption. Two types of pressure interact to drive each of these movements: hydrostatic pressure and osmotic pressure.",True,Bulk Flow,,,,
+b0218183-8f11-4444-957a-b9fbf8856d3a,https://open.oregonstate.education/aandp/,20.3 Capillary Exchange,https://open.oregonstate.education/aandp/chapter/20-3-capillary-exchange/,The Role of Lymphatic Capillaries,False,The Role of Lymphatic Capillaries,,,,
+d9f4a419-f4dd-496d-8b12-16568ed677bb,https://open.oregonstate.education/aandp/,20.3 Capillary Exchange,https://open.oregonstate.education/aandp/chapter/20-3-capillary-exchange/,"Since overall CHP is higher than BCOP, it is inevitable that more net fluid will exit the capillary through filtration at the arterial end than enters through reabsorption at the venous end. Considering all capillaries over the course of a day, this can be quite a substantial amount of fluid: Approximately 24 liters per day are filtered, whereas 20.4 liters are reabsorbed. This excess fluid is picked up by capillaries of the lymphatic system. These extremely thin-walled vessels have copious numbers of valves that ensure unidirectional flow through ever-larger lymphatic vessels that eventually drain into the subclavian veins in the neck. An important function of the lymphatic system is to return the fluid (lymph) to the blood. Lymph may be thought of as recycled blood plasma. (Seek additional content for more detail on the lymphatic system.)",True,The Role of Lymphatic Capillaries,,,,
+9ed6e329-4b42-465d-9ae9-cc629b79685f,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Blood flow refers to the movement of blood through a vessel, tissue, or organ, and is usually expressed in terms of volume of blood per unit of time. It is initiated by the contraction of the ventricles of the heart. If we consider the entire cardiovascular system, blood flow equals cardiac output. Ventricular contraction ejects blood into the major arteries, resulting in flow from regions of higher pressure to regions of lower pressure. This section discusses a number of critical variables that contribute to blood flow throughout the body. It also discusses resistance which is due to factors that impede or slow blood flow.",True,The Role of Lymphatic Capillaries,,,,
+f0e0ed11-bf7e-48a1-b1a1-f485270aa735,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"As noted earlier, hydrostatic pressure is the force exerted by a fluid due to gravitational pull, usually against the wall of the container in which it is located. One form of hydrostatic pressure is blood pressure, the force exerted by blood upon the walls of the blood vessels or the chambers of the heart. Blood pressure may be measured in both the systemic and pulmonary circulation; however, the term blood pressure without any specific descriptors typically refers to systemic arterial blood pressure—that is, the pressure of blood flowing in the arteries of the systemic circulation. In clinical practice, this pressure is measured in mm Hg and is usually obtained using the brachial artery of the arm.",True,The Role of Lymphatic Capillaries,,,,
+bae9225b-89b1-47f4-ad83-cdb6f2877354,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Arterial Blood Pressure,False,Arterial Blood Pressure,,,,
+e07da81a-8522-4db3-8fb9-a8d75c2e3933,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Arterial blood pressure in the larger vessels varies between systolic and diastolic pressures. Pulse pressure and mean arterial pressure are calculated values based upon the systolic and diastolic pressures (Figure 20.2.1).,True,Arterial Blood Pressure,Figure 20.2.1,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2109_Systemic_Blood_Pressure.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures."
+a529dffb-d54d-43cf-beeb-41f4541c1b70,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Pulse,False,Pulse,,,,
+bd91bc43-2cc0-4be1-9494-ce8709070bae,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"After blood is ejected from the heart, elastic fibers in the arteries help maintain a high-pressure gradient as they expand to accommodate the blood, then recoil to keep pressure on the blood. This expansion and recoiling effect, known as the pulse, can be palpated manually or measured electronically. Although the effect diminishes as the distance from the heart increases, elements of the systolic and diastolic components of the pulse are still evident down to the level of the arterioles.",True,Pulse,,,,
+f9b46739-1a9d-4291-a1da-2758614336e7,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Because pulse indicates heart rate, it is measured clinically to provide clues to a patient’s state of health. It is recorded as beats per minute. Both the rate and the strength of the pulse are important clinically. A high or irregular pulse rate can be caused by physical activity or other temporary factors, but it may also indicate a heart condition. The pulse strength indicates the strength of ventricular contraction and cardiac output. If the pulse is strong, then systolic pressure is high. If it is weak, systolic pressure has fallen, and medical intervention may be warranted.",True,Pulse,,,,
+5a8da6ce-883c-46bc-8246-5937f1cc5eb6,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Pulse can be palpated manually by lightly pressing the tips of the fingers across an artery that runs close to the body surface. While this procedure is normally performed using the radial artery in the wrist or the common carotid artery in the neck, any superficial artery that can be palpated may be used (Figure 20.2.2). Common sites to find a pulse include temporal and facial arteries in the head, brachial arteries in the upper arm, femoral arteries in the thigh, popliteal arteries behind the knees, posterior tibial arteries near the medial tarsal regions, and dorsalis pedis arteries in the feet. A variety of commercial electronic devices are also available to measure pulse.",True,Pulse,Figure 20.2.2,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2110_Pulse_Sites.jpg,"Figure 20.2.2 – Pulse Sites: The pulse is most readily measured at the radial artery, but can be measured at any of the pulse points shown."
+dcc7fe29-c9ab-46ff-a43a-989ce192ee71,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Measurement of Blood Pressure,False,Measurement of Blood Pressure,,,,
+a8f10f5e-db31-4c65-9e67-446a23def46b,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Blood pressure is one of the critical parameters measured on virtually every patient in every healthcare setting. The technique used today was developed more than 100 years ago by a pioneering Russian physician, Dr. Nikolai Korotkoff. Turbulent blood flow through the vessels can be heard as a soft ticking sound while measuring blood pressure; these sounds are known as Korotkoff sounds. The technique of measuring blood pressure requires the use of a sphygmomanometer (a blood pressure cuff attached to a measuring device) and a stethoscope. The technique is as follows:",True,Measurement of Blood Pressure,,,,
+d62eec1d-94c1-4b15-bdde-0c127cd95070,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Although there are five recognized Korotkoff sounds, only two are normally recorded. Initially, no sounds are heard since there is no blood flowing through the vessels, but as air pressure steadily drops, the cuff relaxes, and blood flow becomes pulsatile (turbulent) as it is pushed through the opening vessel.  As shown in Figure 20.2.3, the first sound heard through the stethoscope—the first Korotkoff sound—indicates systolic blood pressure. The clinician measuring the blood pressure will continue to hear tapping sounds for a time, but as more air is released from the cuff, the blood vessel lumen completely opens, and blood is eventually able to flow freely through the brachial artery. Once blood flows freely, all sounds disappear. The point at which the sound disappears is recorded as the patient’s diastolic pressure. Thus, the diastolic pressure is recorded when a clinician expects to hear another sound but does not.",True,Measurement of Blood Pressure,Figure 20.2.3,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/app/uploads/sites/157/2021/02/2111_Blood_Pressure_Graph.jpg,"Figure 20.2.3 – Blood Pressure Measurement: When pressure in a sphygmomanometer cuff is released, a clinician can hear the Korotkoff sounds. In this graph, a blood pressure tracing is aligned to a measurement of systolic and diastolic pressures."
+09dabe5b-ebe9-4545-bb9e-21bbe978ea5a,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,The majority of hospitals and clinics have automated equipment for measuring blood pressure that work on the same principles. An even more recent innovation is a small instrument that wraps around a patient’s wrist. The patient then holds the wrist over the heart while the device measures blood flow and records pressure.,True,Measurement of Blood Pressure,,,,
+e3c5fe61-b6b9-46bd-9fb6-91071d11c143,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Variables Affecting Blood Flow and Blood Pressure,False,Variables Affecting Blood Flow and Blood Pressure,,,,
+af94b6c5-e92f-41bd-af5c-54c54d4f70c3,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Four variables influence blood flow and blood pressure:,False,Four variables influence blood flow and blood pressure:,,,,
+56188638-73ca-46c1-af42-55701e546ab5,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"Recall that blood moves from higher pressure to lower pressure. It is pumped from the heart into the arteries at high pressure. Since pressure in the veins is normally relatively low, for blood to flow back into the heart, the pressure in the atria during atrial diastole must be even lower. It normally approaches zero, except when the atria contract (see Figure 20.2.1).",True,Four variables influence blood flow and blood pressure:,Figure 20.2.1,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/app/uploads/sites/157/2019/07/2109_Systemic_Blood_Pressure.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures."
+9aace896-aa2f-4ffc-bc62-1876a5e40fb3,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,Venous System,False,Venous System,,,,
+4501e605-a274-42c5-8a93-4a1318d2d419,https://open.oregonstate.education/aandp/,"20.2 Blood Flow, Blood Pressure, and Resistance",https://open.oregonstate.education/aandp/chapter/20-2-blood-flow-blood-pressure-and-resistance/,"The pumping action of the heart propels the blood into the arteries, from an area of higher pressure toward an area of lower pressure. If blood is to flow from the veins back into the heart, the pressure in the veins must be greater than the pressure in the atria of the heart. Two factors help maintain this pressure gradient between the veins and the heart. First, the pressure in the atria during diastole is very low, often approaching zero when the atria are relaxed (atrial diastole). Second, two physiologic “pumps” increase pressure in the venous system. The use of the term “pump” implies a physical device that speeds flow. These physiological pumps are less obvious.",True,Venous System,,,,
+fb770a96-cf5b-479a-8f4f-b9366db9526a,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Blood is carried through the body via blood vessels. An artery is a blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels. Eventually, the smallest arteries, vessels called arterioles, further branch into tiny capillaries, where nutrients and wastes are exchanged. Capillaries come together to form venules, small blood vessels that carry blood to a vein, a larger blood vessel that returns blood to the heart.",True,Venous System,,,,
+03b959e7-b265-4583-9849-eaee23effc46,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Arteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit (Figure 20.1.1). Systemic arteries provide blood rich in oxygen to the body’s tissues. The blood returned to the heart through systemic veins has less oxygen, since much of the oxygen carried by the arteries has been delivered to the cells. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation. Although arteries and veins differ structurally and functionally, they share certain features.",True,Venous System,Figure 20.1.1,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2101_Blood_Flow_Through_the_Heart.jpg,"Figure 20.1.1 – Cardiovascular Circulation: The pulmonary circuit moves blood from the right side of the heart to the lungs and back to the heart. The systemic circuit moves blood from the left side of the heart to the head and body and returns it to the right side of the heart to repeat the cycle. The arrows indicate the direction of blood flow, and the colors show the relative levels of oxygen concentration."
+d8deea38-49ac-426f-909d-6502a9486a0a,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Shared Structures,False,Shared Structures,,,,
+4fca5b76-e035-4c20-bd1f-2e4037a2f57f,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Different types of blood vessels vary slightly in their structures, but they share the same general features. Arteries and arterioles have thicker walls than veins and venules because they are closer to the heart and receive blood that is surging at a far greater pressure (Figure 20.1.2). Each type of vessel has a lumen—a hollow passageway through which blood flows. Arteries have smaller lumens than veins, a characteristic that helps to maintain the pressure of blood moving through the system. Together, their thicker walls and smaller diameters give arterial lumens a more rounded appearance in cross section than the lumens of veins.",True,Shared Structures,Figure 20.1.2,,,
+f021ebb9-6cbc-46a5-a34a-c6bf23703dd1,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"By the time blood has passed through capillaries and entered venules, the pressure initially exerted upon it by heart contractions has diminished. In other words, in comparison to arteries, venules and veins are subjected to a much lower pressure from the blood that flows through them. Their walls are considerably thinner and their lumens are correspondingly larger in diameter, allowing more blood to flow with less vessel resistance. In addition, many veins of the body, particularly those of the limbs, contain valves that assist the unidirectional flow of blood toward the heart. This is critical because blood flow becomes sluggish in the extremities, as a result of the lower pressure and the effects of gravity.",True,Shared Structures,,,,
+a4140a0d-168f-4627-87b8-a1f97eca3398,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The walls of arteries and veins are largely composed of living cells and their products (including collagenous and elastic fibers); the cells require nourishment and produce waste. Since blood passes through the larger vessels relatively quickly, there is limited opportunity for blood in the lumen of the vessel to provide nourishment to or remove waste from the vessel’s cells. Further, the walls of the larger vessels are too thick for nutrients to diffuse through to all of the cells. Larger arteries and veins contain small blood vessels within their walls known as the vasa vasorum—literally “vessels of the vessel”—to provide them with this critical exchange. Since the pressure within arteries is relatively high, the vasa vasorum must function in the outer layers of the vessel (see Figure 20.1.2) or the pressure exerted by the blood passing through the vessel would collapse it, preventing any exchange from occurring. The lower pressure within veins allows the vasa vasorum to be located closer to the lumen. The restriction of the vasa vasorum to the outer layers of arteries is thought to be one reason that arterial diseases are more common than venous diseases, since its location makes it more difficult to nourish the cells of the arteries and remove waste products. There are also minute nerves within the walls of both types of vessels that control the contraction and dilation of smooth muscle. These minute nerves are known as the nervi vasorum.",True,Shared Structures,Figure 20.1.2,,,
+84ab9792-ab85-4164-b8e3-15d22bc73237,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Both arteries and veins have the same three distinct tissue layers, called tunics (from the Latin term tunica), for the garments first worn by ancient Romans. From the most interior layer to the outer, these tunics are the tunica intima, the tunica media, and the tunica externa (see Figure 20.1.2). Table 20.1 compares and contrasts the tunics of the arteries and veins.",True,Shared Structures,Figure 20.1.2,,,
+3657837e-ace9-4413-ae76-898904464e9d,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Tunica Intima,False,Tunica Intima,,,,
+b81e996b-d4e9-494d-9ec7-6571793e37b7,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The tunica intima (also called the tunica interna) is composed of epithelial and connective tissue layers. Lining the tunica intima is the specialized simple squamous epithelium called the endothelium, which is continuous throughout the entire vascular system, including the lining of the chambers of the heart. Damage to this endothelial lining and exposure of blood to the collagenous fibers beneath is one of the primary causes of clot formation. Until recently, the endothelium was viewed simply as the boundary between the blood in the lumen and the walls of the vessels. Recent studies, however, have shown that it is physiologically critical to such activities as helping to regulate capillary exchange and altering blood flow. The endothelium releases local chemicals called endothelins that can constrict the smooth muscle within the walls of the vessel to increase blood pressure. Uncompensated overproduction of endothelins may contribute to hypertension (high blood pressure) and cardiovascular disease.",True,Tunica Intima,,,,
+ebe13fe9-dc48-42e6-963e-4efef924b665,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Next to the endothelium is the basement membrane, or basal lamina, that effectively binds the endothelium to the connective tissue. The basement membrane provides strength while maintaining flexibility, and it is permeable, allowing materials to pass through it. The thin outer layer of the tunica intima contains a small amount of areolar connective tissue that consists primarily of elastic fibers to provide the vessel with additional flexibility; it also contains some collagenous fibers to provide additional strength.",True,Tunica Intima,,,,
+73bd5ece-e2a0-4495-b628-e81fd40f700e,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"In larger arteries, there is also a thick, distinct layer of elastic fibers known as the internal elastic membrane (also called the internal elastic lamina) at the boundary with the tunica media. Like the other components of the tunica intima, the internal elastic membrane provides structure while allowing the vessel to stretch. It is permeated with small openings that allow exchange of materials between the tunics. The internal elastic membrane is not apparent in veins. In addition, many veins, particularly in the lower limbs, contain valves formed by sections of thickened endothelium that are reinforced with connective tissue, extending into the lumen.",True,Tunica Intima,,,,
+51263d80-cdbc-4532-9f1b-873b059a1cfc,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Under the microscope, the lumen and the entire tunica intima of a vein will appear smooth, whereas those of an artery will normally appear wavy because of the partial constriction of the smooth muscle in the tunica media, the next layer of blood vessel walls.",True,Tunica Intima,,,,
+5cfe6dd1-ec60-4f5e-a8d8-40cbdc305177,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Tunica Media,False,Tunica Media,,,,
+f21b6be8-0572-42e4-b8ea-1f01e8426352,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The tunica media is the substantial middle layer of the vessel wall (see Figure 20.1.2). It is generally the thickest layer in arteries, and it is much thicker in arteries than it is in veins. The tunica media consists of layers of smooth muscle supported by connective tissue that is primarily made up of elastic fibers, most of which are arranged in circular sheets. Toward the outer portion of the tunic, there are also layers of longitudinal muscle. Contraction and relaxation of the circular muscles decrease and increase the diameter of the vessel lumen, respectively. Specifically in arteries, vasoconstriction decreases blood flow as the smooth muscle in the walls of the tunica media contracts, making the lumen narrower and increasing blood pressure. Similarly, vasodilation increases blood flow as the smooth muscle relaxes, allowing the lumen to widen and blood pressure to drop. Both vasoconstriction and vasodilation are regulated in part by small vascular nerves, known as nervi vasorum, or “nerves of the vessel,” that run within the walls of blood vessels. These are generally all sympathetic fibers, although some trigger vasodilation and others induce vasoconstriction, depending upon the nature of the neurotransmitter and receptors located on the target cell. Parasympathetic stimulation does trigger vasodilation as well in erection during sexual arousal in the external genitalia of both sexes. Nervous control over vessels tends to be more generalized than the specific targeting of individual blood vessels. Local controls, discussed later, account for this type of specific regulation.  Hormones and local chemicals also control blood vessels. Together, these neural and chemical mechanisms reduce or increase blood flow in response to changing body conditions, from exercise to hydration. Regulation of both blood flow and blood pressure is discussed in detail later in this chapter.",True,Tunica Media,Figure 20.1.2,,,
+46c40c0e-857b-4278-bf4d-11dfc6734814,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The smooth muscle layers of the tunica media are supported by a framework of collagenous fibers that also binds the tunica media to the inner and outer tunics. Along with the collagenous fibers are large numbers of elastic fibers that appear as wavy lines in prepared slides. Separating the tunica media from the outer tunica externa in larger arteries is the external elastic membrane (also called the external elastic lamina), which also appears wavy in slides. This structure is not usually seen in smaller arteries, nor is it seen in veins.",True,Tunica Media,,,,
+f304b461-dcdf-434f-b3a3-3f15e3035b3d,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Tunica Externa,False,Tunica Externa,,,,
+5e4ff187-6d0b-463b-a90c-815c0c9c1252,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The outer tunic, the tunica externa (also called the tunica adventitia), is a substantial sheath of connective tissue composed primarily of collagenous fibers. Some bands of elastic fibers are found here as well. The tunica externa in veins also contains groups of smooth muscle fibers. This is normally the thickest tunic in veins and may be thicker than the tunica media in some larger arteries. The outer layers of the tunica externa are not distinct but rather blend with the surrounding connective tissue outside the vessel, helping to hold the vessel in relative position. If you are able to palpate some of the superficial veins on your upper limbs and try to move them, you will find that the tunica externa prevents this. If the tunica externa did not hold the vessel in place, any movement would likely result in disruption of blood flow.",True,Tunica Externa,,,,
+87585cd8-fdc5-4cda-aedc-5a5b879bf37c,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Arteries,False,Arteries,,,,
+298e84e1-f731-4374-a77c-4d82d1f488e2,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"An artery is a blood vessel that conducts blood away from the heart. All arteries have relatively thick walls that can withstand the high pressure of blood ejected from the heart. However, those close to the heart have the thickest walls, containing a high percentage of elastic fibers in all three of their tunics. This type of artery is known as an elastic artery (Figure 20.1.3). Vessels larger than 10 mm in diameter, such as the aorta, pulmonary trunk, common carotid, common iliac and subclavian arteries are typically elastic. Their abundant elastic fibers allow them to expand, as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure. The elastic recoil of the vascular wall helps to maintain the pressure gradient that drives the blood through the arterial system. Between beats, when the heart is relaxed, diastolic pressure is provided by this elastic recoil. An elastic artery is also known as a conducting artery, because the large diameter of the lumen enables it to accept a large volume of blood from the heart and conduct it to smaller branches.",True,Arteries,Figure 20.1.3,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2103_Muscular_and_Elastic_Artery_Arteriole.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries."
+5494049c-8db8-420d-ba6d-2c8b2c548b1f,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Farther from the heart, where the surge of blood has dampened, the percentage of elastic fibers in an artery tunica intima decreases and the amount of smooth muscle in its tunica media increases. The artery at this point is described as a muscular artery also called a distributing artery because the relatively thick tunica media allows precise control of blood vessel diameter to control blood flow to different areas or organs . The diameter of muscular arteries typically ranges from 0.1 mm to 10 mm. Their thick tunica media allows muscular arteries to play a leading role in vasoconstriction. In contrast, their decreased quantity of elastic fibers limits their ability to expand. Fortunately, because the blood pressure has eased by the time it reaches these more distant vessels, elasticity has become less important.",True,Arteries,,,,
+a0d9b2f5-9aab-4189-8829-8cef1f421898,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Notice that although the distinctions between elastic and muscular arteries are important, there is no “line of demarcation” where an elastic artery suddenly becomes muscular. Rather, there is a gradual transition as the vascular tree repeatedly branches. In turn, muscular arteries branch to distribute blood to the vast network of arterioles.",True,Arteries,,,,
+014c3fd3-6716-46a8-8d19-bb801288c091,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Arterioles,False,Arterioles,,,,
+bf283cd9-6c46-4488-8a0f-e2467cc436f1,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"An arteriole is a very small artery that leads to a capillary. Larger arterioles have the same three tunics as the larger vessels, but the thickness of each is greatly diminished. The critical endothelial lining of the tunica intima is intact. The tunica media is restricted to one or two smooth muscle cell layers in thickness. The tunica externa remains but is very thin (see Figure 20.1.3). The smallest arterioles do not have a tunica externa and the tunica media is limited to a single incomplete layer of smooth cells.",True,Arterioles,Figure 20.1.3,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2103_Muscular_and_Elastic_Artery_Arteriole.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries."
+660cc565-798d-4a4e-b649-f8ceeeabd6f4,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"With a lumen averaging 30 micrometers or less in diameter, arterioles are critical in slowing down—or resisting—blood flow and, thus, causing a substantial drop in blood pressure. Because of this, you may see them referred to as resistance vessels. The muscle fibers in arterioles are normally slightly contracted, causing arterioles to maintain a consistent muscle tone—in this case referred to as vascular tone—in a similar manner to the muscular tone of skeletal muscle. In reality, all blood vessels exhibit vascular tone due to the partial contraction of smooth muscle. The importance of the arterioles is that they will be the primary site of both resistance and regulation of blood pressure. The precise diameter of the lumen of an arteriole at any given moment is determined by neural and chemical controls, and vasoconstriction and vasodilation in the arterioles are the primary mechanisms for distribution of blood flow due to local metabolic demands.",True,Arterioles,,,,
+d4c07964-4f80-43af-b62a-5c7e6c5391a4,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Capillaries,False,Capillaries,,,,
+c83c86bc-eb5e-4c4b-91f4-d3ff2b34feb6,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A capillary is a microscopic channel that supplies blood to the tissues themselves, a process called perfusion. Exchange of gases and other substances occurs in the capillaries between the blood and the surrounding cells and their tissue fluid (interstitial fluid). The diameter of a capillary lumen ranges from 5–10 micrometers; the smallest are just barely wide enough for an erythrocyte to squeeze through. Flow through capillaries is often described as microcirculation.",True,Capillaries,,,,
+87619b03-5890-439d-9798-91449ba43f6b,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The wall of a capillary consists of the endothelial layer surrounded by a basement membrane with occasional smooth muscle fibers. There is some variation in wall structure: In a large capillary, several endothelial cells bordering each other may line the lumen; in a small capillary, there may be only a single cell layer that wraps around to contact itself.",True,Capillaries,,,,
+5a3bf30f-0c82-439e-b2cb-3adbb3b94420,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"For capillaries to function, their walls must be leaky, allowing substances to pass through. There are three major types of capillaries, which differ according to their degree of “leakiness:” continuous, fenestrated, and sinusoid capillaries (Figure 20.1.4).",True,Capillaries,Figure 20.1.4,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2104_Three_Major_Capillary_Types.jpg,"Figure 20.1.4 – Types of Capillaries: The three major types of capillaries: continuous, fenestrated, and sinusoid."
+59f48396-18b7-4b89-b8f7-df76dc99f11e,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Continuous Capillaries,False,Continuous Capillaries,,,,
+039fee50-9504-4e14-a215-dfa042019c52,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The most common type of capillary, the continuous capillary, is found in almost all vascularized tissues. Continuous capillaries are characterized by a complete endothelial lining with tight junctions between endothelial cells. Although a tight junction is usually impermeable and only allows for the passage of water and ions, they are often incomplete in capillaries, leaving intercellular clefts that allow for exchange of water and other very small molecules between the blood plasma and the interstitial fluid. Substances that can pass between cells include metabolic products, such as glucose, water, and small hydrophobic molecules like gases and hormones, as well as various leukocytes. Continuous capillaries not associated with the brain are rich in transport vesicles, contributing to either endocytosis or exocytosis. Those in the brain are part of the blood-brain barrier. Here, there are tight junctions and no intercellular clefts, plus a thick basement membrane and astrocyte extensions called end feet; these structures combine to prevent the unregulated movement of nearly all substances.",True,Continuous Capillaries,,,,
+e3a3f214-010a-462b-8c13-dfa5736799f3,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Fenestrated Capillaries,False,Fenestrated Capillaries,,,,
+9100c957-e9b5-4a79-ab48-58a41c55d181,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A fenestrated capillary (fenestra- = “window”) is one that has pores (or fenestrations) in addition to tight junctions in the endothelial lining. These make the capillary permeable to larger molecules. The number of fenestrations and their degree of permeability vary, however, according to their location. Fenestrated capillaries are common in the small intestine, which is the primary site of nutrient absorption, as well as in the kidneys, which filter the blood. They are also found in the choroid plexus of the brain and many endocrine structures, including the hypothalamus, pituitary, pineal, and thyroid glands.",True,Fenestrated Capillaries,,,,
+1cbc9794-0188-4f32-ac2c-8a7e1f16d876,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Sinusoid Capillaries,False,Sinusoid Capillaries,,,,
+803f8839-ac8f-4716-a767-ffe343d5a343,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A sinusoid capillary (or sinusoid) is the least common type of capillary. Sinusoid capillaries are flattened, and they have extensive intercellular gaps and incomplete basement membranes, in addition to intercellular clefts and fenestrations. This gives them an appearance not unlike Swiss cheese. These very large openings allow for the passage of the largest molecules, including plasma proteins and even cells. Blood flow through sinusoids is very slow, allowing more time for exchange of gases, nutrients, and wastes. Sinusoids are found in the liver and spleen, bone marrow and lymph nodes (where they carry lymph, not blood). These specialized capillaries facilitate movement of larger molecules and cells between the blood and interstitial space. For example, when bone marrow forms new blood cells, the cells must enter the blood supply and can only do so through the large openings of a sinusoid capillary; they cannot pass through the small openings of continuous or fenestrated capillaries. The liver also requires extensive specialized sinusoid capillaries in order to process the materials brought to it by the hepatic portal vein from both the digestive tract and spleen, and to release plasma proteins into circulation.",True,Sinusoid Capillaries,,,,
+e25d582d-f9eb-423c-b835-5c12e1b46935,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Metarterioles and Capillary Beds,False,Metarterioles and Capillary Beds,,,,
+77094a86-4eb7-4c0e-8708-522e93224770,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A metarteriole is a type of vessel that has structural characteristics of both an arteriole and a capillary. Slightly larger than the typical capillary, the smooth muscle of the tunica media of the metarteriole is not continuous but forms rings of smooth muscle (sphincters) at the entrance to the capillaries. Each metarteriole arises from a terminal arteriole and branches to supply blood to a capillary bed that may consist of 10–100 capillaries.",True,Metarterioles and Capillary Beds,,,,
+3277e483-6dea-4b27-b011-e37b6ea6a7be,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"The precapillary sphincters, circular smooth muscle cells that surround the capillary at its origin with the metarteriole, tightly regulate the flow of blood from a metarteriole to the capillaries it supplies. Their function is critical: If all of the capillary beds in the body were to open simultaneously, they would collectively hold every drop of blood in the body and there would be none in the arteries, arterioles, venules, veins, or the heart itself. Normally, the precapillary sphincters are closed. When the surrounding tissues need oxygen and have excess waste products, the precapillary sphincters open, allowing blood to flow through and exchange to occur before closing once more (Figure 20.1.5). If all of the precapillary sphincters in a capillary bed are closed, blood will flow from the metarteriole directly into a thoroughfare channel and then into the venous circulation, bypassing the capillary bed entirely. This creates what is known as a vascular shunt. In addition, an arteriovenous anastomosis may bypass the capillary bed and lead directly to the venous system.",True,Metarterioles and Capillary Beds,Figure 20.1.5,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2105_Capillary_Bed.jpg,"Figure 20.1.5 – Capillary Bed: In a capillary bed, arterioles give rise to metarterioles. Precapillary sphincters located at the junction of a metarteriole with a capillary regulate blood flow. A thoroughfare channel connects the metarteriole to a venule. An arteriovenous anastomosis, which directly connects the arteriole with the venule, is shown at the bottom."
+fbb5341c-dd2f-4068-a435-aa360c676f93,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Although you might expect blood flow through a capillary bed to be smooth, in reality, it moves with an irregular, pulsating flow. This pattern is called vasomotion and is regulated by chemical signals that are triggered in response to changes in internal conditions, such as oxygen, carbon dioxide, hydrogen ion, and lactic acid levels. For example, during strenuous exercise when oxygen levels decrease and carbon dioxide, hydrogen ion, and lactic acid levels all increase, the capillary beds in skeletal muscle are open, as they would be in the digestive system when nutrients are present in the digestive tract. During sleep or rest periods, vessels in both areas are largely closed; they open only occasionally to allow oxygen and nutrient supplies to travel to the tissues to maintain basic life processes.",True,Metarterioles and Capillary Beds,,,,
+6d5dc02a-62a2-4bb1-a72c-a3b9009c06a2,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Venules,False,Venules,,,,
+f5122ffe-0cfd-43cb-a316-4e81ba8838ae,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A venule is an extremely small vein, generally 8–100 micrometers in diameter. Postcapillary venules join multiple capillaries exiting from a capillary bed. Multiple venules join to form veins. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica externa (Figure 20.1.6). Venules as well as capillaries are the primary sites of emigration or diapedesis, in which the white blood cells adhere to the endothelial lining of the vessels and then squeeze through adjacent cells to enter the tissue fluid.",True,Venules,Figure 20.1.6,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2106_Large_Medium_Vein_Venule.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins."
+02da71e5-2cc2-4333-b599-fb04894180f0,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Veins,False,Veins,,,,
+e2c886d0-7025-473e-8df3-aab2a4d4fb1c,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"A vein is a blood vessel that conducts blood toward the heart. Compared to arteries, veins are thin-walled vessels with large and irregular lumens (see Figure 20.1.6). Because they are low-pressure vessels, larger veins are commonly equipped with valves that promote the unidirectional flow of blood toward the heart and prevent backflow toward the capillaries caused by the inherent low blood pressure in veins as well as the pull of gravity. Table 20.2 compares the features of arteries and veins.",True,Veins,Figure 20.1.6,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2106_Large_Medium_Vein_Venule.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins."
+abd8ccad-2cfb-403c-95e7-ba6e156d60e7,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,Veins as Blood Reservoirs,False,Veins as Blood Reservoirs,,,,
+87280829-f55d-4513-8c1f-79a61c6cbfd2,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"In addition to their primary function of returning blood to the heart, veins may be considered blood reservoirs, since systemic veins contain approximately 64 percent of the blood volume at any given time (Figure 20.1.8). Their ability to hold this much blood is due to their high capacitance, that is, their capacity to distend (expand) readily to store a high volume of blood, even at a low pressure. The large lumens and relatively thin walls of veins make them far more distensible than arteries; thus, they are said to be capacitance vessels.",True,Veins as Blood Reservoirs,Figure 20.1.8,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2142_Distribution_of_Blood_Flow.jpg,Figure 20.1.8 Distribution of Blood Flow
+9e203800-1a20-48db-8231-59d3f8c1882a,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"When blood flow needs to be redistributed to other portions of the body, the vasomotor center located in the medulla oblongata sends sympathetic stimulation to the smooth muscles in the walls of the veins, causing constriction—or in this case, venoconstriction. Less dramatic than the vasoconstriction seen in smaller arteries and arterioles, venoconstriction may be likened to a “stiffening” of the vessel wall. This increases pressure on the blood within the veins, speeding its return to the heart. As you will note in Figure 20.1.8, approximately 21 percent of the venous blood is located in venous networks within the liver, bone marrow, and integument. This volume of blood is referred to as venous reserve. Through venoconstriction, this “reserve” volume of blood can get back to the heart more quickly for redistribution to other parts of the circulation.",True,Veins as Blood Reservoirs,Figure 20.1.8,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2142_Distribution_of_Blood_Flow.jpg,Figure 20.1.8 Distribution of Blood Flow
+9554db93-76e0-443c-8326-7704934be962,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Vascular surgery is a specialty in which the physician deals primarily with diseases of the vascular portion of the cardiovascular system. This includes repair and replacement of diseased or damaged vessels, removal of plaque from vessels, minimally invasive procedures including the insertion of venous catheters, and traditional surgery. Following completion of medical school, the physician generally completes a 5-year surgical residency followed by an additional 1 to 2 years of vascular specialty training. In the United States, most vascular surgeons are members of the Society of Vascular Surgery.",True,Veins as Blood Reservoirs,,,,
+93606693-bd95-499f-828d-c829ab6d1f1b,https://open.oregonstate.education/aandp/,20.1 Structure and Function of Blood Vessels,https://open.oregonstate.education/aandp/chapter/20-1-structure-and-function-of-blood-vessels/,"Vascular technicians are specialists in imaging technologies that provide information on the health of the vascular system. They may also assist physicians in treating disorders involving the arteries and veins. This profession often overlaps with cardiovascular technology, which would also include treatments involving the heart. Although recognized by the American Medical Association, there are currently no licensing requirements for vascular technicians, and licensing is voluntary. Vascular technicians typically have an Associate’s degree or certificate, involving 18 months to 2 years of training. The United States Bureau of Labor projects this profession to grow by 29 percent from 2010 to 2020.",True,Veins as Blood Reservoirs,,,,
+6324b513-f5ca-43f3-bc3f-713c82c3c165,https://open.oregonstate.education/aandp/,20.0 Introduction,https://open.oregonstate.education/aandp/chapter/20-0-introduction/,"In this chapter, you will learn about the vascular part of the cardiovascular system, that is, the vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.",True,Veins as Blood Reservoirs,,,,
+6f29d03a-fc04-410c-8d91-64cf08a9d064,https://open.oregonstate.education/aandp/,19.5 Development of the Heart,https://open.oregonstate.education/aandp/chapter/19-5-development-of-the-heart/,"The human heart is the first functional organ to develop. It begins beating and pumping blood around day 21 or 22, a mere three weeks after fertilization. This emphasizes the critical nature of the heart in distributing blood through the vessels and the vital exchange of nutrients, oxygen, and wastes both to and from the developing baby. The critical early development of the heart is reflected by the prominent heart bulge that appears on the anterior surface of the embryo.",True,Veins as Blood Reservoirs,,,,
+16bc0617-eadc-47d0-a3e8-f7be01f16f7d,https://open.oregonstate.education/aandp/,19.5 Development of the Heart,https://open.oregonstate.education/aandp/chapter/19-5-development-of-the-heart/,"The heart forms from an embryonic tissue called mesoderm around 18 to 19 days after fertilization. Mesoderm is one of the three primary germ layers that differentiates early in development that collectively gives rise to all subsequent tissues and organs. The heart begins to develop near the head of the embryo in a region known as the cardiogenic area. Following chemical signals called factors from the underlying endoderm (another of the three primary germ layers), the cardiogenic area begins to form two strands called the cardiogenic cords. As the cardiogenic cords develop, a lumen rapidly develops within them. At this point, they are referred to as endocardial tubes (Figure 19.5.1). The two tubes migrate together and fuse to form a single primitive heart tube. The primitive heart tube quickly forms five distinct regions. From head to tail, these include the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. Initially, all venous blood flows into the sinus venosus, and contractions propel the blood from tail to head, or from the sinus venosus to the truncus arteriosus. This is a very different pattern from that of an adult.",True,Veins as Blood Reservoirs,Figure 19.5.1,19.5 Development of the Heart,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2037_Embryonic_Development_of_Heart.jpg,Figure 19.5.1 – Development of the Human Heart: This diagram outlines the embryological development of the human heart during the first eight weeks and the subsequent formation of the four heart chambers.
+3a152ed4-6e43-4221-9852-d3425f978969,https://open.oregonstate.education/aandp/,19.5 Development of the Heart,https://open.oregonstate.education/aandp/chapter/19-5-development-of-the-heart/,"The five regions of the primitive heart tube develop into recognizable structures in a fully developed heart. The truncus arteriosus will eventually divide and give rise to the ascending aorta and pulmonary trunk. The bulbus cordis develops into the right ventricle. The primitive ventricle forms the left ventricle. The primitive atrium becomes the anterior portions of both the right and left atria, and the two auricles. The sinus venosus develops into the posterior portion of the right atrium, the SA node, and the coronary sinus.",True,Veins as Blood Reservoirs,,,,
+12638f00-56a6-41a6-90e5-520a9b8a0f69,https://open.oregonstate.education/aandp/,19.5 Development of the Heart,https://open.oregonstate.education/aandp/chapter/19-5-development-of-the-heart/,"As the primitive heart tube elongates, it begins to fold within the pericardium, eventually forming an S shape, which places the chambers and major vessels into an alignment similar to the adult heart. This process occurs between days 23 and 28. The remainder of the heart development pattern includes development of septa and valves, and remodeling of the actual chambers. Partitioning of the atria and ventricles by the interatrial septum, interventricular septum, and atrioventricular septum is complete by the end of the fifth week, although the fetal blood shunts remain until birth or shortly after. The atrioventricular valves form between weeks five and eight, and the semilunar valves form between weeks five and nine.",True,Veins as Blood Reservoirs,,,,
+0f982ce5-26d4-44fb-b849-e2d152743ea9,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"The autorhythmicity inherent in cardiac cells keeps the heart beating at a regular pace; however, the heart is regulated by and responds to outside influences as well. Neural and endocrine controls are vital to the regulation of cardiac function. In addition, the heart is sensitive to several environmental factors, including electrolytes.",True,Veins as Blood Reservoirs,,,,
+7dfb9030-76a9-43da-a19a-6ea2db4739f5,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Resting Cardiac Output,False,Resting Cardiac Output,,,,
+a440c1f3-09cd-46f3-91c2-846bdefda7a1,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Cardiac output (CO) is a measurement of the amount of blood pumped by each ventricle in one minute. To calculate this value, multiply stroke volume (SV), the amount of blood pumped by each ventricle, by heart rate (HR), in contractions per minute (or beats per minute, bpm). It can be represented mathematically by the following equation:",True,Resting Cardiac Output,,,,
+d00b2c0c-a694-4b4b-895f-121e04a4135f,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,CO = HR × SV,False,CO = HR × SV,,,,
+d107ca3d-b634-4eb2-af19-dfe0619162dd,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"SV is normally measured using an echocardiogram to record EDV and ESV, and calculating the difference: SV = EDV – ESV. SV can also be measured using a specialized catheter, but this is an invasive procedure and far more dangerous to the patient. A mean SV for a resting 70-kg (150-lb) individual would be approximately 70 mL.  This is because typical EDV and ESV values are approximately 120 mL and 50 mL, respectively and 70 mL = 120 mL – 50 mL. Normal range for SV would be 55–100 mL. An average resting HR would be approximately 75 bpm but could range from 60–100 in some individuals. There are several important variables, including size of the heart, physical and mental condition (via hormones and the ANS) of the individual, gender, contractility, duration of contraction, preload or EDV, and afterload or resistance that can affect SV and HR.",True,CO = HR × SV,,,,
+b432a74b-4483-4c6e-9a21-7043655d5b13,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Using these numbers, the mean resting CO is 5.25 L/min, with a range of 4.0–8.0 L/min.  The CO of 5.25 L/min, was calculated using the following values.",True,CO = HR × SV,,,,
+32755430-c711-457f-b1e2-bb50cf7fe0d5,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,CO L/min = 75 beats/min x 0.070 L/beat (where 0.070 L is equal to 70 mL).,True,CO = HR × SV,,,,
+87700fde-ea67-47aa-9d2d-f03d6a2ec965,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Remember, however, that these numbers refer to CO from each ventricle separately, not the total for the heart. In a healthy heart the CO from each ventricle is the same. CO is influenced by HR and by SV. If SV decreases, CO can be maintained by increasing HR. Factors that influence HR are referred to as chronotropic factors. Chrono- refers to time. Positive chronotropic factors increase HR and negative chronotropic factors decrease HR. HR is influenced by the autonomic nervous system, chemicals, and other factors. The factors influencing CO are summarized in Figure 19.4.1.",True,CO = HR × SV,Figure 19.4.1,19.4 Cardiac Physiology,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2031_Factors_in_Cardiac_Output.jpg,"Figure 19.4.1 – Major Factors Influencing Cardiac Output: Cardiac output is influenced by heart rate and stroke volume, both of which are also variable."
+04b8dbc7-cedb-48d7-b26c-3b5fb5c2761e,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"SVs are also used to calculate ejection fraction, which is the portion of the blood that is pumped or ejected from the heart with each contraction. To calculate ejection fraction, SV is divided by EDV. Despite the name, the ejection fraction is normally expressed as a percentage. Ejection fractions range from approximately 55–70 percent, with a mean of 58 percent.  For example, if the average EDV is 120 mL and the SV is 70 mL, the ejection fraction of 58% is calculated as follows:",True,CO = HR × SV,,,,
+a8651c86-6be1-4ea1-b7e2-c609c575764d,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Ejection fraction (%) = (70 mL/120 mL) x 100,False,Ejection fraction (%) = (70 mL/120 mL) x 100,,,,
+7122524d-c57d-4f3c-a2bc-231ef4f90474,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Exercise and Maximum Cardiac Output,False,Exercise and Maximum Cardiac Output,,,,
+cb995235-9599-4e69-8747-d83768814532,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"In healthy young individuals, HR may increase to 150 bpm or higher during exercise. SV can also increase from 70 to approximately 130 mL due to increased strength of contraction. This would increase CO to approximately 19.5 L/min, 4–5 times the resting rate. Top cardiovascular athletes can achieve even higher levels. At their peak performance, they may increase resting CO by 7–8 times.",True,Exercise and Maximum Cardiac Output,,,,
+53767796-fe12-44f4-a119-f1685ab87b94,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Since the heart is a muscle, exercising it increases its efficiency. The difference between maximum and resting CO is known as the cardiac reserve. It measures the residual capacity of the heart to pump blood.",True,Exercise and Maximum Cardiac Output,,,,
+c0397ca7-0177-4e7b-86d7-330f31309136,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Heart Rate and its Control,False,Heart Rate and its Control,,,,
+0455a0a0-2a35-4586-97b8-24c6283ead2b,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"HRs vary considerably, not only with exercise and fitness levels, but also with age. Newborn resting HRs may be 120 bpm. HR gradually decreases until young adulthood and then gradually increases again with age.",True,Heart Rate and its Control,,,,
+def39db9-db56-4b4a-bac6-a555c14b8ec8,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Maximum HRs are normally in the range of 200–220 bpm, although there are some extreme cases in which they may reach higher levels. As one ages, the ability to generate maximum rates decreases. This may be estimated by taking the maximal value of 220 bpm and subtracting the individual’s age. So a 40-year-old individual would be expected to reach a maximum rate of approximately 180, and a 60-year-old person would achieve a HR of 160. Refer to the example below.",True,Heart Rate and its Control,,,,
+5932fb8c-3280-4dba-9c03-c34127a2db91,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,HRMax = 220 – 60 yr,False,HRMax = 220 – 60 yr,,,,
+4ad73d74-b51c-47c7-9383-d98439378bc0,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,HRMax = 160 bpm,False,HRMax = 160 bpm,,,,
+3a2ba175-bac5-4b82-a4d5-38692b073df2,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Initially, physiological conditions that cause HR to increase also trigger an increase in SV. During exercise, the rate of blood returning to the heart increases. However as the HR rises, there is less time spent in diastole and consequently less time for the ventricles to fill with blood. Even though there is less filling time, SV will initially remain high. However, as HR continues to increase, SV gradually decreases due to decreased filling time. CO will initially stabilize as the increasing HR compensates for the decreasing SV, but at very high rates, CO will eventually decrease as increasing rates are no longer able to compensate for the decreasing SV. Consider this phenomenon in a healthy young individual. Initially, as HR increases from resting to approximately 120 bpm, CO will rise. As HR increases from 120 to 160 bpm, CO remains stable, since the increase in rate is offset by decreasing ventricular filling time and, consequently, SV. As HR continues to rise above 160 bpm, CO actually decreases as SV falls faster than HR increases. So although aerobic exercises are critical to maintain the health of the heart, individuals are cautioned to monitor their HR to ensure they stay within the target heart rate range of between 120 and 160 bpm, so CO is maintained.  It is also important to note that the coronary circulation nourishes the heart during diastole so as the HR increases the ability of the coronary circulation to nourish the myocardium decreases. The target HR is loosely defined as the range in which both the heart and lungs receive the maximum benefit from the aerobic workout and is dependent upon age.",True,HRMax = 160 bpm,,,,
+8c46e421-bec3-4fb6-8e2a-b3ee9fcf267b,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Nervous control over HR is centralized within the two paired cardiovascular centers of the medulla oblongata (Figure 19.4.2). The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioacceleratory nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve, cranial nerve X. Both sympathetic and parasympathetic stimulations flow through a paired complex network of nerve fibers known as the cardiac plexus near the base of the heart. The cardioacceleratory center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia (the cervical ganglia plus superior thoracic ganglia T1–T4) to both the SA and AV nodes to increase heart rate, plus additional fibers to the atrial and ventricular myocardium to increase force of contraction (see section on Contractility). The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 100 bpm.",True,HRMax = 160 bpm,Figure 19.4.2,19.4 Cardiac Physiology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2032_Automatic_Innervation.jpg,Figure 19.4.2 – Autonomic Innervation of the Heart: Cardioacceleratory and cardioinhibitory areas are components of the paired cardiac centers located in the medulla oblongata of the brain. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus (parasympathetic) nerves that slow cardiac activity.
+ac451541-5066-4721-bd14-150b91bcdac2,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"At the nodes sympathetic stimulation causes the release of the neurotransmitter norepinephrine (NE) at the neuromuscular junction of the cardiac nerves. NE binds to the beta-1 receptors and opens chemical- or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions. NE shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increase in HR. Some cardiac medications (for example, beta blockers) work by blocking these receptors, thereby slowing HR and are one possible treatment for hypertension. Overprescription of these drugs may lead to bradycardia and even stoppage of the heart.",True,HRMax = 160 bpm,,,,
+f04b5d8f-f228-4ea0-9458-04efe71dbd43,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve (cranial nerve X). The vagus nerve sends branches to both the SA and AV nodes to decrease HR. Parasympathetic stimulation releases the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. ACh slows HR by opening chemical- or ligand-gated potassium ion channels to slow the rate of spontaneous depolarization and increase the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 100 bpm. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove one’s foot from the break and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 100 bpm. Any increases beyond this rate would require sympathetic stimulation. Figure 19.4.3 illustrates the effects of parasympathetic and sympathetic stimulation on the normal sinus rhythm.",True,HRMax = 160 bpm,Figure 19.4.3,19.4 Cardiac Physiology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2033_Depolarization_in_Sinus_Rhythm.jpg,"Figure 19.4.3 – Effects of Parasympathetic and Sympathetic Stimulation on Normal Sinus Rhythm: The wave of depolarization in a normal sinus rhythm shows a stable resting HR. Following parasympathetic stimulation, HR slows. Following sympathetic stimulation, HR increases."
+192aeeb5-b2c1-447f-95d7-d79d56af45f9,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"The cardiovascular center receives input from the limbic system as well as a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors. Collectively, these inputs normally enable the cardiovascular centers to regulate heart function precisely, a process known as cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. Any such increase in physical activity would logically warrant increased blood flow. The cardiac centers monitor these increased rates of firing, and suppress parasympathetic stimulation and increase sympathetic stimulation as needed in order to increase blood flow.",True,HRMax = 160 bpm,,,,
+05a0226b-bbbc-40f4-a01d-ff473311364b,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the rightatrium. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic stimulation. As pressure and stretch decrease, the rate of baroreceptor firing decreases, and the cardiac centers increase sympathetic stimulation and decrease parasympathetic stimulation.",True,HRMax = 160 bpm,,,,
+3e4d4a73-108b-4c0e-b55d-e1ece43921fe,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase HR.",True,HRMax = 160 bpm,,,,
+c1f0ea85-2059-4eb8-b91c-b1316965b307,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Increased metabolic byproducts associated with increased activity, such as carbon dioxide, hydrogen ions, and lactic acid, plus falling oxygen levels, are detected by a suite of chemoreceptors innervated by the glossopharyngeal and vagus nerves. These chemoreceptors provide feedback to the cardiovascular centers about the need for increased or decreased blood flow, based on the relative levels of these substances.",True,HRMax = 160 bpm,,,,
+2c0062cc-e5df-43dc-8c2c-01add95e7541,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"The limbic system can also significantly impact HR related to emotional state. During periods of stress, it is not unusual to identify higher than normal HRs, often accompanied by a surge in the stress hormone cortisol. Individuals experiencing extreme anxiety may manifest panic attacks with symptoms that resemble those of heart attacks. These events are typically transient and treatable. Meditation techniques have been developed to ease anxiety and have been shown to lower HR effectively. Doing simple deep and slow breathing exercises with one’s eyes closed can also significantly reduce this anxiety and HR.",True,HRMax = 160 bpm,,,,
+e7d23bc8-755c-4afd-a27f-2e8c3c6da575,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Other Factors Influencing Heart Rate and Force of Contraction,False,Other Factors Influencing Heart Rate and Force of Contraction,,,,
+5be509bb-06b4-4230-ba30-5fb5b597ab4f,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Using a combination of autorhythmicity and innervation, the cardiovascular centers are able to provide relatively precise control over HR. However, there are a number of other factors that have an impact on HR as well, including epinephrine, NE, and thyroid hormones; levels of various ions including calcium, potassium, and sodium; body temperature; hypoxia; and pH balance (Table 19.1 and Table 19.2). Many of these factors also influence contractility which refers to the force of contraction of the heart muscle.  After reading this section, the importance of maintaining homeostasis should become even more apparent.",True,Other Factors Influencing Heart Rate and Force of Contraction,,,,
+be9b7aca-0292-4f60-bef4-a41d1822da5f,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,Stroke Volume,False,Stroke Volume,,,,
+758fd97f-301b-4b8f-8da0-342af4daac5f,https://open.oregonstate.education/aandp/,19.4 Cardiac Physiology,https://open.oregonstate.education/aandp/chapter/19-4-cardiac-physiology/,"Many of the same factors that regulate HR also impact cardiac function by altering SV. While a number of variables are involved, SV is ultimately dependent upon the difference between EDV and ESV. The three primary factors to consider are preload, or the stretch on the ventricles prior to contraction; the contractility, or the force or strength of the contraction itself; and afterload, the force the ventricles must generate to pump blood against the resistance in the vessels. These factors are summarized in Table 19.1 and Table 19.2.",True,Stroke Volume,,,,
+86472935-e501-4e63-a8bd-2c3c48224f40,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle (Figure 19.3.1). The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole. Both the atria and ventricles undergo systole and diastole, and it is essential that these components be carefully regulated and coordinated to ensure blood is pumped efficiently to the body.",True,Stroke Volume,Figure 19.3.1,19.3 Cardiac Cycle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2014_Phase_of_Cardiac_Cycle_revised.png,"Figure 19.3.1 – Overview of the Cardiac Cycle: The cardiac cycle begins with atrial systole and progresses to ventricular systole, atrial diastole, and ventricular diastole, when the cycle begins again. Correlations to the ECG are highlighted."
+f5e6a6b2-3a8f-4103-8795-1a18ae59384b,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,Pressures and Flow,False,Pressures and Flow,,,,
+159b4a93-a835-4ecf-8a33-70aa310223dc,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"Fluids, whether gases or liquids, are materials that flow according to pressure gradients—that is, they move from regions that are higher in pressure to regions that are lower in pressure. Accordingly, when the heart chambers are relaxed (diastole), blood will flow into the atria from the veins, which are higher in pressure. As blood flows into the atria, the pressure will rise, so the blood will initially move passively from the atria into the ventricles. When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles. During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle. Again, as you consider this flow and relate it to the conduction pathway, the elegance of the system should become apparent.",True,Pressures and Flow,,,,
+e101c7f6-5644-4085-8c23-6373d7417628,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,Phases of the Cardiac Cycle,False,Phases of the Cardiac Cycle,,,,
+adf85c8a-7021-43e0-97f6-2c207e08bddc,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"At the beginning of the cardiac cycle, both the atria and ventricles are relaxed (diastole). Blood is flowing into the right atrium from the superior and inferior venae cavae and the coronary sinus. Blood flows into the left atrium from the four pulmonary veins. The two atrioventricular valves, the tricuspid and mitral valves, are both open, so blood flows unimpeded from the atria and into the ventricles. Approximately 70–80 percent of ventricular filling occurs by this method. The two semilunar valves, the pulmonary and aortic valves, are closed, preventing backflow of blood into the right and left ventricles from the pulmonary trunk on the right and the aorta on the left.",True,Phases of the Cardiac Cycle,,,,
+a6bbb5ca-3493-4690-8940-60020a3b053c,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,Heart Sounds,False,Heart Sounds,,,,
+e71a0889-ea71-42e6-8a98-3eb42c92a4da,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"One of the simplest, yet effective, diagnostic techniques applied to assess the state of a patient’s heart is auscultation using a stethoscope.",True,Heart Sounds,,,,
+d74d9cb5-43cf-4d15-b6d1-5d8b76bf1de3,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a “lub,” or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a “dub” (Figure 19.3.3). In both cases, as the valves close, the openings within the atrioventricular septum guarded by the valves will become reduced, and blood flow through the opening will become more turbulent until the valves are fully closed. There is a third heart sound, S3, but it is rarely heard in healthy individuals. It may be the sound of blood flowing into the atria, or blood sloshing back and forth in the ventricle, or even tensing of the chordae tendineae. S3 may be heard in youth, some athletes, and pregnant women. If the sound is heard later in life, it may indicate congestive heart failure, warranting further tests. Some cardiologists refer to the collective S1, S2, and S3 sounds as the “Kentucky gallop,” because they mimic those produced by a galloping horse. The fourth heart sound, S4, results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs prior to S1 and the collective sounds S4, S1, and S2 are referred to by some cardiologists as the “Tennessee gallop,” because of their similarity to the sound produced by a galloping horse with a different gait. A few individuals may have both S3 and S4, and this combined sound is referred to as S7.",True,Heart Sounds,Figure 19.3.3,19.3 Cardiac Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2029_Cardiac_Cycle_vs_Heart_Sounds_revised.png,"Figure 19.3.3 – Heart Sounds and the Cardiac Cycle: In this illustration, the x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure."
+2b3862d7-37b6-494f-8a74-777fb25f89b1,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"The term murmur is used to describe an unusual sound coming from the heart that is caused by the turbulent flow of blood, usually due to valve problesms. For example an incompetent valve does not close completely leading to a “swish” sound as the blood flows backwards through the valve. A high pitch sound results as blood moves through a stiff (stenotic) valve.  Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the most difficult sound to detect, and the least serious. The most severe is a 6. Phonocardiograms or auscultograms can be used to record both normal and abnormal sounds using specialized electronic stethoscopes.",True,Heart Sounds,,,,
+484ef81e-5ae4-435a-a718-57a56aa7b615,https://open.oregonstate.education/aandp/,19.3 Cardiac Cycle,https://open.oregonstate.education/aandp/chapter/19-3-cardiac-cycle/,"During auscultation, it is common practice for the clinician to ask the patient to breathe deeply. This procedure not only allows for listening to airflow, but it may also amplify heart murmurs. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs. Figure 19.3.4 indicates proper placement of the bell of the stethoscope to facilitate auscultation.",True,Heart Sounds,Figure 19.3.4,19.3 Cardiac Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2030_Stethoscope_Placement.jpg,"Figure 19.3.4 – Stethoscope Placement for Auscultation: Proper placement of the bell of the stethoscope facilitates auscultation. At each of the four locations on the chest, a different valve can be heard."
+4d943edf-882c-4241-841c-1f783f1307bf,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Describe the structure of cardiac muscle,False,Describe the structure of cardiac muscle,,,,
+6073e493-0134-4065-b1f8-0e3f732f56a8,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Identify and describe the components of the conducting system that distributes electrical impulses through the heart,True,Describe the structure of cardiac muscle,,,,
+09ea4dff-f64a-47f5-8615-5a761b1c63ef,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Compare the effect of ion movement on membrane potential of cardiac conductive and contractile cells,True,Describe the structure of cardiac muscle,,,,
+05e3a5bf-0f1d-4acd-a944-5c0b6e50d0ca,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Relate characteristics of an electrocardiogram to events in the cardiac cycle,True,Describe the structure of cardiac muscle,,,,
+3e490862-fb3e-48cd-9f9a-ab90a898d36a,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Identify blocks that can interrupt the cardiac cycle,False,Identify blocks that can interrupt the cardiac cycle,,,,
+9e6ec247-4ebd-4a0c-a751-e9a798988913,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"Recall that cardiac muscle shares a few characteristics with both skeletal muscle and smooth muscle, but it has some unique properties of its own. Contractions of the heart (heartbeats) are controlled by specialized cardiac muscle cells called pacemaker cells that directly control heart rate.  This property is known as autorhythmicity. Neither smooth nor skeletal muscle can do this. Although cardiac muscle cannot be consciously controlled, the pacemaker cells respond to signals from the autonomic nervous system (ANS) to speed up or slow down the heart rate. The pacemaker cells can also respond to various hormones that modulate heart rate to control blood pressure.",True,Identify blocks that can interrupt the cardiac cycle,,,,
+055281fc-cd42-47da-9b2a-c39125b31990,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"There are two major types of cardiac muscle cells: myocardial contractile cells and myocardial conducting cells. The myocardial contractile cells constitute the bulk (99 percent) of the cells in the atria and ventricles. Contractile cells conduct impulses and are responsible for contractions that pump blood through the body. The myocardial conducting cells (1 percent of the cells) are the autorhythmic cells and form the conduction system of the heart. Except for Purkinje cells, they are generally much smaller than the contractile cells and have few of the myofibrils or filaments needed for contraction. Their function is similar in many respects to neurons, although they are specialized muscle cells. Myocardial conduction cells initiate and propagate the action potential (the electrical impulse) that travels throughout the heart  muscle and triggers the contractions that propel the blood.",True,Identify blocks that can interrupt the cardiac cycle,,,,
+c12800dd-3020-4229-bfc3-10a80bac287e,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Structure of Cardiac Muscle,False,Structure of Cardiac Muscle,,,,
+cd9a0103-2d16-419c-a7d9-29f738700dea,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell (Figure 19.2.1a). These contractile elements are virtually identical to skeletal muscle. T (transverse) tubules penetrate from the surface plasma membrane, the sarcolemma, to the interior of the cell, allowing the electrical impulse to reach the interior. The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. In addition, the sarcoplasmic reticulum stores few calcium ions, so most of the calcium ions must come from outside the cells. The result is a slower onset of contraction. Mitochondria are plentiful, providing energy for the contractions of the heart.  Typically, cardiomyocytes have a single, central nucleus, but two or more nuclei may be found in some cells.",True,Structure of Cardiac Muscle,Figure 19.2.1,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2017abc_Cardiac_Muscle.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)"
+36cb583b-6e1e-4164-a4ce-12a5fb14d0f1,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"Cardiac muscle cells branch freely. A junction between two adjoining cells is marked by a critical structure called an intercalated disc, which helps support the synchronized contraction of the muscle (Figure 19.2.1b). The sarcolemmas from adjacent cells bind together at the intercalated discs. They consist of desmosomes, specialized linking proteoglycans, tight junctions, and large numbers of gap junctions that allow the passage of ions between the cells and help to synchronize the contraction (Figure 19.2.1c). Intercellular connective tissue also helps to bind the cells together. The importance of strongly binding these cells together is necessitated by the forces exerted by contraction.",True,Structure of Cardiac Muscle,Figure 19.2.1,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2017abc_Cardiac_Muscle.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)"
+bbf11e28-3aa5-410c-b65c-06b7f86518aa,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Conduction System of the Heart,False,Conduction System of the Heart,,,,
+e4ec84e1-51f5-484a-9508-401158df795b,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"The wave of contraction that allows the heart to work as a unit, called a functional syncytium, begins with the pacemaker cells. This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called autorhythmicity; they do this at set intervals which determine heart rate. Because they are connected with gap junctions to surrounding muscle fibers, the specialized fibers of the heart’s conduction system, the pacemaker cells are able to transfer the depolarization to the other cardiac muscle fibers in a manner that allows the heart to contract in a coordinated manner.",True,Conduction System of the Heart,,,,
+7a9504a1-ab9a-44b2-8c91-583be6faa933,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"If embryonic heart cells are separated into a Petri dish and kept alive, each is capable of generating its own electrical impulse followed by contraction. When two independently beating embryonic cardiac muscle cells are placed together, the cell with the higher inherent rate sets the pace, and the impulse spreads from the faster to the slower cell to trigger a contraction. As more cells are joined together, the fastest cell continues to assume control of the rate. A fully developed adult heart maintains the capability of generating its own electrical impulse, triggered by the fastest cells, as part of the cardiac conduction system. The components of the cardiac conduction system include the sinoatrial node, the atrioventricular node, the atrioventricular bundle, the atrioventricular bundle branches, and the Purkinje cells (Figure 19.2.2).",True,Conduction System of the Heart,Figure 19.2.2,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2018_Conduction_System_of_Heart.jpg,"Figure 19.2.2 -Conduction System of the Heart: Specialized conducting components of the heart include the sinoatrial node, the internodal pathways, the atrioventricular node, the atrioventricular bundle, the right and left bundle branches, and the Purkinje fibers."
+b6f0bb22-fc4d-4574-b9be-a6a28a40b6c6,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Membrane Potentials and Ion Movement in Cardiac Cells,False,Membrane Potentials and Ion Movement in Cardiac Cells,,,,
+4952ea37-71aa-40d3-9ea5-f4956a44001c,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Electrocardiogram,False,Electrocardiogram,,,,
+0ca8057d-320a-474f-bbbf-c4a8b2934782,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"By careful placement of surface electrodes on the body, it is possible to record the complex, composite electrical signal of the heart. This tracing of the electrical signal is the electrocardiogram (ECG), also commonly abbreviated EKG (K coming kardiology, from the German term for cardiology). Careful analysis of the ECG reveals a detailed picture of both normal and abnormal heart function, and is an indispensable clinical diagnostic tool. The standard electrocardiograph (the instrument that generates an ECG) uses 3, 5, or 12 leads. The greater the number of leads an electrocardiograph uses, the more information the ECG provides. The term “lead” may be used to refer to the cable from the electrode to the electrical recorder, but it typically describes the voltage difference between two electrodes (bipolar leads). The 12-lead electrocardiograph uses 10 electrodes placed in standard locations on the patient’s skin (Figure 19.2.6), the chest electrodes are unipolar and the appendage leads are bipolar. In continuous ambulatory electrocardiographs, the patient wears a small, portable, battery-operated device known as a Holter monitor, or simply a Holter, that continuously monitors heart electrical activity, typically for a period of 24 hours during the patient’s normal routine.",True,Electrocardiogram,Figure 19.2.6,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2021_ECG_Placement_of_Electrodes.jpg,"Figure 19.2.6 – Standard Placement of ECG Leads: In a 12-lead ECG, six electrodes are placed on the chest, and four electrodes are placed on the limbs."
+db6ee1fe-5a3f-44d5-9eaa-d142717edc7b,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"A normal ECG tracing is presented in Figure 19.2.7. Each component, segment, and interval is labeled and corresponds to important electrical events, demonstrating the relationship between these events and contraction in the heart.",True,Electrocardiogram,Figure 19.2.7,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2022_Electrocardiogram.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments."
+64287e19-09f7-4fd3-b897-2915e7bdea12,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"There are five prominent components (points) on the ECG: the P wave, the QRS complex, and the T wave. The small P wave represents the depolarization of the atria. The atria begin contracting approximately 25 ms after the start of the P wave. The large QRS complex represents the depolarization of the ventricles, which requires a much stronger electrical signal because of the larger size of the ventricular cardiac muscle. The ventricles begin to contract as the QRS reaches the peak of the R wave. Lastly, the T wave represents the repolarization of the ventricles. The repolarization of the atria occurs during the QRS complex, which masks it on an ECG.",True,Electrocardiogram,,,,
+64b66c71-5f60-425d-98e7-64b686569238,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"The major segments and intervals of an ECG tracing are indicated in Figure 19.2.7. Segments are defined as the regions between two waves. Intervals include one segment plus one or more waves. For example, the PR segment begins at the end of the P wave and ends at the beginning of the QRS complex. The PR interval starts at the beginning of the P wave and ends with the beginning of the QRS complex. The PR interval is more clinically relevant, as it measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. Since the Q wave may be difficult to view in some tracings, the measurement is often extended to the R that is more easily visible. Should there be a delay in passage of the impulse from the SA node to the AV node, it would be visible in the PR interval. Figure 19.2.8 correlates events of heart contraction to the corresponding segments and intervals of an ECG.",True,Electrocardiogram,Figure 19.2.7,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2022_Electrocardiogram.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments."
+bff18739-025a-43e9-8f50-501d41f12b21,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,junctional rhythm,False,junctional rhythm,,,,
+c6056b22-52cc-4ea8-8f8e-b8468578d4b4,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Cardiac Muscle Metabolism,False,Cardiac Muscle Metabolism,,,,
+c183cf52-665a-4016-bb24-6068c4e06de3,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,"Normally, cardiac muscle metabolism is entirely aerobic. Oxygen from the lungs is brought to the heart, and every other organ, attached to the hemoglobin molecules within the erythrocytes. Heart cells also store appreciable amounts of oxygen in myoglobin. Normally, these two mechanisms, circulating oxygen and oxygen attached to myoglobin, can supply sufficient oxygen to the heart, even during peak performance.",True,Cardiac Muscle Metabolism,,,,
+f3d25141-1c1a-4bcf-bdb3-e463fb094932,https://open.oregonstate.education/aandp/,19.2 Cardiac Muscle and Electrical Activity,https://open.oregonstate.education/aandp/chapter/19-2-cardiac-muscle-and-electrical-activity/,Fatty acids and glucose from the circulation are broken down within the mitochondria to release energy in the form of ATP. Both fatty acid droplets and glycogen are stored within the sarcoplasm and provide additional nutrient supply. (Seek additional content for more detail about metabolism.),True,Cardiac Muscle Metabolism,,,,
+cea328fe-7362-4ce1-9ee9-c7b8efa3cdfb,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The vital importance of the heart is obvious. If one assumes an average rate of contraction of 75 contractions per minute, a human heart would contract approximately 108,000 times in one day, more than 39 million times in one year, and nearly 3 billion times during a 75-year lifespan. Each of the major pumping chambers of the heart ejects approximately 70 mL blood per contraction in a resting adult. This would be equal to 5.25 liters of fluid per minute and approximately 14,000 liters per day. Over one year, that would equal 10,000,000 liters or 2.6 million gallons of blood sent through roughly 60,000 miles of vessels. In order to understand how that happens, it is necessary to understand the anatomy and physiology of the heart.",True,Cardiac Muscle Metabolism,,,,
+153b1fee-c593-4746-8882-c43d7f1315dc,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,Location and Size of the Heart,False,Location and Size of the Heart,,,,
+9eb3a7b6-7f3d-4ee5-90ea-f9498f3e3fa2,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.1.1 shows the position of the heart within the thoracic cavity. Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity. The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base. The base of the heart is located at the level of the third costal cartilage, as seen in Figure 19.1.1. The inferior tip of the heart, the apex, lies just to the left of the sternum between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The right side of the heart is deflected anteriorly, and the left side is deflected posteriorly. It is important to remember the position and orientation of the heart when placing a stethoscope on the chest of a patient and listening for heart sounds, and also when looking at images taken from a midsagittal perspective. The slight deviation of the apex to the left is reflected in a depression in the medial surface of the inferior lobe of the left lung, called the cardiac notch.",True,Location and Size of the Heart,Figure 19.1.1,19.1 Heart Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2001_Heart_Position_in_Thorax_revised.png,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base."
+621e9204-01af-4477-9817-0141e1d5038a,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,Shape and Size of the Heart,False,Shape and Size of the Heart,,,,
+a0938f1b-cdd2-4608-9f7a-e68184e58e22,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The shape of the heart is similar to a inverted pear, rather broad at the superior surface and tapering to the apex (see Figure 19.1.1). A typical heart is approximately the size of your fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness. Given the size difference between most members of the sexes, the weight of a female heart is approximately 250–300 grams (9 to 11 ounces), and the weight of a male heart is approximately 300–350 grams (11 to 12 ounces). The heart of a well-trained athlete, especially one specializing in aerobic sports, can be considerably larger than this. Cardiac muscle responds to exercise in a manner similar to that of skeletal muscle. That is, exercise results in the addition of protein myofilaments that increase the size of the individual cells without increasing their numbers, a concept called hypertrophy. Hearts of athletes can pump blood more effectively at lower rates than those of nonathletes. Enlarged hearts are not always a result of exercise; they can result from pathologies, such as hypertrophic cardiomyopathy. The cause of such an abnormally enlarged heart muscle is unknown, but the condition is often undiagnosed and can cause sudden death in apparently otherwise healthy young people.",True,Shape and Size of the Heart,Figure 19.1.1,19.1 Heart Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2001_Heart_Position_in_Thorax_revised.png,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base."
+3898ea53-c979-411b-87cb-463d678765c7,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,Circulation through the Heart and Body,False,Circulation through the Heart and Body,,,,
+35f8bcad-ad5b-4467-8dcb-49b4c9da431c,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The human heart consists of four chambers: The left side and the right side each have one atrium and one ventricle. Each of the upper chambers, the right atrium (plural = atria) and the left atrium, act as receiving chambers and the combination of gravity and atrial contraction move blood into the lower chambers, the right ventricle and the left ventricle. The ventricles serve as the primary pumping chambers of the heart, propelling blood to the lungs or to the rest of the body.",True,Circulation through the Heart and Body,,,,
+f4ceda0f-3dec-4dab-8482-2f3d77daa75a,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"There are two distinct but linked circuits in the human circulation called the pulmonary and systemic circuits. Although both circuits transport blood and everything it carries (see section 18.1), we can initially view the circuits from the point of view of gases. The pulmonary circuit transports blood to and from the lungs, where it picks up oxygen and delivers carbon dioxide for exhalation. The systemic circuit transports oxygenated blood to virtually all of the tissues of the body and returns relatively deoxygenated blood and carbon dioxide to the heart to be sent back to the pulmonary circulation. These two circulations function simultaneously and thus the heart functions as a dual pump.",True,Circulation through the Heart and Body,,,,
+48fe3562-7b56-4c08-b9e2-3e8f9d58aa60,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The right ventricle pumps deoxygenated blood into the pulmonary trunk, which leads toward the lungs and bifurcates into the left and right pulmonary arteries. Arteries carry blood away from the heart. These vessels in turn branch many times before reaching the pulmonary capillaries, where gas exchange occurs: Carbon dioxide diffuses out of the blood and oxygen diffuses into the blood. The pulmonary trunk arteries and their branches are the only arteries in the post-natal body that carry relatively deoxygenated blood. Highly oxygenated blood returning from the pulmonary capillaries in the lungs passes through a series of vessels that join together to form the pulmonary veins—the only post-natal veins in the body that carry highly oxygenated blood. Veins carry blood toward the heart. The pulmonary veins conduct blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and on to the many branches of the systemic circuit. Eventually, these vessels will lead to the systemic capillaries, where exchange with the tissue fluid and cells of the body occurs. In this case, oxygen and nutrients out of the systemic capillaries to be used by the cells in their metabolic processes, and carbon dioxide and waste products diffuse into the blood.",True,Circulation through the Heart and Body,,,,
+9a54c580-a6fc-425a-bb78-e0ef37736c33,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"The blood exiting the systemic capillaries is lower in oxygen concentration than when it entered. The capillaries will ultimately unite to form venules, joining to form ever-larger veins, eventually flowing into the two major systemic veins, the superior vena cava and the inferior vena cava, which return blood to the right atrium. The blood in the superior and inferior venae cavae flows into the right atrium, which pumps blood into the right ventricle. This process of blood circulation continues as long as the individual remains alive. Understanding the flow of blood through the pulmonary and systemic circuits is critical to all health professions (Figure 19.1.2).",True,Circulation through the Heart and Body,Figure 19.1.2,19.1 Heart Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2003_Dual_System_of_Human_Circulation_revised.png,"Figure 19.1.2 – Dual System of the Human Blood Circulation: Blood flows from the right atrium to the right ventricle, where it is pumped into the pulmonary circuit. The blood in the pulmonary artery branches is low in oxygen but relatively high in carbon dioxide. Gas exchange occurs in the pulmonary capillaries (oxygen into the blood, carbon dioxide out), and blood high in oxygen and low in carbon dioxide is returned to the left atrium. From here, blood enters the left ventricle, which pumps it into the systemic circuit. Following exchange in the systemic capillaries (oxygen and nutrients out of the capillaries and carbon dioxide and wastes in), blood returns to the right atrium and the cycle is repeated."
+1e37bd25-cb68-448b-9f04-304d370ff097,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"Coverings, Surface Features, and Layers",False,"Coverings, Surface Features, and Layers",,,,
+c34aa99c-1cd7-44a9-9a6b-ef1f11bf7c8c,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"Our exploration of more in-depth heart structures begins by examining the coverings that surround the heart, the prominent surface features of the heart, and the layers that form the wall of the heart. Each of these components plays its own unique role in terms of function.",True,"Coverings, Surface Features, and Layers",,,,
+606c85f4-53d1-45b6-8771-776b6d85a750,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,Internal Structure of the Heart,False,Internal Structure of the Heart,,,,
+6d2cbdf8-2789-49b3-92a7-80bbe5efb859,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because the right and left pair of chambers simultaneously pump blood into the pulmonary and systemic circulations respectively. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in Figure 19.1.8.",True,Internal Structure of the Heart,Figure 19.1.8,19.1 Heart Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2008_Internal_Anatomy_of_the_HeartN.jpg,"Figure 19.1.8 – Internal Structures of the Heart: This anterior view of the heart shows the four chambers, the major vessels and their early branches, as well as the four valves. The presence of the pulmonary trunk and aorta covers the interatrial septum, and the atrioventricular septum is cut away to show the atrioventricular valves."
+bed19af1-b335-48b1-85b4-0ef388984c57,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"Cardiologists are medical doctors that specialize in the diagnosis and treatment of diseases of the heart. After completing 4 years of medical school, cardiologists complete a three-year residency in internal medicine followed by an additional three or more years in cardiology. Following this 10-year period of medical training and clinical experience, they qualify for a rigorous two-day examination administered by the Board of Internal Medicine that tests their academic training and clinical abilities, including diagnostics and treatment. After successful completion of this examination, a physician becomes a board-certified cardiologist. Some board-certified cardiologists may be invited to become a Fellow of the American College of Cardiology (FACC). This professional recognition is awarded to outstanding physicians based upon merit, including outstanding credentials, achievements, and community contributions to cardiovascular medicine.",True,Internal Structure of the Heart,,,,
+bb1391c5-d022-4755-8d04-3c48d0a1c02b,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"Cardiovascular technologists/technicians are trained professionals who perform a variety of imaging techniques, such as sonograms or echocardiograms, used by physicians to diagnose and treat diseases of the heart. Nearly all of these positions require an associate degree, and these technicians earn a median salary of $49,410 as of May 2010, according to the U.S. Bureau of Labor Statistics. Growth within the field is fast, projected at 29 percent from 2010 to 2020.",True,Internal Structure of the Heart,,,,
+6dbe0764-8519-437c-82c8-5b28f424e586,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"There is a considerable overlap and complementary skills between cardiac technicians and vascular technicians, and so the term cardiovascular technician is often used. Special certifications within the field require documenting appropriate experience and completing additional and often expensive certification examinations. These subspecialties include Certified Rhythm Analysis Technician (CRAT), Certified Cardiographic Technician (CCT), Registered Congenital Cardiac Sonographer (RCCS), Registered Cardiac Electrophysiology Specialist (RCES), Registered Cardiovascular Invasive Specialist (RCIS), Registered Cardiac Sonographer (RCS), Registered Vascular Specialist (RVS), and Registered Phlebology Sonographer (RPhS).",True,Internal Structure of the Heart,,,,
+c2383dda-d921-4ef1-a460-1dfd2a66c2a9,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,Coronary Circulation,False,Coronary Circulation,,,,
+50847ff9-c968-42a8-b6b4-76f0b8c8e783,https://open.oregonstate.education/aandp/,19.1 Heart Anatomy,https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/,"You will recall that the heart is a remarkable pump composed largely of cardiac muscle cells that are incredibly active throughout life. Like all other cells, a cardiomyocyte requires a reliable supply of oxygen and nutrients, and a way to remove wastes, so it needs a dedicated, complex, and extensive coronary circulation to supply the thick myocardium. And because of the critical and nearly ceaseless activity of the heart throughout life, this need for a blood supply is even greater than for a typical cell. However, coronary circulation is not continuous; rather, it cycles, reaching a peak when the heart muscle is relaxed and nearly ceasing while it is contracting.",True,Coronary Circulation,,,,
+e6399f6f-7c6a-4389-b103-87d2ce250bd6,https://open.oregonstate.education/aandp/,19.0 Introduction,https://open.oregonstate.education/aandp/chapter/19-0-introduction/,"In this chapter, you will explore the remarkable pump that propels the blood into the vessels. There is no single better word to describe the function of the heart other than “pump,” since its contraction develops the pressure that ejects blood into the major vessels: the aorta and pulmonary trunk. From these vessels, the blood is distributed to the remainder of the body. Although the connotation of the term “pump” suggests a mechanical device made of steel and plastic, the anatomical structure is a living, sophisticated muscle. As you read this chapter, try to keep these twin concepts in mind: pump and muscle.",True,Coronary Circulation,,,,
+31732258-9f0a-472c-93ad-18616a4e5362,https://open.oregonstate.education/aandp/,19.0 Introduction,https://open.oregonstate.education/aandp/chapter/19-0-introduction/,"Although the term “heart” is an English word, cardiac (heart-related) terminology can be traced back to the Latin term, “kardia.” Cardiology is the study of the heart, and cardiologists are the physicians who deal primarily with the heart.",True,Coronary Circulation,,,,
+8439c407-e31f-46f9-9b58-6abdf3f6f88e,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,Explain the significance of ABO and Rh blood groups in blood transfusions,True,Coronary Circulation,,,,
+a768244b-07bf-4e6b-be50-07b1febf4db1,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Blood transfusions in humans were risky procedures until the discovery of the major human blood groups by Karl Landsteiner, an Austrian biologist and physician, in 1900. Until that point, physicians did not understand that death sometimes followed blood transfusions, when the type of donor blood infused into the patient was incompatible with the patient’s own blood. Blood groups are determined by the presence or absence of specific marker molecules on the plasma membranes of erythrocytes. With their discovery, it became possible for the first time to match patient-donor blood types and prevent transfusion reactions and deaths.",True,Coronary Circulation,,,,
+4e67408a-664d-4a55-9b67-6dab8a4b7c2e,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Antigens, Antibodies, and Transfusion Reactions",False,"Antigens, Antibodies, and Transfusion Reactions",,,,
+11deb054-9b4a-4856-a1e7-dea020ef2c12,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Antigens are substances that the body does not recognize as belonging to the “self” and that therefore trigger a defensive response from the leukocytes of the immune system. Here, we will focus on the role of immunity in blood transfusion reactions. With RBCs in particular, you may see the antigens referred to as isoantigens or agglutinogens (surface antigens) and the antibodies referred to as isoantibodies or agglutinins. In this chapter, we will use the more common terms antigens and antibodies.",True,"Antigens, Antibodies, and Transfusion Reactions",,,,
+2b100b13-f0b4-4576-a946-57d8e4517459,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Antigens are generally large proteins, but may include other classes of organic molecules, including carbohydrates, lipids, and nucleic acids. Following a transfusion of incompatible blood, erythrocytes with foreign antigens appear in the bloodstream and trigger an immune response. Proteins called antibodies (immunoglobulins), which are produced by certain B lymphocytes called plasma cells, attach to the antigens on the plasma membranes of the transfused erythrocytes and cause them to adhere to one another.",True,"Antigens, Antibodies, and Transfusion Reactions",,,,
+3751682b-ec64-4d6d-9d0e-a3a9886e0b85,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"More than 50 antigens have been identified on erythrocyte membranes, but the most significant in terms of their potential harm to patients are classified in two groups: the ABO blood group and the Rh blood group.",True,"Antigens, Antibodies, and Transfusion Reactions",,,,
+d64954fc-1d9d-4470-a705-08dfb2017a42,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,The ABO Blood Group,False,The ABO Blood Group,,,,
+192107b4-0d4a-49be-976e-e5b9f95cc50d,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Although the ABO blood group name consists of three letters, ABO blood typing designates the presence or absence of just two antigens, A and B. Both are glycoproteins. People whose erythrocytes have A antigens on their erythrocyte membrane surfaces are designated blood type A, and those whose erythrocytes have B antigens are blood type B. People can also have both A and B antigens on their erythrocytes, in which case they are blood type AB. People with neither A nor B antigens are designated blood type O. ABO blood types are genetically determined.",True,The ABO Blood Group,,,,
+364c47ce-bc4e-4b44-93e2-3637b65d657f,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Normally the body must be exposed to a foreign antigen before an antibody can be produced. This is not the case for the ABO blood group. Individuals with type A blood—without any prior exposure to incompatible blood—have preformed antibodies to the B antigen circulating in their blood plasma. These antibodies, referred to as anti-B antibodies, will cause agglutination and hemolysis if they ever encounter erythrocytes with B antigens. Similarly, an individual with type B blood has pre-formed anti-A antibodies. Individuals with type AB blood, which has both antigens, do not have preformed antibodies to either of these. People with type O blood lack antigens A and B on their erythrocytes, but both anti-A and anti-B antibodies circulate in their blood plasma.",True,The ABO Blood Group,,,,
+dc4c8b65-f6e8-4b86-bef4-8b8f7761be28,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,Rh Blood Groups,False,Rh Blood Groups,,,,
+507d3b7c-5d48-4373-bf8d-e361ba01d9b5,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"The Rh blood group is classified according to the presence or absence of a second erythrocyte antigen identified as Rh. (It was first discovered in a type of primate known as a rhesus macaque, which is often used in research, because its blood is similar to that of humans.) Although dozens of Rh antigens have been identified, only one, designated D, is clinically important. Those who have the Rh D antigen present on their erythrocytes—about 85 percent of Americans—are described as Rh positive (Rh+) and those who lack it are Rh negative (Rh−). Note that the Rh group is distinct from the ABO group, so any individual, no matter their ABO blood type, may have or lack this Rh antigen. When identifying a patient’s blood type, the Rh group is designated by adding the word positive or negative to the ABO type. For example, A positive (A+) means ABO group A blood with the Rh antigen present, and AB negative (AB−) means ABO group AB blood without the Rh antigen.",True,Rh Blood Groups,,,,
+46aea82a-dbd3-4819-9a97-27b5c692cd4c,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,Table 18.2 summarizes the distribution of the ABO and Rh blood types within the United States.,True,Rh Blood Groups,,,,
+100b1cd3-d262-4cc6-905a-95a8b517a81b,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"In contrast to the ABO group antibodies, which are preformed, antibodies to the Rh antigen are produced only in Rh− individuals after exposure to the antigen. This process, called sensitization, occurs following a transfusion with Rh-incompatible blood or, more commonly, with the birth of an Rh+ baby to an Rh− mother. Problems are rare in a first pregnancy, since the baby’s Rh+ cells rarely cross the placenta (the organ of gas and nutrient exchange between the baby and the mother). However, during or immediately after birth, the Rh− mother can be exposed to the baby’s Rh+ cells (Figure 18.6.1). Research has shown that this occurs in about 13−14 percent of such pregnancies. After exposure, the mother’s immune system begins to generate anti-Rh antibodies. If the mother should then conceive another Rh+ baby, the Rh antibodies she has produced can cross the placenta into the fetal bloodstream and destroy the fetal RBCs. This condition, known as hemolytic disease of the newborn (HDN) or erythroblastosis fetalis, may cause anemia in mild cases, but the agglutination and hemolysis can be so severe that without treatment the fetus may die in the womb or shortly after birth.",True,Rh Blood Groups,Figure 18.6.1,18.6 Blood Typing,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1910_Erythroblastosis_Fetalis.jpg,"Figure 18.6.1 – Erythroblastosis Fetalis: The first exposure of an Rh− mother to Rh+ erythrocytes during pregnancy induces sensitization. Anti-Rh antibodies begin to circulate in the mother’s bloodstream. A second exposure occurs with a subsequent pregnancy with an Rh+ fetus in the uterus. Maternal anti-Rh antibodies may cross the placenta and enter the fetal bloodstream, causing agglutination and hemolysis of fetal erythrocytes."
+491df4c8-8b64-4e73-b14c-cae67433446e,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"A drug known as RhoGAM, short for Rh immune globulin, can temporarily prevent the development of Rh antibodies in the Rh− mother, thereby averting this potentially serious disease for the fetus. RhoGAM antibodies destroy any fetal Rh+ erythrocytes that may cross the placental barrier. RhoGAM is normally administered to Rh− mothers during weeks 26−28 of pregnancy and within 72 hours following birth. It has proven remarkably effective in decreasing the incidence of HDN. Earlier we noted that the incidence of HDN in an Rh+ subsequent pregnancy to an Rh− mother is about 13–14 percent without preventive treatment. Since the introduction of RhoGAM in 1968, the incidence has dropped to about 0.1 percent in the United States.",True,Rh Blood Groups,,,,
+62169c31-8a92-499a-b9b0-53919fe7d2e4,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,Determining ABO Blood Types,False,Determining ABO Blood Types,,,,
+0de4754f-18d3-49ea-a092-cef42cc0a19f,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"Clinicians are able to determine a patient’s blood type quickly and easily using commercially prepared antibodies. An unknown blood sample is allocated into separate wells. Into one well a small amount of anti-A antibody is added, and to another a small amount of anti-B antibody. If the antigen is present, the antibodies will cause visible agglutination of the cells (Figure 18.6.2). The blood should also be tested for Rh antibodies.",True,Determining ABO Blood Types,Figure 18.6.2,18.6 Blood Typing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1912_Cross_Matching_Blood_Types.jpg,"Figure 18.6.2 – Cross Matching Blood Types: This sample of a commercially produced “bedside” card enables quick typing of both a recipient’s and donor’s blood before transfusion. The card contains three reaction sites or wells. One is coated with an anti-A antibody, one with an anti-B antibody, and one with an anti-D antibody (tests for the presence of Rh factor D). Mixing a drop of blood and saline into each well enables the blood to interact with a preparation of type-specific antibodies. Agglutination of RBCs in a given site indicates a positive identification of the blood antigens, in this case A and Rh antigens for blood type A+. For the purpose of transfusion, the donor’s and recipient’s blood types must match."
+2dd951b3-16fa-4d0f-a1ff-9d75abde159a,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,ABO Transfusion Protocols,False,ABO Transfusion Protocols,,,,
+ea678cd7-4f8e-4f2d-844d-16db963fb6c2,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"To avoid transfusion reactions, it is best to transfuse only matching blood types; that is, a type B+ recipient should ideally receive blood only from a type B+ donor and so on. That said, in emergency situations, when acute hemorrhage threatens the patient’s life, there may not be time for cross matching to identify blood type. In these cases, blood from a universal donor—an individual with type O− blood—may be transfused. Recall that type O erythrocytes do not display A or B antigens. Thus, anti-A or anti-B antibodies that might be circulating in the patient’s blood plasma will not encounter any erythrocyte surface antigens on the donated blood and therefore will not be provoked into a response. Ideally, the transfusion is not whole blood, but only red blood cells and saline, avoiding the problem of type A or type B antibodies in the donor’s plasma being transfused to the patient. If whole blood is transfused instead, and the the O− donor had prior exposure to Rh antigen, Rh antibodies may be present in the donated blood. Also, introducing type O blood into an individual with type A, B, or AB blood would introduce antibodies against both A and B antigens, as these are always circulating in the type O blood plasma. This may cause problems for the recipient, but because the volume of blood transfused is much lower than the volume of the patient’s own blood, the adverse effects of the relatively few infused plasma antibodies are typically limited. For these reasons, it is preferable to cross match a patient’s blood before transfusing, or only transfuse red blood cells and saline. In a true life-threatening emergency situation, this is not always possible, and the universal donor (O-) whole blood could be used.",True,ABO Transfusion Protocols,,,,
+8622fa9e-d68f-434f-8a12-a72dd7f885c2,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"A patient with blood type AB+ is known as the universal recipient. This patient can theoretically receive any type of blood, because the patient’s own blood—having both A and B antigens on the erythrocyte surface—does not produce anti-A or anti-B antibodies. In addition, an Rh+ patient can receive both Rh+ and Rh− blood.  Figure 18.6.3 summarizes the blood types and transfusion compatibility.",True,ABO Transfusion Protocols,Figure 18.6.3,18.6 Blood Typing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1913_ABO_Blood_Groups.jpg,Figure 18.6.3 – ABO Blood Group: This chart summarizes the characteristics of the blood types in the ABO blood group. See the text for more on the concept of a universal donor or recipient.
+c64dc1cc-f9c8-4efa-962f-e1354692006d,https://open.oregonstate.education/aandp/,18.6 Blood Typing,https://open.oregonstate.education/aandp/chapter/18-6-blood-typing/,"At the scene of multiple-vehicle accidents, military engagements, and natural or human-caused disasters, many victims may suffer simultaneously from acute hemorrhage, yet type O blood may not be immediately available. In these circumstances, medics may at least try to replace some of the volume of blood that has been lost. This is done by intravenous administration of a saline solution that provides fluids and electrolytes in proportions equivalent to those of normal blood plasma. Research is ongoing to develop a safe and effective artificial blood that would carry out the oxygen-carrying function of blood without the RBCs, enabling transfusions in the field without concern for incompatibility. These blood substitutes normally contain hemoglobin- as well as perfluorocarbon-based oxygen carriers.",True,ABO Transfusion Protocols,,,,
+9ea882dc-a617-447c-a3c5-7a125284b634,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Describe the process of hemostasis,False,Describe the process of hemostasis,,,,
+9369cbfc-d8ba-4e1e-b001-e7f88377c38d,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"Platelets are key players in hemostasis, the process by which the body seals a ruptured blood vessel and prevents further loss of blood. Although rupture of larger vessels usually requires medical intervention, hemostasis is quite effective in dealing with small, simple wounds. There are three steps to the process: vascular spasm, the formation of a platelet plug, and coagulation (blood clotting). Failure of any of these steps will result in hemorrhage—excessive bleeding.",True,Describe the process of hemostasis,,,,
+ceee3ffd-ddd6-4763-aba5-23a92a802727,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Vascular Spasm,False,Vascular Spasm,,,,
+5837fc29-ec49-4a20-8c30-968afa21669a,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"When a vessel is severed or punctured, or when the wall of a vessel is damaged, vascular spasm occurs. In vascular spasm, the smooth muscle in the walls of the vessel contracts dramatically. This smooth muscle has both circular layers; larger vessels also have longitudinal layers. The circular layers tend to constrict the flow of blood, whereas the longitudinal layers, when present, draw the vessel back into the surrounding tissue, often making it more difficult for a surgeon to locate, clamp, and tie off a severed vessel. The vascular spasm response is believed to be triggered by several chemicals called endothelins that are released by vessel-lining cells and by pain receptors in response to vessel injury. This phenomenon typically lasts for up to 30 minutes, although it can last for hours.",True,Vascular Spasm,,,,
+6a6b7d69-91ce-47d4-ba4c-9afa20886f8a,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Formation of the Platelet Plug,False,Formation of the Platelet Plug,,,,
+00dcd3de-0af1-4fd9-bc0a-e2d51947d665,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"In the second step, platelets, which normally float free in the plasma, encounter the area of vessel rupture with the exposed underlying connective tissue and collagenous fibers. The platelets begin to clump together, become spiked and sticky, and bind to the exposed collagen and endothelial lining. This process is assisted by a glycoprotein in the blood plasma called von Willebrand factor, which helps stabilize the growing platelet plug. As platelets collect, they simultaneously release chemicals from their granules into the plasma that further contribute to hemostasis. Among the substances released by the platelets are:",True,Formation of the Platelet Plug,,,,
+fbf721dd-dc28-4412-b446-d33e243680c8,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"A platelet plug can temporarily seal a small opening in a blood vessel. Plug formation, in essence, buys the body time while more sophisticated and durable repairs are being made.",True,Formation of the Platelet Plug,,,,
+a6e157ec-1d9b-4f38-99f4-db2015b82dc0,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Coagulation,False,Coagulation,,,,
+7ef07214-8dee-4a31-b3d5-8255176d4074,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"More sophisticated and durable repairs made beyond the plug formation are collectively called coagulation, the formation of a blood clot. The process is sometimes characterized as a cascade, because one event prompts the next as in a multi-level waterfall. The result is the production of a gelatinous but robust clot made up of a mesh of fibrin—an insoluble filamentous protein derived from fibrinogen, the plasma protein introduced earlier—in which platelets and blood cells are trapped. Figure 18.5.1 summarizes the three steps of hemostasis following injury.",True,Coagulation,Figure 18.5.1,18.5 Hemostasis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1909_Blood_Clotting.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)"
+bd871b53-a9de-42a8-8008-2ea3e9f785a2,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Fibrinolysis,False,Fibrinolysis,,,,
+9417cf49-8269-4192-905d-7a9a5b347494,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"The stabilized clot is acted upon by contractile proteins within the platelets. As these proteins contract, they pull on the fibrin threads, bringing the edges of the clot more tightly together, somewhat as we do when tightening loose shoelaces (see Figure 18.5.1a). This process also wrings out of the clot a small amount of fluid called serum, which is blood plasma without its clotting factors.",True,Fibrinolysis,Figure 18.5.1,18.5 Hemostasis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1909_Blood_Clotting.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)"
+fa566517-0fdb-4d99-90ac-91e2e3861753,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"To restore normal blood flow as the vessel heals, the clot must eventually be removed. Fibrinolysis is the gradual degradation of the clot. Again, there is a fairly complicated series of reactions that involves factor XII and protein-catabolizing enzymes. During this process, the inactive protein plasminogen is converted into the active plasmin, which gradually breaks down the fibrin of the clot. Additionally, bradykinin, a vasodilator, is released, reversing the effects of the serotonin and prostaglandins from the platelets. This allows the smooth muscle in the walls of the vessels to relax and helps to restore the circulation.",True,Fibrinolysis,,,,
+c36d7ed5-b2ef-4368-b332-194de9ad79a4,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Plasma Anticoagulants,False,Plasma Anticoagulants,,,,
+b2338ac0-8e87-40bc-a3f6-ab8b995c3017,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"An anticoagulant is any substance that opposes coagulation. Several circulating plasma anticoagulants play a role in limiting the coagulation process to the region of injury and restoring a normal, clot-free condition of blood. For instance, a cluster of proteins collectively referred to as the protein C system inactivates clotting factors involved in the intrinsic pathway. TFPI (tissue factor pathway inhibitor) inhibits the conversion of the inactive factor VII to the active form in the extrinsic pathway. Antithrombin inactivates factor X and opposes the conversion of prothrombin (factor II) to thrombin in the common pathway. And as noted earlier, basophils release heparin, a short-acting anticoagulant that also opposes prothrombin. Heparin is also found on the surfaces of cells lining the blood vessels. A pharmaceutical form of heparin is often administered therapeutically, for example, in surgical patients at risk for blood clots.",True,Plasma Anticoagulants,,,,
+725e8a77-7784-4d19-85b8-5dc36e4a1ad0,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,Disorders of Clotting,False,Disorders of Clotting,,,,
+3a7cbbc7-866d-42d5-af05-fe46122a705c,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"Either an insufficient or an excessive production of platelets can lead to severe disease or death. As discussed earlier, an insufficient number of platelets, called thrombocytopenia, typically results in the inability of blood to form clots. This can lead to excessive bleeding, even from minor wounds.",True,Disorders of Clotting,,,,
+f1efb9c6-968f-4676-a853-c81d02752bcc,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"Another reason for failure of the blood to clot is the inadequate production of functional amounts of one or more clotting factors. This is the case in the genetic disorder hemophilia, which is actually a group of related disorders, the most common of which is hemophilia A, accounting for approximately 80 percent of cases. This disorder results in the inability to synthesize sufficient quantities of factor VIII. Hemophilia B is the second most common form, accounting for approximately 20 percent of cases. In this case, there is a deficiency of factor IX. Both of these defects are linked to the X chromosome and are typically passed from a healthy (carrier) mother to her male offspring, since males are XY. Females would need to inherit a defective gene from each parent to manifest the disease, since they are XX. Patients with hemophilia bleed from even minor internal and external wounds, and leak blood into joint spaces after exercise and into urine and stool. Hemophilia C is a rare condition that is triggered by an autosomal (not sex) chromosome that renders factor XI nonfunctional. It is not a true recessive condition, since even individuals with a single copy of the mutant gene show a tendency to bleed. Regular infusions of clotting factors isolated from healthy donors can help prevent bleeding in hemophiliac patients. At some point, genetic therapy will become a viable option.",True,Disorders of Clotting,,,,
+7dbf1854-b29b-4984-9c62-16134f5aef04,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"In contrast to the disorders characterized by coagulation failure is thrombocytosis, also mentioned earlier, a condition characterized by excessive numbers of platelets that increases the risk for excessive clot formation, a condition known as thrombosis. A thrombus (plural = thrombi) is an aggregation of platelets, erythrocytes, and even WBCs typically trapped within a mass of fibrin strands. While the formation of a clot is normal following the hemostatic mechanism just described, thrombi can form within an intact or only slightly damaged blood vessel. In a large vessel, a thrombus will adhere to the vessel wall and decrease the flow of blood, and is referred to as a mural thrombus. In a small vessel, it may actually totally block the flow of blood and is termed an occlusive thrombus. Thrombi are most commonly caused by vessel damage to the endothelial lining, which activates the clotting mechanism. These may include venous stasis, when blood in the veins, particularly in the legs, remains stationary for long periods. This is one of the dangers of long airplane flights in crowded conditions and may lead to deep vein thrombosis or atherosclerosis, an accumulation of debris in arteries. Thrombophilia, also called hypercoagulation, is a condition in which there is a tendency to form thrombosis. This may be familial (genetic) or acquired. Acquired forms include the autoimmune disease lupus, immune reactions to heparin, polycythemia vera, thrombocytosis, sickle cell disease, pregnancy, and even obesity. A thrombus can seriously impede blood flow to or from a region and will cause a local increase in blood pressure. If flow is to be maintained, the heart will need to generate a greater pressure to overcome the resistance.",True,Disorders of Clotting,,,,
+c7ef1c7c-c41e-4056-8d43-a866c573fdfe,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"When a portion of a thrombus breaks free from the vessel wall and enters the circulation, it is referred to as an embolus. An embolus that is carried through the bloodstream can be large enough to block a vessel critical to a major organ. When it becomes trapped, an embolus is called an embolism. In the heart, brain, or lungs, an embolism may accordingly cause a heart attack, a stroke, or a pulmonary embolism. These are medical emergencies.",True,Disorders of Clotting,,,,
+083b8164-57b9-4462-bcd3-b8415f33b012,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"Among the many known biochemical activities of aspirin is its role as an anticoagulant. Aspirin (acetylsalicylic acid) is very effective at inhibiting the aggregation of platelets. It is routinely administered during a heart attack or stroke to reduce the adverse effects. Physicians sometimes recommend that patients at risk for cardiovascular disease take a low dose of aspirin on a daily basis as a preventive measure. However, aspirin can also lead to serious side effects, including increasing the risk of ulcers. A patient is well advised to consult a physician before beginning any aspirin regimen.",True,Disorders of Clotting,,,,
+d5cf0bbc-9c66-4dbb-a5d0-22742401b492,https://open.oregonstate.education/aandp/,18.5 Hemostasis,https://open.oregonstate.education/aandp/chapter/18-5-hemostasis/,"A class of drugs collectively known as thrombolytic agents can help speed up the degradation of an abnormal clot. If a thrombolytic agent is administered to a patient within 3 hours following a thrombotic stroke, the patient’s prognosis improves significantly. However, some strokes are not caused by thrombi, but by hemorrhage. Thus, the cause must be determined before treatment begins. Tissue plasminogen activator is an enzyme that catalyzes the conversion of plasminogen to plasmin, the primary enzyme that breaks down clots. It is released naturally by endothelial cells but is also used in clinical medicine. New research is progressing using compounds isolated from the venom of some species of snakes, particularly vipers and cobras, which may eventually have therapeutic value as thrombolytic agents.",True,Disorders of Clotting,,,,
+37b0abd2-9df1-474e-ab81-80b019f63668,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Classify and characterize leukocytes (white blood cells),False,Classify and characterize leukocytes (white blood cells),,,,
+4654c801-4b35-481d-8106-78f0de0c0446,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"The leukocyte, commonly known as a white blood cell (WBC), is a major component of the body’s defenses against disease. Leukocytes protect the body against invading microorganisms and body cells with mutated DNA, and they clean up debris. Platelets are essential for the repair of blood vessels when damage has occurred; they also provide growth factors for healing and repair. See Chapter 18.3 Erythrocytes for a summary of leukocytes and platelets.",True,Classify and characterize leukocytes (white blood cells),,,,
+509be51c-10f0-44cb-9071-cd4612e26184,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Characteristics of Leukocytes,False,Characteristics of Leukocytes,,,,
+ae177a48-6a58-4f8f-945f-03e1e6b41ab1,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Although leukocytes and erythrocytes both originate from hematopoietic stem cells in the bone marrow, they are very different from each other in many significant ways. For instance, leukocytes are far less numerous than erythrocytes: Typically there are only 5000 to 10,000 per µL. They are also larger than erythrocytes and are the only formed elements that are complete cells, possessing a nucleus and organelles. And although there is just one type of erythrocyte, there are many types of leukocytes. Most of these types have a much shorter lifespan than that of erythrocytes, some as short as a few hours or even a few minutes in the case of acute infection.",True,Characteristics of Leukocytes,,,,
+b5572700-1075-4a8c-9427-0e317c9b138c,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"One of the most distinctive characteristics of leukocytes is their movement. Whereas erythrocytes spend their days circulating within the blood vessels, leukocytes routinely leave the bloodstream to perform their defensive functions in the body’s tissues. For leukocytes, the vascular network is a highway they travel and then exit to reach their destination. These cells are sometimes given distinct names depending on their function, such as macrophage or microglia, . As shown in Figure 18.4.1, they leave the capillaries—the smallest blood vessels—or other small vessels through a process known as emigration (from the Latin for “removal”) or diapedesis (dia- = “through”; -pedan = “to leap”) in which they squeeze through adjacent cells in a blood vessel wall.",True,Characteristics of Leukocytes,Figure 18.4.1,18.4 Leukocytes and Platelets,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1906_Emigration.jpg,"Figure 18.4.1 – Emigration: Leukocytes exit the blood vessel and then move through the connective tissue of the dermis toward the site of a wound. Some leukocytes, such as the eosinophil and neutrophil, are characterized as granular leukocytes. They release chemicals from their granules that destroy pathogens; they are also capable of phagocytosis. The monocyte, an agranular leukocyte, differentiates into a macrophage that then phagocytizes the pathogens."
+d4bcc9b6-f6f1-4d4d-9790-7b249a18e3b1,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Once they have exited the capillaries, some leukocytes will take up fixed positions in lymphatic tissue, bone marrow, the spleen, the thymus, or other organs. Others will move about through the tissue spaces very much like amoebas, continuously extending their plasma membranes, sometimes wandering freely, and sometimes moving toward the direction in which they are drawn by chemical signals. This attracting of leukocytes occurs because of positive chemotaxis (literally “movement in response to chemicals”), a phenomenon in which injured or infected cells and nearby leukocytes emit the equivalent of a chemical “emergency” call, attracting more leukocytes to the site. In clinical medicine, the differential counts of the types and percentages of leukocytes present are often key indicators in making a diagnosis and selecting a treatment.",True,Characteristics of Leukocytes,,,,
+e303d150-75bf-48e3-a1b3-30a72cd2f11f,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Classification of Leukocytes,False,Classification of Leukocytes,,,,
+62b33509-dd9f-4c8f-9a58-ad6d92b047d7,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"When scientists first began to observe stained blood slides, it quickly became evident that leukocytes could be divided into two groups, according to whether their cytoplasm contained highly visible granules:",True,Classification of Leukocytes,,,,
+15176072-5a89-49c5-a403-d0a6af35bd58,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Lifecycle of Leukocytes,False,Lifecycle of Leukocytes,,,,
+aed36b11-ccf1-4fc2-9cb2-40f0de154651,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Most leukocytes have a relatively short lifespan, typically measured in hours or days. Production of all leukocytes begins in the bone marrow under the influence of colony-stimulating factors (CSFs) and interleukins. Secondary production and maturation of lymphocytes occurs in specific regions of lymphatic tissue known as germinal centers. Lymphocytes are fully capable of mitosis and may produce clones of cells with identical properties. This capacity enables an individual to maintain immunity throughout life to many threats that have been encountered in the past.",True,Lifecycle of Leukocytes,,,,
+301e1994-ed3a-429c-a3f1-29813d96ab8e,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Disorders of Leukocytes,False,Disorders of Leukocytes,,,,
+b670dcf4-ae26-45f6-b359-db52f7760745,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Leukopenia is a condition in which too few leukocytes are produced. If this condition is pronounced, the individual may be unable to ward off disease. Excessive leukocyte proliferation is known as leukocytosis. Although leukocyte counts are high, the cells themselves are often nonfunctional, leaving the individual at increased risk for disease.",True,Disorders of Leukocytes,,,,
+a9bed099-29dd-4c7d-8355-9ffdfd814eae,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Leukemia is a cancer involving an abundance of leukocytes. It may involve only one specific type of leukocyte from either the myeloid line (myelocytic leukemia) or the lymphoid line (lymphocytic leukemia). In chronic leukemia, mature leukocytes accumulate and fail to die. In acute leukemia, there is an overproduction of young, immature leukocytes. In both conditions the cells do not function properly.",True,Disorders of Leukocytes,,,,
+193fa943-a8d0-4089-8177-0574b64ecf52,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Lymphoma is a form of cancer in which masses of malignant T and/or B lymphocytes collect in lymph nodes, the spleen, the liver, and other tissues. As in leukemia, the malignant leukocytes do not function properly, and the patient is vulnerable to infection. Some forms of lymphoma tend to progress slowly and respond well to treatment. Others tend to progress quickly and require aggressive treatment, without which they are rapidly fatal.",True,Disorders of Leukocytes,,,,
+f2e6921e-8d90-451d-81a7-9490c5ad1b99,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Platelets,False,Platelets,,,,
+e7b30914-aeac-4b48-a9b8-9b49a79d6159,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"You may occasionally see platelets referred to as thrombocytes, but because this name suggests they are a type of cell, it is not accurate. A platelet is not a cell but rather a fragment of the cytoplasm of a cell called a megakaryocyte that is surrounded by a plasma membrane. Megakaryocytes are descended from myeloid stem cells (see Chapter 18.2 Production of the Formed Elements) and are large, typically 50–100 µm in diameter, and contain an enlarged, lobed nucleus. As noted earlier, thrombopoietin, a glycoprotein secreted by the kidneys and liver, stimulates the proliferation of megakaryoblasts, which mature into megakaryocytes. These remain within bone marrow tissue (Figure 18.4.3) and ultimately form platelet-precursor extensions that extend through the walls of bone marrow capillaries to release into the circulation thousands of cytoplasmic fragments, each enclosed by a bit of plasma membrane. These enclosed fragments are platelets. Each megakarocyte releases 2000–3000 platelets during its lifespan. Following platelet release, megakaryocyte remnants, which are little more than a cell nucleus, are consumed by macrophages.",True,Platelets,Figure 18.4.3,18.4 Leukocytes and Platelets,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1908_Platelet_Development.jpg,Figure 18.4.3 – Platelets: Platelets are derived from cells called megakaryocytes.
+9ebb6be2-dcbb-4c77-b8ec-81daf9b3ea9a,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Platelets are relatively small, 2–4 µm in diameter, but numerous, with typically 150,000–160,000 per µL of blood. After entering the circulation, approximately one-third migrate to the spleen for storage for later release in response to any rupture in a blood vessel. They then become activated to perform their primary function, which is to limit blood loss. Platelets remain only about 10 days, then are phagocytized by macrophages.",True,Platelets,,,,
+4de50435-046f-4142-9498-2a9e903e001a,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Platelets are critical to hemostasis, the stoppage of blood flow following damage to a vessel. They also secrete a variety of growth factors essential for growth and repair of tissue, particularly connective tissue. Infusions of concentrated platelets are now being used in some therapies to stimulate healing.",True,Platelets,,,,
+ef271346-8827-4317-a299-c49a5f1dc30c,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,Disorders of Platelets,False,Disorders of Platelets,,,,
+2e74e85a-15f9-4672-931e-05a69f33265e,https://open.oregonstate.education/aandp/,18.4 Leukocytes and Platelets,https://open.oregonstate.education/aandp/chapter/18-4-leukocytes-and-platelets/,"Thrombocytosis is a condition in which there are too many platelets. This may trigger formation of unwanted blood clots (thrombosis), a potentially fatal disorder. If there is an insufficient number of platelets, called thrombocytopenia, blood may not clot properly, and excessive bleeding may result.",True,Disorders of Platelets,,,,
+d859e7dd-ef03-4ac4-acfa-69ad513b8035,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,Discuss the structure and function of erythrocytes (red blood cells) and hemoglobin,True,Disorders of Platelets,,,,
+937447af-b002-456c-8d4a-2f12c818d073,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"The erythrocyte, commonly known as a red blood cell (or RBC), is by far the most common formed element: A single drop of blood contains millions of erythrocytes and only thousands of leukocytes (Figure 18.3.1). Specifically, males have about 5.4 million erythrocytes per microliter (µL) of blood, and females have approximately 4.8 million per µL. In fact, erythrocytes are estimated to make up about 25 percent of the total cells in the body. They are small cells, with a mean diameter of 7–8 micrometers (µm). The primary function of erythrocytes is to pick up oxygen from the lungs and transport it to the body’s tissues, and to pick up carbon dioxide at the tissues and transport it to the lungs. Although leukocytes typically leave the blood vessels to perform their defensive functions, movement of erythrocytes from the blood vessels is abnormal.",True,Disorders of Platelets,Figure 18.3.1,18.3 Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1914_Table_19_3_1-scaled.jpg,Figure 18.3.1 Summary of Formed Elements in Blood
+cbc14d31-5408-4335-99c9-db16d0634d38,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,Shape and Structure of Erythrocytes,False,Shape and Structure of Erythrocytes,,,,
+4d5966d2-3c02-4e05-bd3a-90f76fb21b80,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"As an erythrocyte matures in the red bone marrow, it extrudes its nucleus and most of its other organelles. During the first day or two that it is in the circulation, an immature erythrocyte, known as a reticulocyte, will still typically contain remnants of organelles. Reticulocytes should comprise approximately 1–2 percent of the erythrocyte count and provide a rough estimate of the rate of RBC production. Abnormally low or high levels of reticulocytes indicate deviations in the production of these erythrocytes. These organelle remnants are quickly shed, so circulating erythrocytes have few internal cellular structural components. They lack endoplasmic reticula and do not synthesize proteins.",True,Shape and Structure of Erythrocytes,,,,
+530cd335-8433-4eee-9d9a-6f9bc07d0498,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"The erythrocytes’ function of transporting blood gases is complimented by their structure, such as their lack of organelles, particularly mitochondria, their biconcave shape, and the presence of a flexible cytoskeletal protein element called spectrin.  Since erythrocytes lack mitochondria and must rely on anaerobic metabolism, they do not utilize any of the oxygen they are transporting as they deliver it to the tissues. Erythrocytes are biconcave disks; that is, they are plump at their periphery and very thin in the center (Figure 18.3.2). Since they lack most organelles, there is more interior space for the presence of the hemoglobin molecules that, as you will see shortly, transport gases. The biconcave shape also provides a greater surface area across which gas exchange can occur, relative to its volume; a sphere of a similar diameter would have a lower surface area-to-volume ratio. In the capillaries, the oxygen carried by the erythrocytes can diffuse into the plasma and then through the capillary walls to reach the cells, whereas some of the carbon dioxide produced by the cells as a waste product diffuses into the capillaries to be picked up by the erythrocytes. Capillary beds are extremely narrow, slowing the passage of the erythrocytes and providing an extended opportunity for gas exchange to occur. However, the space within capillaries can be so small that, despite their own small size, erythrocytes travel in single-file and sometimes fold in on themselves to pass through. Fortunately, their structural proteins like spectrin, are flexible, allowing them to fold and then spring back again when they enter a wider vessel.",True,Shape and Structure of Erythrocytes,Figure 18.3.2,18.3 Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1903_Shape_of_Red_Blood_Cells.jpg,"Figure 18.3.2 – Shape of Red Blood Cells: Erythrocytes are biconcave discs with very shallow centers. This shape optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels."
+55db50ca-dd31-4ac9-8cab-32085803fdc4,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,Hemoglobin,False,Hemoglobin,,,,
+9bb81ad5-5a6f-40f5-9608-69ac040f4209,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Hemoglobin is a large molecule made up of proteins and iron. It consists of four folded chains of the protein globin, designated alpha 1 and 2, and beta 1 and 2 (Figure 18.3.3a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains an iron ion (Fe2+) (Figure 18.3.3b).",True,Hemoglobin,Figure 18.3.3,18.3 Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1904_Hemoglobin.jpg,"Figure 18.3.3 – Hemoglobin: (a) A molecule of hemoglobin contains four globin proteins, each of which is bound to one molecule of the iron-containing pigment heme. (b) A single erythrocyte can contain 300 million hemoglobin molecules, and thus more than 1 billion oxygen molecules."
+678a897f-2d3e-4d91-95de-9b6cd811492d,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Each iron ion in the heme can bind to one oxygen molecule, therefore, each hemoglobin molecule can transport four oxygen molecules. An individual erythrocyte may contain about 300 million hemoglobin molecules, and can bind to and transport up to 1.2 billion oxygen molecules.",True,Hemoglobin,,,,
+d729ec16-fb34-44b0-9e27-d6ec567c9020,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"In the lungs, hemoglobin picks up oxygen, which binds to the iron ions, forming oxyhemoglobin. The bright red, oxygenated hemoglobin travels to the capillaries of the body tissues, where it releases some of the oxygen molecules, becoming darker red deoxyhemoglobin. Oxygen release depends on the need for oxygen in the surrounding tissues, so hemoglobin rarely leaves all of its oxygen behind. At the time time, carbon dioxide (CO2) enters the bloodstream. About 76 percent of the CO2 dissolves in the plasma, some of it remaining as dissolved CO2, and the remainder forming bicarbonate (CO2 + H2O <==> H2CO3 <==> HCO3– + H+), where HCO3– is bicarbonate ion. About 23–24 percent of it binds to the amino acids in hemoglobin, forming a molecule known as carbaminohemoglobin. From the capillaries, the hemoglobin carries CO2 back to the lungs.",True,Hemoglobin,,,,
+7866843a-060b-49ea-8e89-00907f04ad67,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Changes in the levels of RBCs can have significant effects on the body’s ability to effectively deliver oxygen to the tissues. An overproduction of RBCs produces a condition called polycythemia. The primary drawback with polycythemia is not a failure to deliver enough oxygen to the tissues, but rather the increased viscosity of the blood, which makes it more difficult for the heart to circulate the blood. Ineffective hematopoiesis results in insufficient numbers of RBCs and results in one of several forms of anemia. In patients with insufficient hemoglobin, the tissues may not receive sufficient oxygen, resulting in another form of anemia.",True,Hemoglobin,,,,
+31798f41-320d-44ee-b313-040cd1dd4c22,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"In determining oxygenation of tissues, the value of greatest interest in healthcare is the percent saturation; that is, the percentage of hemoglobin sites occupied by oxygen in a patient’s blood. Clinically this value is commonly referred to simply as “percent sat.” Percent saturation is normally monitored using a device known as a pulse oximeter, which is applied to a thin part of the body, typically the tip of the patient’s finger. The device works by sending two different wavelengths of light (one red, the other infrared) through the finger and measuring the light with a photodetector as it exits. Hemoglobin absorbs light differentially depending upon its saturation with oxygen. The machine calibrates the amount of light received by the photodetector against the amount absorbed by the partially oxygenated hemoglobin and presents the data as percent saturation. Normal pulse oximeter readings range from 95–100 percent. Lower percentages reflect hypoxemia, or low blood oxygen. The term hypoxia is more generic and simply refers to low oxygen levels. Oxygen levels are also directly monitored from free oxygen in the plasma typically following an arterial stick. When this method is applied, the amount of oxygen present is expressed in terms of partial pressure of oxygen or simply pO2 and is typically recorded in units of millimeters of mercury, mm Hg.",True,Hemoglobin,,,,
+1db2397b-ee12-4ed8-8bed-9eb524c14b54,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Receptors for oxygenation saturation are found in the kidneys, which is an ideal site to monitor saturation, since the kidneys filter about 180 liters (~380 pints) of blood in an average adult each day. In response to hypoxemia, less oxygen is diffused into the kidney, resulting in hypoxia of the kidney cells where oxygen concentration is actually monitored. Interstitial fibroblasts within the kidney secrete erythropoietin (EPO), leading to increased erythrocyte production and eventually restoring oxygen levels. In a negative-feedback loop, as oxygen saturation rises, EPO secretion falls, and vice versa, thereby maintaining homeostasis. Populations dwelling at high elevations, with inherently lower levels of oxygen in the atmosphere, naturally maintain a hematocrit higher than people living at sea level. Consequently, people traveling to high elevations may experience symptoms of hypoxemia, such as fatigue, headache, and shortness of breath, for a few days after their arrival. In response to the hypoxemia, the kidneys secrete EPO to step up the production of erythrocytes until homeostasis is achieved once again. To avoid the symptoms of hypoxemia, or altitude sickness, mountain climbers typically rest for several days to a week or more at a series of camps situated at increasing elevations to allow EPO levels and, consequently, erythrocyte counts to rise. When climbing the tallest peaks, such as Mt. Everest and K2 in the Himalayas, many mountain climbers rely upon bottled oxygen as they near the summit.",True,Hemoglobin,,,,
+308c9f29-9c8b-482f-933c-3dba0f18e37e,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,Lifecycle of Erythrocytes,False,Lifecycle of Erythrocytes,,,,
+4975ac06-035d-4b79-8e52-396bca9e6c36,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Production of erythrocytes in the marrow occurs at the staggering rate of more than 2 million cells per second. For this production to occur, a number of raw materials must be present in adequate amounts. These include the same nutrients that are essential to the production and maintenance of any cell, such as glucose, lipids, and amino acids. However, erythrocyte production also requires several trace elements:",True,Lifecycle of Erythrocytes,,,,
+59bc9280-c431-4aaf-86a6-68463eab668a,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Erythrocytes live up to 120 days in the circulation, after which the worn-out cells are removed by a type of myeloid phagocytic cell called a macrophage, located primarily within the bone marrow, liver, and spleen. The components of the degraded erythrocytes’ hemoglobin are further processed as follows:",True,Lifecycle of Erythrocytes,,,,
+6fec579b-541f-45f8-91f3-5258df1c6c2e,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"The breakdown pigments formed from the destruction of hemoglobin can be seen in a variety of situations. At the site of an injury, green biliverdin from damaged RBCs produces some of the dramatic colors associated with bruising. With a failing liver, bilirubin cannot be removed effectively from circulation and causes the body to assume a yellowish tinge associated with jaundice. Stercobilins within the feces produce the typical brown color associated with this waste. And the yellow of urine is associated with the urobilins.",True,Lifecycle of Erythrocytes,,,,
+3722881c-134c-4634-983d-caf8a27c9616,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,The erythrocyte lifecycle is summarized in Figure 18.3.4.,True,Lifecycle of Erythrocytes,Figure 18.3.4,18.3 Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1905_Erythrocyte_Life_Cycle-scaled.jpg,"Figure 18.3.4 – Erythrocyte Lifecycle: Erythrocytes are produced in the bone marrow and sent into the circulation. At the end of their lifecycle, they are destroyed by macrophages, and their components are recycled."
+5de1b41b-06c5-4f64-8ee7-0fd70ff3f08d,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,Disorders of Erythrocytes,False,Disorders of Erythrocytes,,,,
+ef376ecb-2add-4548-aa53-144ac546e81e,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"The size, shape, and number of erythrocytes, and the number of hemoglobin molecules can have a major impact on a person’s health. When the number of RBCs or hemoglobin is deficient, the general condition is called anemia. There are more than 400 types of anemia and more than 3.5 million Americans suffer from this condition. Anemia can be broken down into three major groups: those caused by blood loss, those caused by faulty or decreased RBC production, and those caused by excessive destruction of RBCs. Clinicians often use two groupings in diagnosis: The kinetic approach focuses on evaluating the production, destruction, and removal of RBCs, whereas the morphological approach examines the RBCs themselves, paying particular emphasis to their size. A common test is the mean corpuscle volume (MCV), which measures size. Normal-sized cells are referred to as normocytic, smaller-than-normal cells are referred to as microcytic, and larger-than-normal cells are referred to as macrocytic. Reticulocyte counts are also important and may reveal inadequate production of RBCs. The effects of the various anemias are widespread, because reduced numbers of RBCs or hemoglobin will result in lower levels of oxygen being delivered to body tissues. Since oxygen is required for tissue functioning, anemia produces fatigue, lethargy, and an increased risk for infection. An oxygen deficit in the brain impairs the ability to think clearly, and may prompt headaches and irritability. Lack of oxygen leaves the patient short of breath, even as the heart and lungs work harder in response to the deficit.",True,Disorders of Erythrocytes,,,,
+d816bbf2-fb9f-4548-9ac6-54f74bf8a5b5,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Blood loss anemias are fairly straightforward. In addition to bleeding from wounds or other lesions, these forms of anemia may be due to ulcers, hemorrhoids, inflammation of the stomach (gastritis), and some cancers of the gastrointestinal tract. The excessive use of aspirin or other nonsteroidal anti-inflammatory drugs such as ibuprofen can trigger ulceration and gastritis. Excessive menstruation and loss of blood during childbirth are also potential causes.",True,Disorders of Erythrocytes,,,,
+bca3dcc0-a717-4d2c-be05-dcee118c5f6e,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"Anemias caused by faulty or decreased RBC production include sickle cell anemia, iron deficiency anemia, vitamin deficiency anemia, and diseases of the bone marrow and stem cells.",True,Disorders of Erythrocytes,,,,
+ce9281b8-3f7c-4bb2-9c68-f4c5982942a9,https://open.oregonstate.education/aandp/,18.3 Erythrocytes,https://open.oregonstate.education/aandp/chapter/18-3-erythrocytes/,"In contrast to anemia, an elevated RBC count is called polycythemia and is detected in a patient’s elevated hematocrit. It can occur transiently in a person who is dehydrated; when water intake is inadequate or water losses are excessive, the plasma volume falls. As a result, the hematocrit rises. For reasons mentioned earlier, a mild form of polycythemia is chronic but normal in people living at high altitudes. Some elite athletes train at high elevations specifically to induce this phenomenon. Finally, a type of bone marrow disease called polycythemia vera (from the Greek vera = “true”) causes an excessive production of immature erythrocytes. Polycythemia vera can dangerously elevate the viscosity of blood, raising blood pressure and making it more difficult for the heart to pump blood throughout the body. It is a relatively rare disease that occurs more often in men than women, and is more likely to be present in elderly patients those over 60 years of age.",True,Disorders of Erythrocytes,,,,
+cb4e6c06-89fd-4034-97d3-480a53912206,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Describe the formation of the formed element components of blood,False,Describe the formation of the formed element components of blood,,,,
+4546a612-6002-45bb-9ba4-4e7e7fa14fa8,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"The lifespan of the formed elements is very brief. Although one type of leukocyte called memory cells can survive for years, most erythrocytes, leukocytes, and platelets normally live only a few hours to a few weeks. Thus, the body must form new blood cells and platelets quickly and continuously. If you donate a unit of blood during a blood drive (approximately 475 mL, or about 1 pint), your body typically replaces the donated plasma within 24 hours, but it takes about 4 to 6 weeks to replace the blood cells. This restricts the frequency with which donors can contribute their blood. The process by which this replacement occurs is called hemopoiesis, or hematopoiesis (from the Greek root haima- = “blood”; -poiesis = “production”).",True,Describe the formation of the formed element components of blood,,,,
+59f205bc-3922-4026-ac48-59d6675fd028,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Sites of Hemopoiesis,False,Sites of Hemopoiesis,,,,
+5392d1f5-ef49-41bb-9080-c19f19bf9516,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"Prior to birth, hemopoiesis occurs in a number of tissues, beginning with the yolk sac of the developing embryo, and continuing in the fetal liver, spleen, lymphatic tissue, and eventually the red bone marrow. Following birth, most hemopoiesis occurs in the red marrow, a connective tissue within the spaces of spongy (cancellous) bone tissue. In children, hemopoiesis can occur in the medullary cavity of long bones; in adults, the process is largely restricted to the cranial and pelvic bones, the vertebrae, the sternum, and the proximal epiphyses of the femur and humerus.",True,Sites of Hemopoiesis,,,,
+940c2cd6-f125-4878-a35b-fa2ac203f1e5,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"Throughout adulthood, the liver and spleen maintain their ability to generate the formed elements. This process is referred to as extramedullary hemopoiesis (meaning hemopoiesis outside the medullary cavity of adult bones). When a disease such as bone cancer destroys the bone marrow, causing hemopoiesis to fail, extramedullary hemopoiesis may be initiated.",True,Sites of Hemopoiesis,,,,
+930546ba-bc48-40fe-a1b3-9ce63da96337,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Differentiation of Formed Elements from Stem Cells,False,Differentiation of Formed Elements from Stem Cells,,,,
+80ec4c42-1cd6-4c79-94ff-b74b22b8f6a4,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"All formed elements arise from stem cells of the red bone marrow. Recall that stem cells undergo mitosis plus cytokinesis (cellular division) to give rise to new daughter cells. One of these daughter cells remains a stem cell and the other differentiates into one of any number of diverse cell types. Stem cells may be viewed as occupying a hierarchal system, with some loss of the ability to diversify at each step. The totipotent stem cell is the zygote, or fertilized egg. The totipotent (toti- = “all”) stem cell gives rise to all cells of the human body. The next level is the pluripotent stem cell, which gives rise to multiple types of cells of the body and some of the supporting fetal membranes. Beneath this level, the mesenchymal cell is a stem cell that develops only into types of connective tissue, including fibrous connective tissue, bone, cartilage, and blood, but not epithelium, muscle, and nervous tissue. One step lower on the hierarchy of stem cells is the hemopoietic stem cell, or hemocytoblast. All of the formed elements of blood originate from this specific type of cell.",True,Differentiation of Formed Elements from Stem Cells,,,,
+f6746a42-73e6-49d9-922b-c4088e5fcd02,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"Hemopoiesis begins when the hemopoietic stem cell is exposed to appropriate chemical stimuli collectively called hemopoietic growth factors, which prompt it to divide and differentiate. One daughter cell remains a hemopoietic stem cell, allowing hemopoiesis to continue. The other daughter cell becomes either of two types of more specialized stem cells (Figure 18.2.1):",True,Differentiation of Formed Elements from Stem Cells,Figure 18.2.1,18.2 Production of the Formed Elements,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2204_The_Hematopoietic_System_of_the_Bone_Marrow_new.jpg,"Figure 18.2.1. Hematopoietic System of Bone Marrow. Hemopoiesis is the proliferation and differentiation of the formed elements of blood. Lymphoid stem cells give rise to lymphocytes including T cells, B cells, and natural killer (NK) cells. Myeloid stem cells give rise to all the other formed elements."
+fcb69648-6043-417e-b9dc-295f8891eff9,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"Lymphoid and myeloid stem cells do not immediately divide and differentiate into mature formed elements. As you can see in Figure 1, there are several intermediate stages of precursor cells, many of which can be recognized by their names, which have the suffix -blast. For instance, megakaryoblasts are the precursors of megakaryocytes, and proerythroblasts become reticulocytes, which eject their nucleus and most other organelles before maturing into erythrocytes.",True,Differentiation of Formed Elements from Stem Cells,,,,
+dd29f6af-8ff0-44f8-af7a-e5a22bab832e,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Hemopoietic Growth Factors,False,Hemopoietic Growth Factors,,,,
+17f25194-e6c1-4485-9d70-3435c253d73e,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Development from stem cells to precursor cells to mature cells is initiated by hemopoietic growth factors. These include the following:,True,Hemopoietic Growth Factors,,,,
+12914987-77b4-4623-8ad7-a1e43aecbfd3,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,Bone Marrow Sampling and Transplants,False,Bone Marrow Sampling and Transplants,,,,
+b8bf6d8b-93fd-44b6-8e78-3e93bd684c0a,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"For certain medical conditions a healthcare provider could order a bone marrow biopsy, a diagnostic test of a sample of red bone marrow, or a bone marrow transplant, a treatment in which a donor’s healthy bone marrow—and its stem cells—replaces the faulty or damaged bone marrow of a patient. These tests and procedures are often used to assist in the diagnosis and treatment of various severe forms of anemia, such as thalassemia major and sickle cell anemia, as well as some types of cancer, specifically leukemia.",True,Bone Marrow Sampling and Transplants,,,,
+4624900f-1b75-4712-a906-33d16aca6b19,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"In the past, when a bone marrow sample or transplant was necessary, the procedure would have required inserting a large-bore needle into the region near the iliac crest of the pelvic bones. This location was preferred, since its location close to the body surface makes it more accessible, and it is relatively isolated from most vital organs. Unfortunately, the procedure is quite painful.",True,Bone Marrow Sampling and Transplants,,,,
+0f181c43-d2e2-4966-892e-909fce8b196e,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"Now, direct sampling of bone marrow can often be avoided. In many cases, stem cells can be isolated in just a few hours from a sample of a patient’s blood. The isolated stem cells are then grown in culture using the appropriate hemopoietic growth factors, and analyzed or sometimes frozen for later use.",True,Bone Marrow Sampling and Transplants,,,,
+fdc3a10a-c5c9-4055-9c7f-b2c13d6ecf6b,https://open.oregonstate.education/aandp/,18.2 Production of the Formed Elements,https://open.oregonstate.education/aandp/chapter/18-2-production-of-the-formed-elements/,"For an individual requiring a transplant, a matching donor is essential to prevent the immune system from destroying the donor cells—a phenomenon known as tissue rejection. To treat patients with bone marrow transplants, it is first necessary to destroy the patient’s own diseased marrow through radiation and/or chemotherapy. Donor bone marrow stem cells are then intravenously infused. From the bloodstream, they establish themselves in the recipient’s bone marrow.",True,Bone Marrow Sampling and Transplants,,,,
+d10aad13-1bff-4676-820f-0539a2bd9593,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Identify the primary functions of blood, its fluid and cellular components, and its characteristics",True,Bone Marrow Sampling and Transplants,,,,
+3aa82023-9430-4d97-ab22-b98917c980e9,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Recall that blood is a connective tissue. Like all connective tissues, it is made up of cellular elements and an extracellular matrix. The cellular elements—referred to as the formed elements—include red blood cells (RBCs), white blood cells (WBCs), and cell fragments called platelets. The extracellular matrix, called plasma, makes blood unique among connective tissues because it is fluid. This fluid, which is mostly water, suspends the formed elements and enables them to circulate throughout the body within the cardiovascular system.",True,Bone Marrow Sampling and Transplants,,,,
+99a19237-d988-422f-a2ca-f40966e71039,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Functions of Blood,False,Functions of Blood,,,,
+2e0bd3b3-19f7-4447-af21-bc20faf07a73,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"The primary function of blood is to deliver oxygen and nutrients to, and remove wastes from, the body cells; but that is only the beginning of the story. The specific functions of blood also include defense, and maintenance of homeostasis, such as distributing heat where it is needed.",True,Functions of Blood,,,,
+cd58ae62-2b66-41d7-bd6a-847ec4560956,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Composition of Blood,False,Composition of Blood,,,,
+35e364d9-51b9-4866-b242-ce53915500b3,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"If you have had a blood test, it was likely drawn from a superficial vein in your arm, which was then sent to a lab for analysis. Some of the most common blood tests—for instance, those measuring lipid or glucose levels in plasma—determine which substances are present within blood and in what quantities. Other blood tests check for the composition of the blood itself, including the quantities and types of formed elements.",True,Composition of Blood,,,,
+766fdf27-fb7d-4b96-8f77-3b7567d1b6fd,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"One such test examines hematocrit, which measures the percentage of RBCs (erythrocytes) in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.1.1). Because the densest elements in blood are the erythrocytes, these settle at the bottom of the hematocrit tube. Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs (leukocytes) and the platelets (thrombocytes). This layer is referred to as the buffy coat, and it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, straw-colored fluid, which constitutes the remainder of the sample.",True,Composition of Blood,Figure 18.1.1,18.1 Functions of Blood,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1901_Composition_of_Blood.jpg,"Figure 18.1.1. Composition of Blood: The cellular elements of blood include a vast number of erythrocytes and comparatively fewer leukocytes and platelets. Plasma is the fluid in which the formed elements are suspended. A sample of blood spun in a centrifuge reveals that plasma is the least dense component. It floats at the top of the tube separated from the densest elements, the erythrocytes, which are separated by a buffy coat of leukocytes and platelets. Hematocrit is the percentage of the total sample that is comprised of erythrocytes. Depressed and elevated hematocrit levels are shown for comparison."
+fef4a08c-0d1b-42ad-998e-bebcddca43f7,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"The volume of erythrocytes after centrifugation is also commonly referred to as packed cell volume. Typically, blood contains about 45 percent erythrocytes, however, samples can vary significantly from about 36–50 percent. Normal hematocrit values for females range from 37 to 47%, with a mean value of 41%; for males, hematocrit ranges from 42 to 52%, with a mean of 47%. The percentage of other formed elements, the WBCs and platelets, is extremely small so it is not normally considered with the hematocrit. Therefore, the mean plasma percentage is the percent of blood that is not erythrocytes: for females, approximately 59% (or 100 minus 41), and for males, approximately 53% (or 100 minus 47).",True,Composition of Blood,,,,
+a3dded94-d31c-44c9-b7f7-92ff8bb0f71f,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Characteristics of Blood,False,Characteristics of Blood,,,,
+a53fec77-8b78-455a-885f-05396f4736c2,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"When you think about blood, the first characteristic that probably comes to mind is its color. Blood that has just taken up oxygen in the lungs is bright red, and blood that has released oxygen in the tissues is a darker red. This is because hemoglobin is a pigment that changes color, depending upon the degree of oxygen saturation.",True,Characteristics of Blood,,,,
+f59e011a-4b75-4b71-abb3-b404d8612144,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Blood is viscous, with a viscosity approximately five times greater than water. Viscosity is a measure of a fluid’s thickness or resistance to flow, and is influenced by the presence of the plasma proteins and formed elements within the blood. The viscosity of blood has a dramatic impact on blood pressure and flow. Consider the difference in flow between water and honey. The more viscous honey would demonstrate a greater resistance to flow than the less viscous water. The same principle applies to blood.  Blood viscosity is inversely proportional to hydration; the more hydrated you are, the less viscous your blood becomes. In severely dehydrated individuals, blood can become excessively viscous sometimes resulting in infarction or other cardiovascular events.",True,Characteristics of Blood,,,,
+ad7ce8cf-583c-486a-937c-da9efc588426,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"The normal temperature of blood is slightly higher than normal body temperature—about 38 °C (or 100.4 °F), compared to 37 °C (or 98.6 °F) for an internal body temperature reading. Although the surface of a blood vessel is relatively smooth, blood experiences friction and resistance to its flow. This produces heat, accounting for the slightly higher temperature of blood.",True,Characteristics of Blood,,,,
+03e84665-e153-45e6-82d4-a54ac33f111a,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"The pH of blood averages about 7.4; however, it can range from 7.35 to 7.45 in a healthy person. Blood is therefore somewhat more basic (alkaline) on a chemical scale than pure water, which has a pH of 7.0. Blood contains numerous buffers that help to regulate pH.",True,Characteristics of Blood,,,,
+67b343f4-32f4-479a-80ba-e41acf9ae142,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Blood constitutes approximately 8 percent of adult body weight. Adult males typically average about 5-6 liters of blood, and females average 4–5 liters.",True,Characteristics of Blood,,,,
+20273f15-adee-4172-8f1d-e9a381f8884b,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Blood Plasma,False,Blood Plasma,,,,
+b30d421b-4aa1-40f0-b946-5d23506710fa,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Plasma is 92% water. Dissolved or suspended within this water is a mixture of substances, most of which are proteins. There are hundreds of substances dissolved in the plasma, although many of them are found only in very small quantities.",True,Blood Plasma,,,,
+5c624bbe-32b6-459f-8ef4-14b13869e00a,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Phlebotomists are professionals trained to draw blood (phleb- = “a blood vessel”; -tomy = “to cut”). When more than a few drops of blood are required, phlebotomists perform a venipuncture, typically of a surface vein in the arm. They perform a capillary stick on a finger, an earlobe, or the heel of an infant when only a small quantity of blood is required. An arterial stick is collected from an artery and used to analyze blood gases. After collection, the blood may be analyzed by medical laboratories or perhaps used for transfusions, donations, or research. While many allied health professionals practice phlebotomy, the American Society of Phlebotomy Technicians issues certificates to individuals passing a national examination, and some large labs and hospitals hire individuals expressly for their skill in phlebotomy.",True,Blood Plasma,,,,
+7d8110bf-69c1-465e-9b47-e23ce2e20ed6,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Medical or clinical laboratories employ a variety of individuals in technical positions:,True,Blood Plasma,,,,
+836c9749-9ea1-4289-8cbb-5c8d3a58266e,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Medical technologists (MT), also known as clinical laboratory technologists (CLT), typically hold a bachelor’s degree and certification from an accredited training program. They perform a wide variety of tests on various body fluids, including blood. The information they provide is essential to the primary care providers in determining a diagnosis and in monitoring the course of a disease and response to treatment.",True,Blood Plasma,,,,
+98398381-b4aa-4b4e-b2a6-6489e70c2e1d,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,Medical laboratory technicians (MLT) typically have an associate’s degree but may perform duties similar to those of an MT.,True,Blood Plasma,,,,
+ec0fdb51-b601-42b5-ba17-3791154af41a,https://open.oregonstate.education/aandp/,18.1 Functions of Blood,https://open.oregonstate.education/aandp/chapter/18-1-functions-of-blood/,"Medical laboratory assistants (MLA) spend the majority of their time processing samples and carrying out routine assignments within the lab. Clinical training is required, but a degree may not be essential to obtaining a position.",True,Blood Plasma,,,,
+44e5467d-7148-476e-92e1-a707a77be929,https://open.oregonstate.education/aandp/,18.0 Introduction,https://open.oregonstate.education/aandp/chapter/18-0-introduction/,"Single-celled organisms do not need blood. They obtain nutrients directly from and excrete wastes directly into their environment. The human organism cannot do that. Our large, complex bodies need blood to deliver nutrients to and remove wastes from our trillions of cells. The heart pumps blood throughout the body in a network of blood vessels. Together, these three components—blood, heart, and vessels—makes up the cardiovascular system. This chapter focuses on the medium of transport: blood.",True,Blood Plasma,,,,
+79e46118-8084-4e1b-af20-0570309b80f7,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"The endocrine system arises from all three embryonic germ layers. The endocrine glands that produce the steroid hormones, such as the gonads and adrenal cortex, arise from the mesoderm. In contrast, endocrine glands that arise from the endoderm and ectoderm produce the amine, peptide, and protein hormones. The pituitary gland arises from two distinct areas of the ectoderm: the anterior pituitary gland arises from the oral ectoderm, whereas the posterior pituitary gland arises from the neural ectoderm at the base of the hypothalamus. The pineal gland also arises from the ectoderm. The two structures of the adrenal glands arise from two different germ layers: the adrenal cortex from the mesoderm and the adrenal medulla from ectoderm neural cells. The endoderm gives rise to the thyroid and parathyroid glands, as well as the pancreas and the thymus.",True,Blood Plasma,,,,
+06891e3f-e154-4701-bbda-3795233056e3,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"As the body ages, changes occur that affect the endocrine system, sometimes altering the production, secretion, and catabolism of hormones. For example, the structure of the anterior pituitary gland changes as vascularization decreases and the connective tissue content increases with increasing age. This restructuring affects the gland’s hormone production. For example, the amount of human growth hormone that is produced declines with age, resulting in the reduced muscle mass commonly observed in the elderly.",True,Blood Plasma,,,,
+01ca3169-fcf9-4563-a233-3ec8fffa2986,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"The adrenal glands also undergo changes as the body ages; as fibrous tissue increases, the production of cortisol and aldosterone decreases. Interestingly, the production and secretion of epinephrine and norepinephrine remain normal throughout the aging process.",True,Blood Plasma,,,,
+2b3d4616-9eb1-4af7-81b2-0e114ea4cc21,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"A well-known example of the aging process affecting an endocrine gland is menopause and the decline of ovarian function. With increasing age, the ovaries decrease in both size and weight and become progressively less sensitive to gonadotropins. This gradually causes a decrease in estrogen and progesterone levels, leading to menopause and the inability to reproduce. Low levels of estrogens and progesterone are also associated with some disease states, such as osteoporosis, atherosclerosis, and hyperlipidemia, or abnormal blood lipid levels.",True,Blood Plasma,,,,
+3e36881f-d29b-4d43-aeb7-63d6d2fd6bd0,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"Testosterone levels also decline with age, a condition called andropause (or viropause); however, this decline is much less dramatic than the decline of estrogens in women, and much more gradual, rarely affecting sperm production until very old age. Although this means that males maintain their ability to father children for decades longer than females, the quantity, quality, and motility of their sperm is often reduced.",True,Blood Plasma,,,,
+3543ee66-fa04-4e87-8ba6-03aa2fdd59cd,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"As the body ages, the thyroid gland produces less of the thyroid hormones, causing a gradual decrease in the basal metabolic rate. The lower metabolic rate reduces the production of body heat and increases levels of body fat. Parathyroid hormones, on the other hand, increase with age. This may be because of reduced dietary calcium levels, causing a compensatory increase in parathyroid hormone. However, increased parathyroid hormone levels combined with decreased levels of calcitonin (and estrogens in women) can lead to osteoporosis as PTH stimulates demineralization of bones to increase blood calcium levels. Notice that osteoporosis is common in both elderly males and females.",True,Blood Plasma,,,,
+8012d445-b67a-46e9-9ce8-51a9f8a52200,https://open.oregonstate.education/aandp/,17.11 Development and Aging of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-11-development-and-aging-of-the-endocrine-system/,"Increasing age also affects glucose metabolism, as blood glucose levels spike more rapidly and take longer to return to normal in the elderly. In addition, increasing glucose intolerance may occur because of a gradual decline in cellular insulin sensitivity. Almost 27 percent of Americans aged 65 and older have diabetes.",True,Blood Plasma,,,,
+35ed275c-d463-4c51-b04a-6e089ddb5076,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"Describe the hormones produced by organs with secondary endocrine functions, and their effects",True,Blood Plasma,,,,
+cbf3915d-a859-4964-9f38-8bf9abf43c15,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"In your study of anatomy and physiology, you have already encountered a few of the many organs of the body that have secondary endocrine functions. Here, you will learn about the hormone-producing activities of the heart, gastrointestinal tract, kidneys, skeleton, adipose tissue, skin, and thymus.",True,Blood Plasma,,,,
+9c727478-35ef-4c54-b183-e9da7d7631b0,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Heart,False,Heart,,,,
+98ecd65a-798c-48f1-bf27-87dd4af74501,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"When the body experiences an increase in blood volume or pressure, the cells of the heart’s atrial wall stretch. In response, specialized cells in the wall of the atria produce and secrete the peptide hormone atrial natriuretic peptide (ANP). ANP signals the kidneys to reduce sodium reabsorption, thereby decreasing the amount of water reabsorbed from the urine filtrate and reducing blood volume. Other actions of ANP include inhibition of vasodilation and the inhibition of renin secretion and of the renin-angiotensin-aldosterone system (RAAS). Therefore, ANP aids in decreasing blood pressure, blood volume, and blood sodium levels.",True,Heart,,,,
+b9c9aedc-21f4-4764-88e1-42983ba2dfb8,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Gastrointestinal Tract,False,Gastrointestinal Tract,,,,
+8ba883b7-0cba-4472-944d-4174ecaea8f8,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"The endocrine cells of the GI tract (also referred to as enteroendocrine cells) are located in the mucosa of the stomach and small intestine. Some of these hormones are secreted in response to eating a meal and aid in digestion. An example of a hormone secreted by the stomach cells is gastrin, a peptide hormone secreted in response to stomach distention that stimulates the release of hydrochloric acid. Secretin is a peptide hormone secreted by the small intestine as acidic chyme (partially digested food and fluid) moves from the stomach. It stimulates the release of bicarbonate from the pancreas, which buffers the acidic chyme, and inhibits the further secretion of hydrochloric acid by the stomach. Cholecystokinin (CCK) is another peptide hormone released from the small intestine. It promotes the secretion of pancreatic enzymes and the release of bile from the gallbladder, both of which facilitate digestion. Other hormones produced by the intestinal cells aid in glucose metabolism, such as by stimulating the pancreatic beta cells to secrete insulin, reducing glucagon secretion from the alpha cells, or enhancing cellular sensitivity to insulin.",True,Gastrointestinal Tract,,,,
+0d68d431-643d-4d1c-a683-afef56a0b7f5,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Kidneys,False,Kidneys,,,,
+a521019f-e7e8-4d33-b5a3-ecb993e368ba,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"The kidneys participate in several complex endocrine pathways and produce certain hormones. A decline in blood flow to the kidneys stimulates them to release the enzyme renin, triggering the renin-angiotensin-aldosterone (RAAS) system, and stimulating the reabsorption of sodium and water. The reabsorption increases blood flow and blood pressure. The kidneys also play a role in regulating blood calcium levels through the production of calcitriol from vitamin D3, which is released in response to the secretion of parathyroid hormone (PTH). In addition, the kidneys produce the hormone erythropoietin (EPO) in response to low oxygen levels. EPO stimulates the production of red blood cells (erythrocytes) in the bone marrow, thereby increasing oxygen delivery to tissues. You may have heard of EPO as a performance-enhancing drug (in a synthetic form).",True,Kidneys,,,,
+0bdbc2be-bad6-442c-8391-c0b6ae6a60a7,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Skeleton,False,Skeleton,,,,
+fe3e69a0-af8c-4ce0-80f2-1f27b3820bd3,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"Although bone has long been recognized as a target for hormones, only recently have researchers recognized that the skeleton itself produces at least two hormones. Fibroblast growth factor 23 (FGF23) is produced by bone cells in response to increased blood levels of vitamin D3 or phosphate. It triggers the kidneys to inhibit the formation of calcitriol from vitamin D3 and to increase phosphorus excretion. Osteocalcin, produced by osteoblasts, stimulates the pancreatic beta cells to increase insulin production. It also acts on peripheral tissues to increase their sensitivity to insulin and their utilization of glucose.",True,Skeleton,,,,
+77acf5dc-3ea5-45b7-b2c0-b694328ccf3e,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Adipose Tissue,False,Adipose Tissue,,,,
+949edc46-cd20-4c0d-8c47-02bf14766305,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"Adipose tissue produces and secretes several hormones involved in lipid metabolism and storage. One important example is leptin, a protein manufactured by adipose cells that circulates in amounts directly proportional to levels of body fat. Leptin is released in response to food consumption and acts by binding to brain neurons involved in energy intake and expenditure. Binding of leptin produces a feeling of satiety after a meal, thereby reducing appetite. It also appears that the binding of leptin to brain receptors triggers the sympathetic nervous system to regulate bone metabolism. Adiponectin—another hormone synthesized by adipose cells—appears to reduce cellular insulin resistance and to protect blood vessels from inflammation and atherosclerosis. Its levels are lower in people who are obese, and rise following weight loss.",True,Adipose Tissue,,,,
+ede3b013-2e8f-4765-a8e6-61fda8fd4937,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Skin,False,Skin,,,,
+fc6c4d46-446b-448c-9928-966aa8cbc73a,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"The skin functions as an endocrine organ in the production of the inactive form of vitamin D3, cholecalciferol. When cholesterol present in the epidermis is exposed to ultraviolet radiation, it is converted to cholecalciferol, which then enters the blood. In the liver, cholecalciferol is converted to an intermediate that travels to the kidneys and is further converted to calcitriol, the active form of vitamin D3. Calcitriol is important in a variety of physiological processes, including intestinal calcium absorption and immune system function. In some studies, low levels of calcitriol have been associated with increased risks of cancer, severe asthma, and multiple sclerosis. Calcitriol deficiency in children causes rickets, and in adults, osteomalacia—both of which are characterized by bone deterioration.",True,Skin,,,,
+6aa44f60-e21d-4070-8bec-2389a40f760a,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Thymus,False,Thymus,,,,
+d61e36a4-d1c8-4151-a4e6-88ba1092faec,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"The thymus is an organ of the immune system that is larger and more active during infancy and early childhood, and begins to atrophy as we age. Its endocrine function is the production of a group of hormones called thymosins that contribute to the development and differentiation of T lymphocytes, which are immune cells. Although the role of thymosins is not yet well understood, it is clear that they contribute to the immune response. Thymosins have been found in tissues other than the thymus and have a wide variety of functions, so the thymosins cannot be strictly categorized as thymic hormones.",True,Thymus,,,,
+ada35f93-5902-477b-b136-55cc5fe353b1,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,Liver,False,Liver,,,,
+c1cd38d7-82fa-4186-8f15-2e1d2f2ebbc2,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,"The liver is responsible for secreting at least four important hormones or hormone precursors: insulin-like growth factor (somatomedin), angiotensinogen, thrombopoetin, and hepcidin. Insulin-like growth factor-1 is the immediate stimulus for growth in the body, especially of the bones. Angiotensinogen is the precursor to angiotensin, mentioned earlier, which increases blood pressure. Thrombopoetin stimulates the production of the blood’s platelets. Hepcidins block the release of iron from cells in the body, helping to regulate iron homeostasis in our body fluids.",True,Liver,,,,
+a30e9e1a-7e9f-4d7a-9686-1e0995738842,https://open.oregonstate.education/aandp/,17.10 Organs with Secondary Endocrine Functions,https://open.oregonstate.education/aandp/chapter/17-10-organs-with-secondary-endocrine-functions/,The major hormones discussed above are summarized in Table 17.8.,True,Liver,,,,
+2ac8010d-86e9-4b7e-bff1-6459879ec653,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,Explain the role of the pancreatic endocrine cells in the regulation of blood glucose,True,Liver,,,,
+a0440ffa-dbdd-48c2-8a5c-b2d58c68ad4c,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,"The pancreas is a long, slender organ, most of which is located posterior to the bottom half of the stomach (Figure 17.9.1). Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas also has endocrine cells. Its pancreatic islets—clusters of cells formerly known as the islets of Langerhans—secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide (PP).",True,Liver,Figure 17.9.1,17.9 The Pancreas,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1820_The_Pancreas.jpg,Figure 17.9.1 – Pancreas   Pancreas endocrine function involves the secretion of insulin (produced by beta cells) and glucagon (produced by alpha cells) within the pancreatic islets. These two hormones regulate the rate of glucose metabolism in the body. The micrograph reveals pancreatic islets. LM × 760. Also shown are the exocrine acinar cells. (Micrograph provided by the Regents of University of Michigan Medical School © 2012.
+777b8b33-154f-4ad5-aefd-cbd1127c17c0,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,Cells and Secretions of the Pancreatic Islets,False,Cells and Secretions of the Pancreatic Islets,,,,
+d00761b6-9450-4cd2-8270-4e183d94e1bf,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,The pancreatic islets each contain four varieties of cells:,False,The pancreatic islets each contain four varieties of cells:,,,,
+f1f3208d-619e-44c6-ab9c-0e4c2de233b3,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,Regulation of Blood Glucose Levels by Insulin and Glucagon,False,Regulation of Blood Glucose Levels by Insulin and Glucagon,,,,
+1e73b1bd-b3a0-4e95-b75b-4ed694150732,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,"Glucose is utilized in cellular respiration as a fuel for cells of the body. The body derives glucose from the breakdown of the carbohydrate-containing foods and drinks we consume. Glucose not immediately taken up by cells for fuel can be stored by the liver and muscles as glycogen, or converted to triglycerides and stored in the adipose tissue. Hormones regulate both the storage and the utilization of glucose as required. Receptors located in the pancreas sense blood glucose levels, and subsequently the pancreatic cells secrete glucagon or insulin to maintain appropriate blood glucose.",True,Regulation of Blood Glucose Levels by Insulin and Glucagon,,,,
+3052533e-2677-49d1-a147-1c65e9d4ef69,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,diabetes mellitus,False,diabetes mellitus,,,,
+e24503ac-3037-4ce5-b665-7bc69176628d,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,hyperglycemia,False,hyperglycemia,,,,
+cfeb3e8a-b335-47d4-8ed7-16d7fe1d8bfc,https://open.oregonstate.education/aandp/,17.9 The Pancreas,https://open.oregonstate.education/aandp/chapter/17-9-the-pancreas/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+b3f0e954-81e0-4482-ab26-2d0fa9eb4a8e,https://open.oregonstate.education/aandp/,17.8 Gonadal and Placental Hormones,https://open.oregonstate.education/aandp/chapter/17-8-gonadal-and-placental-hormones/,Discuss the hormonal regulation of the reproductive system,False,Discuss the hormonal regulation of the reproductive system,,,,
+b97d9a75-fd61-4c15-9f73-790c88a33bf6,https://open.oregonstate.education/aandp/,17.8 Gonadal and Placental Hormones,https://open.oregonstate.education/aandp/chapter/17-8-gonadal-and-placental-hormones/,"This section briefly discusses the hormonal role of the gonads—the male testes and female ovaries—which produce the sex cells (sperm and ova) and secrete the gonadal hormones. The roles of the gonadotropins released from the anterior pituitary, follicle stimulating hormone (FSH) and luteinizing hormone (LH), were discussed earlier in the section regarding the pituitary gland and the hypothalamus.",True,Discuss the hormonal regulation of the reproductive system,,,,
+7bfffc6f-f57c-4925-b7fb-2a7eb2760e28,https://open.oregonstate.education/aandp/,17.8 Gonadal and Placental Hormones,https://open.oregonstate.education/aandp/chapter/17-8-gonadal-and-placental-hormones/,"The primary hormone produced by the male testes is testosterone, a steroid hormone important in the development of the male reproductive system, the maturation of sperm cells, and the development of male secondary sex characteristics such as a deepened voice, body hair, and increased muscle mass. Testosterone is also produced in the female ovaries, but at a much reduced level. The testes also produce the peptide hormone inhibin, which inhibits the secretion of FSH from the anterior pituitary gland. FSH stimulates spermatogenesis.",True,Discuss the hormonal regulation of the reproductive system,,,,
+b027ebc3-21dd-4f7a-aa0b-79cd85efbd8a,https://open.oregonstate.education/aandp/,17.8 Gonadal and Placental Hormones,https://open.oregonstate.education/aandp/chapter/17-8-gonadal-and-placental-hormones/,"The primary hormones produced by the ovaries are estrogens, which include estradiol, estriol, and estrone. Estrogens play an important role in a larger number of physiological processes, including the development of the female reproductive system, regulation of the menstrual cycle, the development of female secondary sex characteristics such as increased adipose tissue and the development of breast tissue, and the maintenance of pregnancy. Another significant ovarian hormone is progesterone, which contributes to regulation of the menstrual cycle and is important in preparing the body for pregnancy as well as maintaining pregnancy. In addition, the granulosa cells of the ovarian follicles produce inhibin, which—as in males—inhibits the secretion of FSH. During the initial stages of pregnancy, an organ called the placenta develops within the uterus. The placenta supplies oxygen and nutrients to the fetus, excretes waste products, and produces and secretes estrogens and progesterone. The placenta produces human chorionic gonadotropin (hCG) as well. The hCG hormone promotes progesterone synthesis and reduces the mother’s immune function to protect the fetus from immune rejection. It also secretes human placental lactogen (hPL), which plays a role in preparing the breasts for lactation, and relaxin, which is thought to help soften and widen the pubic symphysis in preparation for childbirth. The hormones related to sex characteristics and reproduction are summarized in Table 17.6.",True,Discuss the hormonal regulation of the reproductive system,,,,
+906d921c-48c9-45aa-a5b9-1889500e1a13,https://open.oregonstate.education/aandp/,17.8 Gonadal and Placental Hormones,https://open.oregonstate.education/aandp/chapter/17-8-gonadal-and-placental-hormones/,"The use of performance-enhancing drugs is banned by all major collegiate and professional sports organizations in the United States because they impart an unfair advantage to athletes who take them. In addition, the drugs can cause significant and dangerous side effects. For example, anabolic steroid use can increase cholesterol levels, raise blood pressure, and damage the liver. Altered testosterone levels (both too low or too high) have been implicated in causing structural damage to the heart, and increasing the risk for cardiac arrhythmias, heart attacks, congestive heart failure, and sudden death. Paradoxically, steroids can have a feminizing effect in males, including atrophied testicles and enlarged breast tissue. In females, their use can cause masculinizing effects such as an enlarged clitoris and growth of facial hair. In both sexes, their use can promote increased aggression (commonly known as “roid-rage”), depression, sleep disturbances, severe acne, and infertility.",True,Discuss the hormonal regulation of the reproductive system,,,,
+edf99b01-6759-4ad1-8b18-84abccfcedde,https://open.oregonstate.education/aandp/,17.7 The Pineal Gland,https://open.oregonstate.education/aandp/chapter/17-7-the-pineal-gland/,"Summarize the site of production, regulation, and effects of the hormone of the pineal glands",True,Discuss the hormonal regulation of the reproductive system,,,,
+e06bef48-4df8-4f1b-81a3-24d864e587d0,https://open.oregonstate.education/aandp/,17.7 The Pineal Gland,https://open.oregonstate.education/aandp/chapter/17-7-the-pineal-gland/,"The pineal gland, found inferior but somewhat posterior to the thalamus, is a tiny endocrine gland whose functions are not entirely understood. The pinealocyte cells that make up the pineal gland are known to produce and secrete the amine hormone melatonin, which is derived from serotonin.",True,Discuss the hormonal regulation of the reproductive system,,,,
+c3346c8a-c035-4ea1-84ab-4f53749a753f,https://open.oregonstate.education/aandp/,17.7 The Pineal Gland,https://open.oregonstate.education/aandp/chapter/17-7-the-pineal-gland/,"The secretion of melatonin varies according to the level of light received from the environment. When photons of light stimulate the retinas of the eyes, a nerve impulse is sent to a region of the hypothalamus called the suprachiasmatic nucleus (SCN), which is important in regulating biological rhythms. From the SCN, the nerve signal is carried to the spinal cord and eventually to the pineal gland, where the production of melatonin is inhibited. As a result, blood levels of melatonin fall, promoting wakefulness. In contrast, as light levels decline—such as during the evening—melatonin production increases, boosting blood levels and causing drowsiness.",True,Discuss the hormonal regulation of the reproductive system,,,,
+1fc74f3e-149b-4b9d-870e-e3998f8846a1,https://open.oregonstate.education/aandp/,17.7 The Pineal Gland,https://open.oregonstate.education/aandp/chapter/17-7-the-pineal-gland/,"The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. High melatonin levels in children may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty until melatonin production declines. Finally, an antioxidant role of melatonin is the subject of current research.",True,Discuss the hormonal regulation of the reproductive system,,,,
+53a63e52-3935-4dd6-b364-1de0d7308aec,https://open.oregonstate.education/aandp/,17.7 The Pineal Gland,https://open.oregonstate.education/aandp/chapter/17-7-the-pineal-gland/,"Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep.",True,Discuss the hormonal regulation of the reproductive system,,,,
+28a3c560-b941-41df-bfe4-4c2c491e238a,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The adrenal glands are glandular and neuroendocrine tissue adhering to the top of the kidneys by a fibrous capsule (Figure 17.6.1). The adrenal glands have a rich blood supply and have one of the highest rates of blood flow in the body. They are supplied by several arteries branching off the aorta, including the suprarenal and renal arteries. Blood first flows through the adrenal cortex and then drains into the adrenal medulla. Adrenal hormones are released into the circulation via the left and right suprarenal veins.",True,Discuss the hormonal regulation of the reproductive system,Figure 17.6.1,17.6 The Adrenal Glands,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1818_The_Adrenal_Glands.jpg,"Figure 17.6.1 – Adrenal Glands: Both adrenal glands sit atop the kidneys and are composed of an outer cortex and an inner medulla, all surrounded by a connective tissue capsule. The cortex can be subdivided into additional zones, all of which produce different types of hormones. LM × 204. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+994ad022-d497-40ee-8fc2-97d6a0fa2bf5,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The adrenal gland consists of an outer cortex of glandular tissue and an inner medulla of nervous tissue. The cortex itself is divided into three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. Each region secretes its own set of hormones.",True,Discuss the hormonal regulation of the reproductive system,,,,
+4c240921-dd0f-4aa0-aa19-56c334e30aa9,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The adrenal cortex, as a component of the hypothalamic-pituitary-adrenal (HPA) axis, secretes steroid hormones important for the regulation of the long-term stress response, blood pressure and blood volume, nutrient uptake and storage, fluid and electrolyte balance, and inflammation. The HPA axis involves the hypothalamus stimulating the release of adrenocorticotropic hormone (ACTH) from the pituitary. ACTH then stimulates the adrenal cortex to produce the hormone from the cortex (corticosteroids). This pathway will be discussed in more detail below.",True,Discuss the hormonal regulation of the reproductive system,,,,
+86e775d6-9aef-48bd-acdf-13e645d77c28,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The adrenal medulla is neuroendocrine tissue composed of postganglionic sympathetic neurons. It is really an extension of the autonomic nervous system. This neuroendocrine pathway, controlled by the hypothalamus, involves stimulation of the medulla by impulses from preganglionic sympathetic neurons originating in the thoracic spinal cord. Stimulation causes the medulla to secrete the amine hormones epinephrine and norepinephrine.",True,Discuss the hormonal regulation of the reproductive system,,,,
+d3ac5a60-065a-4b2f-867b-bd6f42c34a45,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"One of the major functions of the adrenal gland is to respond to stress. Stress can be either physical, psychological or both. Physical stresses may include injury, exposure to severe temperatures or malnutrition. Psychological stresses include the perception of a physical threat, a fight with a loved one, or just a bad day at school.",True,Discuss the hormonal regulation of the reproductive system,,,,
+6865c046-6617-4d55-bf20-11306b460dda,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The body responds in different ways to short-term stress and long-term stress following a pattern known as the general adaptation syndrome (GAS). Stage one of GAS is called the alarm reaction. This is short-term stress, the fight-or-flight response, mediated by the hormones epinephrine and norepinephrine from the adrenal medulla. Their function is to prepare the body for extreme physical exertion. Once this stress is relieved, the body quickly returns to normal. The section on the adrenal medulla covers this response in more detail.",True,Discuss the hormonal regulation of the reproductive system,,,,
+b577e139-d82d-450c-a0df-34e399a9046b,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"If the stress is not soon relieved, the body adapts to the stress in the second stage called the stage of resistance. If a person is starving for example, the body may send signals to the gastrointestinal tract to maximize the absorption of nutrients from food.",True,Discuss the hormonal regulation of the reproductive system,,,,
+9ca66844-1c0b-4430-bcc0-4265524214c4,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"If the stress continues for a longer term however, the body responds with symptoms quite different than the fight-or-flight response. During the stage of exhaustion, individuals may begin to suffer depression, the suppression of their immune response, severe fatigue, or even a fatal heart attack. These symptoms are mediated by the hormones of the adrenal cortex, especially cortisol, released as a result of signals from the HPA axis.",True,Discuss the hormonal regulation of the reproductive system,,,,
+55c8e657-0fbb-4f8c-bfc2-2bea98a2c28e,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"Adrenal hormones also have several non–stress-related functions, including the increase of blood sodium and glucose levels, which will be described in detail below.",True,Discuss the hormonal regulation of the reproductive system,,,,
+9f7496f0-96c9-4acd-916a-067da1ab4410,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,Adrenal Cortex,False,Adrenal Cortex,,,,
+417b6166-4831-4e44-910a-f33b31ebaceb,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,The adrenal cortex consists of multiple layers of lipid-storing cells that occur in three structurally distinct regions. Each of these regions produces different hormones.,True,Adrenal Cortex,,,,
+4cea4fcc-0359-42dc-be84-a0db6c1320ed,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,Adrenal Medulla,False,Adrenal Medulla,,,,
+c6346451-92d4-48a1-9244-6e35caf55d60,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"As noted earlier, the adrenal cortex releases glucocorticoids in response to long-term stress such as severe illness. In contrast, the adrenal medulla releases its hormones in response to acute, short-term stress mediated by the sympathetic nervous system (SNS).",True,Adrenal Medulla,,,,
+b8165749-8fa6-4bc6-ba5b-910aa468ed04,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The medullary tissue is composed of modified postganglionic neurons called chromaffin cells, which are large and irregularly shaped, and produce the neurotransmitters epinephrine (also called adrenaline) and norepinephrine (or noradrenaline). Epinephrine is produced in greater quantities—approximately a 4 to 1 ratio with norepinephrine—and is the more powerful hormone. Because the chromaffin cells release epinephrine and norepinephrine into the systemic circulation, where they travel widely and exert effects on distant cells, they are considered hormones. Derived from the amino acid tyrosine, they are chemically classified as catecholamines.",True,Adrenal Medulla,,,,
+8e4d5b7b-bad4-44b7-b772-7abf71dc5839,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"The secretion of medullary epinephrine and norepinephrine is controlled by a neural pathway that originates from the hypothalamus in response to danger or stress. Both epinephrine and norepinephrine signal the liver and skeletal muscle cells to convert glycogen into glucose, resulting in increased blood glucose levels. These hormones increase heart rate and blood pressure to prepare the body to fight the perceived threat or flee from it. In addition, the pathway dilates the airways, raising blood oxygen levels. It also prompts vasodilation, further increasing the oxygenation of organs essential to fight or flight such as the lungs, brain, heart, and skeletal muscle. At the same time, it triggers vasoconstriction to blood vessels supplying organs less essential to fight or flight such as the gastrointestinal tract, kidneys, and skin. Other effects include a dry mouth, loss of appetite, pupil dilation, and a loss of peripheral vision. The major hormones of the adrenal glands are summarized in Table 17.5.",True,Adrenal Medulla,,,,
+d5115338-1cd4-4fc1-9df7-a7441f48100b,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,Disorders Involving the Adrenal Glands,False,Disorders Involving the Adrenal Glands,,,,
+15a5a4e8-7e3d-426b-ae08-6273fd88e7fc,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"Several disorders are caused by the dysregulation of the hormones produced by the adrenal glands. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. It is caused by hypersecretion of cortisol. The most common source of Cushing’s disease is a pituitary tumor that secretes ACTH in abnormally high amounts. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss. Long term glucocorticoid use for inflammatory conditions such as rheumatoid arthritis or to prevent transplant rejection can cause symptoms similar to those in Cushing’s disease.",True,Disorders Involving the Adrenal Glands,,,,
+c0d62a1e-8300-4c4b-9e6e-e01932da4d4b,https://open.oregonstate.education/aandp/,17.6 The Adrenal Glands,https://open.oregonstate.education/aandp/chapter/17-6-the-adrenal-glands/,"In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food. Treatment involves injections of glucocorticoids.",True,Disorders Involving the Adrenal Glands,,,,
+f8965a16-9adc-481f-99fa-5c14bcf1773d,https://open.oregonstate.education/aandp/,17.5 The Parathyroid Glands,https://open.oregonstate.education/aandp/chapter/17-5-the-parathyroid-glands/,"The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (Figure 17.5.1). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels. The gland also contains oxyphil cells but their function is not clear.",True,Disorders Involving the Adrenal Glands,Figure 17.5.1,17.5 The Parathyroid Glands,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1814_The_Parathyroid_Glands.jpg,Figure 17.5.1 – Parathyroid Glands: The small parathyroid glands are embedded in the posterior surface of the thyroid gland. LM × 760. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+a861b29a-af74-480d-a873-b9c7f77b4d94,https://open.oregonstate.education/aandp/,17.5 The Parathyroid Glands,https://open.oregonstate.education/aandp/chapter/17-5-the-parathyroid-glands/,"The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (Figure 17.5.2). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.",True,Disorders Involving the Adrenal Glands,Figure 17.5.2,17.5 The Parathyroid Glands,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1817_The_Role_of_Parathyroid_Hormone_in_Maintaining_Blood_Calcium_Homeostasis.jpg,"Figure 17.5.2 – Parathyroid Hormone in Maintaining Blood Calcium Homeostasis: Parathyroid hormone increases blood calcium levels when they drop too low. Conversely, calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too high. These two mechanisms constantly maintain blood calcium concentration at homeostasis."
+092fc75b-07fb-4294-9076-5df51b2ec114,https://open.oregonstate.education/aandp/,17.5 The Parathyroid Glands,https://open.oregonstate.education/aandp/chapter/17-5-the-parathyroid-glands/,"Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium phosphate deposits may collect in the body’s tissues and organs (extraosseous calcification), impairing their functioning.",True,Disorders Involving the Adrenal Glands,,,,
+a33e60ef-2a36-4081-aabe-7aa811b48071,https://open.oregonstate.education/aandp/,17.5 The Parathyroid Glands,https://open.oregonstate.education/aandp/chapter/17-5-the-parathyroid-glands/,"In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism, which may develop following injury or surgery involving the thyroid gland. Low blood calcium increases membrane permeability to sodium, resulting in muscle twitching, cramping, spasms, or convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal.",True,Disorders Involving the Adrenal Glands,,,,
+af089285-5851-4f5d-9343-c0185b9a3f2c,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.4.1). The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells. These follicles are the center of thyroid hormone production and that production is dependent on the hormones’ essential and unique component: iodine.",True,Disorders Involving the Adrenal Glands,Figure 17.4.1,17.4 The Thyroid Gland,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1811_The_Thyroid_Gland_revised-e1568244258246.png,Figure 17.4.1 – Thyroid Gland: The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+dc9595ba-4586-42b9-8e9d-1174b9436225,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,Synthesis and Release of Thyroid Hormones,False,Synthesis and Release of Thyroid Hormones,,,,
+5d91b584-0233-4522-9dbe-1063d2854d19,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"Hormones are produced in the colloid when atoms of the mineral iodine attach to a glycoprotein, called thyroglobulin, that is secreted into the colloid by the follicle cells. The following steps outline the hormones’ assembly:",True,Synthesis and Release of Thyroid Hormones,,,,
+b7e5e52c-796d-48af-a457-20c2c24eac38,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"These hormones remain in the colloid center of the thyroid follicles until TSH stimulates endocytosis of colloid back into the follicle cells. There, lysosomal enzymes break apart the thyroglobulin colloid, releasing free T3 and T4, which diffuse across the follicle cell membrane and enter the bloodstream.",True,Synthesis and Release of Thyroid Hormones,,,,
+199dc9e6-944d-43bf-b235-26b900e9bd43,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"In the bloodstream, less than one percent of the circulating T3 and T4 remains unbound. This free T3 and T4 can cross the lipid bilayer of cell membranes and be taken up by cells. The remaining 99 percent of circulating T3 and T4 is bound to specialized transport proteins called thyroxine-binding globulins (TBGs) or to other plasma proteins such as albumin. This “packaging” prevents free hormone diffusion into body cells. When blood levels of T3 and T4 begin to decline, bound T3 and T4 are released from these plasma proteins and readily cross the membrane of target cells. T3 is more potent than T4, and many cells convert T4 to T3 through the removal of an iodine atom.",True,Synthesis and Release of Thyroid Hormones,,,,
+9808f439-e8fb-497f-8d6e-504ece08c38b,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,Regulation of TH Synthesis,False,Regulation of TH Synthesis,,,,
+70abe358-5377-43ec-a272-6aa058f0a52b,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"The release of T3 and T4 from the thyroid gland is regulated by thyroid-stimulating hormone (TSH). As shown in Figure 17.4.2, low blood levels of T3 and T4 stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus, which triggers secretion of TSH from the anterior pituitary. In turn, TSH stimulates the thyroid gland to secrete T3 and T4. The levels of TRH, TSH, T3, and T4 are regulated by a negative feedback system in which increasing levels of T3 and T4 decrease the production and secretion of TSH.",True,Regulation of TH Synthesis,Figure 17.4.2,17.4 The Thyroid Gland,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1813_A_Classic_Negative_Feedback_Loop.jpg,Figure 17.4.2 – Classic Negative Feedback Loop: A classic negative feedback loop controls the regulation of thyroid hormone levels.
+7840c34e-711f-467c-abd2-b537716d7a47,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,Functions of Thyroid Hormones,False,Functions of Thyroid Hormones,,,,
+f6a68c87-1792-41de-9fa2-5a00611fed29,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"The thyroid hormones, T3 and T4, are often referred to as metabolic hormones because their levels influence the body’s basal metabolic rate, the amount of energy used by the body at rest. When T3 and T4 bind to intracellular receptors located on the mitochondria, they cause an increase in nutrient breakdown and the use of oxygen to produce ATP. In addition, T3 and T4 initiate the transcription of genes involved in glucose oxidation. These mechanisms prompt cells to produce more ATP which causes an increase in heat production. This so-called calorigenic effect (calor- = “heat”) raises body temperature.",True,Functions of Thyroid Hormones,,,,
+8336d590-09ff-4370-9cf9-97eb28bc3e29,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"Adequate levels of thyroid hormones are also required for protein synthesis and for fetal and childhood tissue development and growth. They are especially critical for normal development of the nervous system both in utero and in early childhood, and they continue to support neurological function in adults. These thyroid hormones have a complex interrelationship with reproductive hormones, and deficiencies can influence libido, fertility, and other aspects of reproductive function. Finally, thyroid hormones increase the body’s sensitivity to catecholamines (epinephrine and norepinephrine) from the adrenal medulla by upregulation of receptors in the blood vessels. When levels of T3 and T4 hormones are excessive, this effect accelerates the heart rate, strengthens the heart contractility, and increases blood pressure. Because thyroid hormones regulate metabolism, heat production, protein synthesis, and many other body functions, thyroid disorders can have severe and widespread consequences.",True,Functions of Thyroid Hormones,,,,
+55871829-5f1d-4731-a5d6-f76aa061dee3,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,goiter,False,goiter,,,,
+34df5e6f-5123-4488-9b6f-a15653f5b840,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,hypothyroidism,False,hypothyroidism,,,,
+35510d92-2259-47d2-8c1e-eabfc845f6dc,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,Calcitonin,False,Calcitonin,,,,
+3bc28650-b423-440a-8a10-7645cfaa235b,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,The thyroid gland also secretes a hormone called calcitonin that is produced by the parafollicular cells (also called C cells) that are located between follicles. Calcitonin is released in response to a rise in blood calcium levels. It appears to have a function in decreasing blood calcium concentrations by:,True,Calcitonin,,,,
+278d2a87-05f4-4a0c-8650-c85670320043,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"However, these functions are usually not significant in maintaining calcium homeostasis, so the importance of calcitonin is not entirely understood. Pharmaceutical preparations of calcitonin are sometimes prescribed to reduce osteoclast activity in people with osteoporosis and to reduce the degradation of cartilage in people with osteoarthritis. The hormones secreted by thyroid are summarized in Table 17.4.",True,Calcitonin,,,,
+0645f378-81df-42d3-a869-4c921838130c,https://open.oregonstate.education/aandp/,17.4 The Thyroid Gland,https://open.oregonstate.education/aandp/chapter/17-4-the-thyroid-gland/,"Calcium is critical for many other biological processes. It is a second messenger in many signaling pathways, and is essential for muscle contraction, nerve impulse transmission, and blood clotting. Given these roles, it is not surprising that blood calcium levels are tightly regulated by the endocrine system. The organs primarily involved in the regulation are the parathyroid glands.",True,Calcitonin,,,,
+a5d39613-1046-42c3-bc98-2ec3d92986c7,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The hypothalamus–pituitary complex can be thought of as the “command center” of the endocrine system. This complex secretes several hormones that directly produce responses in target tissues, as well as hormones that regulate the synthesis and secretion of hormones of other glands. In addition, the hypothalamus–pituitary complex coordinates the messages of the endocrine and nervous systems. In many cases stimuli received by the nervous system must pass through the hypothalamus–pituitary complex to release hormones that can initiate a response.",True,Calcitonin,,,,
+4259c26c-0fd7-49b2-b9f3-afbfe6625c60,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The hypothalamus is a structure of the diencephalon of the brain located anterior and inferior to the thalamus (Figure 17.3.1). It has both neural and endocrine functions, producing and secreting many hormones. In addition, the hypothalamus is anatomically and functionally related to the pituitary gland (or hypophysis), a bean-sized organ suspended from it by a stem called the infundibulum (or pituitary stalk). The pituitary gland is cradled within the sella turcica of the sphenoid bone of the skull. It consists of two lobes that arise from distinct parts of embryonic tissue: the posterior pituitary (neurohypophysis) is neural tissue, whereas the anterior pituitary (also known as the adenohypophysis [adeno=glandular]) is glandular tissue. The hormones secreted by the posterior and anterior pituitary, and the intermediate zone between the lobes are summarized in Table 17.3.",True,Calcitonin,Figure 17.3.1,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1806_The_Hypothalamus-Pituitary_Complex_revised-e1568244059979.png,"Figure 17.3.1 – Hypothalamus–Pituitary Complex: The hypothalamus region lies inferior and anterior to the thalamus. It connects to the pituitary gland by the stalk-like infundibulum. The pituitary gland consists of an anterior and posterior lobe, with each lobe secreting different hormones in response to signals from the hypothalamus."
+8aab027e-f1ee-4dbe-9734-b36237d4e08e,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,Posterior Pituitary,False,Posterior Pituitary,,,,
+4d99c28e-c616-4c83-90b9-07f6bfab3abc,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The posterior pituitary is actually an extension of the neurons of the paraventricular and supraoptic nuclei of the hypothalamus. The cell bodies of these nuclei are located in the hypothalamus, but their axons descend as the hypothalamic–hypophyseal tract within the infundibulum, and end in axon terminals within the posterior pituitary (Figure 17.3.2).",True,Posterior Pituitary,Figure 17.3.2,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1807_The_Posterior_Pituitary_Complex.jpg,Figure 17.3.2 – Posterior Pituitary: Neurosecretory cells in the hypothalamus release oxytocin (OT) or ADH into the posterior lobe of the pituitary gland. These hormones are stored or released into the blood via the capillary plexus.
+3f8c57f9-0e47-4aa8-9e27-79495c78e894,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The posterior pituitary gland does not produce hormones, but rather stores and secretes hormones produced by the hypothalamus. Neurons of the paraventricular nucleus produce the hormone oxytocin, whereas neurons of the supraoptic nucleus produce ADH. These hormones travel along the axons into axon terminals within the posterior pituitary. In response to action potentials from the same hypothalamic neurons that produced them, these hormones are released from vesicles within the axon terminals into the bloodstream.",True,Posterior Pituitary,,,,
+1bb11ed6-fe86-4a6b-a9a6-a44cf6b74de0,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,Anterior Pituitary,False,Anterior Pituitary,,,,
+f25da362-3171-4fe5-986e-12265057e2f7,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The anterior pituitary originates from epithelial tissue derived from an invagination of the oral mucusa in the embryo which migrates toward the brain during fetal development. There are three regions: the pars distalis is the most anterior, the pars intermedia is adjacent to the posterior pituitary, and the pars tuberalis is a slender “tube” that wraps the infundibulum.",True,Anterior Pituitary,,,,
+52781a84-011b-4532-be95-49fe252d9c19,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"Recall that the posterior pituitary does not synthesize hormones, but merely stores them. In contrast, the anterior pituitary does manufacture hormones. Like the posterior pituitary the release of hormones from the anterior pituitary is controlled by the hypothalamus. This control is mediated by secretion of releasing or inhibiting hormones into the blood.",True,Anterior Pituitary,,,,
+fbfba720-27b1-49dc-bd9f-0c5de7ddd361,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"Within the infundibulum is a bridge of capillaries that connects the hypothalamus to the anterior pituitary. This network, called the hypophyseal portal system, allows hypothalamic hormones to be transported to the anterior pituitary without becoming diluted in systemic circulation. This portal system begins with a primary capillary plexus originating from the superior hypophyseal artery, a branches of the internal carotid artery. Blood from the first capillary bed supplies a secondary capillary plexus in the anterior pituitary via the hypophyseal portal veins (see Figure 17.3.3). Hypothalamic releasing and inhibiting hormones are released into the primary capillary plexus which drain into the portal veins carrying them to the secondary capillary plexus where they stimulate (or inhibit) the endocrine cells of the anterior pituitary. Hormones produced by the anterior pituitary (in response to hypothalamic releasing hormones) enter the secondary capillary plexus continuing into general circulation.",True,Anterior Pituitary,Figure 17.3.3,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1808_The_Anterior_Pituitary_Complex.jpg,Figure 17.3.3 – Anterior Pituitary: The anterior pituitary manufactures seven hormones. The hypothalamus produces separate hormones that stimulate or inhibit hormone production in the anterior pituitary. Hormones from the hypothalamus reach the anterior pituitary via the hypophyseal portal system.
+69eedf71-8895-4cfa-a137-f828be32669c,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The anterior pituitary produces seven hormones. These are growth hormone (GH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), beta endorphin, and prolactin. Of the hormones of the anterior pituitary, TSH, ACTH, FSH, and LH are collectively referred to as tropic hormones (trope- = “turning”) because they stimulate or inhibit secretion of hormones from other glands.",True,Anterior Pituitary,,,,
+222a45ab-8ecc-4d27-abaf-a7e5936f2a42,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,Intermediate Pituitary: Melanocyte-Stimulating Hormone,False,Intermediate Pituitary: Melanocyte-Stimulating Hormone,,,,
+8fc88617-a6e2-4296-9744-ae8e51cf7d02,https://open.oregonstate.education/aandp/,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/aandp/chapter/17-3-the-pituitary-gland-and-hypothalamus/,"The cells in the zone between the pituitary lobes secrete a hormone known as melanocyte-stimulating hormone (MSH) that is formed by cleavage of the pro-opiomelanocortin (POMC) precursor protein. Local production of MSH in the skin is responsible for melanin production in response to UV light exposure. The role of MSH made by the pituitary is more complicated. For instance, people with lighter skin generally have the same amount of MSH as people with darker skin. Nevertheless, this hormone is capable of darkening of the skin by inducing melanin production in the skin’s melanocytes. Women also show increased MSH production during pregnancy; in combination with estrogens, it can lead to darker skin pigmentation, especially the skin of the areolas and labia minora. Figure 17.3.5 is a summary of the pituitary hormones and their principal effects.",True,Intermediate Pituitary: Melanocyte-Stimulating Hormone,Figure 17.3.5,17.3 The Pituitary Gland and Hypothalamus,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1810_Major_Pituitary_Hormones_revised.png,Figure 17.3.5 – Major Pituitary Hormones: Major pituitary hormones and their target organs.
+cf9fdd50-9a38-46d7-97ab-a25963fd4413,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"When released into the blood, a hormone circulates freely throughout the body.  However, a hormone will only affect the activity of its target cells; that is, cells with receptors for that particular hormone. Once the hormone binds to the receptor, a chain of events is initiated that leads to the target cell’s response.  The major hormones of the human body and their effects are identified in Table 17.2.",True,Intermediate Pituitary: Melanocyte-Stimulating Hormone,,,,
+33e5d569-014f-4501-b959-d0f7f98d5cda,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,Types of Hormones,False,Types of Hormones,,,,
+d2b3970c-b484-4bff-961e-5ac3010b2741,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"The hormones of the human body can be structurally divided into three major groups: amino acid derivatives (amines), peptides, and steroids (Figure 17.2.1). These chemical groups affect a hormone’s distribution, the type of receptors it binds to, and other aspects of its function..",True,Types of Hormones,Figure 17.2.1,17.2 Hormones,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1802_Examples_of_Amine_Peptide_Protein_and_Steroid_Hormone_Structure.jpg,"Figure 17.2.1:  Amine, Peptide, Protein, and Steroid Hormone Structure"
+056c5115-ec9f-47a1-b1ab-848c47a17925,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,Pathways of Hormone Action,False,Pathways of Hormone Action,,,,
+aa2beebe-5237-4a7f-a1c0-04a4a3f355a5,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"The message a hormone sends is received by a hormone receptor, a protein located either inside the cell or within the cell membrane. The receptor will process the message by initiating other signaling events or cellular mechanisms that result in the target cell’s response. Hormone receptors recognize molecules with specific shapes and side groups, and respond only to those hormones that are recognized. The same type of receptor may be located on cells in different body tissues, and trigger somewhat different responses. Thus, the response triggered by a hormone depends not only on the hormone, but also on the receptor present on the target cell.",True,Pathways of Hormone Action,,,,
+9cfe509e-0225-4eb4-a4b2-01fe47736677,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"Once the target cell receives the hormone signal, it can respond in a variety of ways. The response may include the stimulation of protein synthesis, activation or deactivation of enzymes, alteration in the permeability of the cell membrane, altered rates of mitosis and cell growth, and stimulation of the secretion of products. Moreover, a single hormone may be capable of inducing multiple responses in a given cell.",True,Pathways of Hormone Action,,,,
+4517b0cf-048d-4458-b205-1de365bb9fe2,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,Factors Affecting Target Cell Response,False,Factors Affecting Target Cell Response,,,,
+6d29c468-61fb-4f03-b8e1-eea9a0183481,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"You will recall that target cells must have receptors specific to a given hormone if that hormone is to trigger a response. But several other factors influence the target cell response. For example, the presence of a significant level of a hormone circulating in the bloodstream can cause its target cells to decrease their number of receptors for that hormone. This process is called downregulation, and it allows cells to become less reactive to the excessive hormone levels. When the level of a hormone is chronically reduced, target cells engage in upregulation to increase their number of receptors. This process allows cells to be more sensitive to the hormone that is present. Cells can also alter the sensitivity of the receptors themselves to various hormones.",True,Factors Affecting Target Cell Response,,,,
+2d6cf695-4ff7-4fa4-a8a7-319912b5b094,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,Two or more hormones can interact to affect the response of cells in a variety of ways. The three most common types of interaction are as follows:,True,Factors Affecting Target Cell Response,,,,
+ec6b0832-7b8d-4b8d-96cc-55f259f5034b,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,Regulation of Hormone Secretion,False,Regulation of Hormone Secretion,,,,
+69caee8e-2a70-4a24-a770-7b41300c95a1,https://open.oregonstate.education/aandp/,17.2 Hormones,https://open.oregonstate.education/aandp/chapter/17-2-hormones/,"To prevent abnormal hormone levels and a potential disease state, hormone levels must be tightly controlled. The body maintains this control by balancing hormone production and degradation. Feedback loops govern the initiation and maintenance of most hormone secretion in response to various stimuli.",True,Regulation of Hormone Secretion,,,,
+3bac335c-d74d-4713-a4b1-21e334acdc72,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,Communication within the human body involves the transmission of signals to control and coordinate actions in an effort to maintain homeostasis.  There are two major organ systems responsible for providing these communication pathways: the nervous system and the endocrine system.,True,Regulation of Hormone Secretion,,,,
+71b9f1cd-3200-4e1f-8706-78f1e2a97482,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"The nervous system is primarily responsible for rapid communication throughout the body.  As discussed in previous chapters, the nervous system utilizes two types of signals – electrical and chemical (Table 17.1).  Electrical signals are sent via the generation and propagation of action potentials which move along the membrane of a cell.  Once the action potential reaches the synaptic terminal, the electrical signal is converted to a chemical signal as neurotransmitters are released into the synaptic cleft.  When the neurotransmitters binds with receptors on the receiving (post-synaptic) cell, a new electrical signal is generated and quickly continues on to its destination.  In this way, neural communication enables body functions that involve quick, brief actions, such as movement, sensation, and cognition.",True,Regulation of Hormone Secretion,,,,
+5bb57683-56c8-4140-b8c2-797fd4f13eaf,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"In contrast, the endocrine system relies on only a single method of communication: chemical signaling (Table 1).  Hormones are the chemicals released by endocrine cells that regulate other cells in the body.   Hormones are transported primarily via the bloodstream throughout the body, where they bind to receptors on target cells, triggering a response.  Because of this dependence on the cardiovascular system for transport, this type of communication is much slower than that observed for neural signaling.  As such, hormonal communication is usually associated with activities that go on for relatively long periods of time.",True,Regulation of Hormone Secretion,,,,
+32fd5757-686f-4029-a8ee-9675bcb1bdee,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"In general, the nervous system involves quick responses to rapid changes in the external environment, and the endocrine system is usually slower acting—taking care of the internal environment of the body, maintaining homeostasis, and controlling reproduction. This does not mean, however, that the two systems are completely independent of one another.  Take for example the release of adrenaline from the adrenal medulla as part of the ‘fight-or-flight’ response.  Although adrenaline uses blood for transportation throughout the body, the effects are evident within seconds after the event has occurred;  how does the response happen so quickly if hormones are usually slower acting?   It occurs so rapidly because the nervous and endocrine system are both involved in the process: it is the fast action of the nervous system responding to the danger in the environment that stimulates the adrenal glands to quickly secrete their hormones.  In such a situation, the nervous system causes a rapid endocrine response to deal with sudden changes in both the external and internal environments when necessary.",True,Regulation of Hormone Secretion,,,,
+a2543b27-a796-49d7-8765-4dfda1229b37,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,Endocrine Organs,False,Endocrine Organs,,,,
+d28ba82f-7f02-4f84-90fa-552ae50ca97e,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"Hormones are released by secretory cells that are derived from epithelial tissue.  Often, these cells are clustered together, forming endocrine glands.  Unlike exocrine glands, which have a duct for conveying secretions to the outside of the body (e.g., sweat gland), endocrine glands secrete substances directly into the surrounding interstitial fluid.  From there, hormones then enter the bloodstream for distribution throughout the body.",True,Endocrine Organs,,,,
+cca80d1f-25de-44ed-b65f-b286d42ae3ab,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"The major endocrine glands found in the human body include the pituitary gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pineal gland, testes, and ovaries (Figure 17.1.1). While some of the glands are pure endocrine (e.g., thyroid gland), others serve both endocrine and exocrine function. For example, the pancreas contains cells that secrete digestive enzymes and juices into the small intestine (exocrine function) and cells that secrete the hormones insulin and glucagon, which regulate blood glucose levels.",True,Endocrine Organs,Figure 17.1.1,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1801_The_Endocrine_System.jpg,Figure 17.1.1 – Endocrine System: Endocrine glands and cells are located throughout the body and play an important role in homeostasis.
+fef9ac7d-3dfd-4913-a7d2-02b51646389c,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"In addition to the endocrine glands, major organs of the body show endocrine function including the hypothalamus, heart, kidneys, stomach, small intestine, and liver.  Moreover, adipose tissue has long been known to produce hormones, and recent research has revealed a role for bone tissue in hormone production and secretion.",True,Endocrine Organs,,,,
+45292a59-62df-46b5-9e9c-4c9e507fe064,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,Other Types of Chemical Signals,False,Other Types of Chemical Signals,,,,
+5bb6f011-14e3-4046-ba7e-fbef06f90b9c,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"In the classical definition of the endocrine system, hormones are secreted into the interstitial fluid and then diffuse into the blood or lymph for circulation throughout the body to reach target tissues.  However, in certain instances, target cells are local and do not require hormones to enter the blood.  If a chemical signal is released into the interstitial fluid and targets neighboring cells, then the activity is referred to as paracrine.  Neurotransmitter communication between a pre- and post-synaptic neuron is a good example of paracrine activity.  Alternatively, chemicals released by a cell elicit a response in the same cell that secreted it, demonstrating autocrine activity.  An example of this is type of activity is Interleukin-1, signaling molecule released in an inflammatory response that binds to receptors located on the surface of the cell releasing the molecule.",True,Other Types of Chemical Signals,,,,
+ddf71b4f-47c9-479d-931e-4016e59c2293,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"Endocrinology is a specialty in the field of medicine that focuses on the treatment of endocrine system disorders. Endocrinologists, the medical doctors who specialize in this field, are experts in treating diseases associated with hormonal systems, ranging from thyroid disease to diabetes mellitus.",True,Other Types of Chemical Signals,,,,
+e8697e13-47df-431c-97ef-f35adf4f19ca,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"Patients who are referred to endocrinologists may have signs and symptoms or blood test results that suggest excessive or impaired functioning of an endocrine gland or endocrine cells. The endocrinologist may order additional blood tests to determine whether the patient’s hormonal levels are abnormal, or they may stimulate or suppress the function of the suspect endocrine gland and then have blood taken for analysis. Treatment varies according to the diagnosis. Some endocrine disorders, such as type 2 diabetes, may respond to lifestyle changes such as modest weight loss, adoption of a healthy diet, and regular physical activity. Other disorders may require medication, such as hormone replacement, and routine monitoring by the endocrinologist. These include disorders of the pituitary gland that can affect growth and disorders of the thyroid gland that can result in a variety of metabolic problems.",True,Other Types of Chemical Signals,,,,
+11427fdb-925b-4ead-ac36-4014fa6ed4b7,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,Some patients experience health problems as a result of the normal decline in hormones that can accompany aging. These patients can consult with an endocrinologist to weigh the risks and benefits of hormone replacement therapy intended to boost their natural levels of reproductive hormones.,True,Other Types of Chemical Signals,,,,
+d9edb8f2-2131-4737-afa9-47389c3e3a37,https://open.oregonstate.education/aandp/,17.1 An Overview of the Endocrine System,https://open.oregonstate.education/aandp/chapter/17-1-an-overview-of-the-endocrine-system/,"In addition to treating patients, endocrinologists may be involved in research to improve the understanding of endocrine system disorders and develop new treatments for these diseases.",True,Other Types of Chemical Signals,,,,
+dba5def1-0c7c-40dc-8062-6ce89b8d10ae,https://open.oregonstate.education/aandp/,17.0 Introduction,https://open.oregonstate.education/aandp/chapter/17-0-introduction/,"You may never have thought of it this way, but when you send a text message to two friends to meet you at the dining hall at six, you’re sending digital signals that (you hope) will affect their behavior—even though they are some distance away. Similarly, certain cells send chemical signals to other cells in the body that influence their behavior. This long-distance intercellular communication, coordination, and control is critical for homeostasis, and it is the fundamental function of the endocrine system.",True,Other Types of Chemical Signals,,,,
+b9874dff-c43b-4c2f-90f3-832a2d0cff84,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"An important way to understand the effects of native neurochemicals in the autonomic system is in considering the effects of pharmaceutical drugs. This can be considered in terms of how drugs change autonomic function. These effects will primarily be based on how drugs act at the receptors of the autonomic system neurochemistry. The signaling molecules of the nervous system interact with proteins in the cell membranes of various target cells. In fact, no effect can be attributed to just the signaling molecules themselves without considering the receptors. A chemical that the body produces to interact with those receptors is called an endogenous chemical, whereas a chemical introduced to the system from outside is an exogenous chemical. Exogenous chemicals may be of a natural origin, such as a plant extract, or they may be synthetically produced in a pharmaceutical laboratory.",True,Other Types of Chemical Signals,,,,
+4f9340dc-d416-436b-9186-869a7d54fa2e,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,Broad Autonomic Effects,False,Broad Autonomic Effects,,,,
+6058bc8d-d0cc-4b3e-8b78-6f0a05755db5,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,One important drug that affects the autonomic system broadly is not a pharmaceutical therapeutic agent associated with the system. This drug is nicotine. The effects of nicotine on the autonomic nervous system are important in considering the role smoking can play in health.,True,Broad Autonomic Effects,,,,
+c1046963-92e3-4060-91d3-a48fc02d79f5,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"All ganglionic neurons of the autonomic system, in both sympathetic and parasympathetic ganglia, are activated by ACh released from preganglionic fibers. The ACh receptors on these neurons are of the nicotinic type, meaning that they are ligand-gated ion channels. When the neurotransmitter released from the preganglionic fiber binds to the receptor protein, a channel opens to allow positive ions to cross the cell membrane. The result is depolarization of the ganglia. Nicotine acts as an ACh analog at these synapses, so when someone takes in the drug, it binds to these ACh receptors and activates the ganglionic neurons, causing them to depolarize.",True,Broad Autonomic Effects,,,,
+27ab9439-ae65-4553-b903-36f3110c96ef,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"Ganglia of both divisions are activated equally by the drug. For many target organs in the body, this results in no net change. The competing inputs to the system cancel each other out and nothing significant happens. For example, the sympathetic system will cause sphincters in the digestive tract to contract, limiting digestive propulsion, but the parasympathetic system will cause the contraction of other muscles in the digestive tract, which will try to push the contents of the digestive system along. The end result is that the food does not really move along and the digestive system has not appreciably changed.",True,Broad Autonomic Effects,,,,
+9b1ec2e5-6106-404d-91b9-e254f1db4753,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"The system in which this can be problematic is in the cardiovascular system, which is why smoking is a risk factor for cardiovascular disease. First, there is no significant parasympathetic regulation of blood pressure. Only a limited number of blood vessels are affected by parasympathetic input, so nicotine will preferentially cause the vascular tone to become more sympathetic, which means blood pressure will be increased. Second, the autonomic control of the heart is special. Unlike skeletal or smooth muscles, cardiac muscle is intrinsically active, meaning that it generates its own action potentials. The autonomic system does not cause the heart to beat, it just speeds it up (sympathetic) or slows it down (parasympathetic). The mechanisms for this are not mutually exclusive, so the heart receives conflicting signals, and the rhythm of the heart can be affected (Figure 16.4.1).",True,Broad Autonomic Effects,Figure 16.4.1,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1512_Connections_to_Heart.jpg,"Figure 16.4.1 – Autonomic Connections to Heart and Blood Vessels: The nicotinic receptor is found on all autonomic ganglia, but the cardiovascular connections are particular, and do not conform to the usual competitive projections that would just cancel each other out when stimulated by nicotine. The opposing signals to the heart would both depolarize and hyperpolarize the heart cells that establish the rhythm of the heartbeat, likely causing arrhythmia. Only the sympathetic system governs systemic blood pressure so nicotine would cause an increase."
+50a15b74-6874-4269-85b5-a7ef69db937a,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,Sympathetic Effect,False,Sympathetic Effect,,,,
+68fa3caa-6997-4943-b65c-a61437805830,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"The neurochemistry of the sympathetic system is based on the adrenergic system. Norepinephrine and epinephrine influence target effectors by binding to the α-adrenergic or β-adrenergic receptors. Drugs that affect the sympathetic system affect these chemical systems. The drugs can be classified by whether they enhance the functions of the sympathetic system or interrupt those functions. A drug that enhances adrenergic function is known as a sympathomimetic drug, whereas a drug that interrupts adrenergic function is a sympatholytic drug.",True,Sympathetic Effect,,,,
+a6b39496-b8dd-4826-a32d-9b3d56733610,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,Parasympathetic Effects,False,Parasympathetic Effects,,,,
+f7f7b2da-bb59-404c-982e-90c29e2d2994,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"Drugs affecting parasympathetic functions can be classified into those that increase or decrease activity at postganglionic terminals. Parasympathetic postganglionic fibers release ACh, and the receptors on the targets are muscarinic receptors. There are several types of muscarinic receptors, M1–M5, but the drugs are not usually specific to the specific types. Parasympathetic drugs can be either muscarinic agonists or antagonists, or have indirect effects on the cholinergic system. Drugs that enhance cholinergic effects are called parasympathomimetic drugs, whereas those that inhibit cholinergic effects are referred to as anticholinergic drugs.",True,Parasympathetic Effects,,,,
+d8e485f7-6ee2-4b4d-a8fd-e122eee61842,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"Pilocarpine is a nonspecific muscarinic agonist commonly used to treat disorders of the eye. It reverses mydriasis, such as is caused by phenylephrine, and can be administered after an eye exam. Along with constricting the pupil through the smooth muscle of the iris, pilocarpine will also cause the ciliary muscle to contract. This will open perforations at the base of the cornea, allowing for the drainage of aqueous humor from the anterior compartment of the eye and, therefore, reducing intraocular pressure related to glaucoma.",True,Parasympathetic Effects,,,,
+724b0975-e0d0-4e89-84f0-262e54ba429a,https://open.oregonstate.education/aandp/,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/aandp/chapter/16-4-drugs-that-affect-the-autonomic-system/,"Atropine and scopolamine are part of a class of muscarinic antagonists that come from the Atropa genus of plants that include belladonna or deadly nightshade (Figure 16.4.3). The name of one of these plants, belladonna, refers to the fact that extracts from this plant were used cosmetically for dilating the pupil. The active chemicals from this plant block the muscarinic receptors in the iris and allow the pupil to dilate, which is considered attractive because it makes the eyes appear larger. Humans are instinctively attracted to anything with larger eyes, which comes from the fact that the ratio of eye-to-head size is different in infants (or baby animals) and can elicit an emotional response. The cosmetic use of belladonna extract was essentially acting on this response. Atropine is no longer used in this cosmetic capacity for reasons related to the other name for the plant, which is deadly nightshade. Suppression of parasympathetic function, especially when it becomes systemic, can be fatal. Autonomic regulation is disrupted and anticholinergic symptoms develop. The berries of this plant are highly toxic, but can be mistaken for other berries. The antidote for atropine or scopolamine poisoning is pilocarpine.",True,Parasympathetic Effects,Figure 16.4.3,16.4 Drugs that Affect the Autonomic System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1514_Belladona_Plant.jpg,"Figure 16.4.3 – Belladonna Plant: The plant from the genus Atropa, which is known as belladonna or deadly nightshade, was used cosmetically to dilate pupils, but can be fatal when ingested. The berries on the plant may seem attractive as a fruit, but they contain the same anticholinergic compounds as the rest of the plant."
+f837880c-ccdc-41db-8055-a3b37f6d017a,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,"The pupillary light reflex (Figure 16.3.1) begins when light hits the retina and causes a signal to travel along the optic nerve. This is visual sensation, because the afferent branch of this reflex is simply sharing the special sense pathway. Bright light hitting the retina leads to the parasympathetic response, through the oculomotor nerve, followed by the postganglionic fiber from the ciliary ganglion, which stimulates the circular fibers of the iris to contract and constrict the pupil. When light hits the retina in one eye, both pupils contract. When that light is removed, both pupils dilate again back to the resting position. When the stimulus is unilateral (presented to only one eye), the response is bilateral (both eyes). The same is not true for somatic reflexes. If you touch a hot radiator, you only pull that arm back, not both. Central control of autonomic reflexes is different than for somatic reflexes. The hypothalamus, along with other CNS locations, controls the autonomic system.",True,Parasympathetic Effects,Figure 16.3.1,16.3 Central Control,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1509_Pupillary_Reflex_Pathways.jpg,"Figure 16.3.1 – Pupillary Reflex Pathways: The pupil is under competing autonomic control in response to light levels hitting the retina. The sympathetic system will dilate the pupil when the retina is not receiving enough light, and the parasympathetic system will constrict the pupil when too much light hits the retina."
+484fb632-5478-4959-9120-afc9953e0e49,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,Forebrain Structures,False,Forebrain Structures,,,,
+8fb1ef82-fc34-4e5e-925a-ae5d42e744ba,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,"Autonomic control is based on the visceral reflexes, composed of the afferent and efferent branches. These homeostatic mechanisms are based on the balance between the two divisions of the autonomic system, which results in tone for various organs that is based on the predominant input from the sympathetic or parasympathetic systems. Coordinating that balance requires integration that begins with forebrain structures like the hypothalamus and continues into the brain stem and spinal cord.",True,Forebrain Structures,,,,
+4f6f211b-6958-4cc5-80f0-1cbbf450e901,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,The Medulla,False,The Medulla,,,,
+e7ab6b26-9ce2-444e-ac2f-5dcb0ef697cc,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,"The medulla contains nuclei referred to as the cardiovascular center, which controls the smooth and cardiac muscle of the cardiovascular system through autonomic connections. When the homeostasis of the cardiovascular system shifts, such as when blood pressure changes, the coordination of the autonomic system can be accomplished within this region. Furthermore, when descending inputs from the hypothalamus stimulate this area, the sympathetic system can increase activity in the cardiovascular system, such as in response to anxiety or stress. The preganglionic sympathetic fibers that are responsible for increasing heart rate are referred to as the cardiac accelerator nerves, whereas the preganglionic sympathetic fibers responsible for constricting blood vessels compose the vasomotor nerves.",True,The Medulla,,,,
+bd6a0b84-a091-4b26-958b-af0d7350be17,https://open.oregonstate.education/aandp/,16.3 Central Control,https://open.oregonstate.education/aandp/chapter/16-3-central-control/,"Several brain stem nuclei are important for the visceral control of major organ systems. One brain stem nucleus involved in cardiovascular function is the solitary nucleus. It receives sensory input about blood pressure and cardiac function from the glossopharyngeal and vagus nerves, and its output will activate sympathetic stimulation of the heart or blood vessels through the upper thoracic lateral horn. Another brain stem nucleus important for visceral control is the dorsal motor nucleus of the vagus nerve, which is the motor nucleus for the parasympathetic functions ascribed to the vagus nerve, including decreasing the heart rate, relaxing bronchial tubes in the lungs, and activating digestive function through the enteric nervous system. The nucleus ambiguus, which is named for its ambiguous histology, also contributes to the parasympathetic output of the vagus nerve and targets muscles in the pharynx and larynx for swallowing and speech, as well as contributing to the parasympathetic tone of the heart along with the dorsal motor nucleus of the vagus.",True,The Medulla,,,,
+f5965c33-90fb-4519-a8c8-5786c3a94179,https://open.oregonstate.education/aandp/,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/aandp/chapter/16-2-autonomic-reflexes-and-homeostasis/,"The autonomic nervous system regulates organ systems through circuits that resemble the reflexes described in the somatic nervous system. The main difference between the somatic and autonomic systems is in what target tissues are effectors. Somatic responses are solely based on skeletal muscle contraction. The autonomic system, however, targets cardiac and smooth muscle, as well as glandular tissue. Whereas the basic circuit is a reflex arc, there are differences in the structure of those reflexes for the somatic and autonomic systems.",True,The Medulla,,,,
+2fc86ee2-fbb7-42ad-9aca-9c2e5f56e26c,https://open.oregonstate.education/aandp/,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/aandp/chapter/16-2-autonomic-reflexes-and-homeostasis/,The Structure of Reflexes,False,The Structure of Reflexes,,,,
+1d294549-f391-4c1c-b6cc-108f3c0a2916,https://open.oregonstate.education/aandp/,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/aandp/chapter/16-2-autonomic-reflexes-and-homeostasis/,"One difference between a somatic reflex, such as the withdrawal reflex, and a visceral reflex, which is an autonomic reflex, is in the efferent branch. The output of a somatic reflex is the lower motor neuron in the ventral horn of the spinal cord that projects directly to a skeletal muscle to cause its contraction. The output of a visceral reflex is a two-step pathway starting with the preganglionic fiber emerging from a lateral horn neuron in the spinal cord, or a cranial nucleus neuron in the brain stem, to a ganglion—followed by the postganglionic fiber projecting to a target effector. The other part of a reflex, the afferent branch, is often the same between the two systems. Sensory neurons receiving input from the periphery—with cell bodies in the sensory ganglia, either of a cranial nerve or a dorsal root ganglion adjacent to the spinal cord—project into the CNS to initiate the reflex (Figure 16.2.1). The Latin root “effere” means “to carry.” Adding the prefix “ef-” suggests the meaning “to carry away,” whereas adding the prefix “af-” suggests “to carry toward or inward.”",True,The Structure of Reflexes,Figure 16.2.1,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1505_Comparison_of_Somatic_and_Visceral_Reflexes-scaled.jpg,"Figure 16.2.1 – Comparison of Somatic and Visceral Reflexes: The afferent inputs to somatic and visceral reflexes are essentially the same, whereas the efferent branches are different. Somatic reflexes, for instance, involve a direct connection from the ventral horn of the spinal cord to the skeletal muscle. Visceral reflexes involve a projection from the central neuron to a ganglion, followed by a second projection from the ganglion to the target effector."
+852d76b6-5443-4e43-8c8c-6001ee6f3c7b,https://open.oregonstate.education/aandp/,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/aandp/chapter/16-2-autonomic-reflexes-and-homeostasis/,Balance in Competing Autonomic Reflex Arcs,False,Balance in Competing Autonomic Reflex Arcs,,,,
+6360d178-537f-4a7e-8db5-53eae9804d3a,https://open.oregonstate.education/aandp/,16.2 Autonomic Reflexes and Homeostasis,https://open.oregonstate.education/aandp/chapter/16-2-autonomic-reflexes-and-homeostasis/,"The autonomic nervous system is important for homeostasis because its two divisions compete at the target effector. The balance of homeostasis is attributable to the competing inputs from the sympathetic and parasympathetic divisions (dual innervation). At the level of the target effector, the signal of which system is sending the message is strictly chemical. A signaling molecule binds to a receptor that causes changes in the target cell, which in turn causes the tissue or organ to respond to the changing conditions of the body.",True,Balance in Competing Autonomic Reflex Arcs,,,,
+1082fca5-f4ad-4067-b818-e702270c5ce7,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The motor branch of the nervous system can be divided into two functional parts: the somatic nervous system and the autonomic nervous system. The major differences between the two systems are evident in the responses that each produces. The somatic nervous system causes contraction of skeletal muscles. The autonomic nervous system controls cardiac and smooth muscle, as well as glandular tissue. The somatic nervous system is associated with voluntary responses (though many can happen without conscious awareness, like breathing), and the autonomic nervous system is associated with involuntary responses, such as those related to homeostasis.",True,Balance in Competing Autonomic Reflex Arcs,,,,
+6c2638a8-8bd3-49f9-81a0-4d2655091408,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The autonomic nervous system regulates many of the internal organs through a balance of two aspects, or divisions. In addition to the endocrine system, the autonomic nervous system is instrumental in homeostatic mechanisms in the body. The two divisions of the autonomic nervous system are the sympathetic division and the parasympathetic division. The sympathetic system is associated with the fight-or-flight response, and parasympathetic activity is referred to by the epithet of rest and digest. Homeostasis is the balance between the two systems. At each target effector, dual innervation determines activity. For example, the heart receives connections from both the sympathetic and parasympathetic divisions. One causes heart rate to increase, whereas the other causes heart rate to decrease.",True,Balance in Competing Autonomic Reflex Arcs,,,,
+b18ecccf-beaa-4248-8aa3-f5e46ce0f699,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,Sympathetic Division of the Autonomic Nervous System,False,Sympathetic Division of the Autonomic Nervous System,,,,
+4bc5886f-9ffe-4daa-9ea4-732c326849d5,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"To respond to a threat—to fight or to run away—the sympathetic system causes divergent effects as many different effector organs are activated together for a common purpose. More oxygen needs to be inhaled and delivered to skeletal muscle. The respiratory, cardiovascular, and musculoskeletal systems are all activated together. Additionally, sweating keeps the excess heat that comes from muscle contraction from causing the body to overheat. The digestive system shuts down so that blood is not absorbing nutrients when it should be delivering oxygen to skeletal muscles. To coordinate all these responses, the connections in the sympathetic system diverge from a limited region of the central nervous system (CNS) to a wide array of ganglia that project to the many effector organs simultaneously. The complex set of structures that compose the output of the sympathetic system make it possible for these disparate effectors to come together in a coordinated, systemic change.",True,Sympathetic Division of the Autonomic Nervous System,,,,
+43e147e0-5762-4d8c-af33-3fe109c0c86e,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The sympathetic division of the autonomic nervous system influences the various organ systems of the body through connections emerging from the thoracic and upper lumbar spinal cord. It is referred to as the thoracolumbar system to reflect this anatomical basis. A central neuron in the lateral horn of any of these spinal regions projects to ganglia adjacent to the vertebral column through the ventral spinal roots. The majority of ganglia of the sympathetic system belong to a network of sympathetic chain ganglia that runs alongside the vertebral column. The ganglia appear as a series of clusters of neurons linked by axonal bridges. There are typically 23 ganglia in the chain on either side of the spinal column. Three correspond to the cervical region, 12 are in the thoracic region, four are in the lumbar region, and four correspond to the sacral region. The cervical and sacral levels are not connected to the spinal cord directly through the spinal roots, but through ascending or descending connections through the bridges within the chain.",True,Sympathetic Division of the Autonomic Nervous System,,,,
+c662cbe4-bcbf-44d3-9e22-c13e7142b157,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"A diagram that shows the connections of the sympathetic system is somewhat like a circuit diagram that shows the electrical connections between different receptacles and devices. In Figure 16.1.1, the “circuits” of the sympathetic system are intentionally simplified.",True,Sympathetic Division of the Autonomic Nervous System,Figure 16.1.1,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1501_Connections_of_the_Sympathetic_Nervous_System.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.
+c7faa5a6-9f77-41f0-a85a-1f5101c07d4a,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 16.1.2). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 16.1.2a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons.",True,Sympathetic Division of the Autonomic Nervous System,Figure 16.1.2,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+179dbfe6-f754-42db-a8e5-6084f7fb698d,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 16.1.2b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain.",True,Sympathetic Division of the Autonomic Nervous System,Figure 16.1.2,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+a3d582bb-4d47-47ec-a961-cefa16c43cfe,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 16.1.2c).",True,Sympathetic Division of the Autonomic Nervous System,Figure 16.1.2,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+da6763fc-2d9a-4253-8447-4d9f36d01d75,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 16.1.1). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system.",True,Sympathetic Division of the Autonomic Nervous System,Figure 16.1.1,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1501_Connections_of_the_Sympathetic_Nervous_System.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.
+66a98272-6be6-47cb-b3cf-0b95159a42a0,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"An axon from the central neuron that projects to a sympathetic ganglion is referred to as a preganglionic fiber or neuron, and represents the output from the CNS to the ganglion. Because the sympathetic ganglia are adjacent to the vertebral column, preganglionic sympathetic fibers are relatively short, and they are myelinated. A postganglionic fiber—the axon from a ganglionic neuron that projects to the target effector—represents the output of a ganglion that directly influences the organ. Compared with the preganglionic fibers, postganglionic sympathetic fibers are long because of the relatively greater distance from the ganglion to the target effector. These fibers are unmyelinated. (Note that the term “postganglionic neuron” may be used to describe the projection from a ganglion to the target. The problem with that usage is that the cell body is in the ganglion, and only the fiber is postganglionic. Typically, the term neuron applies to the entire cell.)",True,Sympathetic Division of the Autonomic Nervous System,,,,
+99a7324c-cdb1-4ad3-976a-987a24da276e,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"One type of preganglionic sympathetic fiber does not terminate in a ganglion. These are the axons from central sympathetic neurons that project to the adrenal medulla, the interior portion of the adrenal gland. These axons are still referred to as preganglionic fibers, but the target is not a ganglion. The adrenal medulla releases signaling molecules into the bloodstream, rather than using axons to communicate with target structures. The cells in the adrenal medulla that are contacted by the preganglionic fibers are called chromaffin cells. These cells are neurosecretory cells that develop from the neural crest along with the sympathetic ganglia, reinforcing the idea that the gland is, functionally, a sympathetic ganglion.",True,Sympathetic Division of the Autonomic Nervous System,,,,
+aa1313a1-9c09-4a23-b50a-ceb7747a190f,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The projections of the sympathetic division of the autonomic nervous system diverge widely, resulting in a broad influence of the system throughout the body. As a response to a threat, the sympathetic system would increase heart rate and breathing rate and cause blood flow to the skeletal muscle to increase and blood flow to the digestive system to decrease. Sweat gland secretion should also increase as part of an integrated response. All of those physiological changes are going to be required to occur together to run away from the hunting lioness, or the modern equivalent. This divergence is seen in the branching patterns of preganglionic sympathetic neurons—a single preganglionic sympathetic neuron may have 10–20 targets. An axon that leaves a central neuron of the lateral horn in the thoracolumbar spinal cord will pass through the white ramus communicans and enter the sympathetic chain, where it will branch toward a variety of targets. At the level of the spinal cord at which the preganglionic sympathetic fiber exits the spinal cord, a branch will synapse on a neuron in the adjacent chain ganglion. Some branches will extend up or down to a different level of the chain ganglia. Other branches will pass through the chain ganglia and project through one of the splanchnic nerves to a collateral ganglion. Finally, some branches may project through the splanchnic nerves to the adrenal medulla. All of these branches mean that one preganglionic neuron can influence different regions of the sympathetic system very broadly, by acting on widely distributed organs.",True,Sympathetic Division of the Autonomic Nervous System,,,,
+ce68de20-b353-439c-9982-758658d0ae16,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,Parasympathetic Division of the Autonomic Nervous System,False,Parasympathetic Division of the Autonomic Nervous System,,,,
+ebd72446-f7a8-41df-a347-457040ee89b7,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,The parasympathetic division of the autonomic nervous system is named because its central neurons are located on either side of the thoracolumbar region of the spinal cord (para- = “beside” or “near”). The parasympathetic system can also be referred to as the craniosacral system (or outflow) because the preganglionic neurons are located in nuclei of the brain stem and the lateral horn of the sacral spinal cord.,True,Parasympathetic Division of the Autonomic Nervous System,,,,
+743b88b6-2263-491a-ad12-3ffb1df5d985,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The connections, or “circuits,” of the parasympathetic division are similar to the general layout of the sympathetic division with a few specific differences (Figure 16.1.3). The preganglionic fibers from the cranial region travel in cranial nerves, whereas preganglionic fibers from the sacral region travel in spinal nerves. The targets of these fibers are terminal ganglia, which are located near—or even within—the target effector. These ganglia are often referred to as intramural ganglia when they are found within the walls of the target organ. The postganglionic fiber projects from the terminal ganglia a short distance to the target effector, or to the specific target tissue within the organ. Comparing the relative lengths of axons in the parasympathetic system, the preganglionic fibers are long and the postganglionic fibers are short because the ganglia are close to—and sometimes within—the target effectors.",True,Parasympathetic Division of the Autonomic Nervous System,Figure 16.1.3,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1503_Connections_of_the_Parasympathetic_Nervous_System-scaled.jpg,"Figure 16.1.3 – Connections of Parasympathetic Division of the Autonomic Nervous System: Neurons from brain-stem nuclei, or from the lateral horn of the sacral spinal cord, project to terminal ganglia near or within the various organs of the body. Axons from these ganglionic neurons then project the short distance to those target effectors."
+a4da97fd-41e6-4bc1-99e1-ce1632097f02,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The cranial component of the parasympathetic system is based in particular nuclei of the brain stem. In the midbrain, the Edinger–Westphal nucleus is part of the oculomotor complex, and axons from those neurons travel with the fibers in the oculomotor nerve (cranial nerve III) that innervate the extraocular muscles. The preganglionic parasympathetic fibers within cranial nerve III terminate in the ciliary ganglion, which is located in the posterior orbit. The postganglionic parasympathetic fibers then project to the smooth muscle of the iris to control pupillary size. In the upper medulla, the salivatory nuclei contain neurons with axons that project through the facial and glossopharyngeal nerves to ganglia that control salivary glands. Tear production is influenced by parasympathetic fibers in the facial nerve, which activate a ganglion, and ultimately the lacrimal (tear) gland. Neurons in the dorsal nucleus of the vagus nerve and the nucleus ambiguus project through the vagus nerve (cranial nerve X) to the terminal ganglia of the thoracic and abdominal cavities. Parasympathetic preganglionic fibers primarily influence the heart, bronchi, and esophagus in the thoracic cavity and the stomach, liver, pancreas, gall bladder, and small intestine of the abdominal cavity. The postganglionic fibers from the ganglia activated by the vagus nerve are often incorporated into the structure of the organ, such as the mesenteric plexus of the digestive tract organs and the intramural ganglia.",True,Parasympathetic Division of the Autonomic Nervous System,,,,
+7773a5bb-67ef-4be3-a1cc-997fd4a26be5,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,Chemical Signaling in the Autonomic Nervous System,False,Chemical Signaling in the Autonomic Nervous System,,,,
+56440a47-0d0d-453e-bfd2-45123f9ee59c,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"Where an autonomic neuron connects with a target, there is a synapse. The electrical signal of the action potential causes the release of a signaling molecule, which will bind to receptor proteins on the target cell. Synapses of the autonomic system are classified as either cholinergic, meaning that acetylcholine (ACh) is released, or adrenergic, meaning that norepinephrine is released. The terms cholinergic and adrenergic refer not only to the signaling molecule that is released but also to the class of receptors that each binds.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+5e87ee4b-3507-4c26-8c4d-4a5d8f47f670,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein–coupled receptor. The receptors are named for, and differentiated by, other molecules that bind to them. Whereas nicotine will bind to the nicotinic receptor, and muscarine will bind to the muscarinic receptor, there is no cross-reactivity between the receptors. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—that are opened by two separate keys. The classroom key will not open the office door and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the Biology Department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors. The molecules that define these receptors are not crucial—they are simply tools for researchers to use in the laboratory. These molecules are exogenous, meaning that they are made outside of the human body, so a researcher can use them without any confounding endogenous results (results caused by the molecules produced in the body).",True,Chemical Signaling in the Autonomic Nervous System,,,,
+83daf676-97eb-454c-988e-b6d3ae4e6b5a,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The adrenergic system also has two types of receptors, named the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. Unlike cholinergic receptors, these receptor types are not classified by which drugs can bind to them. All of them are G protein–coupled receptors. There are three types of α-adrenergic receptors, termed α1, α2, and α3, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second signaling molecule called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference, in which a methyl group is missing.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+adfb5a31-7112-465f-b3c8-e94425701ddd,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described at the beginning of the chapter. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. A similar construction from Greek instead of Latin results in the word epinephrine (epi- = “above”; nephr- = “kidney”). In scientific usage, epinephrine is preferred in the United States, whereas adrenaline is preferred in Great Britain, because “adrenalin” was once a registered, proprietary drug name in the United States. Though the drug is no longer sold, the convention of referring to this molecule by the two different names persists. Similarly, norepinephrine and noradrenaline are two names for the same molecule.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+ea354296-0dbf-43da-90ac-8de372cecc65,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"Having understood the cholinergic and adrenergic systems, their role in the autonomic system is relatively simple to understand. All preganglionic fibers, both sympathetic and parasympathetic, release ACh. All ganglionic neurons—the targets of these preganglionic fibers—have nicotinic receptors in their cell membranes. The nicotinic receptor is a ligand-gated cation channel that results in depolarization of the postsynaptic membrane. The postganglionic parasympathetic fibers also release ACh, but the receptors on their targets are muscarinic receptors, which are G protein–coupled receptors and do not exclusively cause depolarization of the postsynaptic membrane. Postganglionic sympathetic fibers release norepinephrine, except for fibers that project to sweat glands and to blood vessels associated with skeletal muscles, which release ACh (Table 16.1).",True,Chemical Signaling in the Autonomic Nervous System,,,,
+631ebf12-c456-47e2-8a9a-988a0a1c9950,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"Signaling molecules can belong to two broad groups. Neurotransmitters are released at synapses, whereas hormones are released into the bloodstream. These are simplistic definitions, but they can help to clarify this point. Acetylcholine can be considered a neurotransmitter because it is released by axons at synapses. The adrenergic system, however, presents a challenge. Postganglionic sympathetic fibers release norepinephrine, which can be considered a neurotransmitter. But the adrenal medulla releases epinephrine and norepinephrine into circulation, so they should be considered hormones.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+e330f2e1-440c-479d-aec8-86a22fc6ae1f,https://open.oregonstate.education/aandp/,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/aandp/chapter/16-1-divisions-of-the-autonomic-nervous-system/,"What are referred to here as synapses may not fit the strictest definition of synapse. Some sources will refer to the connection between a postganglionic fiber and a target effector as neuroeffector junctions; neurotransmitters, as defined above, would be called neuromodulators. The structure of postganglionic connections are not the typical synaptic end bulb that is found at the neuromuscular junction, but rather are chains of swellings along the length of a postganglionic fiber called a varicosity (Figure 16.1.4).",True,Chemical Signaling in the Autonomic Nervous System,Figure 16.1.4,16.1 Divisions of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1504_Autonomic_Varicosities.jpg,"Figure 16.1.4 – Autonomic Varicosities: The connection between autonomic fibers and target effectors is not the same as the typical synapse, such as the neuromuscular junction. Instead of a synaptic end bulb, a neurotransmitter is released from swellings along the length of a fiber that makes an extended network of connections in the target effector."
+d6023c5c-3e39-4dbf-b295-beea5a580bb9,https://open.oregonstate.education/aandp/,16.0 Introduction,https://open.oregonstate.education/aandp/chapter/16-0-introduction/,"The autonomic nervous system is often associated with the “fight-or-flight response,” which refers to the preparation of the body to either run away from a threat or to stand and fight in the face of that threat. To suggest what this means, consider the (very unlikely) situation of seeing a lioness hunting out on the savannah. Though this is not a common threat that humans deal with in the modern world, it represents the type of environment in which the human species thrived and adapted. The spread of humans around the world to the present state of the modern age occurred much more quickly than any species would adapt to environmental pressures such as predators. However, the reactions modern humans have in the modern world are based on these prehistoric situations. If your boss is walking down the hallway on Friday afternoon looking for “volunteers” to come in on the weekend, your response is the same as the prehistoric human seeing the lioness running across the savannah: fight or flight.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+3a51e17c-ad37-4eb2-9a56-0a615f22ef1e,https://open.oregonstate.education/aandp/,16.0 Introduction,https://open.oregonstate.education/aandp/chapter/16-0-introduction/,"Most likely, your response to your boss—not to mention the lioness—would be flight. Run away! The autonomic system is responsible for the physiological response to make that possible, and hopefully successful. Adrenaline starts to flood your circulatory system. Your heart rate increases. Sweat glands become active. The bronchi of the lungs dilate to allow more air exchange. Pupils dilate to increase visual information. Blood pressure increases in general, and blood vessels dilate in skeletal muscles. Time to run. Similar physiological responses would occur in preparation for fighting off the threat.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+51699243-d160-45db-a6bd-a4de9eb932d6,https://open.oregonstate.education/aandp/,16.0 Introduction,https://open.oregonstate.education/aandp/chapter/16-0-introduction/,"This response should sound a bit familiar. The autonomic nervous system is tied into emotional responses as well, and the fight-or-flight response probably sounds like a panic attack. In the modern world, these sorts of reactions are associated with anxiety as much as with response to a threat. It is engrained in the nervous system to respond like this. In fact, the adaptations of the autonomic nervous system probably predate the human species and are likely to be common to all mammals, and perhaps shared by many animals. That lioness might herself be threatened in some other situation.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+c185e975-dd32-4af6-b6c1-94b0c80947b4,https://open.oregonstate.education/aandp/,16.0 Introduction,https://open.oregonstate.education/aandp/chapter/16-0-introduction/,"However, the autonomic nervous system is not just about responding to threats. Besides the fight-or-flight response, there are the responses referred to as “rest and digest.” If that lioness is successful in her hunting, then she is going to rest from the exertion. Her heart rate will slow. Breathing will return to normal. The digestive system has a big job to do. Much of the function of the autonomic system is based on the connections within an autonomic, or visceral, reflex.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+8995e60b-3a9c-4590-9d6d-c769e9aff185,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes. The eyes are located within either orbit in the skull. The bony orbits surround the eyeballs, protecting them and anchoring the soft tissues of the eye (Figure 15.5.1). The eyelids, with lashes at their leading edges, help to protect the eye from abrasions by blocking particles that may land on the surface of the eye. The inner surface of each lid is a thin membrane known as the palpebral conjunctiva. The conjunctiva extends over the white areas of the eye (the sclera), connecting the eyelids to the eyeball. Tears are produced by the lacrimal gland, located beneath the lateral edges of the nose. Tears produced by this gland flow through the lacrimal duct to the medial corner of the eye, where the tears flow over the conjunctiva, washing away foreign particles.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.1,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1411_Eye_in_The_Orbit.jpg,Figure 15.5.1 – The Eye in the Orbit: The eye is located within the orbit and surrounded by soft tissues that protect and support its function. The orbit is surrounded by cranial bones of the skull.
+a01ad384-3eee-43fe-bd27-283c43ad74b4,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"Movement of the eye within the orbit is accomplished by the contraction of six extraocular muscles that originate from the bones of the orbit and insert into the surface of the eyeball (Figure 15.5.2). Four of the muscles are arranged at the cardinal points around the eye and are named for those locations. They are the superior rectus, medial rectus, inferior rectus, and lateral rectus. When each of these muscles contract, the eye to moves toward the contracting muscle. For example, when the superior rectus contracts, the eye rotates to look up. The superior oblique originates at the posterior orbit, near the origin of the four rectus muscles. However, the tendon of the oblique muscles threads through a pulley-like piece of cartilage known as the trochlea. The tendon inserts obliquely into the superior surface of the eye. The angle of the tendon through the trochlea means that contraction of the superior oblique rotates the eye medially. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. Rotation of the eye by the two oblique muscles is necessary because the eye is not perfectly aligned on the sagittal plane. When the eye looks up or down, the eye must also rotate slightly to compensate for the superior rectus pulling at approximately a 20-degree angle, rather than straight up. The same is true for the inferior rectus, which is compensated by contraction of the inferior oblique. A seventh muscle in the orbit is the levator palpebrae superioris, which is responsible for elevating and retracting the upper eyelid, a movement that usually occurs in concert with elevation of the eye by the superior rectus (see Figure 15.5.1).",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.2,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1412_Extraocular_Muscles.jpg,Figure 15.5.2 – Extraocular Muscles: The extraocular muscles move the eye within the orbit.
+f7de08a6-97a1-4bd8-bfdf-afd601c02a92,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The extraocular muscles are innervated by three cranial nerves. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. The superior oblique is innervated by the trochlear nerve. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. The motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+199e7162-00ac-4e78-bcc8-815a41220839,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The eye itself is a hollow sphere composed of three layers of tissue. The outermost layer is the fibrous tunic, which includes the white sclera and clear cornea. The sclera accounts for five sixths of the surface of the eye, most of which is not visible, though humans are unique compared with many other species in having so much of the “white of the eye” visible (Figure 15.5.3). The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. The middle layer of the eye is the vascular tunic, which is mostly composed of the choroid, ciliary body, and iris. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball. The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye. The iris is a smooth muscle that opens or closes the pupil, which is the hole at the center of the eye that allows light to enter. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. The innermost layer of the eye is the neural tunic, or retina, which contains the nervous tissue responsible for photoreception.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.3,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+68c2db6d-0eb7-4bd0-8650-11e965c431bc,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The eye is also divided into two cavities: the anterior cavity and the posterior cavity. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. It is filled with a watery fluid called the aqueous humor. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. The posterior cavity is filled with a more viscous fluid called the vitreous humor.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+db371f50-4f66-473f-a084-bc9eaf3213fd,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. The change in membrane potential alters the amount of neurotransmitter that the photoreceptor cells release onto bipolar cells in the outer synaptic layer. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The axons of RGCs, which lie at the innermost layer of the retina, collect at the optic disc and leave the eye as the optic nerve (see Figure 15.5.3). Because these axons pass through the retina, there are no photoreceptors at the very back of the eye, where the optic nerve begins. This creates a “blind spot” in the retina, and a corresponding blind spot in our visual field.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.3,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+e8550904-56fa-47bc-a265-29f0df045a8d,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"Note that the photoreceptors in the retina (rods and cones) are located behind the axons, RGCs, bipolar cells, and retinal blood vessels. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. However, at the exact center of the retina is a small area known as the fovea. At the fovea, the retina lacks the supporting cells and blood vessels, and only contains photoreceptors. Therefore, visual acuity, or the sharpness of vision, is greatest at the fovea. This is because the fovea is where the least amount of incoming light is absorbed by other retinal structures (see Figure 15.5.3). As one moves in either direction from this central point of the retina, visual acuity drops significantly. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. The visual stimulus in the middle of the field of view falls on the fovea and is in the sharpest focus. Without moving your eyes off that word, notice that words at the beginning or end of the paragraph are not in focus. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. As a result, a large part of the neural function of the eyes is concerned with moving the eyes and head so that important visual stimuli are centered on the fovea.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.3,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+c75c913d-90f9-454a-8425-df448a9214b9,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment (Figure 15.5.4). The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.4,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1414_Rods_and_Cones.jpg,"Figure 15.5.4 – Photoreceptor: (a) All photoreceptors have inner segments containing the nucleus and other important organelles and outer segments with membrane arrays containing the photosensitive opsin molecules. Rod outer segments are long columnar shapes with stacks of membrane-bound discs that contain the rhodopsin pigment. Cone outer segments are short, tapered shapes with folds of membrane in place of the discs in the rods. (b) Tissue of the retina shows a dense layer of nuclei of the rods and cones. LM × 800. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+a774893d-b349-4c37-a13b-64287ae7fe52,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. A single unit of light is called a photon, which is described in physics as a packet of energy with properties of both a particle and a wave. The energy of a photon is represented by its wavelength, with each wavelength of visible light corresponding to a particular color. Visible light is electromagnetic radiation with a wavelength between 380 and 720 nm. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. Light with a wavelength of 380 nm is blue whereas light with a wavelength of 720 nm is dark red. All other colors fall between red and blue at various points along the wavelength scale.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+a4d56e1b-0994-4fd0-ab6e-ac7c2d5d9461,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"Opsin pigments are actually transmembrane proteins that contain a cofactor known as retinal. Retinal is a hydrocarbon molecule related to vitamin A. When a photon hits retinal, the long hydrocarbon chain of the molecule is biochemically altered. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. This process is called photoisomerization. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. This molecule is referred to as 11-cis-retinal. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans– conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 15.5.5).",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.5,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1415_Retinal_Isomers.jpg,"Figure 15.5.5 – Retinal Isomers: The retinal molecule has two isomers, (a) one before a photon interacts with it and (b) one that is altered through photoisomerization."
+2e9c3505-a77b-436e-8028-b9dfe27db7dc,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The shape change of retinal in the photoreceptors initiates visual transduction in the retina. Activation of retinal and the opsin proteins result in activation of a G protein. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. After a bright flash of light, afterimages are usually seen in negative. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+895d91b7-6fb2-4ed0-8c50-f136be1be78d,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The opsins are sensitive to limited wavelengths of light. Rhodopsin, the photopigment in rods, is most sensitive to light at a wavelength of 498 nm. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 15.5.6). The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In normal sunlight, rhodopsin will be constantly bleached while the cones are active. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Rods are so sensitive to light that a single photon can result in an action potential from a rod’s corresponding RGC.",True,Chemical Signaling in the Autonomic Nervous System,Figure 15.5.6,15.5 Vision,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1416_Color_Sensitivity.jpg,Figure 15.5.6 – Comparison of Color Sensitivity of Photopigments: Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths.
+25d054d2-2edc-4f7f-bea1-5fb3257701d1,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,"The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Therefore, our low-light vision is—in essence—in grayscale. In other words, in a dark room, everything appears as a shade of gray. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory.",True,Chemical Signaling in the Autonomic Nervous System,,,,
+4f8f8428-53f6-417b-831b-e73c89f73417,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,optic tract,False,optic tract,,,,
+46d4ae73-cc5b-489f-a579-c463eeb5a7aa,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,suprachiasmatic nucleus,False,suprachiasmatic nucleus,,,,
+d523e456-26b4-4561-a6c8-16ec79a4fe0c,https://open.oregonstate.education/aandp/,15.5 Vision,https://open.oregonstate.education/aandp/chapter/15-5-vision/,primary sensory cortex,False,primary sensory cortex,,,,
+352396ed-338f-4bd0-b217-412a472cacfd,https://open.oregonstate.education/aandp/,15.4 Equilibrium,https://open.oregonstate.education/aandp/chapter/15-4-equilibrium/,"Along with audition, the inner ear is responsible for encoding information about equilibrium, the sense of balance. A similar mechanoreceptor—a hair cell with stereocilia—senses head position, head movement, and whether our bodies are in motion. These cells are located within the vestibule of the inner ear. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum.",True,primary sensory cortex,,,,
+9d6eb5ef-f84b-4d90-b288-c3b1a38bad66,https://open.oregonstate.education/aandp/,15.4 Equilibrium,https://open.oregonstate.education/aandp/chapter/15-4-equilibrium/,"The utricle and saccule are both largely composed of macula tissue (plural = maculae). The macula is composed of hair cells surrounded by support cells. The stereocilia of the hair cells extend into a viscous gel called the otolithic membrane (Figure 15.4.1). On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. The otoliths essentially make the otolithic membrane top-heavy. The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization.",True,primary sensory cortex,Figure 15.4.1,15.4 Equilibrium,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1409_Maculae_and_Equilibrium.jpg,"Figure 15.4.1 – Linear Acceleration Coding by Maculae: The maculae are specialized for sensing linear acceleration, such as when gravity acts on the tilting head, or if the head starts moving in a straight line. The difference in inertia between the hair cell stereocilia and the otolithic membrane in which they are embedded leads to a shearing force that causes the stereocilia to bend in the direction of that linear acceleration."
+c82e0ce6-ae81-4a7b-bf49-31e6db2ccb79,https://open.oregonstate.education/aandp/,15.4 Equilibrium,https://open.oregonstate.education/aandp/chapter/15-4-equilibrium/,"The semicircular canals are three ring-like extensions of the vestibule. One is oriented in the horizontal plane, whereas the other two are oriented in the vertical plane. The anterior and posterior vertical canals are oriented at approximately 45 degrees relative to the sagittal plane (Figure 15.4.2). The base of each semicircular canal, where it meets with the vestibule, connects to an enlarged region known as the ampulla. The ampulla contains the hair cells that respond to rotational movement, such as turning the head while saying “no.” The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement. The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.",True,primary sensory cortex,Figure 15.4.2,15.4 Equilibrium,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1410_Equilibrium_and_Semicircular_Canals.jpg,"Figure 15.4.2 – Rotational Coding by Semicircular Canals: Rotational movement of the head is encoded by the hair cells in the base of the semicircular canals. As one of the canals moves in an arc with the head, the internal fluid moves in the opposite direction, causing the cupula and stereocilia to bend. The movement of two canals within a plane results in information about the direction in which the head is moving, and activation of all six canals can give a very precise indication of head movement in three dimensions."
+b35784a8-e8db-4f42-bc3e-2bfc4a9325b7,https://open.oregonstate.education/aandp/,15.4 Equilibrium,https://open.oregonstate.education/aandp/chapter/15-4-equilibrium/,"Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals. The system contributes to controlling head and neck movements in response to vestibular signals. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Most of the axons terminate in the vestibular nuclei of the medulla. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information.",True,primary sensory cortex,,,,
+9ad4c4e8-7c9d-490a-bc82-03d7871ab430,https://open.oregonstate.education/aandp/,15.4 Equilibrium,https://open.oregonstate.education/aandp/chapter/15-4-equilibrium/,"Neurons in the vestibular nuclei project their axons to targets in the brain stem. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. These connections constitute the pathway of the vestibulo-ocular reflex (VOR), which compensates for head and body movement by stabilizing images on the retina (Figure 15.4.3). Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium.",True,primary sensory cortex,Figure 15.4.3,15.4 Equilibrium,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1419_Vestibulo-Ocular_Reflex.jpg,"Figure 15.4.3 – Vestibulo-ocular Reflex: Connections between the vestibular system and the cranial nerves controlling eye movement keep the eyes centered on a visual stimulus, even though the head is moving. During head movement, the eye muscles move the eyes in the opposite direction as the head movement, keeping the visual stimulus centered in the field of view."
+d555a927-2599-4a3f-9abe-dbf1c72d5ee7,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"Hearing, or audition, is the transduction of sound waves into a neural signal that is made possible by the structures of the ear (Figure 15.3.1). The large, fleshy structure on the lateral aspect of the head is known as the auricle. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The C-shaped curves of the auricle direct sound waves toward the auditory canal. The canal enters the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal is the tympanic membrane, or ear drum, which vibrates after it is struck by sound waves. The auricle, ear canal, and tympanic membrane are often referred to as the external ear. The middle ear consists of a space spanned by three small bones called the ossicles. The three ossicles are the malleus, incus, and stapes, which are Latin names that roughly translate to hammer, anvil, and stirrup. The malleus is attached to the tympanic membrane and articulates with the incus. The incus, in turn, articulates with the stapes. The stapes is then attached to the inner ear, where the sound waves will be transduced into a neural signal. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning.",True,primary sensory cortex,Figure 15.3.1,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1404_The_Structures_of_the_Ear.jpg,"Figure 15.3.1 – Structures of the Ear: The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively."
+7cc44b14-80ad-4b6f-9500-051f2114964b,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"The inner ear is often described as a bony labyrinth, as it is composed of a series of canals embedded within the temporal bone. It has two separate regions, the cochlea and the vestibule, which are responsible for hearing and balance, respectively. The neural signals from these two regions are relayed to the brain stem through separate fiber bundles. However, these two distinct bundles travel together from the inner ear to the brain stem as the vestibulocochlear nerve. Sound is transduced into neural signals within the cochlear region of the inner ear, which contains the sensory neurons of the spiral ganglia. These ganglia are located within the spiral-shaped cochlea of the inner ear. The cochlea is attached to the stapes through the oval window.",True,primary sensory cortex,,,,
+7521af5b-943f-44ce-a020-b579e05ee6f1,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"The oval window is located at the beginning of a fluid-filled tube within the cochlea called the scala vestibuli. The scala vestibuli extends from the oval window, travelling above the cochlear duct, which is the central cavity of the cochlea that contains the sound-transducing neurons. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. The scala tympani ends at the round window, which is covered by a membrane that contains the fluid within the scala. As vibrations of the ossicles travel through the oval window, the fluid of the scala vestibuli and scala tympani moves in a wave-like motion. The frequency of the fluid waves match the frequencies of the sound waves (Figure 15.3.2). The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani.",True,primary sensory cortex,Figure 15.3.2,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1405_Sound_Waves_and_the_Ear.jpg,"Figure 15.3.2 – Transmission of Sound Waves to Cochlea: A sound wave causes the tympanic membrane to vibrate. This vibration is amplified as it moves across the malleus, incus, and stapes. The amplified vibration is picked up by the oval window causing pressure waves in the fluid of the scala vestibuli and scala tympani. The complexity of the pressure waves is determined by the changes in amplitude and frequency of the sound waves entering the ear."
+7a1fbc9b-e2eb-4e8f-9956-6aa12f80fbf3,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"A cross-sectional view of the cochlea shows that the scala vestibuli and scala tympani run along both sides of the cochlear duct (Figure 15.3.3). The cochlear duct contains several organs of Corti, which tranduce the wave motion of the two scala into neural signals. The organs of Corti lie on top of the basilar membrane, which is the side of the cochlear duct located between the organs of Corti and the scala tympani. As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea. Lower frequency waves move the region of the basilar membrane that is near the tip of the cochlea.",True,primary sensory cortex,Figure 15.3.3,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1406_Cochlea.jpg,"Figure 15.3.3 – Cross Section of the Cochlea: The three major spaces within the cochlea are highlighted. The scala tympani and scala vestibuli lie on either side of the cochlear duct. The organ of Corti, containing the mechanoreceptor hair cells, is adjacent to the scala tympani, where it sits atop the basilar membrane."
+e595c5d8-bf26-4dae-bec0-7c85131744be,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cell’s apical surfaces (Figure 15.3.4). The stereocilia are an array of microvilli-like structures arranged from tallest to shortest. Protein fibers tether adjacent hairs together within each array, such that the array will bend in response to movements of the basilar membrane. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. When the pressure waves from the scala move the basilar membrane, the tectorial membrane slides across the stereocilia. This bends the stereocilia either toward or away from the tallest member of each array. When the stereocilia bend toward the tallest member of their array, tension in the protein tethers opens ion channels in the hair cell membrane. This will depolarize the hair cell membrane, triggering nerve impulses that travel down the afferent nerve fibers attached to the hair cells. When the stereocilia bend toward the shortest member of their array, the tension on the tethers slackens and the ion channels close. When no sound is present, and the stereocilia are standing straight, a small amount of tension still exists on the tethers, keeping the membrane potential of the hair cell slightly depolarized.",True,primary sensory cortex,Figure 15.3.4,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1407_The_Hair_Cell.jpg,"Figure 15.3.4 – Hair Cell: The hair cell is a mechanoreceptor with an array of stereocilia emerging from its apical surface. The stereocilia are tethered together by proteins that open ion channels when the array is bent toward the tallest member of their array, and closed when the array is bent toward the shortest member of their array."
+11dab03c-88a0-494f-8878-1a18abd7d68b,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 15.3.6). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.",True,primary sensory cortex,Figure 15.3.6,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1408_Frequency_Coding_in_The_Cochlea.jpg,"Figure 15.3.6 – Frequency Coding in the Cochlea: The standing sound wave generated in the cochlea by the movement of the oval window deflects the basilar membrane on the basis of the frequency of sound. Therefore, hair cells at the base of the cochlea are activated only by high frequencies, whereas those at the apex of the cochlea are activated only by low frequencies."
+c3ff2da8-e76c-4b5d-8079-ed3fa28ddb21,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears.",True,primary sensory cortex,,,,
+fecbd5ef-cc31-4dd1-8212-26557abe2eeb,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"Sound localization is a feature of central processing in the auditory nuclei of the brain stem. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 15.3.7). This time difference is an example of an interaural time difference. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. This is an example of an interaural intensity difference.",True,primary sensory cortex,Figure 15.3.7,15.3 Hearing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1418_Auditory_Brainstem_Mechanisms.jpg,Figure 15.3.7 – Auditory Brain Stem Mechanisms of Sound Localization: Localizing sound in the horizontal plane is achieved by processing in the medullary nuclei of the auditory system. Connections between neurons on either side are able to compare very slight differences in sound stimuli that arrive at either ear and represent interaural time and intensity differences.
+514e7c3f-bf35-4646-b2b7-2943b0c9906e,https://open.oregonstate.education/aandp/,15.3 Hearing,https://open.oregonstate.education/aandp/chapter/15-3-hearing/,"Auditory processing continues on to a nucleus in the midbrain called the inferior colliculus. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus.",True,primary sensory cortex,,,,
+148997ac-bb14-474f-9e20-274a6c01afba,https://open.oregonstate.education/aandp/,15.2 Smell,https://open.oregonstate.education/aandp/chapter/15-2-smell/,"Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. The olfactory receptor neurons are located in a small region within the superior nasal cavity (Figure 15.2.1). This region is referred to as the olfactory epithelium and contains bipolar sensory neurons. Each olfactory sensory neuron has dendrites that extend from the apical surface of the epithelium into the mucus lining the cavity. As airborne molecules are inhaled through the nose, they pass over the olfactory epithelial region and dissolve into the mucus. These odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites. The odorant–protein complex binds to a receptor protein within the cell membrane of an olfactory dendrite. These receptors are G protein–coupled, and will produce a graded membrane potential in the olfactory neurons.",True,primary sensory cortex,Figure 15.2.1,15.2 Smell,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1403_Olfaction.jpg,Figure 15.2.1 – The Olfactory System: (a) The olfactory system begins in the peripheral structures of the nasal cavity. (b) The olfactory receptor neurons are within the olfactory epithelium. (c) Axons of the olfactory receptor neurons project through the cribriform plate of the ethmoid bone and synapse with the neurons of the olfactory bulb (tissue source: simian). LM × 812. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+3a3a5225-177f-4763-b407-1e1833fa42ca,https://open.oregonstate.education/aandp/,15.2 Smell,https://open.oregonstate.education/aandp/chapter/15-2-smell/,"The axon of an olfactory neuron extends from the basal surface of the epithelium, through an olfactory foramen in the cribriform plate of the ethmoid bone, and into the brain. The group of axons called the olfactory tract connect to the olfactory bulb on the ventral surface of the frontal lobe. From there, the axons split to travel to several brain regions. Some travel to the cerebrum, specifically to the primary olfactory cortex that is located in the inferior and medial areas of the temporal lobe. Others project to structures within the limbic system and hypothalamus, where smells become associated with long-term memory and emotional responses. This is how certain smells trigger emotional memories, such as the smell of food associated with one’s birthplace. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. As a result, scents can not wake us from sleep: they do not excite the reticular activating system. This is why we use smoke detectors to alert us to fire danger using sound and smelling salts that burn the nasal epithelium to wake unconscious individuals. However, the intimate connection between the olfactory system and the cerebral cortex is one reason why smell can be a potent trigger of memories and emotion.",True,primary sensory cortex,,,,
+247bf358-8176-4f69-a8c1-eb62c7a93392,https://open.oregonstate.education/aandp/,15.2 Smell,https://open.oregonstate.education/aandp/chapter/15-2-smell/,"The nasal epithelium, including the olfactory cells, can be harmed by airborne toxic chemicals. Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. These new axons grow along the axons that are already in place in the cranial nerve.",True,primary sensory cortex,,,,
+aec1881f-4ab8-4894-8b6f-65bdf124fec8,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Only a few recognized submodalities exist within the sense of taste, or gustation. Until recently, only four tastes were recognized: sweet, salty, sour, and bitter. Research at the turn of the 20th century led to recognition of the fifth taste, umami, during the mid-1980s. Umami is a Japanese word that means “delicious taste,” and is often translated to mean savory. Very recent research has suggested that there may also be a sixth taste for fats, or lipids.",True,primary sensory cortex,,,,
+3045b11f-acb2-4736-a2ff-9b7171ed07b2,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Gustation is the special sense associated with the tongue. The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. Raised bumps called papillae (singular = papilla) contain the structures for gustatory transduction. There are four types of papillae, based on their appearance (Figure 15.1.1): circumvallate, foliate, filiform, and fungiform. Within the structure of the papillae are taste buds that contain specialized gustatory receptor cells for the transduction of taste stimuli. These receptor cells are sensitive to the chemicals contained within foods that are ingested, and they release neurotransmitters based on the amount of the chemical in the food. Neurotransmitters from the gustatory cells can activate sensory neurons in the facial, glossopharyngeal, and vagus cranial nerves.",True,primary sensory cortex,Figure 15.1.1,15.1 Taste,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1402_The_Tongue.jpg,"Figure 15.1.1 – The Tongue: The tongue is covered with small bumps, called papillae, which contain taste buds that are sensitive to chemicals in ingested food or drink. Different types of papillae are found in different regions of the tongue. The taste buds contain specialized gustatory receptor cells that respond to chemical stimuli dissolved in the saliva. These receptor cells activate sensory neurons that are part of the facial and glossopharyngeal nerves. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+ab48314c-12bf-4fe5-9485-0e8e9462c9d3,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Salty taste is simply the perception of sodium ions (Na+) in the saliva. When you eat something salty, the salt crystals dissociate into the component ions Na+ and Cl–, which dissolve into the saliva in your mouth. The Na+ concentration becomes high outside the gustatory cells, creating a strong concentration gradient that drives the diffusion of the ion into the cells. The entry of Na+ into these cells results in the depolarization of the cell membrane and the generation of a receptor potential.",True,primary sensory cortex,,,,
+f6b6de0d-c919-4893-abeb-68525b02cc29,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Sour taste is the perception of H+ concentration. Just as with sodium ions in salty flavors, these hydrogen ions enter the cell and trigger depolarization. Sour flavors are, essentially, the perception of acids in our food. Increasing hydrogen ion concentrations in the saliva (lowering saliva pH) triggers progressively stronger graded potentials in the gustatory cells. For example, orange juice—which contains citric acid—will taste sour because it has a pH value of approximately 3. Of course, it is often sweetened so that the sour taste is masked.",True,primary sensory cortex,,,,
+61891638-6d15-486d-a998-a2cc04d9ccbf,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"The first two tastes (salty and sour) are triggered by the cations Na+ and H+. The other tastes result from food molecules binding to a G protein–coupled receptor. A G protein signal transduction system ultimately leads to depolarization of the gustatory cell. The sweet taste is the sensitivity of gustatory cells to the presence of glucose dissolved in the saliva. Other monosaccharides such as fructose, or artificial sweeteners such as aspartame (NutraSweet™), saccharine, or sucralose (Splenda™) also activate the sweet receptors. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G protein–coupled receptor differently.",True,primary sensory cortex,,,,
+7048622e-513d-4562-95ba-38cc250c441e,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Bitter taste is similar to sweet in that food molecules bind to G protein–coupled receptors. However, there are a number of different ways in which this can happen because there are a large diversity of bitter-tasting molecules. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Likewise, some bitter molecules increase G protein activation within the gustatory cells, whereas other bitter molecules decrease G protein activation. The specific response depends on which molecule is binding to the receptor.",True,primary sensory cortex,,,,
+f1a8d4b0-a38c-4424-b34e-5e3a668efbcd,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"One major group of bitter-tasting molecules are alkaloids. Alkaloids are nitrogen containing molecules that are commonly found in bitter-tasting plant products, such as coffee, hops (in beer), tannins (in wine), tea, and aspirin. By containing toxic alkaloids, the plant is less susceptible to microbe infection and less attractive to herbivores.",True,primary sensory cortex,,,,
+5125f605-3690-46f2-a5f0-37e7599da2fc,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Therefore, the function of bitter taste may primarily be related to stimulating the gag reflex to avoid ingesting poisons. Because of this, many bitter foods that are normally ingested are often combined with a sweet component to make them more palatable (cream and sugar in coffee, for example). The highest concentration of bitter receptors appear to be in the posterior tongue, where a gag reflex could still spit out poisonous food.",True,primary sensory cortex,,,,
+7585d2fa-c58f-45d2-a537-bfb000e1593e,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"The taste known as umami is often referred to as the savory taste. Like sweet and bitter, it is based on the activation of G protein–coupled receptors by a specific molecule. The molecule that activates this receptor is the amino acid L-glutamate. Therefore, the umami flavor is often perceived while eating protein-rich foods. Not surprisingly, dishes that contain meat are often described as savory.",True,primary sensory cortex,,,,
+93b7131c-174b-4bb1-898d-51b91c499452,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. The facial nerve connects to taste buds in the anterior third of the tongue. The glossopharyngeal nerve connects to taste buds in the posterior two thirds of the tongue. The vagus nerve connects to taste buds in the extreme posterior of the tongue, verging on the pharynx, which are more sensitive to noxious stimuli such as bitterness.",True,primary sensory cortex,,,,
+7ab87957-aaf4-48fb-9533-e1a82aebbc83,https://open.oregonstate.education/aandp/,15.1 Taste,https://open.oregonstate.education/aandp/chapter/15-1-taste/,"The sensory pathway for gustation travels along the facial,  glossopharyngeal and vagus cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Axons from the solitary nucleus then project to the ventral posterior nucleus of the thalamus. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived.",True,primary sensory cortex,,,,
+8c50256d-585c-4945-b0fa-f3a77a3e860f,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,Sensory Pathways,False,Sensory Pathways,,,,
+48664d89-39f0-4619-9008-936823103e66,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Specific regions of the CNS coordinate different somatic processes using sensory inputs and motor outputs of peripheral nerves. A simple case is a reflex caused by a synapse between a dorsal sensory neuron axon and a motor neuron in the ventral horn. More complex arrangements are possible to integrate peripheral sensory information with higher processes. The important regions of the CNS that play a role in somatic processes can be separated into the spinal cord brain stem, diencephalon, cerebral cortex, and subcortical structures.",True,Sensory Pathways,,,,
+e1c3e23a-040f-47f0-8294-80468318564f,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,Cortical Processing,False,Cortical Processing,,,,
+6ecb27f0-4561-414a-b887-3cba544639f7,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"As described earlier, many of the sensory axons are positioned in the same way as their corresponding receptor cells in the body. This allows identification of the position of a stimulus on the basis of which receptor cells are sending information. The cerebral cortex also maintains this sensory topography in the particular areas of the cortex that correspond to the position of the receptor cells. The somatosensory cortex provides an example in which, in essence, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex. This mapping is often depicted using a sensory homunculus (Figure 14.5.2).",True,Cortical Processing,Figure 14.5.2,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1421_Sensory_Homunculus.jpg,Figure 14.5.2 – The Sensory Homunculus: A cartoon representation of the sensory homunculus arranged adjacent to the cortical region in which the processing takes place.
+de3a35ae-763c-4373-9d6c-3fda4be6a361,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The term homunculus comes from the Latin word for “little man” and refers to a map of the human body that is laid across a portion of the cerebral cortex. In the somatosensory cortex, the external genitals, feet, and lower legs are represented on the medial face of the gyrus within the longitudinal fissure. As the gyrus curves out of the fissure and along the surface of the parietal lobe, the body map continues through the thighs, hips, trunk, shoulders, arms, and hands. The head and face are just lateral to the fingers as the gyrus approaches the lateral sulcus. The representation of the body in this topographical map is medial to lateral from the lower to upper body. It is a continuation of the topographical arrangement seen in the dorsal column system, where axons from the lower body are carried in the fasciculus gracilis, whereas axons from the upper body are carried in the fasciculus cuneatus. As the dorsal column system continues into the medial lemniscus, these relationships are maintained. Also, the head and neck axons running from the trigeminal nuclei to the thalamus run adjacent to the upper body fibers. The connections through the thalamus maintain topography such that the anatomic information is preserved. Note that this correspondence does not result in a perfectly miniature scale version of the body, but rather exaggerates the more sensitive areas of the body, such as the fingers and lower face. Less sensitive areas of the body, such as the shoulders and back, are mapped to smaller areas on the cortex.",True,Cortical Processing,,,,
+f31a6c48-dc98-40d2-9ee9-1800be7997cd,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The cortex has been described as having specific regions that are responsible for processing specific information; there is the visual cortex, somatosensory cortex, gustatory cortex, etc. However, our experience of these senses is not divided. Instead, we experience what can be referred to as a seamless percept. Our perceptions of the various sensory modalities—though distinct in their content—are integrated by the brain so that we experience the world as a continuous whole.",True,Cortical Processing,,,,
+eef40952-c5ea-45eb-92e2-341901269957,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"In the cerebral cortex, sensory processing begins at the primary sensory cortex, then proceeds to an association area, and finally, into a multimodal integration area. For example, somatosensory information inputs directly into the primary somatosensory cortex in the post-central gyrus of the parietal lobe where general awareness of sensation (location and type of sensation) begins. In the somatosensory association cortex details are integrated into a whole. In the highest level of association cortex details are integrated from entirely different modalities to form complete representations as we experience them.",True,Cortical Processing,,,,
+ad034bdc-75ca-4151-81cb-cbc7de2d00d8,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The defining characteristic of the somatic nervous system is that it controls skeletal muscles. Somatic senses inform the nervous system about the external environment, but the response to that is through voluntary muscle movement. The term “voluntary” suggests that there is a conscious decision to make a movement. However, some aspects of the somatic system use voluntary muscles without conscious control. One example is the ability of our breathing to switch to unconscious control while we are focused on another task. However, the muscles that are responsible for the basic process of breathing are also utilized for speech, which is entirely voluntary.",True,Cortical Processing,,,,
+10736676-31fb-4e71-9cde-288a75050d77,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Let’s start with sensory stimuli that have been registered through receptor cells and the information relayed to the CNS along ascending pathways. In the cerebral cortex, the initial processing of sensory perception progresses to associative processing and then integration in multimodal areas of cortex. These levels of processing can lead to the incorporation of sensory perceptions into memory, but more importantly, they lead to a response. The completion of cortical processing through the primary, associative, and integrative sensory areas initiates a similar progression of motor processing, usually in different cortical areas.",True,Cortical Processing,,,,
+2ebc0fd8-1022-45ba-bdcf-cffe5668b162,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Whereas the sensory cortical areas are located in the occipital, temporal, and parietal lobes, motor functions are largely controlled by the frontal lobe. The most anterior regions of the frontal lobe—the prefrontal areas—are important for executive functions, which are those cognitive functions that lead to goal-directed behaviors. These higher cognitive processes include working memory, which has been called a “mental scratch pad,” that can help organize and represent information that is not in the immediate environment. The prefrontal lobe is responsible for aspects of attention, such as inhibiting distracting thoughts and actions so that a person can focus on a goal and direct behavior toward achieving that goal.",True,Cortical Processing,,,,
+a7f901b5-7f67-4e7c-a2c3-9a5f51037901,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The functions of the prefrontal cortex are integral to the personality of an individual, because it is largely responsible for what a person intends to do and how they accomplish those plans. A famous case of damage to the prefrontal cortex is that of Phineas Gage, dating back to 1848. He was a railroad worker who had a metal spike impale his prefrontal cortex (Figure 14.5.3). He survived the accident, but according to second-hand accounts, his personality changed drastically. Friends described him as no longer acting like himself. Whereas he was a hardworking, amiable man before the accident, he turned into an irritable, temperamental, and lazy man after the accident. Many of the accounts of his change may have been inflated in the retelling, and some behavior was likely attributable to alcohol used as a pain medication. However, the accounts suggest that some aspects of his personality did change. Also, there is new evidence that though his life changed dramatically, he was able to become a functioning stagecoach driver, suggesting that the brain has the ability to recover even from major trauma such as this.",True,Cortical Processing,Figure 14.5.3,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Phineas_gage_-_1868_skull_diagram.jpg,"Figure 14.5.3 – Phineas Gage: The victim of an accident while working on a railroad in 1848, Phineas Gage had a large iron rod impaled through the prefrontal cortex of his frontal lobe. After the accident, his personality appeared to change, but he eventually learned to cope with the trauma and lived as a coach driver even after such a traumatic event. (credit b: John M. Harlow, MD)"
+36dae701-8b3f-4599-adf0-78c9462c69d9,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"In generating motor responses, the executive functions of the prefrontal cortex will need to initiate actual movements. One way to define the prefrontal area is any region of the frontal lobe that does not elicit movement when electrically stimulated. These are primarily in the anterior part of the frontal lobe. The regions of the frontal lobe that remain are the regions of the cortex that produce movement. The prefrontal areas project into the secondary motor cortices, which include the premotor cortex and the supplemental motor area.",True,Cortical Processing,,,,
+30baf4cd-1d06-4d10-9f98-ef48f88d2238,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Two important regions that assist in planning and coordinating movements are located adjacent to the primary motor cortex. The premotor cortex is more lateral, whereas the supplemental motor area is more medial and superior. The premotor area aids in controlling movements of the core muscles to maintain posture during movement, whereas the supplemental motor area is hypothesized to be responsible for planning and coordinating movement. The supplemental motor area also manages sequential movements that are based on prior experience (that is, learned movements). Neurons in these areas are most active leading up to the initiation of movement. For example, these areas might prepare the body for the movements necessary to drive a car in anticipation of a traffic light changing.",True,Cortical Processing,,,,
+a87ffb3b-ce0f-4bd2-9eb8-bcb7883536a2,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Adjacent to these two regions are two specialized motor planning centers. The frontal eye fields are responsible for moving the eyes in response to visual stimuli. There are direct connections between the frontal eye fields and the superior colliculus. Also, anterior to the premotor cortex and primary motor cortex is Broca’s area. This area is responsible for controlling movements of the structures of speech production. The area is named after a French surgeon and anatomist who studied patients who could not produce speech. They did not have impairments to understanding speech, only to producing speech sounds, suggesting a damaged or underdeveloped Broca’s area.",True,Cortical Processing,,,,
+585f0697-9010-4343-99f2-a6a569903067,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The primary motor cortex is located in the precentral gyrus of the frontal lobe. A neurosurgeon, Walter Penfield, described much of the basic understanding of the primary motor cortex by electrically stimulating the surface of the cerebrum. Penfield would probe the surface of the cortex while the patient was only under local anesthesia so that he could observe responses to the stimulation. This led to the belief that the precentral gyrus directly stimulated muscle movement. We now know that the primary motor cortex receives input from several areas that aid in planning movement, and its principle output stimulates spinal cord neurons to stimulate skeletal muscle contraction.",True,Cortical Processing,,,,
+fd27de35-aec6-4dfe-baee-e7f5efbcd3d9,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The primary motor cortex is arranged in a similar fashion to the primary somatosensory cortex, in that it has a topographical map of the body, creating a motor homunculus (see Chapter 14.2 Figure 14.2.5). The neurons responsible for musculature in the feet and lower legs are in the medial wall of the precentral gyrus, with the thighs, trunk, and shoulder at the crest of the longitudinal fissure. The hand and face are in the lateral face of the gyrus. Also, the relative space allotted for the different regions is exaggerated in muscles that have greater enervation. The greatest amount of cortical space is given to muscles that perform fine, agile movements, such as the muscles of the fingers and the lower face that are parts of small motor units. The “power muscles” that perform coarser movements, such as the buttock and back muscles, occupy much less space on the motor cortex.",True,Cortical Processing,Figure 14.2.5,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1317_CFS_Circulation.jpg,"Figure 14.2.5 – Cerebrospinal Fluid Circulation: The choroid plexus in the four ventricles produce CSF, which is circulated through the ventricular system and then enters the subarachnoid space through the median and lateral apertures. The CSF is then reabsorbed into the blood at the arachnoid granulations, where the arachnoid membrane emerges into the dural sinuses."
+0fa604dc-43bf-47cd-90ef-5ade8b5a435e,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,Descending Pathways,False,Descending Pathways,,,,
+ea3feeb7-f36f-4427-818e-6ddb3ea5d701,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The motor output from the cortex descends into the brain stem and to the spinal cord to control the musculature through motor neurons. Neurons located in the primary motor cortex, named Betz cells, are large cortical neurons that synapse with lower motor neurons in the spinal cord or the brain stem. The two descending pathways travelled by the axons of Betz cells are the corticospinal tract and the corticobulbar tract. Both tracts are named for their origin in the cortex and their targets—either the spinal cord or the brain stem (the term “bulbar” refers to the brain stem as the bulb, or enlargement, at the top of the spinal cord).",True,Descending Pathways,,,,
+d4f2c6b6-c3f7-4c81-90b1-5952fb6c8385,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"These two descending pathways are responsible for the conscious or voluntary movements of skeletal muscles. Any motor command from the primary motor cortex is sent down the axons of the Betz cells to activate upper motor neurons in either the cranial motor nuclei or in the ventral horn of the spinal cord. The axons of the corticobulbar tract are ipsilateral, meaning they project from the cortex to the motor nucleus on the same side of the nervous system. Conversely, the axons of the corticospinal tract are largely contralateral, meaning that they cross the midline of the brain stem or spinal cord and synapse on the opposite side of the body. Therefore, the right motor cortex of the cerebrum controls muscles on the left side of the body, and vice versa.",True,Descending Pathways,,,,
+3e609b08-9717-4e43-af52-a63b8592ce1a,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The corticospinal tract descends from the cortex through the deep white matter of the cerebrum. It then passes between the caudate nucleus and putamen of the basal nuclei as a bundle called the internal capsule. The tract then passes through the midbrain as the cerebral peduncles, after which it burrows through the pons. Upon entering the medulla, the tracts make up the large white matter tract referred to as the pyramids (Figure 14.5.4). The defining landmark of the medullary-spinal border is the pyramidal decussation, which is where most of the fibers in the corticospinal tract cross over to the opposite side of the brain. At this point, the tract separates into two parts, which have control over different domains of the musculature.",True,Descending Pathways,Figure 14.5.4,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1426_Corticospinal_Pathway.jpg,"Figure 14.5.4 – Corticospinal Tract: The major descending tract that controls skeletal muscle movements is the corticospinal tract. It is composed of two neurons, the upper motor neuron and the lower motor neuron. The upper motor neuron has its cell body in the primary motor cortex of the frontal lobe and synapses on the lower motor neuron, which is in the ventral horn of the spinal cord and projects to the skeletal muscle in the periphery."
+b8d8637e-22e5-4b78-9ce8-f34aa19508d7,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,Extrapyramidal Controls,False,Extrapyramidal Controls,,,,
+6718f96d-fe5c-4b0e-baa4-dba6ba1efcaf,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Other descending connections between the brain and the spinal cord are called the extrapyramidal system. The name comes from the fact that this system is outside the corticospinal pathway, which includes the pyramids in the medulla. A few pathways originating from the brain stem contribute to this system.",True,Extrapyramidal Controls,,,,
+daefa9c7-588d-4ea4-9af2-bdf51ff2464b,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The tectospinal tract projects from the midbrain to the spinal cord and is important for postural movements that are driven by the superior colliculus. The name of the tract comes from an alternate name for the superior colliculus, which is the tectum. The reticulospinal tract connects the reticular system, a diffuse region of gray matter in the brain stem, with the spinal cord. This tract influences trunk and proximal limb muscles related to posture and locomotion. The reticulospinal tract also contributes to muscle tone and influences autonomic functions. The vestibulospinal tract connects the brain stem nuclei of the vestibular system with the spinal cord. This allows posture, movement, and balance to be modulated on the basis of equilibrium information provided by the vestibular system.",True,Extrapyramidal Controls,,,,
+eac3519a-48fb-482e-ae0c-90ae659501db,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The pathways of the extrapyramidal system are influenced by subcortical structures. For example, connections between the secondary motor cortices and the extrapyramidal system modulate spine and cranium movements. The basal nuclei, which are important for regulating movement initiated by the CNS, influence the extrapyramidal system as well as its thalamic feedback to the motor cortex.",True,Extrapyramidal Controls,,,,
+bd9bcb7f-9e2d-4ce7-bbd7-0d0bb811467a,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"The conscious movement of our muscles is more complicated than simply sending a single command from the precentral gyrus down to the proper motor neurons. During the movement of any body part, our muscles relay information back to the brain, and the brain is constantly sending “revised” instructions back to the muscles. The cerebellum is important in contributing to the motor system because it compares cerebral motor commands with proprioceptive feedback. The corticospinal fibers that project to the ventral horn of the spinal cord have branches that also synapse in the pons, which project to the cerebellum. Also, the proprioceptive sensations of the dorsal column system have a collateral projection to the medulla that projects to the cerebellum. These two streams of information are compared in the cerebellar cortex. Conflicts between the motor commands sent by the cerebrum and body position information provided by the proprioceptors cause the cerebellum to stimulate the red nucleus of the midbrain. The red nucleus then sends corrective commands to the spinal cord along the rubrospinal tract. The name of this tract comes from the word for red that is seen in the English word “ruby.”",True,Extrapyramidal Controls,,,,
+d2abbfb6-4050-421b-a257-f1427af31d39,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"A good example of how the cerebellum corrects cerebral motor commands can be illustrated by walking in water. An original motor command from the cerebrum to walk will result in a highly coordinated set of learned movements. However, in water, the body cannot actually perform a typical walking movement as instructed. The cerebellum can alter the motor command, stimulating the leg muscles to take larger steps to overcome the water resistance. The cerebellum can make the necessary changes through the rubrospinal tract. Modulating the basic command to walk also relies on spinal reflexes, but the cerebellum is responsible for calculating the appropriate response. When the cerebellum does not work properly, coordination and balance are severely affected. The most dramatic example of this is during the overconsumption of alcohol. Alcohol inhibits the ability of the cerebellum to interpret proprioceptive feedback, making it more difficult to coordinate body movements, such as walking a straight line, or guide the movement of the hand to touch the tip of the nose.",True,Extrapyramidal Controls,,,,
+9950a549-1d4c-46f1-9400-c5cc9043bc12,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,The Sensory and Motor Exams,False,The Sensory and Motor Exams,,,,
+303e8f2c-0cce-4bde-8017-60cd71018521,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,"Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 14.5.5). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.",True,The Sensory and Motor Exams,Figure 14.5.5,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1615_Locations_Spinal_Fiber_Tracts.jpg,Figure 14.5.5 Locations of Spinal Fiber Tracts
+31d9b3ad-ea70-4ff1-b139-cf3d56ce2759,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,inferior olive,False,inferior olive,,,,
+c8a42685-2c2f-49b9-8282-08f9bbc7ee15,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,vermis,False,vermis,,,,
+6f2615ef-6743-49de-a6dd-449ed84feecb,https://open.oregonstate.education/aandp/,14.5 Sensory and Motor Pathways,https://open.oregonstate.education/aandp/chapter/14-5-sensory-and-motor-pathways/,check reflex,False,check reflex,,,,
+e5a4f24f-a3c8-469f-afaf-63cc74ccda9e,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"The description of the CNS is concentrated on the structures of the brain, but the spinal cord is another major organ of the system. Whereas the brain develops out of expansions of the neural tube into primary and then secondary vesicles, the spinal cord maintains the tube structure and is only specialized into certain regions. As the spinal cord continues to develop in the newborn, anatomical features mark its surface. The anterior midline is marked by the anterior median fissure, and the posterior midline is marked by the posterior median sulcus. Axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.",True,check reflex,,,,
+a175454a-33cf-4813-a5c4-905ed80c5960,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions. This comes from the initial development of the spinal cord, which is divided into the basal plate and the alar plate. The basal plate is closest to the ventral midline of the neural tube, which will become the anterior face of the spinal cord and gives rise to motor neurons. The alar plate is on the dorsal side of the neural tube and gives rise to neurons that will receive sensory input from the periphery.",True,check reflex,,,,
+8a61d477-9082-4d4e-ae3a-9f390416a71b,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"The length of the spinal cord is divided into regions that correspond to the regions of the vertebral column. The name of a spinal cord region corresponds to the level at which spinal nerves pass through the intervertebral foramina. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, then the lumbar, and finally the sacral region. The spinal cord is not the full length of the vertebral column because the spinal cord does not grow significantly longer after the first or second year, but the skeleton continues to grow. The nerves that emerge from the spinal cord pass through the intervertebral formina at the respective levels. As the vertebral column grows, these nerves grow with it and result in a long bundle of nerves that resembles a horse’s tail and is named the cauda equina. The sacral spinal cord is at the level of the upper lumbar vertebral bones. The spinal nerves extend from their various levels to the proper level of the vertebral column.",True,check reflex,,,,
+28eef0a4-5a1a-4870-9077-ac2eb76889cb,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 14.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.",True,check reflex,Figure 14.4.1,14.4 The Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1313_Spinal_Cord_Cross_Section.jpg,"Figure 14.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+2eee94d5-62af-47df-9314-2868d9b12260,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"Some of the largest neurons of the spinal cord are the multipolar motor neurons in the anterior horn. The fibers that cause contraction of skeletal muscles are the axons of these neurons. The motor neuron that causes contraction of the big toe, for example, is located in the sacral spinal cord. The axon that has to reach all the way to the belly of that muscle may be a meter in length. The neuronal cell body that maintains that long fiber must be quite large, possibly several hundred micrometers in diameter, making it one of the largest cells in the body.",True,check reflex,,,,
+ad57367c-16ab-4391-ad93-c3b1a053d768,https://open.oregonstate.education/aandp/,14.4 The Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-4-the-spinal-cord/,"Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.",True,check reflex,,,,
+64998010-25bc-42a2-b469-cc39bc03d673,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The brain and the spinal cord are the central nervous system, and they represent the main organs of the nervous system. The spinal cord is a single structure, whereas the adult brain is described in terms of four major regions: the cerebrum, the diencephalon, the brain stem, and the cerebellum. A person’s conscious experiences are based on neural activity in the brain. The regulation of homeostasis is governed by a specialized region in the brain. The coordination of reflexes depends on the integration of sensory and motor pathways in the spinal cord.",True,check reflex,,,,
+32f41140-3a3c-463f-9a7a-355858f6ef81,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,The Cerebrum,False,The Cerebrum,,,,
+7d29f70b-1694-4e31-89ca-a24bd3faf2e1,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The iconic gray mantle of the human brain, which appears to make up most of the mass of the brain, is the cerebrum (Figure 14.3.1). The wrinkled portion is the cerebral cortex, and the rest of the structure is beneath that outer covering. There is a large separation between the two sides of the cerebrum called the longitudinal fissure. It separates the cerebrum into two distinct halves, a right and left cerebral hemisphere. Deep within the cerebrum, the white matter of the corpus callosum provides the major pathway for communication between the two hemispheres of the cerebral cortex.",True,The Cerebrum,Figure 14.3.1,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1305_CerebrumN-1.jpg,"Figure 14.3.1 – The Cerebrum: The cerebrum is a large component of the CNS in humans, and the most obvious aspect of it is the folded surface called the cerebral cortex."
+92464a38-cf21-4adc-8825-8b9d7b2b1e43,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"Many of the higher neurological functions, such as memory, emotion, and consciousness, are the result of cerebral function. The complexity of the cerebrum is different across vertebrate species. The cerebrum of the most primitive vertebrates is not much more than the connection for the sense of smell. In mammals, the cerebrum comprises the outer gray matter that is the cortex (from the Latin word meaning “bark of a tree”) and several deep nuclei that belong to three important functional groups. The basal nuclei are responsible for cognitive processing, the most important function being that associated with planning movements. The basal forebrain contains nuclei that are important in learning and memory. The limbic cortex is the region of the cerebral cortex that is part of the limbic system, a collection of structures involved in emotion, memory, and behavior.",True,The Cerebrum,,,,
+e86e8b69-c864-4836-9016-e1e6325c2ef3,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,Cognitive Abilities,False,Cognitive Abilities,,,,
+16896b61-5fe4-4ac6-939f-126541f58fe2,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The cerebrum, particularly the cerebral cortex, is the location of important cognitive functions that are the focus of the mental status exam. The regionalization of the cortex, initially described on the basis of anatomical evidence of cytoarchitecture, reveals the distribution of functionally distinct areas. Cortical regions can be described as primary sensory or motor areas, association areas, or multimodal integration areas. The functions attributed to these regions include attention, memory, language, speech, sensation, judgment, and abstract reasoning.",True,Cognitive Abilities,,,,
+54e04788-cc9e-4df6-8ef1-f2f780c65490,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The mental status exam addresses these cognitive abilities through a series of subtests designed to elicit particular behaviors ascribed to these functions. The loss of neurological function can illustrate the location of damage to the cerebrum. Memory functions are attributed to the temporal lobe, particularly the medial temporal lobe structures known as the hippocampus and amygdala, along with the adjacent cortex. Evidence of the importance of these structures comes from the side effects of a bilateral temporal lobectomy that were studied in detail in patient HM.",True,Cognitive Abilities,,,,
+c1083d03-b929-4061-ab4e-6d516a569208,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"Losses of language and speech functions, known as aphasias, are associated with damage to the important integration areas in the left hemisphere known as Broca’s or Wernicke’s areas, as well as the connections in the white matter between them. Different types of aphasia are named for the particular structures that are damaged. Assessment of the functions of the sensorium includes praxis and gnosis. The subtests related to these functions depend on multimodal integration, as well as language-dependent processing.",True,Cognitive Abilities,,,,
+5ea3868d-be19-4626-a70b-59fd364f8759,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The prefrontal cortex contains structures important for planning, judgment, reasoning, and working memory. Damage to these areas can result in changes to personality, mood, and behavior. The famous case of Phineas Gage suggests a role for this cortex in personality, as does the outdated practice of prefrontal lobectomy.",True,Cognitive Abilities,,,,
+c5b0b93b-2ec5-4605-b4cb-0c6318141483,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"Beneath the cerebral cortex are sets of nuclei known as subcortical nuclei that augment cortical processes. The nuclei of the basal forebrain serve as the primary location for acetylcholine production, which modulates the overall activity of the cortex, possibly leading to greater attention to sensory stimuli. Alzheimer’s disease is associated with a loss of neurons in the basal forebrain. The hippocampus and amygdala are medial-lobe structures that, along with the adjacent cortex, are involved in long-term memory formation and emotional responses. The basal nuclei are a set of nuclei in the cerebrum responsible for comparing cortical processing with the general state of activity in the nervous system to influence the likelihood of movement taking place. For example, while a student is sitting in a classroom listening to a lecture, the basal nuclei will keep the urge to jump up and scream from actually happening. (The basal nuclei are also referred to as the basal ganglia, although that is potentially confusing because the term ganglia is typically used for peripheral structures.)",True,Cognitive Abilities,,,,
+aae9b0cd-8286-4b99-a5e5-439793411804,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The major structures of the basal nuclei that control movement are the caudate, putamen, and globus pallidus, which are located deep in the cerebrum. The caudate is a long nucleus that follows the basic C-shape of the cerebrum from the frontal lobe, through the parietal and occipital lobes, into the temporal lobe. The putamen is mostly deep in the anterior regions of the frontal and parietal lobes. Together, the caudate and putamen are called the striatum. The globus pallidus is a layered nucleus that lies just medial to the putamen; they are called the lenticular nuclei because they look like curved pieces fitting together like lenses. The globus pallidus has two subdivisions, the external and internal segments, which are lateral and medial, respectively. These nuclei are depicted in a frontal section of the brain in Figure 14.3.6.",True,Cognitive Abilities,Figure 14.3.6,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1308_Frontal_Section_Basal_Nuclei-1.jpg,"Figure 14.3.6 – Frontal Section of Cerebral Cortex and Basal Nuclei: The major components of the basal nuclei, shown in a frontal section of the brain, are the caudate (just lateral to the lateral ventricle), the putamen (inferior to the caudate and separated by the large white-matter structure called the internal capsule), and the globus pallidus (medial to the putamen)."
+ea8d5f85-d67e-4c6d-8bce-6852bad3edc5,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The basal nuclei in the cerebrum are connected with a few more nuclei in the brain stem that together act as a functional group that forms a motor pathway. Two streams of information processing take place in the basal nuclei. All input to the basal nuclei is from the cortex into the striatum (Figure 14.3.7). The direct pathway is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr). The GPi/SNr then projects to the thalamus, which projects back to the cortex. The indirect pathway is the projection of axons from the striatum to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to GPi/SNr. The two streams both target the GPi/SNr, but one has a direct projection and the other goes through a few intervening nuclei. The direct pathway causes the disinhibition of the thalamus (inhibition of one cell on a target cell that then inhibits the first cell), whereas the indirect pathway causes, or reinforces, the normal inhibition of the thalamus. The thalamus then can either excite the cortex (as a result of the direct pathway) or fail to excite the cortex (as a result of the indirect pathway).",True,Cognitive Abilities,Figure 14.3.7,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1309_Basal_Nuclei_Connections-1.jpg,"Figure 14.3.7 – Connections of Basal Nuclei: Input to the basal nuclei is from the cerebral cortex, which is an excitatory connection releasing glutamate as a neurotransmitter. This input is to the striatum, or the caudate and putamen. In the direct pathway, the striatum projects to the internal segment of the globus pallidus and the substantia nigra pars reticulata (GPi/SNr). This is an inhibitory pathway, in which GABA is released at the synapse, and the target cells are hyperpolarized and less likely to fire. The output from the basal nuclei is to the thalamus, which is an inhibitory projection using GABA."
+322a5003-a694-4622-b955-3d81dc9b1669,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The switch between the two pathways is the substantia nigra pars compacta, which projects to the striatum and releases the neurotransmitter dopamine. Dopamine receptors are either excitatory (D1-type receptors) or inhibitory (D2-type receptors). The direct pathway is activated by dopamine, and the indirect pathway is inhibited by dopamine. When the substantia nigra pars compacta is firing, it signals to the basal nuclei that the body is in an active state, and movement will be more likely. When the substantia nigra pars compacta is silent, the body is in a passive state, and movement is inhibited. To illustrate this situation, while a student is sitting listening to a lecture, the substantia nigra pars compacta would be silent and the student less likely to get up and walk around. Likewise, while the professor is lecturing, and walking around at the front of the classroom, the professor’s substantia nigra pars compacta would be active, in keeping with his or her activity level.",True,Cognitive Abilities,,,,
+03bc117c-88ba-48fd-bbe3-8e58d79cf246,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"However, there are well-documented cases of language functions lost from damage to the right side of the brain. The deficits seen in damage to the left side of the brain are classified as aphasia, a loss of speech function; damage on the right side can affect the use of language. Right-side damage can result in a loss of ability to understand figurative aspects of speech, such as jokes, irony, or metaphors. Nonverbal aspects of speech can be affected by damage to the right side, such as facial expression or body language, and right-side damage can lead to a “flat affect” in speech, or a loss of emotional expression in speech—sounding like a robot when talking. Damage to language areas on the right side causes a condition called aprosodia where the patient has difficulty understanding or expressing the figurative part of speech.",True,Cognitive Abilities,,,,
+241bb31c-b013-48f7-b089-8434f07edc19,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,The Diencephalon,False,The Diencephalon,,,,
+f541c9e8-3e4f-4713-b672-dbcb297c4d95,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The diencephalon is the one region of the adult brain that retains its name from embryologic development. The etymology of the word diencephalon translates to “through brain.” It is the connection between the cerebrum and the rest of the nervous system, with one exception. The rest of the brain, the spinal cord, and the PNS all send information to the cerebrum through the diencephalon. Output from the cerebrum passes through the diencephalon. The single exception is the system associated with olfaction, or the sense of smell, which connects directly with the cerebrum. In the earliest vertebrate species, the cerebrum was not much more than olfactory bulbs that received peripheral information about the chemical environment (to call it smell in these organisms is imprecise because they lived in the ocean).",True,The Diencephalon,,,,
+39ad87e4-5150-4453-9da9-159f231d2d5d,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The diencephalon is deep beneath the cerebrum and constitutes the walls of the third ventricle. The diencephalon can be described as any region of the brain with “thalamus” in its name. The two major regions of the diencephalon are the thalamus itself and the hypothalamus (Figure 14.3.8). There are other structures, such as the epithalamus, which contains the pineal gland, or the subthalamus, which includes the subthalamic nucleus that is part of the basal nuclei.",True,The Diencephalon,Figure 14.3.8,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1310_Diencephalon.jpg,"Figure 14.3.8 – The Diencephalon: The diencephalon is composed primarily of the thalamus and hypothalamus, which together define the walls of the third ventricle. The thalami are two elongated, ovoid structures on either side of the midline that make contact in the middle. The hypothalamus is inferior and anterior to the thalamus, culminating in a sharp angle to which the pituitary gland is attached."
+1fb5c4fb-17a2-4dd3-b78a-d4968b593f7e,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,Brain Stem,False,Brain Stem,,,,
+290fde74-cd01-4641-b270-3d854b35b57c,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The midbrain and the pons and medulla of the hindbrain are collectively referred to as the “brain stem” (Figure 14.3.9). The structure emerges from the ventral surface of the forebrain as a tapering cone that connects the brain to the spinal cord. Attached to the brain stem, but considered a separate region of the adult brain, is the cerebellum. The midbrain coordinates sensory representations of the visual, auditory, and somatosensory perceptual spaces. The pons is the main connection with the cerebellum. The pons and the medulla regulate several crucial functions, including the cardiovascular and respiratory systems.",True,Brain Stem,Figure 14.3.9,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1311_Brain_Stem.jpg,"Figure 14.3.9 – The Brain Stem: The brain stem comprises three regions: the midbrain, the pons, and the medulla."
+831f5657-42c1-49fe-9341-1597fd24e843,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The cranial nerves connect through the brain stem and provide the brain with the sensory input and motor output associated with the head and neck, including most of the special senses. The major ascending and descending pathways between the spinal cord and brain, specifically the cerebrum, pass through the brain stem.",True,Brain Stem,,,,
+9db8d14b-26ba-42d7-9da3-e86b3305e416,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,The Cerebellum,False,The Cerebellum,,,,
+5e05d3c3-6b4f-48f1-a62e-e66f7d0fdb21,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The cerebellum, as the name suggests, is the “little brain.” It is covered in gyri and sulci like the cerebrum, and looks like a miniature version of that part of the brain (Figure 14.3.10). The cerebellum is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord. It accounts for approximately 10 percent of the mass of the brain.",True,The Cerebellum,Figure 14.3.10,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1312_CerebellumN.jpg,"Figure 14.3.10 – The Cerebellum: The cerebellum is situated on the posterior surface of the brain stem. Descending input from the cerebellum enters through the large white matter structure of the pons. Ascending input from the periphery and spinal cord enters through the fibers of the inferior olive. Output goes to the midbrain, which sends a descending signal to the spinal cord."
+c03f5447-a406-4f54-a13c-3d762c88fc7c,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"Descending fibers from the cerebrum have branches that connect to neurons in the pons. Those neurons project into the cerebellum, providing a copy of motor commands sent to the spinal cord. Sensory information from the periphery, which enters through spinal or cranial nerves, is copied to a nucleus in the medulla known as the inferior olive. Fibers from this nucleus enter the cerebellum and are compared with the descending commands from the cerebrum. If the primary motor cortex of the frontal lobe sends a command down to the spinal cord to initiate walking, a copy of that instruction is sent to the cerebellum. Sensory feedback from the muscles and joints, proprioceptive information about the movements of walking, and sensations of balance are sent to the cerebellum through the inferior olive and the cerebellum compares them. If walking is not coordinated, perhaps because the ground is uneven or a strong wind is blowing, then the cerebellum sends out a corrective command to compensate for the difference between the original cortical command and the sensory feedback. The output of the cerebellum is into the midbrain, which then sends a descending input to the spinal cord to correct the messages going to skeletal muscles.",True,The Cerebellum,,,,
+e6a26fce-2dde-43ba-8cd8-51d847009923,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,The Spinal Cord,False,The Spinal Cord,,,,
+e01bcfff-2dde-4d76-80b8-065b52c61a74,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The description of the CNS is concentrated on the structures of the brain, but the spinal cord is another major organ of the system. Whereas the brain develops out of expansions of the neural tube into primary and then secondary vesicles, the spinal cord maintains the tube structure and is only specialized into certain regions. As the spinal cord continues to develop in the newborn, anatomical features mark its surface. The anterior midline is marked by the anterior median fissure, and the posterior midline is marked by the posterior median sulcus. Axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.",True,The Spinal Cord,,,,
+6694569e-f907-414d-979f-49eff7152b17,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions. This comes from the initial development of the spinal cord, which is divided into the basal plate and the alar plate. The basal plate is closest to the ventral midline of the neural tube, which will become the anterior face of the spinal cord and gives rise to motor neurons. The alar plate is on the dorsal side of the neural tube and gives rise to neurons that will receive sensory input from the periphery.",True,The Spinal Cord,,,,
+b38fb0b5-e48b-4817-9611-30c39a9522af,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,"The length of the spinal cord is divided into regions that correspond to the regions of the vertebral column. The name of a spinal cord region corresponds to the level at which spinal nerves pass through the intervertebral foramina. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, then the lumbar, and finally the sacral region. The spinal cord is not the full length of the vertebral column because the spinal cord does not grow significantly longer after the first or second year, but the skeleton continues to grow. The nerves that emerge from the spinal cord pass through the intervertebral formina at the respective levels. As the vertebral column grows, these nerves grow with it and result in a long bundle of nerves that resembles a horse’s tail and is named the cauda equina. The sacral spinal cord is at the level of the upper lumbar vertebral bones. The spinal nerves extend from their various levels to the proper level of the vertebral column.",True,The Spinal Cord,,,,
+6c40ceaf-bcbd-401c-a366-078aa92bef12,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,r?,False,r?,,,,
+f1193741-8c04-4892-a88a-94a67e39e1e3,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,nucleus,False,nucleus,,,,
+83c4d119-d44d-409b-be88-8e00a01a8a71,https://open.oregonstate.education/aandp/,14.3 The Brain and Spinal Cord,https://open.oregonstate.education/aandp/chapter/14-3-the-brain-and-spinal-cord/,tract,False,tract,,,,
+0a55254d-391f-4451-8830-79bd6dca94cc,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"The CNS is crucial to the operation of the body, and any compromise in the brain and spinal cord can lead to severe difficulties. The CNS has a privileged blood supply, as suggested by the blood-brain barrier. The function of the tissue in the CNS is crucial to the survival of the organism, so the contents of the blood cannot simply pass into the central nervous tissue. To protect this region from the toxins and pathogens that may be traveling through the blood stream, there is strict control over what can move out of the general systems and into the brain and spinal cord. Because of this privilege, the CNS needs specialized structures for the maintenance of circulation. This begins with a unique arrangement of blood vessels carrying fresh blood into the CNS. Beyond the supply of blood, the CNS filters that blood into cerebrospinal fluid (CSF), which is then circulated through the cavities of the brain and spinal cord called ventricles.",True,tract,,,,
+4209a623-6730-4531-a142-c7ef25d08d97,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,Blood Supply to the Brain,False,Blood Supply to the Brain,,,,
+7df28724-a000-4101-8b98-7a73b149d4c8,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"A lack of oxygen to the CNS can be devastating, and the cardiovascular system has specific regulatory reflexes to ensure that the blood supply is not interrupted. There are multiple routes for blood to get into the CNS, with specializations to protect that blood supply and to maximize the ability of the brain to get an uninterrupted perfusion.",True,Blood Supply to the Brain,,,,
+e844d8ef-c084-417c-b3b8-1fdb3cc8f67f,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"Damage to the nervous system can be limited to individual structures or can be distributed across broad areas of the brain and spinal cord. Localized, limited injury to the nervous system is most often the result of circulatory problems. Neurons are very sensitive to oxygen deprivation and will start to deteriorate within 1 or 2 minutes, and permanent damage (cell death) could result within a few hours. The loss of blood flow to part of the brain is known as a stroke, or a cerebrovascular accident (CVA).",True,Blood Supply to the Brain,,,,
+c67173af-0214-4b79-919b-8bfcdb692868,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"There are two main types of stroke, depending on how the blood supply is compromised: ischemic and hemorrhagic. An ischemic stroke is the loss of blood flow to an area because vessels are blocked or narrowed. This is often caused by an embolus, which may be a blood clot or fat deposit. Ischemia may also be the result of thickening of the blood vessel wall, or a drop in blood volume in the brain known as hypovolemia.",True,Blood Supply to the Brain,,,,
+7cf3272e-f862-4ef6-940d-58ab807be4a1,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"A related type of CVA is known as a transient ischemic attack (TIA), which is similar to a stroke although it does not last as long. The diagnostic definition of a stroke includes effects that last at least 24 hours. Any stroke symptoms that are resolved within a 24-hour period because of restoration of adequate blood flow are classified as a TIA.",True,Blood Supply to the Brain,,,,
+1e13bdf2-0ffc-487f-a8f2-8bab0c1811a3,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"A hemorrhagic stroke is bleeding into the brain because of a damaged blood vessel. Accumulated blood fills a region of the cranial vault and presses against the tissue in the brain (Figure 14.2.3). Physical pressure on the brain can cause the loss of function, as well as the squeezing of local arteries resulting in compromised blood flow beyond the site of the hemorrhage. As blood pools in the nervous tissue and the vasculature is damaged, the blood-brain barrier can break down and allow additional fluid to accumulate in the region, which is known as edema.",True,Blood Supply to the Brain,Figure 14.2.3,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1602_The_Hemorrhagic_Stroke-02.jpg,Figure 14.2.3 – Hemorrhagic Stroke: (a) A hemorrhage into the tissue of the cerebrum results in a large accumulation of blood with an additional edema in the adjacent tissue. The hemorrhagic area causes the entire brain to be disfigured as suggested here by the lateral ventricles being squeezed into the opposite hemisphere. (b) A CT scan shows an intraparenchymal hemorrhage within the parietal lobe. (credit b: James Heilman)
+041d2ca5-e547-4b7b-974a-892da1c6874a,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,Protective Coverings of the Brain and Spinal Cord,False,Protective Coverings of the Brain and Spinal Cord,,,,
+091f1ceb-f059-456b-bba5-8dd08e612d0e,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"The outer surface of the CNS is covered by a series of membranes composed of connective tissue called the meninges, which protect the brain. The dura mater is a thick fibrous layer and a strong protective sheath over the entire brain and spinal cord. It is anchored to the inner surface of the cranium and vertebral cavity. The arachnoid mater is a membrane of thin fibrous tissue that forms a loose sac around the CNS. Beneath the arachnoid is a thin, filamentous mesh called the arachnoid trabeculae, which looks like a spider web, giving this layer its name. Directly adjacent to the surface of the CNS is the pia mater, a thin fibrous membrane that follows the convolutions of gyri and sulci in the cerebral cortex and fits into other grooves and indentations (Figure 14.2.4).",True,Protective Coverings of the Brain and Spinal Cord,Figure 14.2.4,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1316_Meningeal_LayersN.jpg,"Figure 14.2.4 – Meningeal Layers of Superior Sagittal Sinus: The layers of the meninges in the longitudinal fissure of the superior sagittal sinus are shown, with the dura mater adjacent to the inner surface of the cranium, the pia mater adjacent to the surface of the brain, and the arachnoid and subarachnoid space between them. An arachnoid villus is shown emerging into the dural sinus to allow CSF to filter back into the blood for drainage."
+734e3b76-59da-491e-97b5-3b83be0ec37d,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,The Ventricular System,False,The Ventricular System,,,,
+2302102f-ee0c-4c88-b113-0597ae37d140,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,"Cerebrospinal fluid (CSF) circulates throughout and around the CNS. In other tissues, water and small molecules are filtered through capillaries as the major contributor to the interstitial fluid. In the brain, CSF is produced in special structures to perfuse through the nervous tissue of the CNS and is continuous with the interstitial fluid. Specifically, CSF circulates to remove metabolic wastes from the interstitial fluids of nervous tissues and return them to the blood stream. The ventricles are the open spaces within the brain where CSF circulates. In some of these spaces, CSF is produced by filtering of the blood that is performed by a specialized membrane known as a choroid plexus. The CSF circulates through all of the ventricles to eventually emerge into the subarachnoid space where it will be reabsorbed into the blood.",True,The Ventricular System,,,,
+301d532f-d270-4f5b-acc2-773f636532fb,https://open.oregonstate.education/aandp/,14.2 Blood Flow the meninges and Cerebrospinal Fluid Production and Circulation,https://open.oregonstate.education/aandp/chapter/14-2-blood-flow-the-meninges-and-cerebrospinal-fluid-production-and-circulation/,FAST,False,FAST,,,,
+2dade6fd-c785-41f8-b150-244b010ffab1,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"The brain is a complex organ composed of gray parts and white matter, which can be hard to distinguish. Starting from an embryologic perspective allows you to understand more easily how the parts relate to each other. The embryonic nervous system begins as a very simple structure—essentially just a straight line, which then gets increasingly complex. Looking at the development of the nervous system with a couple of early snapshots makes it easier to understand the whole complex system.",True,FAST,,,,
+6fae881c-e529-458a-827d-5fb6545af6fe,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"Many structures that appear to be adjacent in the adult brain are not connected, and the connections that exist may seem arbitrary. But there is an underlying order to the system that comes from how different parts develop. By following the developmental pattern, it is possible to learn what the major regions of the nervous system are.",True,FAST,,,,
+f581ef8d-6469-43c5-9566-cc21a53daefa,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,The Neural Tube,False,The Neural Tube,,,,
+5d0585f7-5c74-4b78-aa01-04c804be2091,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"To begin, a sperm cell and an egg cell fuse to become a fertilized egg. The fertilized egg cell, or zygote, starts dividing to generate the cells that make up an entire organism. Sixteen days after fertilization, the developing embryo’s cells belong to one of three germ layers that give rise to the different tissues in the body. The endoderm, or inner tissue, is responsible for generating the lining tissues of various spaces within the body, such as the mucosae of the digestive and respiratory systems. The mesoderm, or middle tissue, gives rise to most of the muscle and connective tissues. Finally the ectoderm, or outer tissue, develops into the integumentary system (the skin) and the nervous system. It is probably not difficult to see that the outer tissue of the embryo becomes the outer covering of the body. But how is it responsible for the nervous system?",True,The Neural Tube,,,,
+bf17f6b8-3291-4e83-a6c8-ee987289f9eb,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"As the embryo develops, a portion of the ectoderm differentiates into a specialized region of neuroectoderm, which is the precursor for the tissue of the nervous system. Molecular signals induce cells in this region to differentiate into the neuroepithelium, forming a neural plate. The cells then begin to change shape, causing the tissue to buckle and fold inward (Figure 14.1.1). A neural groove forms, visible as a line along the dorsal surface of the embryo. The ridge-like edge on either side of the neural groove is referred as the neural fold. As the neural folds come together and converge, the underlying structure forms into a tube just beneath the ectoderm called the neural tube. Cells from the neural folds then separate from the ectoderm to form a cluster of cells referred to as the neural crest, which runs lateral to the neural tube. The neural crest migrates away from the nascent, or embryonic, central nervous system (CNS) that will form along the neural groove and develops into several parts of the peripheral nervous system (PNS), including the enteric nervous tissue. Many tissues that are not part of the nervous system also arise from the neural crest, such as craniofacial cartilage and bone, and melanocytes.",True,The Neural Tube,Figure 14.1.1,14.1 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1301_Neural_Tube_Dev.jpg,"Figure 14.1.1 – Early Embryonic Development of Nervous System: The neuroectoderm begins to fold inward to form the neural groove. As the two sides of the neural groove converge, they form the neural tube, which lies beneath the ectoderm. The anterior end of the neural tube will develop into the brain, and the posterior portion will become the spinal cord. The neural crest develops into peripheral structures."
+527121d7-93ac-465c-823f-6e3e7f1e54df,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"At this point, the early nervous system is a simple, hollow tube. It runs from the anterior end of the embryo to the posterior end. Beginning at 25 days, the anterior end develops into the brain, and the posterior portion becomes the spinal cord. This is the most basic arrangement of tissue in the nervous system, and it gives rise to the more complex structures by the fourth week of development.",True,The Neural Tube,,,,
+37c4d4ab-1311-4e2b-b924-3618ac851a74,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,Primary Vesicles,False,Primary Vesicles,,,,
+f771cf9c-17b0-4947-8239-67e8e4b9d19d,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"As the anterior end of the neural tube starts to develop into the brain, it undergoes a couple of enlargements; the result is the production of sac-like vesicles. Similar to a child’s balloon animal, the long, straight neural tube begins to take on a new shape. Three vesicles form at the first stage, which are called primary vesicles. These vesicles are given names that are based on Greek words, the main root word being enkephalon, which means “brain” (en- = “inside”; kephalon = “head”). The prefix to each generally corresponds to its position along the length of the developing nervous system.",True,Primary Vesicles,,,,
+60ef3aae-aa6a-44a8-91f0-33c08c9d3023,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"The prosencephalonforebrain. The mesencephalon (mes- = “middle”) is the next vesicle, which can be called the midbrain. The third vesicle at this stage is the rhombencephalon. The first part of this word is also the root of the word rhombus, which is a geometrical figure with four sides of equal length (a square is a rhombus with 90° angles). Whereas prosencephalon and mesencephalon translate into the English words forebrain and midbrain, there is not a word for “four-sided-figure-brain.” However, the third vesicle can be called the hindbrain. One way of thinking about how the brain is arranged is to use these three regions—forebrain, midbrain, and hindbrain—which are based on the primary vesicle stage of development (Figure 14.1.2a).",True,Primary Vesicles,Figure 14.1.2,14.1 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1302_Brain_Vesicle_DevN.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions."
+f86298df-746c-4bc9-a9e4-abc4023f8cfd,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,Secondary Vesicles,False,Secondary Vesicles,,,,
+04f5a2d3-cf5e-4e4a-afa0-a6aa79f06d3a,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"The brain continues to develop, and the vesicles differentiate further (see Figure 14.1.2b). The three primary vesicles become five secondary vesicles. The prosencephalon enlarges into two new vesicles called the telencephalon and the diencephalon. The telecephalon will become the cerebrum. The diencephalon gives rise to several adult structures; two that will be important are the thalamus and the hypothalamus. In the embryonic diencephalon, a structure known as the eye cup develops, which will eventually become the retina, the nervous tissue of the eye called the retina. This is a rare example of nervous tissue developing as part of the CNS structures in the embryo, but becoming a peripheral structure in the fully formed nervous system.",True,Secondary Vesicles,Figure 14.1.2,14.1 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1302_Brain_Vesicle_DevN.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions."
+72e830d8-ca77-43ff-8e94-3b30dd5837e4,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"The mesencephalon does not differentiate into any finer divisions. The midbrain is an established region of the brain at the primary vesicle stage of development and remains that way. The rest of the brain develops around it and constitutes a large percentage of the mass of the brain. Dividing the brain into forebrain, midbrain, and hindbrain is useful in considering its developmental pattern, but the midbrain is a small proportion of the entire brain, relatively speaking.",True,Secondary Vesicles,,,,
+e0a490c7-aea8-4e6b-9f61-7efbd826d924,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"The rhombencephalon develops into the metencephalon and myelencephalon. The metencephalon corresponds to the adult structure known as the pons and also gives rise to the cerebellum. The cerebellum (from the Latin meaning “little brain”) accounts for about 10 percent of the mass of the brain and is an important structure in itself. The most significant connection between the cerebellum and the rest of the brain is at the pons, because the pons and cerebellum develop out of the same vesicle. The myelencephalon corresponds to the adult structure known as the medulla oblongata. The structures that come from the mesencephalon and rhombencephalon, except for the cerebellum, are collectively considered the brain stem, which specifically includes the midbrain, pons, and medulla.",True,Secondary Vesicles,,,,
+7d95615b-fab4-4063-84bd-418e35f7e933,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,Spinal Cord Development,False,Spinal Cord Development,,,,
+d4319315-93b1-48b7-be77-ec2f6e7ea484,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"While the brain is developing from the anterior neural tube, the spinal cord is developing from the posterior neural tube. However, its structure does not differ from the basic layout of the neural tube. It is a long, straight cord with a small, hollow space down the center. The neural tube is defined in terms of its anterior versus posterior portions, but it also has a dorsal–ventral dimension. As the neural tube separates from the rest of the ectoderm, the side closest to the surface is dorsal, and the deeper side is ventral.",True,Spinal Cord Development,,,,
+2d47e9d2-04ce-4a68-b608-07e089f5b525,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"As the spinal cord develops, the cells making up the wall of the neural tube proliferate and differentiate into the neurons and glia of the spinal cord. The dorsal tissues will be associated with sensory functions, and the ventral tissues will be associated with motor functions.",True,Spinal Cord Development,,,,
+f8e6ebe1-2485-4c94-b5a7-94f7c1fa7036,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,Relating Embryonic Development to the Adult Brain,False,Relating Embryonic Development to the Adult Brain,,,,
+e4028384-f37a-4f88-8519-72cb6e724574,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension of the nervous system, which is called the neuraxis. The embryonic nervous system in mammals can be said to have a standard arrangement. Humans (and other primates, to some degree) make this complicated by standing up and walking on two legs. The anterior–posterior dimension of the neuraxis overlays the superior–inferior dimension of the body. However, there is a major curve between the brain stem and forebrain, which is called the cephalic flexure. Because of this, the neuraxis starts in an inferior position—the end of the spinal cord—and ends in an anterior position, the front of the cerebrum. If this is confusing, just imagine a four-legged animal standing up on two legs. Without the flexure in the brain stem, and at the top of the neck, that animal would be looking straight up instead of straight in front (Figure 14.1.3).",True,Relating Embryonic Development to the Adult Brain,Figure 14.1.3,14.1 Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1303_Human_Neuroaxis.jpg,"Figure 14.1.3 – Human Neuraxis: The mammalian nervous system is arranged with the neural tube running along an anterior to posterior axis, from nose to tail for a four-legged animal like a dog. Humans, as two-legged animals, have a bend in the neuraxis between the brain stem and the diencephalon, along with a bend in the neck, so that the eyes and the face are oriented forward."
+a74b4c4d-57ea-4604-92e2-765162ac4e20,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"In summary, the primary vesicles help to establish the basic regions of the nervous system: forebrain, midbrain, and hindbrain. These divisions are useful in certain situations, but they are not equivalent regions. The midbrain is small compared with the hindbrain and particularly the forebrain. The secondary vesicles go on to establish the major regions of the adult nervous system that will be followed in this text. The telencephalon is the cerebrum, which is the major portion of the human brain. The diencephalon continues to be referred to by this Greek name, because there is no better term for it (dia- = “through”). The diencephalon is between the cerebrum and the rest of the nervous system and can be described as the region through which all projections have to pass between the cerebrum and everything else. The brain stem includes the midbrain, pons, and medulla, which correspond to the mesencephalon, metencephalon, and myelencephalon. The cerebellum, being a large portion of the brain, is considered a separate region. Table 14.1 connects the different stages of development to the adult structures of the CNS.",True,Relating Embryonic Development to the Adult Brain,,,,
+513030b4-82e4-493f-9292-f41f432a4526,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,"One other benefit of considering embryonic development is that certain connections are more obvious because of how these adult structures are related. The retina, which began as part of the diencephalon, is primarily connected to the diencephalon. The eyes are just inferior to the anterior-most part of the cerebrum, but the optic nerve extends back to the thalamus as the optic tract, with branches into a region of the hypothalamus. There is also a connection of the optic tract to the midbrain, but the mesencephalon is adjacent to the diencephalon, so that is not difficult to imagine. The cerebellum originates out of the metencephalon, and its largest white matter connection is to the pons, also from the metencephalon. There are connections between the cerebellum and both the medulla and midbrain, which are adjacent structures in the secondary vesicle stage of development. In the adult brain, the cerebellum seems close to the cerebrum, but there is no direct connection between them.",True,Relating Embryonic Development to the Adult Brain,,,,
+694733bd-abc5-4495-a940-8de451dcce40,https://open.oregonstate.education/aandp/,14.1 Embryonic Development,https://open.oregonstate.education/aandp/chapter/14-1-embryonic-development/,Another aspect of the adult CNS structures that relates to embryonic development is the ventricles—open spaces within the CNS where cerebrospinal fluid circulates. They are the remnant of the hollow center of the neural tube. The four ventricles and the tubular spaces associated with them can be linked back to the hollow center of the embryonic brain (see Table 14.1).,True,Relating Embryonic Development to the Adult Brain,,,,
+e4849212-7f8a-4761-b621-00b206316681,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The twelve cranial nerves are typically covered in introductory anatomy courses, and memorizing their names is facilitated by numerous mnemonics developed by students over the years of this practice. But knowing the names of the nerves in order often leaves much to be desired in understanding what the nerves do. The nerves can be categorized by functions, and subtests of the cranial nerve exam can clarify these functional groupings.",True,Relating Embryonic Development to the Adult Brain,,,,
+7d51da22-8a64-4dd4-a73f-60d263750eb9,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Three of the nerves are strictly responsible for special senses whereas four others contain fibers for special and general senses. Three nerves are connected to the extraocular muscles resulting in the control of gaze. Four nerves connect to muscles of the face, oral cavity, and pharynx, controlling facial expressions, mastication, swallowing, and speech. Four nerves make up the cranial component of the parasympathetic nervous system responsible for pupillary constriction, salivation, and the regulation of the organs of the thoracic and upper abdominal cavities. Finally, one nerve controls the muscles of the neck, assisting with spinal control of the movement of the head and neck.",True,Relating Embryonic Development to the Adult Brain,,,,
+afe6ae40-163b-4c12-ac79-f1147173362a,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The cranial nerve exam allows directed tests of forebrain and brain stem structures. The twelve cranial nerves serve the head and neck. The vagus nerve (cranial nerve X) has autonomic functions in the thoracic and superior abdominal cavities. The special senses are served through the cranial nerves, as well as the general senses of the head and neck. The movement of the eyes, face, tongue, throat, and neck are all under the control of cranial nerves. Preganglionic parasympathetic nerve fibers that control pupillary size, salivary glands, and the thoracic and upper abdominal viscera are found in four of the nerves. Tests of these functions can provide insight into damage to specific regions of the brain stem and may uncover deficits in adjacent regions.",True,Relating Embryonic Development to the Adult Brain,,,,
+db9dfbfc-7b31-41d9-92ca-ec192fcde7e1,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,Sensory Nerves,False,Sensory Nerves,,,,
+3c679572-063f-47a2-94b3-fef7436baf45,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The olfactory, optic, and vestibulocochlear nerves (cranial nerves I, II, and VIII) are dedicated to four of the special senses: smell, vision, equilibrium, and hearing, respectively. Taste sensation is relayed to the brain stem through fibers of the facial and glossopharyngeal nerves. The trigeminal nerve is a mixed nerve that carries the general somatic senses from the head, similar to those coming through spinal nerves from the rest of the body.",True,Sensory Nerves,,,,
+4e1bbea3-dfd0-4cf5-975f-5001366b04cd,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Testing smell is straightforward, as common smells are presented to one nostril at a time. The patient should be able to recognize the smell of coffee or mint, indicating the proper functioning of the olfactory system. Loss of the sense of smell is called anosmia and can be lost following blunt trauma to the head or through aging. The short axons of the first cranial nerve regenerate on a regular basis. The neurons in the olfactory epithelium have a limited life span, and new cells grow to replace the ones that die off. The axons from these neurons grow back into the CNS by following the existing axons—representing one of the few examples of such growth in the mature nervous system. If all of the fibers are sheared when the brain moves within the cranium, such as in a motor vehicle accident, then no axons can find their way back to the olfactory bulb to re-establish connections. If the nerve is not completely severed, the anosmia may be temporary as new neurons can eventually reconnect.",True,Sensory Nerves,,,,
+76ab2ba5-7d05-485f-afe3-86e3a85d715d,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Olfaction is not the pre-eminent sense, but its loss can be quite detrimental. The enjoyment of food is largely based on our sense of smell. Anosmia means that food will not seem to have the same taste, though the gustatory sense is intact, and food will often be described as being bland. However, the taste of food can be improved by adding ingredients (e.g., salt) that stimulate the gustatory sense.",True,Sensory Nerves,,,,
+b4384c49-897c-4ce1-85c0-aae7a4b42eef,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Testing vision relies on the tests that are common in an optometry office. The Snellen chart (Figure 13.7.1) demonstrates visual acuity by presenting standard Roman letters in a variety of sizes. The result of this test is a rough generalization of the acuity of a person based on the normal accepted acuity, such that a letter that subtends a visual angle of 5 minutes of an arc at 20 feet can be seen. To have 20/60 vision, for example, means that the smallest letters that a person can see at a 20-foot distance could be seen by a person with normal acuity from 60 feet away. Testing the extent of the visual field means that the examiner can establish the boundaries of peripheral vision as simply as holding their hands out to either side and asking the patient when the fingers are no longer visible without moving the eyes to track them. If it is necessary, further tests can establish the perceptions in the visual fields. Physical inspection of the optic disk, or where the optic nerve emerges from the eye, can be accomplished by looking through the pupil with an ophthalmoscope.",True,Sensory Nerves,Figure 13.7.1,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1606_Snellen_Chart-02.jpg,"Figure 13.7.1 – The Snellen Chart: The Snellen chart for visual acuity presents a limited number of Roman letters in lines of decreasing size. The line with letters that subtend 5 minutes of an arc from 20 feet represents the smallest letters that a person with normal acuity should be able to read at that distance. The different sizes of letters in the other lines represent rough approximations of what a person of normal acuity can read at different distances. For example, the line that represents 20/200 vision would have larger letters so that they are legible to the person with normal acuity at 200 feet."
+6fcd0341-5b05-418f-a2d8-0e33cdd23008,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The optic nerves from both sides enter the cranium through the respective optic canals and meet at the optic chiasm at which fibers sort such that the two halves of the visual field are processed by the opposite sides of the brain. Deficits in visual field perception often suggest damage along the length of the optic pathway between the orbit and the diencephalon. For example, loss of peripheral vision may be the result of a pituitary tumor pressing on the optic chiasm (Figure 13.7.2). The pituitary, seated in the sella turcica of the sphenoid bone, is directly inferior to the optic chiasm. The axons that decussate in the chiasm are from the medial retinae of either eye, and therefore carry information from the peripheral visual field.",True,Sensory Nerves,Figure 13.7.2,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1614_Pituitary_Tumor-02.jpg,"Figure 13.7.2 – Pituitary Tumor: The pituitary gland is located in the sella turcica of the sphenoid bone within the cranial floor, placing it immediately inferior to the optic chiasm. If the pituitary gland develops a tumor, it can press against the fibers crossing in the chiasm. Those fibers are conveying peripheral visual information to the opposite side of the brain, so the patient will experience “tunnel vision”—meaning that only the central visual field will be perceived."
+a2cc97ae-4ae4-4514-9764-8795217ccb9f,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The vestibulocochlear nerve (CN VIII) carries both equilibrium and auditory sensations from the inner ear to the medulla. Though the two senses are not directly related, anatomy is mirrored in the two systems. Problems with balance, such as vertigo, and deficits in hearing may both point to problems with the inner ear. Within the petrous region of the temporal bone is the bony labyrinth of the inner ear. The vestibule is the portion for equilibrium, composed of the utricle, saccule, and the three semicircular canals. The cochlea is responsible for transducing sound waves into a neural signal. The sensory nerves from these two structures travel side-by-side as the vestibulocochlear nerve, though they are really separate divisions. They both emerge from the inner ear, pass through the internal auditory meatus, and synapse in nuclei of the superior medulla. Though they are part of distinct sensory systems, the vestibular nuclei and the cochlear nuclei are close neighbors with adjacent inputs. Deficits in one or both systems could occur from damage that encompasses structures close to both. Damage to structures near the two nuclei can result in deficits to one or both systems.",True,Sensory Nerves,,,,
+34af1773-b25f-4a2f-b042-6982bce1e999,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Balance or hearing deficits may be the result of damage to the middle or inner ear structures. Ménière’s disease is a disorder that can affect both equilibrium and audition in a variety of ways. The patient can suffer from vertigo, a low-frequency ringing in the ears, or a loss of hearing. From patient to patient, the exact presentation of the disease can be different. Additionally, within a single patient, the symptoms and signs may change as the disease progresses. Use of the neurological exam subtests for the vestibulocochlear nerve illuminates the changes a patient may go through. The disease appears to be the result of accumulation, or over-production, of fluid in the inner ear, in either the vestibule or cochlea.",True,Sensory Nerves,,,,
+a9a8354c-d58b-4f82-a2b2-dea90d453a5e,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Tests of equilibrium are important for coordination and gait and are related to other aspects of the neurological exam. The vestibulo-ocular reflex involves the cranial nerves for gaze control. Balance and equilibrium, as tested by the Romberg test, are part of spinal and cerebellar processes and involved in those components of the neurological exam, as discussed later.",True,Sensory Nerves,,,,
+703e2288-b2ea-43d6-a73c-4599d405c072,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Hearing is tested by using a tuning fork in a couple of different ways. The Rinne test involves using a tuning fork to distinguish between conductive hearing and sensorineural hearing. Conductive hearing relies on vibrations being conducted through the ossicles of the middle ear. Sensorineural hearing is the transmission of sound stimuli through the neural components of the inner ear and cranial nerve. A vibrating tuning fork is placed on the mastoid process and the patient indicates when the sound produced from this is no longer present. Then the fork is immediately moved to just next to the ear canal so the sound travels through the air. If the sound is not heard through the ear, meaning the sound is conducted better through the temporal bone than through the ossicles, a conductive hearing deficit is present. The Weber test also uses a tuning fork to differentiate between conductive versus sensorineural hearing loss. In this test, the tuning fork is placed at the top of the skull, and the sound of the tuning fork reaches both inner ears by travelling through bone. In a healthy patient, the sound would appear equally loud in both ears. With unilateral conductive hearing loss, however, the tuning fork sounds louder in the ear with hearing loss. This is because the sound of the tuning fork has to compete with background noise coming from the outer ear, but in conductive hearing loss, the background noise is blocked in the damaged ear, allowing the tuning fork to sound relatively louder in that ear. With unilateral sensorineural hearing loss, however, damage to the cochlea or associated nervous tissue means that the tuning fork sounds quieter in that ear.",True,Sensory Nerves,,,,
+0da86847-c1ee-4f4c-98f1-d098f8d04e41,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The trigeminal system of the head and neck is the equivalent of the ascending spinal cord systems of the dorsal column and the spinothalamic pathways. Somatosensation of the face is conveyed along the nerve to enter the brain stem at the level of the pons. Synapses of those axons, however, are distributed across nuclei found throughout the brain stem. The mesencephalic nucleus processes proprioceptive information of the face, which is the movement and position of facial muscles. It is the sensory component of the jaw-jerk reflex, a stretch reflex of the masseter muscle. The chief nucleus, located in the pons, receives information about light touch as well as proprioceptive information about the mandible, which are both relayed to the thalamus and, ultimately, to the postcentral gyrus of the parietal lobe. The spinal trigeminal nucleus, located in the medulla, receives information about crude touch, pain, and temperature to be relayed to the thalamus and cortex. Essentially, the projection through the chief nucleus is analogous to the dorsal column pathway for the body, and the projection through the spinal trigeminal nucleus is analogous to the spinothalamic pathway.",True,Sensory Nerves,,,,
+17fc745f-14c8-4361-8e4b-55e31a33d245,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Subtests for the sensory component of the trigeminal system are the same as those for the sensory exam targeting the spinal nerves. The primary sensory subtest for the trigeminal system is sensory discrimination. A cotton-tipped applicator, which is cotton attached to the end of a thin wooden stick, can be used easily for this. The wood of the applicator can be snapped so that a pointed end is opposite the soft cotton-tipped end. The cotton end provides a touch stimulus, while the pointed end provides a painful, or sharp, stimulus. While the patient’s eyes are closed, the examiner touches the two ends of the applicator to the patient’s face, alternating randomly between them. The patient must identify whether the stimulus is sharp or dull. These stimuli are processed by the trigeminal system separately. Contact with the cotton tip of the applicator is a light touch, relayed by the chief nucleus, but contact with the pointed end of the applicator is a painful stimulus relayed by the spinal trigeminal nucleus. Failure to discriminate these stimuli can localize problems within the brain stem. If a patient cannot recognize a painful stimulus, that might indicate damage to the spinal trigeminal nucleus in the medulla. The medulla also contains important regions that regulate the cardiovascular, respiratory, and digestive systems, as well as being the pathway for ascending and descending tracts between the brain and spinal cord. Damage, such as a stroke, that results in changes in sensory discrimination may indicate these unrelated regions are affected as well.",True,Sensory Nerves,,,,
+c1733b3e-8239-4098-8dec-b3dc1cb888e7,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,Gaze Control,False,Gaze Control,,,,
+a61ff612-0358-409f-aa80-0b691f190ba2,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The three nerves that control the extraocular muscles are the oculomotor, trochlear, and abducens nerves, which are the third, fourth, and sixth cranial nerves. As the name suggests, the abducens nerve is responsible for abducting the eye, which it controls through contraction of the lateral rectus muscle. The trochlear nerve controls the superior oblique muscle to rotate the eye along its axis in the orbit medially, which is called intorsion, and is a component of focusing the eyes on an object close to the face. The oculomotor nerve controls all the other extraocular muscles, as well as a muscle of the upper eyelid. Movements of the two eyes need to be coordinated to locate and track visual stimuli accurately. When moving the eyes to locate an object in the horizontal plane, or to track movement horizontally in the visual field, the lateral rectus muscle of one eye and medial rectus muscle of the other eye are both active. The lateral rectus is controlled by neurons of the abducens nucleus in the superior medulla, whereas the medial rectus is controlled by neurons in the oculomotor nucleus of the midbrain.",True,Gaze Control,,,,
+437167ab-5cd7-46d7-9f09-74ebd5b457d9,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Coordinated movement of both eyes through different nuclei requires integrated processing through the brain stem. In the midbrain, the superior colliculus integrates visual stimuli with motor responses to initiate eye movements. The paramedian pontine reticular formation (PPRF) will initiate a rapid eye movement, or saccade, to bring the eyes to bear on a visual stimulus quickly. These areas are connected to the oculomotor, trochlear, and abducens nuclei by the medial longitudinal fasciculus (MLF) that runs through the majority of the brain stem. The MLF allows for conjugate gaze, or the movement of the eyes in the same direction, during horizontal movements that require the lateral and medial rectus muscles. Control of conjugate gaze strictly in the vertical direction is contained within the oculomotor complex. To elevate the eyes, the oculomotor nerve on either side stimulates the contraction of both superior rectus muscles; to depress the eyes, the oculomotor nerve on either side stimulates the contraction of both inferior rectus muscles.",True,Gaze Control,,,,
+9471df54-4576-4b75-816d-a472e9206d5d,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Purely vertical movements of the eyes are not very common. Movements are often at an angle, so some horizontal components are necessary, adding the medial and lateral rectus muscles to the movement. The rapid movement of the eyes used to locate and direct the fovea onto visual stimuli is called a saccade. Notice that the paths that are traced in Figure 13.7.3 are not strictly vertical. The movements between the nose and the mouth are closest, but still have a slant to them. Also, the superior and inferior rectus muscles are not perfectly oriented with the line of sight. The origin for both muscles is medial to their insertions, so elevation and depression may require the lateral rectus muscles to compensate for the slight adduction inherent in the contraction of those muscles, requiring MLF activity as well.",True,Gaze Control,Figure 13.7.3,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1607_Saccadic_Movements.jpg,"Figure 13.7.3 – Saccadic Eye Movements: Saccades are rapid, conjugate movements of the eyes to survey a complicated visual stimulus, or to follow a moving visual stimulus. This image represents the shifts in gaze typical of a person studying a face. Notice the concentration of gaze on the major features of the face and the large number of paths traced between the eyes or around the mouth."
+b4a5dd84-365e-4cba-aa75-4cf1d51a5014,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"Testing eye movement is simply a matter of having the patient track the tip of a pen as it is passed through the visual field. This may appear similar to testing visual field deficits related to the optic nerve, but the difference is that the patient is asked to not move the eyes while the examiner moves a stimulus into the peripheral visual field. Here, the extent of movement is the point of the test. The examiner is watching for conjugate movements representing proper function of the related nuclei and the MLF. Failure of one eye to abduct while the other adducts in a horizontal movement is referred to as internuclear ophthalmoplegia. When this occurs, the patient will experience diplopia, or double vision, as the two eyes are temporarily pointed at different stimuli. Diplopia is not restricted to failure of the lateral rectus, because any of the extraocular muscles may fail to move one eye in perfect conjugation with the other.",True,Gaze Control,,,,
+10cdf71f-828b-4ce5-a89e-defe1f67537d,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The final aspect of testing eye movements is to move the tip of the pen in toward the patient’s face. As visual stimuli move closer to the face, the two medial recti muscles cause the eyes to move in the one nonconjugate movement that is part of gaze control. When the two eyes move to look at something closer to the face, they both adduct, which is referred to as convergence. To keep the stimulus in focus, the eye also needs to change the shape of the lens, which is controlled through the parasympathetic fibers of the oculomotor nerve. The change in focal power of the eye is referred to as accommodation. Accommodation ability changes with age; focusing on nearer objects, such as the written text of a book or on a computer screen, may require corrective lenses later in life. Coordination of the skeletal muscles for convergence and coordination of the smooth muscles of the ciliary body for accommodation are referred to as the accommodation–convergence reflex.",True,Gaze Control,,,,
+533c5600-b0c4-4499-9bd1-a782dde0b99f,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of the retina. The vestibulo-ocular reflex (VOR) coordinates all of the components (Figure 13.7.4), both sensory and motor, that make this possible. If the head rotates in one direction—for example, to the right—the horizontal pair of semicircular canals in the inner ear indicate the movement by increased activity on the right and decreased activity on the left. The information is sent to the abducens nuclei and oculomotor nuclei on either side to coordinate the lateral and medial rectus muscles. The left lateral rectus and right medial rectus muscles will contract, rotating the eyes in the opposite direction of the head, while nuclei controlling the right lateral rectus and left medial rectus muscles will be inhibited to reduce antagonism of the contracting muscles. These actions stabilize the visual field by compensating for the head rotation with opposite rotation of the eyes in the orbits. Deficits in the VOR may be related to vestibular damage, such as in Ménière’s disease, or from dorsal brain stem damage that would affect the eye movement nuclei or their connections through the MLF.",True,Gaze Control,Figure 13.7.4,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1608_Vestibulo-Ocular_Reflex-02.jpg,"Figure 13.7.4 – Vestibulo-ocular Reflex: If the head is turned in one direction, the coordination of that movement with the fixation of the eyes on a visual stimulus involves a circuit that ties the vestibular sense with the eye movement nuclei through the MLF."
+d429f44c-6192-4318-9caf-91bd3f1f65d4,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,Nerves of the Face and Oral Cavity,False,Nerves of the Face and Oral Cavity,,,,
+80b19830-6265-4515-b35e-79405fe572dc,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"An iconic part of a doctor’s visit is the inspection of the oral cavity and pharynx, suggested by the directive to “open your mouth and say ‘ah.’” This is followed by inspection, with the aid of a tongue depressor, of the back of the mouth, or the opening of the oral cavity into the pharynx known as the fauces. Whereas this portion of a medical exam inspects for signs of infection, such as in tonsillitis, it is also the means to test the functions of the cranial nerves that are associated with the oral cavity.",True,Nerves of the Face and Oral Cavity,,,,
+293ff880-d7ad-48b6-8ac8-65835a2c4927,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The facial and glossopharyngeal nerves convey gustatory stimulation to the brain. Testing this is as simple as introducing salty, sour, bitter, or sweet stimuli to either side of the tongue. The patient should respond to the taste stimulus before retracting the tongue into the mouth. Stimuli applied to specific locations on the tongue will dissolve into the saliva and may stimulate taste buds connected to either the left or right of the nerves, masking any lateral deficits. Along with taste, the glossopharyngeal nerve relays general sensations from the pharyngeal walls. These sensations, along with certain taste stimuli, can stimulate the gag reflex. If the examiner moves the tongue depressor to contact the lateral wall of the fauces, this should elicit the gag reflex. Stimulation of either side of the fauces should elicit an equivalent response. The motor response, through contraction of the muscles of the pharynx, is mediated through the vagus nerve. Normally, the vagus nerve is considered autonomic in nature. The vagus nerve directly stimulates the contraction of skeletal muscles in the pharynx and larynx to contribute to the swallowing and speech functions. Further testing of vagus motor function has the patient repeating consonant sounds that require movement of the muscles around the fauces. The patient is asked to say “lah-kah-pah” or a similar set of alternating sounds while the examiner observes the movements of the soft palate and arches between the palate and tongue.",True,Nerves of the Face and Oral Cavity,,,,
+fc23c3c5-2478-4aef-b6dc-01758a8d4d4a,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The facial and glossopharyngeal nerves are also responsible for the initiation of salivation. Neurons in the salivary nuclei of the medulla project through these two nerves as preganglionic fibers, and synapse in ganglia located in the head. The parasympathetic fibers of the facial nerve synapse in the pterygopalatine ganglion, which projects to the submandibular gland and sublingual gland. The parasympathetic fibers of the glossopharyngeal nerve synapse in the otic ganglion, which projects to the parotid gland. Salivation in response to food in the oral cavity is based on a visceral reflex arc within the facial or glossopharyngeal nerves. Other stimuli that stimulate salivation are coordinated through the hypothalamus, such as the smell and sight of food.",True,Nerves of the Face and Oral Cavity,,,,
+1f995db4-5f0a-46e6-9fd8-cd00e799d21d,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The hypoglossal nerve is the motor nerve that controls the muscles of the tongue, except for the palatoglossus muscle, which is controlled by the vagus nerve. There are two sets of muscles of the tongue. The extrinsic muscles of the tongue are connected to other structures, whereas the intrinsic muscles of the tongue are completely contained within the lingual tissues. While examining the oral cavity, movement of the tongue will indicate whether hypoglossal function is impaired. The test for hypoglossal function is the “stick out your tongue” part of the exam. The genioglossus muscle is responsible for protrusion of the tongue. If the hypoglossal nerves on both sides are working properly, then the tongue will stick straight out. If the nerve on one side has a deficit, the tongue will stick out to that side—pointing to the side with damage. Loss of function of the tongue can interfere with speech and swallowing. Additionally, because the location of the hypoglossal nerve and nucleus is near the cardiovascular center, inspiratory and expiratory areas for respiration, and the vagus nuclei that regulate digestive functions, a tongue that protrudes incorrectly can suggest damage in adjacent structures that have nothing to do with controlling the tongue.",True,Nerves of the Face and Oral Cavity,,,,
+fe22ee8a-032b-4ac3-934c-4a6b71df1d41,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,Motor Nerves of the Neck,False,Motor Nerves of the Neck,,,,
+50ba3b52-c284-478d-a52c-0052057ed384,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The accessory nerve, also referred to as the spinal accessory nerve, innervates the sternocleidomastoid and trapezius muscles (Figure 13.7.5). When both the sternocleidomastoids contract, the head flexes forward; individually, they cause rotation to the opposite side. The trapezius can act as an antagonist, causing extension and hyperextension of the neck. These two superficial muscles are important for changing the position of the head. Both muscles also receive input from cervical spinal nerves. Along with the spinal accessory nerve, these nerves contribute to elevating the scapula and clavicle through the trapezius, which is tested by asking the patient to shrug both shoulders, and watching for asymmetry. For the sternocleidomastoid, those spinal nerves are primarily sensory projections, whereas the trapezius also has lateral insertions to the clavicle and scapula, and receives motor input from the spinal cord. Calling the nerve the spinal accessory nerve suggests that it is aiding the spinal nerves. Though that is not precisely how the name originated, it does help make the association between the function of this nerve in controlling these muscles and the role these muscles play in movements of the trunk or shoulders.",True,Motor Nerves of the Neck,Figure 13.7.5,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1610_Muscles_Controlled_by_the_Accessory_Nerve-02.jpg,"Figure 13.7.5 – Muscles Controlled by the Accessory Nerve: The accessory nerve innervates the sternocleidomastoid and trapezius muscles, both of which attach to the head and to the trunk and shoulders. They can act as antagonists in head flexion and extension, and as synergists in lateral flexion toward the shoulder."
+136b8810-0e68-4cf9-b5e3-ae82f53491f2,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"To test these muscles, the patient is asked to flex and extend the neck or shrug the shoulders against resistance, testing the strength of the muscles. Lateral flexion of the neck toward the shoulder tests both at the same time. Any difference on one side versus the other would suggest damage on the weaker side. These strength tests are common for the skeletal muscles controlled by spinal nerves and are a significant component of the motor exam. Deficits associated with the accessory nerve may have an effect on orienting the head, as described with the VOR.",True,Motor Nerves of the Neck,,,,
+f5a48c1e-3060-4fe6-885f-405b23f8e2d7,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,The Cranial Nerve Exam,False,The Cranial Nerve Exam,,,,
+1f516b61-a8ec-4a3a-8d73-d177351c369b,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The cranial nerves can be separated into four major groups associated with the subtests of the cranial nerve exam. First are the sensory nerves, then the nerves that control eye movement, the nerves of the oral cavity and superior pharynx, and the nerve that controls movements of the neck.",True,The Cranial Nerve Exam,,,,
+8c0b8e15-739d-496c-9f71-5f0c96811b6c,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The olfactory, optic, and vestibulocochlear nerves are strictly sensory nerves for smell, sight, and balance and hearing, whereas the trigeminal, facial, and glossopharyngeal nerves carry somatosensation of the face, and taste—separated between the anterior two-thirds of the tongue and the posterior one-third. Special senses are tested by presenting the particular stimuli to each receptive organ. General senses can be tested through sensory discrimination of touch versus painful stimuli.",True,The Cranial Nerve Exam,,,,
+536ffd27-8945-4690-ad55-94ca68685085,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The oculomotor, trochlear, and abducens nerves control the extraocular muscles and are connected by the medial longitudinal fasciculus to coordinate gaze. Testing conjugate gaze is as simple as having the patient follow a visual target, like a pen tip, through the visual field ending with an approach toward the face to test convergence and accommodation. Along with the vestibular functions of the eighth nerve, the vestibulo-ocular reflex stabilizes gaze during head movements by coordinating equilibrium sensations with the eye movement systems.",True,The Cranial Nerve Exam,,,,
+a50d3ed3-d6f8-4bd3-82a9-0c43b2149e7c,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,"The trigeminal nerve controls the muscles of chewing, which are tested for stretch reflexes. Motor functions of the facial nerve are usually obvious if facial expressions are compromised, but can be tested by having the patient raise their eyebrows, smile, and frown. Movements of the tongue, soft palate, or superior pharynx can be observed directly while the patient swallows, while the gag reflex is elicited, or while the patient says repetitive consonant sounds. The motor control of the gag reflex is largely controlled by fibers in the vagus nerve and constitutes a test of that nerve because the parasympathetic functions of that nerve are involved in visceral regulation, such as regulating the heartbeat and digestion.",True,The Cranial Nerve Exam,,,,
+2be3e49d-f0d2-4253-b82a-c34142b0677b,https://open.oregonstate.education/aandp/,13.7 The Cranial Nerve Exam,https://open.oregonstate.education/aandp/chapter/13-7-the-cranial-nerve-exam/,Movement of the head and neck using the sternocleidomastoid and trapezius muscles is controlled by the accessory nerve. Flexing of the neck and strength testing of those muscles reviews the function of that nerve.,True,The Cranial Nerve Exam,,,,
+2851e578-d7d9-40d4-afd4-ad6f7df86b35,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Connections between the body and the CNS occur through the spinal cord. The cranial nerves connect the head and neck directly to the brain, but the spinal cord receives sensory input and sends motor commands out to the body through the spinal nerves. Whereas the brain develops into a complex series of nuclei and fiber tracts, the spinal cord remains relatively simple in its configuration (Figure 13.6.1). From the initial neural tube early in embryonic development, the spinal cord retains a tube-like structure with gray matter surrounding the small central canal and white matter on the surface in three columns. The dorsal, or posterior, horns of the gray matter are mainly devoted to sensory functions whereas the ventral, or anterior, and lateral horns are associated with motor functions. In the white matter, the dorsal column relays sensory information to the brain, and the anterior column is almost exclusively relaying motor commands to the ventral horn motor neurons. The lateral column, however, conveys both sensory and motor information between the spinal cord and brain.",True,The Cranial Nerve Exam,Figure 13.6.1,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/app/uploads/sites/157/2019/07/1615_Locations_Spinal_Fiber_Tracts.jpg,Figure 13.6.1 Locations of Spinal Fiber Tracts
+0dd8d22d-f8ec-4622-8f78-8ca3f1b62ccc,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,Sensory Modalities and Location,False,Sensory Modalities and Location,,,,
+5a83a657-5263-4453-8847-db7e29b3baf6,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The general senses are distributed throughout the body, relying on nervous tissue incorporated into various organs. Somatic senses are incorporated mostly into the skin, muscles, or tendons, whereas the visceral senses come from nervous tissue incorporated into the majority of organs such as the heart or stomach. The somatic senses are those that usually make up the conscious perception of the how the body interacts with the environment. The visceral senses are most often below the limit of conscious perception because they are involved in homeostatic regulation through the autonomic nervous system.",True,Sensory Modalities and Location,,,,
+e098e753-6a72-46a7-9b3b-fe94481cc1d7,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The sensory exam tests the somatic senses, meaning those that are consciously perceived. Testing of the senses begins with examining the regions known as dermatomes that connect to the cortical region where somatosensation is perceived in the postcentral gyrus. To test the sensory fields, a simple stimulus of the light touch of the soft end of a cotton-tipped applicator is applied at various locations on the skin. The spinal nerves, which contain sensory fibers with dendritic endings in the skin, connect with the skin in a topographically organized manner, illustrated as dermatomes (Figure 13.6.2). For example, the fibers of eighth cervical nerve innervate the medial surface of the forearm and extend out to the fingers. In addition to testing perception at different positions on the skin, it is necessary to test sensory perception within the dermatome from distal to proximal locations in the appendages, or lateral to medial locations in the trunk. In testing the eighth cervical nerve, the patient would be asked if the touch of the cotton to the fingers or the medial forearm was perceptible, and whether there were any differences in the sensations.",True,Sensory Modalities and Location,Figure 13.6.2,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/app/uploads/sites/157/2021/02/1611_Dermatomes-02.jpg,Figure 13.6.2 – Dermatomes: The surface of the skin can be divided into topographic regions that relate to the location of sensory endings in the skin based on the spinal nerve that contains those fibers. (credit: modification of work by Mikael Häggström)
+60c09a01-c6ef-4722-8140-e506eaecb136,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Other modalities of somatosensation can be tested using a few simple tools. The perception of pain can be tested using the broken end of the cotton-tipped applicator. The perception of vibratory stimuli can be testing using an oscillating tuning fork placed against prominent bone features such as the distal head of the ulna on the medial aspect of the elbow. When the tuning fork is still, the metal against the skin can be perceived as a cold stimulus. Using the cotton tip of the applicator, or even just a fingertip, the perception of tactile movement can be assessed as the stimulus is drawn across the skin for approximately 2–3 cm. The patient would be asked in what direction the stimulus is moving. All of these tests are repeated in distal and proximal locations and for different dermatomes to assess the spatial specificity of perception. The sense of position and motion, proprioception, is tested by moving the fingers or toes and asking the patient if they sense the movement. If the distal locations are not perceived, the test is repeated at increasingly proximal joints.",True,Sensory Modalities and Location,,,,
+5eeb1db7-e0d7-42ed-914f-d60940fc7cc1,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The various stimuli used to test sensory input assess the function of the major ascending tracts of the spinal cord. The dorsal column pathway conveys fine touch, vibration, and proprioceptive information, whereas the spinothalamic pathway primarily conveys pain and temperature. Testing these stimuli provides information about whether these two major ascending pathways are functioning properly. Within the spinal cord, the two systems are segregated. The dorsal column information ascends ipsilateral to the source of the stimulus and decussates in the medulla, whereas the spinothalamic pathway decussates at the level of entry and ascends contralaterally. The differing sensory stimuli are segregated in the spinal cord so that the various subtests for these stimuli can distinguish which ascending pathway may be damaged in certain situations.",True,Sensory Modalities and Location,,,,
+1ae5f8b6-7567-464a-84c7-e2d670fa6549,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Whereas the basic sensory stimuli are assessed in the subtests directed at each submodality of somatosensation, testing the ability to discriminate sensations is important. Pairing the light touch and pain subtests together makes it possible to compare the two submodalities at the same time, and therefore the two major ascending tracts at the same time. Mistaking painful stimuli for light touch, or vice versa, may point to errors in ascending projections, such as in a hemisection of the spinal cord that might come from a motor vehicle accident.",True,Sensory Modalities and Location,,,,
+b209caf9-3f56-4589-a1c8-d61d992e559d,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Another issue of sensory discrimination is not distinguishing between different submodalities, but rather location. The two-point discrimination subtest highlights the density of sensory endings, and therefore receptive fields in the skin. The sensitivity to fine touch, which can give indications of the texture and detailed shape of objects, is highest in the fingertips. To assess the limit of this sensitivity, two-point discrimination is measured by simultaneously touching the skin in two locations, such as could be accomplished with a pair of forceps. Specialized calipers for precisely measuring the distance between points are also available. The patient is asked to indicate whether one or two stimuli are present while keeping their eyes closed. The examiner will switch between using the two points and a single point as the stimulus. Failure to recognize two points may be an indication of a dorsal column pathway deficit.",True,Sensory Modalities and Location,,,,
+79273091-27bd-4bab-9692-e46f535c5eff,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Similar to two-point discrimination, but assessing laterality of perception, is double simultaneous stimulation. Two stimuli, such as the cotton tips of two applicators, are touched to the same position on both sides of the body. If one side is not perceived, this may indicate damage to the contralateral posterior parietal lobe. Because there is one of each pathway on either side of the spinal cord, they are not likely to interact. If none of the other subtests suggest particular deficits with the pathways, the deficit is likely to be in the cortex where conscious perception is based. The mental status exam contains subtests that assess other functions that are primarily localized to the parietal cortex, such as stereognosis and graphesthesia.",True,Sensory Modalities and Location,,,,
+07f5b7f3-018f-4627-8704-f1153363e537,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"A final subtest of sensory perception that concentrates on the sense of proprioception is known as the Romberg test. The patient is asked to stand straight with feet together. Once the patient has achieved their balance in that position, they are asked to close their eyes. Without visual feedback that the body is in a vertical orientation relative to the surrounding environment, the patient must rely on the proprioceptive stimuli of joint and muscle position, as well as information from the inner ear, to maintain balance. This test can indicate deficits in dorsal column pathway proprioception, as well as problems with proprioceptive projections to the cerebellum through the spinocerebellar tract.",True,Sensory Modalities and Location,,,,
+69d8ac16-53c6-4bdd-b3ae-afb04b556849,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,Muscle Strength and Voluntary Movement,False,Muscle Strength and Voluntary Movement,,,,
+ded6341a-8470-41fc-a7b3-3c3bd79c4a03,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The skeletomotor system is largely based on the simple, two-cell projection from the precentral gyrus of the frontal lobe to the skeletal muscles. The corticospinal tract represents the neurons that send output from the primary motor cortex. These fibers travel through the deep white matter of the cerebrum, then through the midbrain and pons, into the medulla where most of them decussate, and finally through the spinal cord white matter in the lateral (crossed fibers) or anterior (uncrossed fibers) columns. These fibers synapse on motor neurons in the ventral horn. The ventral horn motor neurons then project to skeletal muscle and cause contraction. These two cells are termed the upper motor neuron (UMN) and the lower motor neuron (LMN). Voluntary movements require these two cells to be active.",True,Muscle Strength and Voluntary Movement,,,,
+1a1c7ef0-1a59-4a91-aa1b-6ec9f65d51c3,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The motor exam tests the function of these neurons and the muscles they control. First, the muscles are inspected and palpated for signs of structural irregularities. Movement disorders may be the result of changes to the muscle tissue, such as scarring, and these possibilities need to be ruled out before testing function. Along with this inspection, muscle tone is assessed by moving the muscles through a passive range of motion. The arm is moved at the elbow and wrist, and the leg is moved at the knee and ankle. Skeletal muscle should have a resting tension representing a slight contraction of the fibers. The lack of muscle tone, known as hypotonicity or flaccidity, may indicate that the LMN is not conducting action potentials that will keep a basal level of acetylcholine in the neuromuscular junction.",True,Muscle Strength and Voluntary Movement,,,,
+e4ae2016-db8a-42be-88d2-ab144ef5b61d,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"If muscle tone is present, muscle strength is tested by having the patient contract muscles against resistance. The examiner will ask the patient to lift the arm, for example, while the examiner is pushing down on it. This is done for both limbs, including shrugging the shoulders. Lateral differences in strength—being able to push against resistance with the right arm but not the left—would indicate a deficit in one corticospinal tract versus the other. An overall loss of strength, without laterality, could indicate a global problem with the motor system. Diseases that result in UMN lesions include cerebral palsy or MS, or it may be the result of a stroke. A sign of UMN lesion is a negative result in the subtest for pronator drift. The patient is asked to extend both arms in front of the body with the palms facing up. While keeping the eyes closed, if the patient unconsciously allows one or the other arm to slowly relax, toward the pronated position, this could indicate a failure of the motor system to maintain the supinated position.",True,Muscle Strength and Voluntary Movement,,,,
+0ab66796-4391-4de0-a389-2252d1c10599,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,Reflexes,False,Reflexes,,,,
+b4f9ffe5-f8d6-4d2c-a316-575bc63b53c2,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Reflexes combine the spinal sensory and motor components with a sensory input that directly generates a motor response. The reflexes that are tested in the neurological exam are classified into two groups. A deep tendon reflex is commonly known as a stretch reflex, and is elicited by a strong tap to a tendon, such as in the knee-jerk reflex. A superficial reflex is elicited through gentle stimulation of the skin and causes contraction of the associated muscles.",True,Reflexes,,,,
+f17779c9-f9be-46c6-9413-6aa6a8b6a6df,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"For the arm, the common reflexes to test are of the biceps, brachioradialis, triceps, and flexors for the digits. For the leg, the knee-jerk reflex of the quadriceps is common, as is the ankle reflex for the gastrocnemius and soleus. The tendon at the insertion for each of these muscles is struck with a rubber mallet. The muscle is quickly stretched, resulting in activation of the muscle spindle that sends a signal into the spinal cord through the dorsal root. The fiber synapses directly on the ventral horn motor neuron that activates the muscle, causing contraction. The reflexes are physiologically useful for stability. If a muscle is stretched, it reflexively contracts to return the muscle to compensate for the change in length. In the context of the neurological exam, reflexes indicate that the LMN is functioning properly.",True,Reflexes,,,,
+4b7a3a18-3af9-483d-b88c-61934007f472,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"The most common superficial reflex in the neurological exam is the plantar reflex that tests for the Babinski sign on the basis of the extension or flexion of the toes at the plantar surface of the foot. The plantar reflex is commonly tested in newborn infants to establish the presence of neuromuscular function. To elicit this reflex, an examiner brushes a stimulus, usually the examiner’s fingertip, along the plantar surface of the infant’s foot. An infant would present a positive Babinski sign, meaning the foot dorsiflexes and the toes extend and splay out. As a person learns to walk, the plantar reflex changes to cause curling of the toes and a moderate plantar flexion. If superficial stimulation of the sole of the foot caused extension of the foot, keeping one’s balance would be harder. The descending input of the corticospinal tract modifies the response of the plantar reflex, meaning that a negative Babinski sign is the expected response in testing the reflex. Other superficial reflexes are not commonly tested, though a series of abdominal reflexes can target function in the lower thoracic spinal segments.",True,Reflexes,,,,
+b2d3b0f7-91b4-49b5-9b0b-1c8ae165741b,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,Comparison of Upper and Lower Motor Neuron Damage,False,Comparison of Upper and Lower Motor Neuron Damage,,,,
+f2429770-8a2f-4114-96a6-070615b1c643,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"Many of the tests of motor function can indicate differences that will address whether damage to the motor system is in the upper or lower motor neurons. Signs that suggest a UMN lesion include muscle weakness, strong deep tendon reflexes, decreased control of movement or slowness, pronator drift, a positive Babinski sign, spasticity, and the clasp-knife response. Spasticity is an excess contraction in resistance to stretch. It can result in hyperflexia, which is when joints are overly flexed. The clasp-knife response occurs when the patient initially resists movement, but then releases, and the joint will quickly flex like a pocket knife closing.",True,Comparison of Upper and Lower Motor Neuron Damage,,,,
+6156496b-fcc2-4db4-9a1a-cafedbe33fa3,https://open.oregonstate.education/aandp/,13.6 Testing the Spinal Nerves (Sensory and Motor Exams),https://open.oregonstate.education/aandp/chapter/13-6-testing-the-spinal-nerves-sensory-and-motor-exams/,"A lesion on the LMN would result in paralysis, or at least partial loss of voluntary muscle control, which is known as paresis. The paralysis observed in LMN diseases is referred to as flaccid paralysis, referring to a complete or partial loss of muscle tone, in contrast to the loss of control in UMN lesions in which tone is retained and spasticity is exhibited. Other signs of an LMN lesion are fibrillation, fasciculation, and compromised or lost reflexes resulting from the denervation of the muscle fibers.",True,Comparison of Upper and Lower Motor Neuron Damage,,,,
+99f21e2b-9135-471f-8a95-e6176163656c,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,Ventral Horn Output,False,Ventral Horn Output,,,,
+6834abba-7589-42fc-b570-d021b3deddd8,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"The somatic nervous system provides output strictly to skeletal muscles. The lower motor neurons, which are responsible for the contraction of these muscles, are found in the ventral horn of the spinal cord. These large, multipolar neurons have a corona of dendrites surrounding the cell body and an axon that extends out of the ventral horn. This axon travels through the ventral nerve root to join the emerging spinal nerve. The axon is relatively long because it needs to reach muscles in the periphery of the body. The diameters of cell bodies may be on the order of hundreds of micrometers to support the long axon; some axons are a meter in length, such as the lumbar motor neurons that innervate muscles in the first digits of the feet.",True,Ventral Horn Output,,,,
+c3239912-3333-4a14-8b75-42e4e99571cb,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"The axons will also branch to innervate multiple muscle fibers. Together, the motor neuron and all the muscle fibers that it controls make up a motor unit. Motor units vary in size. Some may contain up to 1000 muscle fibers, such as in the quadriceps, or they may only have 10 fibers, such as in an extraocular muscle. The number of muscle fibers that are part of a motor unit corresponds to the precision of control of that muscle. Also, muscles that have finer motor control have more motor units connecting to them, and this requires a larger topographical field in the primary motor cortex of the brain, which contains the upper motor neurons.",True,Ventral Horn Output,,,,
+804856eb-c82b-4d47-ad99-9f541dd9db06,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"Motor neuron axons connect to muscle fibers at a neuromuscular junction. This is a specialized synaptic structure at which multiple axon terminals synapse with the muscle fiber sarcolemma. The synaptic end bulbs of the motor neurons secrete acetylcholine, which binds to receptors on the sarcolemma. The binding of acetylcholine opens ligand-gated ion channels, increasing the movement of cations across the sarcolemma. This depolarizes the sarcolemma, initiating muscle contraction. While other synapses result in graded potentials that must reach a threshold in the postsynaptic target, activity at the neuromuscular junction reliably leads to muscle fiber contraction with every nerve impulse received from a motor neuron. However, the strength of contraction and the number of fibers that contract can be affected by the frequency of the motor neuron impulses.",True,Ventral Horn Output,,,,
+e6ea3d0c-a22a-4ef1-a962-34eb1aaa5e1c,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,Reflexes,False,Reflexes,,,,
+ad7f2cc6-baa3-477d-921a-12936b46d8e0,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"Reflexes can be spinal or cranial, depending on the nerves and central components that are involved. The body uses both spinal and cranial reflexes to rapidly respond to important stimuli. All reflex arcs include five basic components; (1) a receptor, (2) a sensory neuron, (3) an integration center, (4) a motor neuron, and (5) an effector. The effector may be a skeletal muscle, as is the case in somatic reflexes. However, in autonomic (or visceral) reflexes, the effector will be cardiac muscle, smooth muscle, or a gland.",True,Reflexes,,,,
+c73ebc6e-6806-48e0-aba0-7950d860424c,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"Somatic spinal reflexes utilize motor neurons of the ventral horn to activate skeletal muscles. The simplest example of this type of reflex is the stretch reflex. In this reflex, when a skeletal muscle is stretched, a muscle spindle receptor is activated. The sensory neuron associated with the muscle spindle synapses directly with the motor neuron in the ventral horn, allowing for an incredibly fast response called a monosynaptic reflex. The reflex helps to maintain muscles at a constant length, and is the reason your head jerks back up after drooping when you begin to fall asleep sitting up. Another common example of this reflex is the knee jerk that is elicited by a rubber hammer struck against the patellar ligament in a physical exam.",True,Reflexes,,,,
+78452dd8-66a1-4f15-adf2-0fbe80ccb619,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,Figure 13.5.1 – Stretch Reflex,True,Reflexes,Figure 13.5.1,,,
+89570870-477c-4c0b-9316-3ac0aee2557e,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"A different somatic spinal nerve reflex involves the response to pain, like when you touch a hot stove and in response withdrawal your arm, typically before you have even registered the pain in your hand. This reflex is called the flexor withdrawal reflex, and it stimulates the withdrawal of the arm through a connection in the spinal cord that leads to contraction of the biceps brachii. Unlike the stretch reflex, the flexor withdrawal reflex is polysynaptic and requires 2 spinal cord synapses to activate the motor neuron. As you withdraw your hand from the stove, you do not want to slow that reflex down. As the biceps brachii contracts, the antagonistic triceps brachii that had been activated to extend the arm toward the stove now needs to relax. Because the neuromuscular junction is strictly excitatory, the biceps will contract when the motor nerve is active. Skeletal muscles do not actively relax. Instead the motor neuron needs to “quiet down,” or be inhibited. In the hot-stove withdrawal reflex, this occurs through an interneuron in the spinal cord. The interneuron’s cell body is located in the dorsal horn of the spinal cord. The interneuron receives a synapse from the axon of the sensory neuron that detects that the hand is being burned. In response to this stimulation from the sensory neuron, the interneuron then inhibits the motor neuron that controls the triceps brachii, in what is known as reciprocal inhibition. This is done by releasing a neurotransmitter or other signal that hyperpolarizes the motor neuron connected to the triceps brachii, making it less likely to initiate an action potential. With this motor neuron being inhibited, the triceps brachii relaxes. Without the antagonistic contraction, withdrawal from the hot stove is faster and keeps further tissue damage from occurring.",True,Reflexes,,,,
+4332e357-4964-4240-ae9c-c56a829efee4,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"The flexor withdrawal reflex is also at play when you step on a painful stimulus, like a tack or a child’s Lego®. The nociceptors that are activated by the painful stimulus activate the motor neurons responsible for contraction of the tibialis anterior muscle. This causes dorsiflexion of the foot. An inhibitory interneuron, activated by a collateral branch of the nociceptor fiber, will inhibit the motor neurons of the gastrocnemius and soleus muscles to cancel plantar flexion. An important difference in this reflex is that plantar flexion is most likely in progress as the foot is pressing down onto the tack. Contraction of the tibialis anterior is not the most important aspect of the reflex, as continuation of plantar flexion will result in further damage from stepping onto the tack. While all this is happening in one lower limb, a contralateral response will be stimulated to help you catch your balance with the other. This is called the crossed extensor reflex.",True,Reflexes,,,,
+76e79019-e11f-4aee-a8c5-04367133cd4f,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"In the cross extensor reflex, the same painful stimulus that initiates the flexor withdrawal reflex simultaneously initiates extension of the opposite limb. In the case of stepping on a painful object and pulling your foot away, the cross extensor reflex activated the contralateral quads and gastrocnemius and soleus to extend the leg while plantar flexing the ankle to shift body weight.",True,Reflexes,,,,
+2529a90e-04f1-47e5-889b-c1647d4b5129,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"All of the somatic spinal nerve reflexes involved so far involve reciprocal inhibition. In each case, a prime mover is stimulated and its antagonist is inhibited. However, in the golgi tendon reflex, the prime mover is inhibited its antagonist is stimulated. This is termed reciprocal activation. In the tendon reflex, prolonged or particularly forceful stretching of the muscle and its tendon trigger the relaxation of the muscle to prevent tearing through the activation of a special receptor, the golgi tendon organ. At the same time, the antagonist muscles is activated to help return the affected muscle and its tendon to their resting lengths.",True,Reflexes,,,,
+a4e225df-5a8b-42ea-b3c1-13d09127ee33,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,Figure 13.5.3 – Golgi Tendon Reflex,True,Reflexes,Figure 13.5.3,,,
+97691d60-ed1d-4945-92f5-027385492622,https://open.oregonstate.education/aandp/,13.5 Ventral Horn Output and Reflexes,https://open.oregonstate.education/aandp/chapter/13-5-ventral-horn-output-and-reflexes/,"Cranial nerve somatic reflexes function similarly, but are integrated in the brainstem. A specialized cranial nerve reflex which protects the surface of the eye is the corneal reflex, or the eye blink reflex. When the cornea is stimulated by a tactile stimulus, or even by bright light in a related reflex, blinking is initiated. The sensory component travels through the trigeminal nerve, which carries somatosensory information from the face, or through the optic nerve, if the stimulus is bright light. The motor response travels through the facial nerve and innervates the orbicularis oculi on the same side. This reflex is commonly tested during a physical exam using an air puff or a gentle touch of a cotton-tipped applicator.",True,Reflexes,,,,
+e0598d48-3a5a-45cf-a478-f95d8939527f,https://open.oregonstate.education/aandp/,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/aandp/chapter/13-4-relationship-of-the-pns-to-the-spinal-cord-of-the-cns/,"Sensory axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The motor axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both. On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions.",True,Reflexes,,,,
+58c00093-a12d-415b-bf67-e1463a69575f,https://open.oregonstate.education/aandp/,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/aandp/chapter/13-4-relationship-of-the-pns-to-the-spinal-cord-of-the-cns/,"The length of the spinal cord is divided into regions that correspond to the regions of the vertebral column. The name of a spinal cord region corresponds to the level at which spinal nerves pass through the intervertebral foramina. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, then the lumbar, and finally the sacral region. The spinal cord is not the full length of the vertebral column because the spinal cord does not grow significantly longer after the first or second year, but the skeleton continues to grow. The nerves that emerge from the spinal cord pass through the intervertebral formina at the respective levels. As the vertebral column grows, these nerves grow with it and result in a long bundle of nerves that resembles a horse’s tail and is named the cauda equina. The sacral spinal cord is at the level of the upper lumbar vertebral bones. The spinal nerves extend from their various levels to the proper level of the vertebral column.",True,Reflexes,,,,
+81c5a76b-85df-497b-9c5b-59351670efad,https://open.oregonstate.education/aandp/,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/aandp/chapter/13-4-relationship-of-the-pns-to-the-spinal-cord-of-the-cns/,"In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in Figure 13.4.1, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.",True,Reflexes,Figure 13.4.1,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1313_Spinal_Cord_Cross_Section.jpg,"Figure 13.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+56c51b84-2b96-4f60-b270-e2106a69b3b5,https://open.oregonstate.education/aandp/,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/aandp/chapter/13-4-relationship-of-the-pns-to-the-spinal-cord-of-the-cns/,"Some of the largest neurons of the spinal cord are the multipolar motor neurons in the anterior horn. The fibers that cause contraction of skeletal muscles are the axons of these neurons. The motor neuron that causes contraction of the big toe, for example, is located in the sacral spinal cord. The axon that has to reach all the way to the belly of that muscle may be a meter in length. The neuronal cell body that maintains that long fiber must be quite large, possibly several hundred micrometers in diameter, making it one of the largest cells in the body.",True,Reflexes,,,,
+fd48e88d-95f8-4648-b276-f3b1e1d6e45a,https://open.oregonstate.education/aandp/,13.4 Relationship of the PNS to the Spinal Cord of the CNS,https://open.oregonstate.education/aandp/chapter/13-4-relationship-of-the-pns-to-the-spinal-cord-of-the-cns/,"Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts carrying sensory information to the brain. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.",True,Reflexes,,,,
+c90f06af-cfe5-464d-9dcc-d5994cee0a90,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"The nerves connected to the spinal cord are the spinal nerves. The arrangement of these nerves is much more regular than that of the cranial nerves. All of the spinal nerves are combined sensory and motor axons that separate into two nerve roots. The sensory axons enter the spinal cord as the dorsal nerve root. The motor fibers, both somatic and autonomic, emerge as the ventral nerve root. The dorsal root ganglion for each nerve is an enlargement of the spinal nerve.",True,Reflexes,,,,
+4eb07ea7-b00f-41a6-ba3e-4b9f52d0da19,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"There are 31 spinal nerves, named for the level of the spinal cord at which each one emerges. There are eight pairs of cervical nerves designated C1 to C8, twelve thoracic nerves designated T1 to T12, five pairs of lumbar nerves designated L1 to L5, five pairs of sacral nerves designated S1 to S5, and one pair of coccygeal nerves. The nerves are numbered from the superior to inferior positions, and each emerges from the vertebral column through the intervertebral foramen at its level. The first nerve, C1, emerges between the first cervical vertebra and the occipital bone. The second nerve, C2, emerges between the first and second cervical vertebrae. The same occurs for C3 to C7, but C8 emerges between the seventh cervical vertebra and the first thoracic vertebra. For the thoracic and lumbar nerves, each one emerges between the vertebra that has the same designation and the next vertebra in the column. The sacral nerves emerge from the sacral foramina along the length of that unique vertebra.",True,Reflexes,,,,
+a94b4006-73c4-4ccb-98eb-4ad10e408e66,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"Spinal nerves extend outward from the vertebral column to enervate the periphery. The nerves in the periphery are not straight continuations of the spinal nerves, but rather the reorganization of the axons in those nerves to follow different courses. Axons from different spinal nerves will come together into a systemic nerve. This occurs at four places along the length of the vertebral column, each identified as a nerve plexus, whereas the other spinal nerves directly correspond to nerves at their respective levels. In this instance, the word plexus is used to describe networks of nerve fibers with no associated cell bodies.",True,Reflexes,,,,
+10dfc9fe-603a-45d9-a001-c76df516acb2,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"Of the four nerve plexuses, two are found at the cervical level, one at the lumbar level, and one at the sacral level (Figure 13.3.1). The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. The other plexus from the cervical level is the brachial plexus. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The radial nerve continues through the arm and is paralleled by the ulnar nerve and the median nerve. The lumbar plexus arises from axons of the ventral rami of spinal nerves T12 through L4 and gives rise to nerves enervating the pelvic region and the anterior leg. The femoral nerve is one of the major nerves from this plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg. The sacral plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4. The most significant systemic nerve to come from this plexus is the sciatic nerve, which is a combination of the tibial nerve and the fibular nerve. The sciatic nerve extends across the hip joint and is most commonly associated with the condition sciatica, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it.",True,Reflexes,Figure 13.3.1,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1321_Spinal_Nerve_Plexuses.jpg,"Figure 13.3.1 – Nerve Plexuses of the Body: There are four main nerve plexuses in the human body. The cervical plexus supplies nerves to the posterior head and neck, as well as to the diaphragm. The brachial plexus supplies nerves to the arm. The lumbar plexus supplies nerves to the anterior leg. The sacral plexus supplies nerves to the posterior leg."
+48c376e0-51b4-441e-83e9-014d6124e1e0,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"These plexuses are described as arising from spinal nerves and giving rise to certain systemic nerves, but they contain fibers that serve sensory functions or fibers that serve motor functions. This means that some fibers extend from cutaneous or other peripheral sensory surfaces and send action potentials into the CNS. Those are axons of sensory neurons in the dorsal root ganglia that enter the spinal cord through the dorsal nerve root. Other fibers are the axons of motor neurons of the anterior horn of the spinal cord, which emerge in the ventral nerve root and send action potentials to cause skeletal muscles to contract in their target regions. For example, the radial nerve contains fibers of cutaneous sensation in the arm, as well as motor fibers that move muscles in the arm.",True,Reflexes,,,,
+25beaa95-86c5-4186-a024-6b28a78ee001,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,"Spinal nerves of the thoracic region, T2 through T11, are not part of the plexuses but rather emerge and give rise to the intercostal nerves found between the ribs, which articulate with the vertebrae surrounding the spinal nerve.",True,Reflexes,,,,
+d5a5f3bc-e941-4415-8f49-794542ef0a2b,https://open.oregonstate.education/aandp/,13.3 Spinal and Cranial Nerves,https://open.oregonstate.education/aandp/chapter/13-3-spinal-and-cranial-nerves/,olfactory nerve,False,olfactory nerve,,,,
+6db63a96-a6aa-4f79-870b-5586fb0d273f,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,Ganglia,False,Ganglia,,,,
+c872e49e-df65-4b22-bdf5-737d17a8efff,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"A ganglion is a group of neuron cell bodies in the periphery (a.k.a. the peripheral nervous system). Ganglia can be categorized, for the most part, as either sensory ganglia or autonomic ganglia, referring to their primary functions. The most common type of sensory ganglion is a dorsal (posterior) root ganglion. These ganglia are the cell bodies of neurons with axons that are associated with sensory endings in the periphery, such as in the skin, and that extend into the CNS through the dorsal nerve root. The ganglion is an enlargement of the nerve root. Note that nerve roots are not surrounded by the pia mater, and as such are part of the peripheral nervous system. Under microscopic inspection, it can be seen to include the cell bodies of the neurons, as well as bundles of fibers that are the dorsal nerve root (Figure 13.2.1). The cells of the dorsal root ganglion are unipolar cells, classifying them by shape. Also, the small round nuclei of satellite cells can be seen surrounding—as if they were orbiting—the neuron cell bodies.",True,Ganglia,Figure 13.2.1,13.2 Ganglia and Nerves,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1318b_Dorsal_Root_Ganglion.jpg,"Figure 13.2.1 – Dorsal Root Ganglion: The cell bodies of sensory neurons, which are unipolar neurons by shape, are seen in this photomicrograph. Also, the fibrous region is composed of the axons of these neurons that are passing through the ganglion to be part of the dorsal nerve root (tissue source: canine). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+72ad7166-3339-4d1a-8a44-139d0f0bdbc1,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"Another type of sensory ganglion is a cranial nerve ganglion. This is analogous to the dorsal root ganglion, except that it is associated with a cranial nerve (associated with the brain) instead of a spinal nerve (associated with the spinal cord). The roots of cranial nerves are within the cranium, whereas the ganglia are outside the skull. For example, the trigeminal ganglion is superficial to the temporal bone whereas its associated nerve is attached to the mid-pons region of the brain stem. Like the sensory neurons associated with the spinal cord, the sensory neurons of cranial nerve ganglia are unipolar in shape with associated satellite cells.",True,Ganglia,,,,
+15257af2-bf57-4987-9b11-29b76d74377e,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"The other major category of ganglia are those of the autonomic nervous system, which is divided into the sympathetic and parasympathetic nervous systems. The sympathetic chain ganglia constitute a row of ganglia along the vertebral column that receive central input from the lateral horn of the thoracic and upper lumbar spinal cord. At the superior end of the chain ganglia are three paravertebral ganglia in the cervical region. Three other autonomic ganglia that are related to the sympathetic chain are the prevertebral ganglia, which are located outside of the chain but have similar functions. They are referred to as prevertebral because they are anterior to the vertebral column. The neurons of these autonomic ganglia are multipolar in shape, with dendrites radiating out around the cell body where synapses from the spinal cord neurons are made. The neurons of the chain, paravertebral, and prevertebral ganglia then project to organs in the head and neck, thoracic, abdominal, and pelvic cavities to regulate the sympathetic aspect of homeostatic mechanisms.",True,Ganglia,,,,
+a614e5e4-1b5e-458c-87c9-ee42767429ec,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"Another group of autonomic ganglia are the terminal ganglia that receive central input from cranial nerves or sacral spinal nerves and are responsible for regulating the parasympathetic aspect of homeostatic mechanisms. These two sets of ganglia, sympathetic and parasympathetic, often project to the same organs—one input from the chain ganglia and one input from a terminal ganglion—to regulate the overall function of an organ. For example, the heart receives two inputs such as these; one increases heart rate, and the other decreases it. The terminal ganglia that receive input from cranial nerves are found in the head and neck, as well as the thoracic and upper abdominal cavities, whereas the terminal ganglia that receive sacral input are in the lower abdominal and pelvic cavities.",True,Ganglia,,,,
+8fb8eaf4-0b7b-453c-b97a-a949002e1dab,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"Terminal ganglia below the head and neck are often incorporated into the wall of the target organ as a plexus. A plexus, in a general sense, is a network of branching interconnected fibers or vessels. This can apply to nervous tissue (as in this instance) or structures containing blood vessels (such as a choroid plexus). For example, the enteric plexus is the extensive network of axons and neurons in the wall of the small and large intestines. The enteric plexus is actually part of the enteric nervous system, along with the gastric plexuses and the esophageal plexus. Though the enteric nervous system receives input originating from central neurons of the autonomic nervous system, it does not require CNS input to function. In fact, it operates independently to regulate the digestive system.",True,Ganglia,,,,
+e2930f70-e748-48b9-9b1a-452b348dad5e,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,Nerves,False,Nerves,,,,
+74f1c6f1-9a1e-487d-b1f9-59e688a8d8bc,https://open.oregonstate.education/aandp/,13.2 Ganglia and Nerves,https://open.oregonstate.education/aandp/chapter/13-2-ganglia-and-nerves/,"Bundles of axons in the PNS are referred to as nerves. These structures in the periphery are different than the central counterpart, called a tract. Unlike tracts, nerves are composed of more than just nervous tissue. They have connective tissues invested in their structure, as well as blood vessels supplying the tissues with nourishment. The outer surface of a nerve is a surrounding layer of fibrous connective tissue called the epineurium. Within the nerve, axons are further bundled into fascicles, which are each surrounded by their own layer of fibrous connective tissue called perineurium. Finally, individual axons are surrounded by loose connective tissue called the endoneurium (Figure 13.2.3). These three layers are similar to the connective tissue sheaths for muscles. Because peripheral axons are surrounded by an endoneurium it is possible for severed axons to regenerated. After they are cut the proximal severed end of the axon sprouts and one of the sprouts will find the endoneurium which is, essentially, an empty tube leading to (or near) the original target. The endoneurim is empty because the distal portion of the severed axon degenerates, a process called Wallerian (anterograde or orthograde) degeneration. Nerves are associated with the region of the CNS to which they are connected, either as cranial nerves connected to the brain or spinal nerves connected to the spinal cord.",True,Nerves,Figure 13.2.3,13.2 Ganglia and Nerves,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1319_Nerve_Structure.jpg,"Figure 13.2.3 – Nerve Structure. The structure of a nerve is organized by the layers of connective tissue on the outside, around each fascicle, and surrounding the individual nerve fibers (tissue source: simian). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+1ad95067-6a15-466d-b88a-d897ceae515f,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"A major role of sensory receptors is to help us learn about the environment around us, or about the state of our internal environment. Different types of stimuli from varying sources are received and changed into the electrochemical signals of the nervous system. This process is called sensory transduction. This occurs when a stimulus is detected by a receptor which generates a graded potential in a sensory neuron. If strong enough, the graded potential causes the sensory neuron to produce an action potential that is relayed into the central nervous system (CNS), where it is integrated with other sensory information—and sometimes higher cognitive functions—to become a conscious perception of that stimulus. The central integration may then lead to a motor response.",True,Nerves,,,,
+9a011c65-32aa-4dbc-a460-9515689c60ad,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Describing sensory function with the term sensation or perception is a deliberate distinction. Sensation is the activation of sensory receptors at the level of the stimulus. Perception is the central processing of sensory stimuli into a meaningful pattern involving awareness. Perception is dependent on sensation, but not all sensations are perceived. Receptors are the structures (and sometimes whole cells) that detect sensations. A receptor or receptor cell is changed directly by a stimulus. A transmembrane protein receptor is a protein in the cell membrane that mediates a physiological change in a neuron, most often through the opening of ion channels or changes in the cell signaling processes. Some transmembrane receptors are activated by chemicals called ligands. For example, a molecule in food can serve as a ligand for taste receptors. Other transmembrane proteins, which are not accurately called receptors, are sensitive to mechanical or thermal changes. Physical changes in these proteins increase ion flow across the membrane, and can generate a graded potential in the sensory neurons.",True,Nerves,,,,
+e0e0bddc-6607-4a00-be49-1df485e430bb,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,Sensory Receptors,False,Sensory Receptors,,,,
+233c7b17-cb15-40fa-85a0-0b9902cf2cb7,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Stimuli in the environment activate specialized receptors or receptor cells in the peripheral nervous system. Different types of stimuli are sensed by different types of receptors. Receptor cells can be classified into types on the basis of three different criteria: cell type, position, and function. Receptors can be classified structurally on the basis of cell type and their position in relation to stimuli they sense. They can also be classified functionally on the basis of the transduction of stimuli, or how the mechanical stimulus, light, or chemical changed the cell membrane potential.",True,Sensory Receptors,,,,
+28689ac0-9940-48a8-b1a3-4b95b6540fea,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,Sensory Modalities,False,Sensory Modalities,,,,
+c0c85a76-edd7-4f3e-a045-b76a839297ef,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Ask anyone what the senses are, and they are likely to list the five major senses—taste, smell, touch, hearing, and sight. However, these are not all of the senses. The most obvious omission from this list is balance. Also, what is referred to simply as touch can be further subdivided into pressure, vibration, stretch, and hair-follicle position, on the basis of the type of mechanoreceptors that perceive these touch sensations. Other overlooked senses include temperature perception by thermoreceptors and pain perception by nociceptors.",True,Sensory Modalities,,,,
+3fc4f034-d4f5-44c0-ad54-4cb2c80cd758,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Within the realm of physiology, senses can be classified as either general or special. A general sense is one that is distributed throughout the body and has receptor cells within the structures of other organs. Mechanoreceptors in the skin, muscles, or the walls of blood vessels are examples of this type. General senses often contribute to the sense of touch, as described above, or to proprioception (body position) and kinesthesia (body movement), or to a visceral sense, which is most important to autonomic functions. A special sense (discussed in Chapter 15) is one that has a specific organ devoted to it, namely the eye, inner ear, tongue, or nose.",True,Sensory Modalities,,,,
+5149d9fd-b2f3-4bfa-88cb-db3f6c4d3ef3,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Each of the senses is referred to as a sensory modality. Modality refers to the way that information is encoded into a perception. The main sensory modalities can be described on the basis of how each stimulus is transduced and perceived. The chemical senses include taste and smell. The general sense that is usually referred to as touch includes chemical sensation in the form of nociception, or pain. Pressure, vibration, muscle stretch, and the movement of hair by an external stimulus, are all sensed by mechanoreceptors and perceived as touch or proprioception. Hearing and balance are also sensed by mechanoreceptors. Finally, vision involves the activation of photoreceptors.",True,Sensory Modalities,,,,
+0cb159c4-2856-483e-8903-1c38acc14f21,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Listing all the different sensory modalities, which can number as many as 17, involves separating the five major senses into more specific categories, or submodalities, of the larger sense. An individual sensory modality represents the sensation of a specific type of stimulus. For example, the general sense of touch, which is known as somatosensation, can be separated into light pressure, deep pressure, vibration, itch, pain, temperature, or hair movement.",True,Sensory Modalities,,,,
+89acdd59-7b82-4829-87f2-09d244dd3145,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"In this chapter we will discuss the general senses which include pain, temperature, touch, pressure, vibration and proprioception. We will discuss the special senses, which include smell, taste, vision, hearing and the vestibular system, in chapter 15.",True,Sensory Modalities,,,,
+ae00326e-1dbd-41d0-9b31-96b485bc7c4d,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Somatosensation is considered a general sense, as opposed to the submodalities discussed in this section. Somatosensation is the group of sensory modalities that are associated with touch and limb position. These modalities include pressure, vibration, light touch, tickle, itch, temperature, pain, proprioception, and kinesthesia. This means that its receptors are not associated with a specialized organ, but are instead spread throughout the body in a variety of organs. Many of the somatosensory receptors are located in the skin, but receptors are also found in muscles, tendons, joint capsules and ligaments.",True,Sensory Modalities,,,,
+87a78d19-2e33-4fcf-8c71-34664b2435ad,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Two types of somatosensory signals that are transduced by free nerve endings are pain and temperature. These two modalities use thermoreceptors and nociceptors to transduce temperature and pain stimuli, respectively. Temperature receptors are stimulated when local temperatures differ from body temperature. Some thermoreceptors are sensitive to just cold and others to just heat. Nociception is the sensation of potentially damaging stimuli. Mechanical, chemical, or thermal stimuli beyond a set threshold will elicit painful sensations. Stressed or damaged tissues release chemicals that activate receptor proteins in the nociceptors. For example, the sensation of pain or heat associated with spicy foods involves capsaicin, the active molecule in hot peppers. Capsaicin molecules bind to a transmembrane ion channel in nociceptors that is sensitive to temperatures above 37°C. The dynamics of capsaicin binding with this transmembrane ion channel is unusual in that the molecule remains bound for a long time. Because of this, it will decrease the ability of other stimuli to elicit pain sensations through the activated nociceptor. For this reason, capsaicin can be used as a topical analgesic, such as in products like Icy Hot™.",True,Sensory Modalities,,,,
+0f667274-2024-4a4c-a28d-5e2ae51cb848,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"If you drag your finger across a textured surface, the skin of your finger will vibrate. Such low frequency vibrations are sensed by mechanoreceptors called Merkel cells, also known as type I cutaneous mechanoreceptors. Merkel cells are located in the stratum basale of the epidermis. Deep pressure and vibration is transduced by lamellated (Pacinian) corpuscles, which are receptors with encapsulated endings found deep in the dermis, or subcutaneous tissue. Light touch is transduced by the encapsulated endings known as tactile (Meissner’s) corpuscles. Follicles are also wrapped in a plexus of nerve endings known as the hair follicle plexus. These nerve endings detect the movement of hair at the surface of the skin, such as when an insect may be walking along the skin. Stretching of the skin is transduced by stretch receptors known as bulbous corpuscles. Bulbous corpuscles are also known as Ruffini corpuscles, or type II cutaneous mechanoreceptors.",True,Sensory Modalities,,,,
+e06409c9-0339-4f1d-bffb-87698c390880,https://open.oregonstate.education/aandp/,13.1 Sensory Receptors,https://open.oregonstate.education/aandp/chapter/13-1-sensory-receptors/,"Other somatosensory receptors are found in the joints and muscles. Stretch receptors monitor the stretching of tendons, muscles, and the components of joints. For example, have you ever stretched your muscles before or after exercise and noticed that you can only stretch so far before your muscles spasm back to a less stretched state? This spasm is a reflex that is initiated by stretch receptors to avoid muscle tearing. Such stretch receptors can also prevent over-contraction of a muscle. In skeletal muscle tissue, these stretch receptors are called muscle spindles. Golgi tendon organs similarly transduce the stretch levels of tendons. Bulbous corpuscles are also present in joint capsules, where they measure stretch in the components of the skeletal system within the joint. Additionally, lamellated corpuscles are found adjacent to joint capsules and detect vibrations associated with movement around joints. The types of nerve endings, their locations, and the stimuli they transduce are presented in the table below.",True,Sensory Modalities,,,,
+d26237fa-5940-4062-9caa-e09c726af36e,https://open.oregonstate.education/aandp/,13.0 Introduction,https://open.oregonstate.education/aandp/chapter/13-0-introduction/,"The peripheral nervous system includes both somatic and autonomic divisions. The autonomic division will primarily be discussed in chapter 16. While the somatic nervous system is traditionally considered a division within the peripheral nervous system, this misses an important point: somatic refers to a functional division, whereas peripheral refers to an anatomic division. The somatic nervous system is responsible for our conscious perception of the environment and for our voluntary responses to that perception by means of skeletal muscles. Peripheral sensory neurons receive input from environmental stimuli, but the neurons that produce motor responses originate in the central nervous system. The distinction between the structures (i.e., anatomy) of the peripheral and central nervous systems and functions (i.e., physiology) of the somatic and autonomic systems can most easily be demonstrated through a simple reflex action. When you touch a hot stove, you pull your hand away. Sensory receptors in the skin sense extreme temperature and the early signs of tissue damage. This triggers an action potential, which travels along the sensory fiber from the skin, through the dorsal spinal root to the spinal cord, and directly activates a lower motor neuron in the ventral horn. That neuron sends a signal along its axon to excite the biceps brachii, causing contraction of the muscle and flexion of the forearm at the elbow to withdraw the hand from the hot stove. The withdrawal reflex has more components, such as inhibiting the opposing muscle and balancing posture while the arm is forcefully withdrawn, which will be further explored at the end of this chapter.",True,Sensory Modalities,,,,
+6008e492-94d3-436b-8c3e-541f9f920640,https://open.oregonstate.education/aandp/,13.0 Introduction,https://open.oregonstate.education/aandp/chapter/13-0-introduction/,"The basic withdrawal reflex explained above includes sensory input (the painful stimulus), central processing (the synapse in the spinal cord), and motor output (activation of a lower motor neuron that causes contraction of the biceps brachii). Expanding the explanation of the withdrawal reflex can include inhibition of the opposing muscle (reciprocal inhibition), or adjusting posture (cross extensor), either of which increase the complexity of the example by involving more central neurons. A collateral branch of the sensory axon would inhibit another ventral horn lower motor neuron so that the triceps brachii relaxes to allow the flexion. The cross extensor reflex provides a counterbalancing movement on the other side of the body, which requires another collateral of the sensory axon to activate contraction of the extensor muscles in the contralateral limb.",True,Sensory Modalities,,,,
+2494da7e-82d1-4b8d-9802-a847e5bf6b37,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,Describe how movement of ions across the neuron membrane leads to an action potential,True,Sensory Modalities,,,,
+72639234-44b0-44d8-9eae-a24d7b718ee1,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"The functions of the nervous system—sensation, integration, and response—depend on the functions of the neurons underlying these pathways. To understand how neurons are able to communicate, it is necessary to describe the role of an excitable membrane in generating these signals. The basis of this process is the action potential. An action potential is a predictable change in membrane potential that occurs due to the open and closing of voltage gated ion channels on the cell membrane.",True,Sensory Modalities,,,,
+178258a6-da8e-4b5a-bb81-6b919a19c2fd,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,Electrically Active Cell Membranes,False,Electrically Active Cell Membranes,,,,
+e52b78b5-93d4-408b-8264-ce734c9b3d66,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"Most cells in the body make use of charged particles (ions) to create electrochemical charge across the cell membrane. In a prior chapter, we described how muscle cells contract based on the movement of ions across the cell membrane. For skeletal muscles to contract, due to excitation–contraction coupling, they require input from a neuron. Both muscle and nerve cells make use of a cell membrane that is specialized for signal conduction to regulate ion movement between the extracellular fluid and cytosol.",True,Electrically Active Cell Membranes,,,,
+d4e528ef-dbfe-4343-b989-db1f941c32c7,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"As you learned in the chapter on cells, the cell membrane is primarily responsible for regulating what can cross the membrane. The cell membrane is a phospholipid bilayer, so only substances that can pass directly through the hydrophobic core can diffuse through unaided. Charged particles, which are hydrophilic, cannot pass through the cell membrane without assistance (Figure 12.5.1). Specific transmembrane channel proteins permit charged ions to move across the membrane. Several passive transport channels, as well as active transport pumps, are necessary to generate a transmembrane potential, and an action potential. Of special interest is the carrier protein referred to as the sodium/potassium pump that uses energy to move sodium ions (Na+) out of a cell and potassium ions (K+) into a cell, thus regulating ion concentration on both sides of the cell membrane.",True,Electrically Active Cell Membranes,Figure 12.5.1,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1215_Cell_Membrane_Channels.jpg,"Figure 12.5.1 – Cell Membrane and Transmembrane Proteins: The cell membrane is composed of a phospholipid bilayer and has many transmembrane proteins, including different types of channel proteins that serve as ion channels."
+b29104fe-3be9-4af1-a374-2480a6dda8b0,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"The sodium/potassium pump requires energy in the form of adenosine triphosphate (ATP), so it is also referred to as an ATPase pump. As was explained in the cell chapter, the concentration of Na+ is higher outside the cell than inside, and the concentration of K+ is higher inside the cell than outside. Therefore, this pump is working against the concentration gradients for sodium and potassium ions, which is why it requires energy. The Na+/K+ ATPase pump maintains these important ion concentration gradients.",True,Electrically Active Cell Membranes,,,,
+b0c8eae9-6802-4845-809a-91eaccf131d6,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"Ion channels are pores that allow specific charged particles to cross the membrane in response to an existing electrochemical gradient. Proteins are capable of spanning the cell membrane, including its hydrophobic core, and can interact with charged ions because of the varied properties of amino acids found within specific regions of the protein channel. Hydrophobic amino acids are found in the regions that are adjacent to the hydrocarbon tails of the phospholipids, where as hydrophilic amino acids are exposed to the fluid environments of the extracellular fluid and cytosol. Additionally, ions will interact with the hydrophilic amino acids, which will be selective for the charge of the ion. Channels for cations (positive ions) will have negatively charged side chains in the pore. Channels for anions (negative ions) will have positively charged side chains in the pore. The diameter of the channel’s pore also impacts the specific ions that can pass through.  Some ion channels are selective for charge but not necessarily for size. These nonspecific channels allow cations—particularly Na+, K+, and Ca2+—to cross the membrane, but exclude anions.",True,Electrically Active Cell Membranes,,,,
+ac7a05a9-9104-4ac1-84d5-e3084f874c58,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"Some ion channels do not allow ions to freely diffuse across the membrane, but are gated instead. A ligand-gated channel opens because a molecule, or ligand, binds to the extracellular region of the channel (Figure 12.5.2).",True,Electrically Active Cell Membranes,Figure 12.5.2,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1216_Ligand-gated_Channels.jpg,"Figure 12.5.2 – Ligand-Gated Channels: When the ligand, in this case the neurotransmitter acetylcholine, binds to a specific location on the extracellular surface of the channel protein, the pore opens to allow select ions through. The ions, in this case, are cations of sodium, calcium, and potassium."
+d42859d0-f93a-45fa-b1f3-7e664144f28a,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"A mechanically-gated channel opens because of a physical distortion of the cell membrane. Many channels associated with the sense of touch are mechanically-gated. For example, as pressure is applied to the skin, mechanically-gated channels on the subcutaneous receptors open and allow ions to enter (Figure 12.5.3).",True,Electrically Active Cell Membranes,Figure 12.5.3,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1217_Mechanically-gated_Channels-02.jpg,"Figure 12.5.3 – Mechanically-Gated Channels: When a mechanical change occurs in the surrounding tissue (such as pressure or stretch) the channel is physically opened, and ions can move through the channel, down their concentration gradient."
+671d9831-9f8e-4607-b2a7-fb267957fb6c,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"A voltage-gated channel is a channel that responds to changes in the electrical properties of the membrane in which it is embedded. Normally, the inner portion of the membrane is at a negative voltage. When that voltage becomes less negative and reaches a value specific to the channel, it opens and allows ions to cross the membrane (Figure 12.5.4).",True,Electrically Active Cell Membranes,Figure 12.5.4,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1218_Voltage-gated_Channels_revised-e1568245968412.png,Figure 12.5.4 – Voltage-Gated Channels: Voltage-gated channels open when the transmembrane voltage changes around them. Amino acids in the structure of the protein are sensitive to charge and cause the pore to open to the selected ion.
+ea7c1456-49b7-4fc7-b36d-94677ebdbb0e,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"A leak channel is randomly gated, meaning that it opens and closes at random, hence the reference to leaking. There is no actual event that opens the channel; instead, it has an intrinsic rate of switching between the open and closed states. Leak channels contribute to the resting transmembrane voltage of the excitable membrane (Figure 12.5.5).",True,Electrically Active Cell Membranes,Figure 12.5.5,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1219_Leakage_Channels.jpg,"Figure 12.5.5 – Leak Channels: These channels open and close at random, allowing ions to pass through when they are open."
+915bf7ee-4fc0-460e-86b6-aaf66b3afe32,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,The Membrane Potential,False,The Membrane Potential,,,,
+156d0d49-7725-4949-a24d-a49000ec3126,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"The membrane potential is a distribution of charge across the cell membrane, measured in millivolts (mV). The standard is to compare the inside of the cell relative to the outside, so the membrane potential is a value representing the charge on the intracellular side of the membrane (based on the outside being zero, relatively speaking; Figure 12.5.6).",True,The Membrane Potential,Figure 12.5.6,12.5 The Action Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1220_Resting_Membrane_Potential.jpg,"Figure 12.5.6 – Measuring Charge across a Membrane with a Voltmeter: A recording electrode is inserted into the cell and a reference electrode is outside the cell. By comparing the charge measured by these two electrodes, the transmembrane voltage is determined. It is conventional to express that value for the cytosol relative to the outside."
+e6cd4f2e-e67a-4bf3-801b-1fd66cb49ec0,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"There is typically an overall net neutral charge between the extracellular and intracellular environments of the neuron. However, a slight difference in charge occurs right at the membrane surface, both internally and externally. It is the difference in this very limited region that holds the power to generate electrical signals, including action potentials, in neurons and muscle cells.",True,The Membrane Potential,,,,
+9186b399-e5e5-455f-b173-b22be07f5272,https://open.oregonstate.education/aandp/,12.5 The Action Potential,https://open.oregonstate.education/aandp/chapter/12-5-the-action-potential/,"When the cell is at rest, ions are distributed across the membrane in a very predictable way. The concentration of Na+ outside the cell is 10 times greater than the concentration inside. Also, the concentration of K+ inside the cell is greater than outside. The cytosol contains a high concentration of anions, in the form of phosphate ions and negatively charged proteins. With the ions distributed across the membrane at these concentrations, the difference in charge is described as the resting membrane potential. The exact value measured for the resting membrane potential varies between cells, but -70 mV is a commonly reported value. This voltage would actually be much lower except for the contributions of some important proteins in the membrane. Leak channels allow Na+ to slowly move into the cell or K+ to slowly move out, and the Na+/K+ pump restores their concentration gradients across the membrane. This may appear to be a waste of energy, but each has a role in maintaining the membrane potential.",True,The Membrane Potential,,,,
+0b6d2746-932f-48bf-9f81-b52fbe2dbf35,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,Describe signal conduction at chemical synapses.,False,Describe signal conduction at chemical synapses.,,,,
+474b2201-67ab-4979-b023-52725c7a2ae4,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,Synapses,False,Synapses,,,,
+e2f90c4d-01a4-4323-854c-a8df661c0f37,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"A synapse is the site of communication between a neuron and another cell. There are two types of synapses: chemical synapses and electrical synapses. In a chemical synapse, a chemical signal— a neurotransmitter—is released from the neuron and it binds to a receptor on the other cell. In an electrical synapse, the membranes of two cells directly connect through a gap junction so that ions can pass directly from one cell to the next, transmitting a signal. Both types of synapses occur in the nervous system, though chemical synapses are more common.",True,Synapses,,,,
+ae97fb08-c93e-4079-938e-0adc4f530157,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"An example of a chemical synapse is the neuromuscular junction (NMJ) described in the chapter on muscle tissue. In the nervous system, there are many additional synapses that utilize the same mechanisms as the NMJ. All chemical synapses have common characteristics, which can be summarized in Table 12.2:",True,Synapses,,,,
+60258178-3614-463a-ba84-5e09ec9e1e42,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"When an action potential reaches the axon terminals, voltage-gated Ca2+ channels in the membrane of the synaptic end bulb open. Ca2+ diffuses down its concentration gradient and enters into the presynaptic neuron axon terminal (end bulb). Once Ca2+ is inside the presynaptic end bulb, it associates with proteins to trigger the exocytosis of neurotransmitter vesicles. The released neurotransmitter moves into the small gap between the cells, the synaptic cleft.",True,Synapses,,,,
+0a4df8ac-82c3-40a5-b476-b78996c3ba7e,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Once in the synaptic cleft, the neurotransmitter diffuses the short distance to the postsynaptic membrane and can bind to neurotransmitter receptors. Receptors are specific for the neurotransmitter, and the two fit together like a lock and key, and so a neurotransmitter will not bind to receptors for other neurotransmitters (Figure 12.4.1).",True,Synapses,Figure 12.4.1,12.4 Communication Between Neurons,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1225_Chemical_Synapse.jpg,"Figure 12.4.1 – The Synapse: The synapse is a connection between a neuron and its target cell (which is not necessarily a neuron). The presynaptic element is the synaptic end bulb of the axon where Ca2+ enters the bulb to cause vesicle fusion and neurotransmitter release. The neurotransmitter diffuses across the synaptic cleft to bind to its receptor. The neurotransmitter is cleared from the synapse either by enzymatic degradation, neuronal reuptake, or glial reuptake."
+a70f992c-ce10-4ee7-8d25-4b10dcc7402e,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,Neurotransmitter and Receptor Systems,False,Neurotransmitter and Receptor Systems,,,,
+4dc04b14-0484-4886-b1d4-5fb77399ad63,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Neurotransmitters vary greatly throughout the body, but one principle applies to all: neurotransmitters must bind to their own specific receptor, of which there can be subtypes. We will use acetylcholine (neurotransmitter) and its receptor (cholinergic) as an example. There are two subtypes of cholinergic receptors both of which bind acetylecholine: nicotinic receptors and muscarinic receptors (their names are based on the other chemicals that can also bind to the receptor). Nicotine will bind to the nicotinic receptor and activate it, just like acetylcholine. Muscarine, a product of certain mushrooms, will bind to the muscarinic receptor, just like acetylcholine. However, nicotine will not bind to the muscarinic receptor and muscarine will not bind to the nicotinic receptor. Skeletal muscle NMJs always involve nicotinic cholinergic receptors and when acteylcholine binds to nicotinic receptors, a Na+ ligand gated channel opens. Muscarinic receptors are found sometimes with with K+ ligand gated channels and other times with Na+ ligand gated channels, differing throughout the body. For example, when acetylcholine binds to a muscarinic receptor on the pace-maker cells of the heart, K+ ligand gated channels open and heart rate slows down. When acetylcholine binds to a muscarinic receptor on the small intestine muscle, a Na+ ligand gated channel opens and the muscle activates (contracts). This variability in receptor/channel combinations is common throughout the body and occurs for many other neurotransmitters like epinephrine (adrenaline), serotonin and dopamine.",True,Neurotransmitter and Receptor Systems,,,,
+8f4d207c-f054-4f99-be9a-cd235a368360,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Neurotransmitters are classified in many ways based on their structural chemical make up or their functional common effects. Chemically, neurotransmitters can be small, amino acid based molecules, released from neurons as amino acids themselves (ie: glutamate, glycine) or as enzymatically modified relatively simple molecules (acetylecholine, ATP or biogenic amines such as dopamine). Larger molecule neurotransmitters are more complex proteins (3-36 amino acids long) called neuropeptides. There are more than 100 different peptides and include those such as enkephalins or endorphins, each with their own receptor types and subtypes that bind them.",True,Neurotransmitter and Receptor Systems,,,,
+1ebac4db-7e34-445e-a7e9-3807325e67d8,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Amino Acids: Glutamate (Glu), GABA (gamma-aminobutyric acid, a derivative of glutamate), and glycine (Gly) are common amino acid neurotransmitters. These amino acids have an amino group and a carboxyl group in their chemical structures. Glutamate is one of the 20 amino acids that are used to make proteins. Each amino acid neurotransmitter would be part of its own system, namely the glutamatergic, GABAergic, and glycinergic systems. They each have their own receptors and do not interact with each other. Amino acid neurotransmitters are eliminated from the synapse by reuptake in the neuron that released them. A pump in the presynaptic cell membrane, or sometimes a neighboring glial cell, removes the amino acid from the synaptic cleft so that it can be recycled, repackaged in vesicles, and released again.",True,Neurotransmitter and Receptor Systems,,,,
+af4257fe-a868-4ee0-bea4-50ea366d7d22,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"The amino acid neurotransmitters, glutamate, glycine, and GABA, are almost exclusively associated with just one effect. Glutamate is often considered an excitatory amino acid, but only because glutamate receptors in the adult cause depolarization of the postsynaptic cell (by changing membrane permeability to Na+ or Ca2+). Glycine and GABA are considered inhibitory amino acids, because their receptors typically cause hyperpolarization (by chaniging membrane permability to Cl– or K+).",True,Neurotransmitter and Receptor Systems,,,,
+fb5be779-4ff7-4ffb-a6c4-f5a63b93d8fc,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Acetylcholine and ATP: Acetylcholine was described above, including its excitatory or inhibitor effects when binding to various cholinergic receptors. ATP, the energy molecule and a purine chemically, has been found to act as a neurotransmitter in both the peripheral and central nervous system, often associated with excitatory effects.",True,Neurotransmitter and Receptor Systems,,,,
+92fd77c2-f99c-440a-996f-6a02bd21accd,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Biogenic amines are a group of neurotransmitters that are enzymatically made from amino acids. They have amino groups in them, but no longer have carboxyl groups and are therefore no longer classified as amino acids. Members of this group include serotonin, histamine and the catecholamines (dopamine, norepinephrine/noradrenaline and epinephrine/adrenaline). Serotonin (which is the basis of the serotonergic system) is made from tryptophan and has its own specific receptors. Dopamine is part of its own system, the dopaminergic system, which has dopamine receptors. Norepinephrine and epinephrine belong to the adrenergic neurotransmitter system. The two molecules are very similar and bind to the same receptors, which are referred to as alpha and beta receptors. The chemical epinephrine (epi- = “on”; “-nephrine” = kidney) is also known as adrenaline (renal = “kidney”), and norepinephrine is sometimes referred to as noradrenaline. The adrenal gland produces epinephrine and norepinephrine to be released into the blood stream as hormones. Once released into the synatpic cleft, all of these neurotransmitters are transported back into their respective presynaptic end bulb for repackaging and re-release.",True,Neurotransmitter and Receptor Systems,,,,
+f7555434-c3ed-41c9-b145-b408875d4d04,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"The biogenic amines have mixed effects. For example, the dopamine receptors that are classified as D1 receptors are excitatory whereas D2-type receptors are inhibitory. Biogenic amine receptors can have even more complex effects because some may not directly affect the membrane potential, but rather have an effect on gene transcription or other metabolic processes in the neuron. The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.",True,Neurotransmitter and Receptor Systems,,,,
+017e0bed-5724-4a97-be66-25f58a964624,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"A neuropeptide is a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds; essentially a mini-protein. Neuropeptides are often released at synapses in combination with another neurotransmitter, and they often act as hormones in other systems of the body, such as oxytocin, vasoactive intestinal peptide (VIP) or substance P. In addition, sometimes neuropeptides contain other neuropeptides within them! In the case of endorphins, once released, endorphins are cleaved by extracellular enzymes to produce enkephalins, both of which bind to opiod receptors to modulate pain perception in the brain.",True,Neurotransmitter and Receptor Systems,,,,
+e702c110-2bc6-4ccb-8df2-c96e7952b110,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,The characteristics of the various neurotransmitter systems presented in this section are organized in Table 12.3.,True,Neurotransmitter and Receptor Systems,,,,
+db49e6b6-0e0e-4698-8783-84250db47610,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"The important thing to remember about neurotransmitters, and signaling chemicals in general, is that the effect is entirely dependent on the receptor. Neurotransmitters bind to one of two classes of receptors at the cell surface, ionotropic or metabotropic (Figure 12.4.2). Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for acetylcholine or the glycine receptor. A metabotropic receptor involves a complex of proteins that result in metabolic changes within the cell. The receptor complex includes the transmembrane receptor protein, a G protein, and an effector protein. The neurotransmitter, referred to as the first messenger, binds to the receptor protein on the extracellular surface of the cell, and the intracellular side of the protein initiates activity of the G protein. The G protein is a guanosine triphosphate (GTP) hydrolase that physically moves from the receptor protein to the effector protein to activate the latter. An effector protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator, or the second messenger.",True,Neurotransmitter and Receptor Systems,Figure 12.4.2,12.4 Communication Between Neurons,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1226_Receptor_Types.jpg,"Figure 12.4.2 – Receptor Types: (a) An ionotropic receptor is a channel that opens when the neurotransmitter binds to it. (b) A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in gene transcription."
+b0d2be7b-b55c-4038-8b88-4f68f550eccd,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Different receptors use different second messengers. Two common examples of second messengers are cyclic adenosine monophosphate (cAMP) and inositol triphosphate (IP3). The enzyme adenylate cyclase (an example of an effector protein) makes cAMP, and phospholipase C is the enzyme that makes IP3. Second messengers, after they are produced by the effector protein, cause metabolic changes within the cell. These changes are most likely the activation of other enzymes in the cell. In neurons, they often modify ion channels, either opening or closing them. These enzymes can also cause changes in the cell, such as the activation of genes in the nucleus, and therefore the increased synthesis of proteins. In neurons, these kinds of changes are often the basis of stronger connections between cells at the synapse and may be the basis of learning and memory.",True,Neurotransmitter and Receptor Systems,,,,
+3623597d-9e43-4cbb-8529-cf3756d57bd7,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Local changes in the membrane potential away from resting levels are called graded potentials and are usually associated with opening gated channels on the membrane a neuron. The type and amount of change in the membrane potential is determined by the ion that crosses the membrane, how many ions cross and for how long. Graded potentials can be of two sorts, either they are depolarizing (above resting membrane potential) or hyperpolarizing (below resting membrane potential) (Figure 12.4.3). Depolarizing graded potentials are often the result of Na+ or Ca2+ entering the cell. Both of these ions have higher concentrations outside the cell than inside; because they have a positive charge, when they move into the cell the membrane becomes less negative inside relative to the outside. Hyperpolarizing graded potentials can be caused by K+ leaving the cell or Cl– entering the cell. The membrane becomes more negative if a positive charge moves out of a cell or if a negative charge enters the cell. Graded potentials are transient and are dissipated as they move away from the site of the initial stimulus.",True,Neurotransmitter and Receptor Systems,Figure 12.4.3,12.4 Communication Between Neurons,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1223_Graded_Potentials_revised.png,"Figure 12.4.3 – Graded Potentials: Graded potentials are temporary changes in the membrane voltage, the characteristics of which depend on the size of the stimulus. Some types of stimuli cause depolarization of the membrane, whereas others cause hyperpolarization. It depends on the specific ion channels that are activated in the cell membrane."
+336a2867-0b22-4403-80c3-980151648764,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"When ion channels are left open longer or more channels are opened (for the same ion), the stimulus affecting a neuron is bigger. A “bigger stimulus” occurs due to a more painful stimulus, a heavier load, a brighter light etc. These larger stimuli induce larger graded potentials of longer duration in neurons and can be either depolarizing or hyperpolarizing.",True,Neurotransmitter and Receptor Systems,,,,
+c7f45919-9f7e-4432-86f7-27f94f4cb259,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"For the unipolar cells of sensory neurons—both those with free nerve endings and those within encapsulations—graded potentials develop in the dendrites and influence the generation of an action potential in the axon of the same cell. This is called a generator potential. For other sensory receptor cells which are not neurons, such as taste cells or photoreceptors of the retina, graded potentials in receptor cell membranes result in the release of neurotransmitters at synapses with sensory neurons. This is called a receptor potential, and we will consider this type of graded potential during a discussion of the special senses.",True,Neurotransmitter and Receptor Systems,,,,
+4107154c-3af4-42ac-89ca-c3876db1278b,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,A postsynaptic potential (PSP) is the graded potential in the dendrites or cell body of a neuron that is receiving synapses from other cells. Postsynaptic potentials can be depolarizing or hyperpolarizing. Depolarization in a postsynaptic potential is called an excitatory postsynaptic potential (EPSP) because it causes the membrane potential to move toward threshold. Hyperpolarization in a postsynaptic potential is an inhibitory postsynaptic potential (IPSP) because it causes the membrane potential to move away from threshold.,True,Neurotransmitter and Receptor Systems,,,,
+b5ac4d42-92d1-4692-8411-f02004d9b982,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"All types of graded potentials will result in small changes (either depolarization or hyperpolarization) in the voltage of a membrane. These changes can lead to the neuron reaching threshold if the changes add together, or summate. The combined effects of different types of graded potentials are illustrated in Figure 12.4.4. If the total change in voltage that reaches the initial segment (or trigger zone) is a positive 15 mV, meaning that the membrane depolarizes from -70 mV (resting membrane potential) to -55 mV (threshold), then the graded potentials will result in the initiation of an action potential.",True,Neurotransmitter and Receptor Systems,Figure 12.4.4,12.4 Communication Between Neurons,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1224_Post_Synaptic_Potential_Summation.jpg,"Figure 12.4.4 – Postsynaptic Potential Summation: The result of summation of postsynaptic potentials is the overall change in the membrane potential. At point A, several different excitatory postsynaptic potentials add up to a large depolarization. At point B, a mix of excitatory and inhibitory postsynaptic potentials result in a different end result for the membrane potential."
+8373b522-4ac6-40a7-9c43-863dfd473a55,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, the initial segment is directly adjacent to the dendritic endings (since the cell body is located more proximally). For all other neurons, the initial segment of the axon is found at the axon hillock and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential and is often referred as the trigger zone.",True,Neurotransmitter and Receptor Systems,,,,
+93ccdd69-0a3e-4241-a760-0bb26f433f96,https://open.oregonstate.education/aandp/,12.4 Communication Between Neurons,https://open.oregonstate.education/aandp/chapter/12-4-communication-between-neurons/,"Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials occurring simultaneously at different locations on the neuron (spatial), or all at the same place but in rapid succession (temporal). Spatial and temporal summation can act together, as well. Since graded potentials dissipated with distance and time, summation is the total change in voltage due to all spatial and temporal graded potentials that reach the trigger zone or initial segment at each moment.",True,Neurotransmitter and Receptor Systems,,,,
+8c655bc3-52e6-4c16-a0a3-7a623210c607,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"Having looked at the components of nervous tissue, and the basic anatomy of the nervous system, next comes an understanding of how nervous tissue is capable of communicating within the nervous system. Before getting to the nuts and bolts of how this works, an illustration of how the components come together will be helpful. An example is summarized in Figure 12.3.1.",True,Neurotransmitter and Receptor Systems,Figure 12.3.1,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+6aff615b-e7e6-474a-b01f-9467222936e3,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,Imagine you are about to take a shower in the morning before going to school. You have turned on the faucet to start the water as you prepare to get in the shower. You put your hand out into the spray of water to test the temperature. What happens next depends on how your nervous system interacts with the stimulus of the water temperature and what you do in response to that stimulus.,True,Neurotransmitter and Receptor Systems,,,,
+a7c544a4-2f83-4181-80f8-4e5554dab05b,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"Found in the skin is a type of sensory receptor that is sensitive to temperature, called a thermoreceptor. When you place your hand under the shower (1 in Figure 12.3.1, close up in Figure 12.3.2), the cell membrane of the thermoreceptors changes its electrical state (voltage). The amount of change is dependent on the strength of the stimulus (in this example, how hot the water is). This is called a graded potential. If the stimulus is strong, the voltage of the cell membrane will change enough to generate an electrical signal that will travel down the axon. The voltage at which such a signal is generated is called the threshold, and the resulting electrical signal is called an action potential. In this example, the action potential travels—a process known as propagation—along the axon from the initial segment found near the receptor to the axon terminals and into the synaptic end bulbs in the central nervous system (2 in Figure 12.3.1). When this signal reaches the end bulbs, it causes the release of a signaling molecule called a neurotransmitter.",True,Neurotransmitter and Receptor Systems,Figure 12.3.1,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+fc2121fd-6272-4aa3-a1e3-d88ccb17c227,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"In the central nervous system (in this case, the spinal cord), the neurotransmitter diffuses across the short distance of the synapse and binds to a receptor protein of the target neuron. When the neurotransmitter binds to the receptor, the cell membrane of the target neuron changes its electrical state and a new graded potential begins. If that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment f that graded potential is strong enough to reach threshold, the second neuron generates an action potential at its initial segment (3 in Figure 12.3.1). The target of this neuron is another neuron in the thalamus of the brain, the part of the CNS that acts as a relay for sensory information. At this synapse, neurotransmitter is released and binds to its receptor. The thalamus then sends the sensory information to the cerebral cortex, the outermost layer of gray matter in the brain, where conscious perception of that water temperature begins.",True,Neurotransmitter and Receptor Systems,Figure 12.3.1,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+1a7ce1d6-2940-4408-8769-99caebe829f4,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"Within the cerebral cortex, information is processed among many neurons, integrating the stimulus of the water temperature with other sensory stimuli, as well as with your emotional state and memories. Finally, a plan is developed about what to do, whether that is to turn the temperature up, turn the whole shower off and go back to bed, or step into the shower. To do any of these things, the cerebral cortex has to send a command out to your body to move muscles.",True,Neurotransmitter and Receptor Systems,,,,
+0c3abe84-2330-4941-b44d-3c15e6f30a94,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron starts in this region, called the precentral gyrus of the frontal cortex, and has an axon that extends all the way down the spinal cord. The upper motor neuron synapses in the spinal cord with a lower motor neuron, which directly stimulates muscle fibers to contract. In the manner described in the chapter on muscle tissue, an action potential travels along the motor neuron axon into the periphery. The lower motor neuron axon terminates on muscle fibers at the neuromuscular junction. Acetylcholine is the neurotransmitter released at this specialized synapse, and binding to receptors on the muscle cell membrane causes the muscle action potential to begin. When the lower motor neuron excites the muscle fiber, the muscle contracts (Figure 12.3.3). All of this occurs in a fraction of a second, but this story is the basis of how the nervous system functions.",True,Neurotransmitter and Receptor Systems,Figure 12.3.3,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1214_Motor_Response_Test_Water.jpg,"Figure 12.3.3 – The Motor Response: On the basis of the sensory input and the integration in the CNS, a motor response is formulated and executed."
+7f57d61d-9b6d-4589-b859-b52e03c436cf,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"There are many pathways to becoming a neurophysiologist. One path is to become a research scientist at an academic institution. A Bachelor’s degree will get you started, and for neurophysiology that might be in biology, psychology, computer science, engineering, or neuroscience. But the real specialization comes in graduate school. There are many different programs out there to study the nervous system, not just neuroscience itself. Most graduate programs are doctoral, and are usually considered five-year programs, with the first two years dedicated to course work and finding a research mentor, and the last three years dedicated to finding a research topic and pursuing that with a near single-mindedness. The research will usually result in a few publications in scientific journals, which will make up the bulk of a doctoral dissertation. After graduating with a Ph.D., researchers will go on to find specialized work called a postdoctoral fellowship within established labs. In this position, a researcher starts to establish their own research career with the hopes of finding an academic position at a research university.",True,Neurotransmitter and Receptor Systems,,,,
+2e8bd1c1-05ec-4a1e-9630-5b6e893ee09d,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"Other options are available if you are interested in how the nervous system works. Especially for neurophysiology, a medical degree might be more suitable so you can learn about the clinical applications of neurophysiology. Biotechnology firms are eager to find motivated scientists ready to tackle the tough questions about how the nervous system works so that therapeutic chemicals can be tested on some of the most challenging disorders such as Alzheimer’s disease or Parkinson’s disease, or spinal cord injury.",True,Neurotransmitter and Receptor Systems,,,,
+3f922bf5-fd99-4e5a-9d96-5e18dd2701fa,https://open.oregonstate.education/aandp/,12.3 The Function of Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-3-the-function-of-nervous-tissue/,"Others with a medical degree and a specialization in neuroscience go on to work directly with patients, diagnosing and treating mental disorders. You can do this as a psychiatrist, a neuropsychologist, a neuroscience nurse, or a neurodiagnostic technician, among other possible career paths.",True,Neurotransmitter and Receptor Systems,,,,
+e1ec1acb-5721-41f5-bb01-d8ff5a830337,https://open.oregonstate.education/aandp/,12.2 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-2-nervous-tissue/,Explain how neurons and glial cells work together to perform and support the nervous system functions.,True,Neurotransmitter and Receptor Systems,,,,
+22f03c43-a459-4915-9c30-f1af753caed4,https://open.oregonstate.education/aandp/,12.2 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-2-nervous-tissue/,"Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to communicate between each other and with target cells. Glial cells, or glia or neuroglia, are much smaller than neurons and play a supporting role for nervous tissue. Glial cells maintain the extracellular environment around neurons, improve signal conduction in neurons and protect them from pathogens. Ongoing research also suggests that glial cell number matches neuron number and that they even can send signals themselves.",True,Neurotransmitter and Receptor Systems,,,,
+6b42da13-76d0-401b-9b47-50849c7c8db6,https://open.oregonstate.education/aandp/,12.2 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-2-nervous-tissue/,Neuron Anatomy,False,Neuron Anatomy,,,,
+e47435db-a1b0-4911-80e5-3311bd13e439,https://open.oregonstate.education/aandp/,12.2 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-2-nervous-tissue/,Glial Cells,False,Glial Cells,,,,
+afc05445-9300-4f49-a923-1034784c29e7,https://open.oregonstate.education/aandp/,12.2 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/12-2-nervous-tissue/,There are six types of glial cells. Four of them are found in the CNS and two are found in the PNS. Table 12.1 outlines some common characteristics and functions.,True,Glial Cells,,,,
+bad176dd-d4c1-40cc-9c14-fcba29761ca9,https://open.oregonstate.education/aandp/,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/aandp/chapter/12-1-structure-and-function-of-the-nervous-system/,Relate the anatomical structures to the basic functions of the nervous system.,True,Glial Cells,,,,
+b9ae3b84-e522-4463-b236-a87a1cfbe8c8,https://open.oregonstate.education/aandp/,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/aandp/chapter/12-1-structure-and-function-of-the-nervous-system/,The Central and Peripheral Nervous Systems,False,The Central and Peripheral Nervous Systems,,,,
+9a5087fd-11a6-4a0a-827b-b4ff9410652c,https://open.oregonstate.education/aandp/,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/aandp/chapter/12-1-structure-and-function-of-the-nervous-system/,"The picture you have in your mind of the nervous system probably includes the brain, the nervous tissue contained within the cranium, and the spinal cord, the extension of nervous tissue within the vertebral column. Additionally, the nervous tissue that reach out from the brain and spinal cord to the rest of the body (nerves) are also part of the nervous system. We can anatomically divide the nervous system into two major regions: the central nervous system (CNS) is the brain and spinal cord, the peripheral nervous system (PNS) is the nerves (Figure 12.1.1). The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral canal of the vertebral column. The peripheral nervous system is so named because it is in the periphery—meaning beyond the brain and spinal cord.",True,The Central and Peripheral Nervous Systems,Figure 12.1.1,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1201_Overview_of_Nervous_System_revised.png,"Figure 12.1.1 – Central and Peripheral Nervous System: The CNS contains the brain and spinal cord, the PNS includes nerves."
+8bc66155-82e2-44e2-8c68-2dd6ba494444,https://open.oregonstate.education/aandp/,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/aandp/chapter/12-1-structure-and-function-of-the-nervous-system/,Functional Divisions of the Nervous System,False,Functional Divisions of the Nervous System,,,,
+265f08f9-58b9-4e64-afc7-87ca42b4da73,https://open.oregonstate.education/aandp/,12.1 Structure and Function of the Nervous System,https://open.oregonstate.education/aandp/chapter/12-1-structure-and-function-of-the-nervous-system/,"In addition to the anatomical divisions listed above, the nervous system can also be divided on the basis of its functions. The nervous system is involved in receiving information about the environment around us (sensory functions, sensation) and generating responses to that information (motor functions, responses) and coordinating the two (integration).",True,Functional Divisions of the Nervous System,,,,
+b8b6fdcc-c236-47d9-af80-2e2ea469c221,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,Relate the anatomical structures to the basic functions of the nervous system.,True,Functional Divisions of the Nervous System,,,,
+ad336230-7221-4a2e-a6ab-73aaf97e509e,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,Explain how neurons and glial cells work together to perform and support the nervous system functions.,True,Functional Divisions of the Nervous System,,,,
+2770d473-9593-4efe-b72d-0a92f34b3197,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,"Describe the pathway involved with neural sensation, integration and motor response.",True,Functional Divisions of the Nervous System,,,,
+57190c0a-7be5-4733-a670-e01de554955e,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,Describe signal conduction at chemical synapses.,False,Describe signal conduction at chemical synapses.,,,,
+40904771-a5cc-4bab-88e7-d5e76dcf2063,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,Link how movement of ions across the neuron membrane creates membrane potentials..,True,Describe signal conduction at chemical synapses.,,,,
+029ad7e4-ff84-40d1-af2c-beba5f1c4c26,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,"The nervous system is a very complex organ system. In Peter D. Kramer’s book Listening to Prozac, a pharmaceutical researcher is quoted as saying, “If the human brain were simple enough for us to understand, we would be too simple to understand it” (1994). That quote is from the early 1990s; in the two decades since, progress has continued at an amazing rate within the scientific disciplines of neuroscience. It is an interesting conundrum to consider that the complexity of the nervous system may be too complex for it (that is, for us) to completely unravel. But our current level of understanding is probably nowhere close to that limit.",True,Describe signal conduction at chemical synapses.,,,,
+480fcad5-b4e9-429a-aeee-50aee4eb3d94,https://open.oregonstate.education/aandp/,12.0 Introduction,https://open.oregonstate.education/aandp/chapter/12-0-introduction/,"One easy way to begin to understand the structure of the nervous system is to start with the large divisions and work through to a more in-depth understanding. In other chapters, the finer details of the nervous system will be explained, but first looking at an overview of the system will allow you to begin to understand how its parts work together. The focus of this chapter is on nervous (neural) tissue, both its structure and its function. But before you learn about that, we will look at the big picture of the system.",True,Describe signal conduction at chemical synapses.,,,,
+774047e9-301a-4df4-9308-73bd10f8bfb6,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"Identify the following muscles and give their origins, insertions, actions and innervations:",True,Describe signal conduction at chemical synapses.,,,,
+29e3bf6e-f6ea-447e-b741-e1328b97efc0,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,APPENDICULAR MUSCLES OF THE PELVIC GIRDLE AND LOWER LIMBS,False,APPENDICULAR MUSCLES OF THE PELVIC GIRDLE AND LOWER LIMBS,,,,
+f4a2bf1c-0ff2-459f-8d16-b4fcdf33e8f1,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The appendicular muscles of the lower body position and stabilize the pelvic girdle, which serves as a foundation for the lower limbs. Comparatively, there is much more movement at the pectoral girdle than at the pelvic girdle. There is very little movement of the pelvic girdle because of its connection with the sacrum at the base of the axial skeleton and because the deep acetabulum provides a stable point of articulation with the head of the femur. The pelvic girdle’s lack of range of motion allows it to stabilize and support the body. The body’s center of gravity is in the area of the pelvis. If the center of gravity were not to remain fixed, standing up would be difficult. Therefore, what the leg muscles lack in range of motion and versatility, they make up for in size and power, facilitating the body’s stabilization, posture, and movement.",True,APPENDICULAR MUSCLES OF THE PELVIC GIRDLE AND LOWER LIMBS,,,,
+671ce96c-39ba-4fe2-82f4-96ebfff82f3d,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,Gluteal Region Muscles That Move the Thigh,False,Gluteal Region Muscles That Move the Thigh,,,,
+22428a29-6ed2-4ccc-a9a9-ee76f9aa57b5,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"Most muscles that insert on the femur (the thigh bone) and move it, originate on the pelvic girdle. The major flexors of the hip are the psoas major and iliac which make up the iliopsoas group. Some of the largest and most powerful muscles in the body are the gluteal muscles or gluteal group. The gluteus maximus, one of the major extensors of the thigh at the hip, is the largest; deep to the gluteus maximus is the gluteus medius, and deep to the gluteus medius is the gluteus minimus, the smallest of the trio (Figure 11.4.22 and Figure 11.4.23).",True,Gluteal Region Muscles That Move the Thigh,Figure 11.4.22,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1122_Gluteal_Muscles_that_Move_the_Femur.jpg,"Figure 11.4.22 – Hip and Thigh Muscles: The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. The muscles that move the lower leg typically originate on the femur and insert into the bones of the knee joint. The anterior muscles of the femur extend the lower leg but also aid in flexing the thigh. The posterior muscles of the femur flex the lower leg but also aid in extending the thigh. A combination of gluteal and thigh muscles also adduct, abduct, and rotate the thigh and lower leg."
+564e5c8f-5323-42b3-8f1f-9da95579f160,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The tensor fascia latae is a thick, squarish muscle in the superior aspect of the lateral thigh. It acts as a synergist of the gluteus medius and iliopsoas in flexing and abducting the thigh. It also helps stabilize the lateral aspect of the knee by pulling on the iliotibial tract (band), making it taut. Deep to the gluteus maximus, the piriformis, obturator internus, obturator externus, superior gemellus, inferior gemellus, and quadratus femoris laterally rotate the thigh at the hip.",True,Gluteal Region Muscles That Move the Thigh,,,,
+09409c3d-3a03-4436-bf11-5d9d62f9a282,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"Deep fascia in the thigh separates it into medial, anterior, and posterior compartments. The muscles in the medial compartment of the thigh responsible for adducting the femur at the hip are the adductor group including the adductor longus, adductor brevis, and adductor magnus which all adduct and medially rotate the thigh. The adductor longus also flexes the thigh, whereas the adductor magnus extends it. Like the adductor longs, the pectineus adducts and flexes the femur at the hip. The pectineus is located in the femoral triangle, which is formed at the junction between the hip and the leg and includes the femoral nerve, the femoral artery, the femoral vein, and the deep inguinal lymph nodes. The strap-like gracilis adducts the thigh in addition to flexing the leg at the knee",True,Gluteal Region Muscles That Move the Thigh,,,,
+d3ce9859-f963-4a30-b0cc-61cd98810c32,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"Thigh Muscles That Move the Femur, Tibia, and Fibula",False,"Thigh Muscles That Move the Femur, Tibia, and Fibula",,,,
+76bd50af-08e1-468d-8ecc-f317ea50e672,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The muscles of the anterior compartment of the thigh flex the thigh and extend the leg. This compartment contains the quadriceps femoris group, which is comprised of four muscles that extend the leg and stabilize the knee. Within the compartment the rectus femoris is on the anterior aspect of the thigh, the vastus lateralis is on the lateral aspect of the thigh, the vastus medialis is on the medial aspect of the thigh, and the vastus intermedius is between the vastus lateralis and vastus medialis and deep to the rectus femoris. The tendon common to all four is the quadriceps tendon (patellar tendon), which inserts into the patella and continues below it as the patellar ligament. The patellar ligament attaches to the tibial tuberosity. In addition to the quadriceps femoris, the sartorius is a band-like muscle that extends from the anterior superior iliac spine to the medial side of the proximal tibia. This versatile muscle flexes the leg at the knee and flexes, abducts, and laterally rotates the thigh at the hip. This muscle allows us to sit cross-legged.",True,"Thigh Muscles That Move the Femur, Tibia, and Fibula",,,,
+afef3d23-48c2-4b3c-aa3c-61943b405eb4,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The posterior compartment of the thigh includes muscles that flex the leg and extend the thigh. The three long muscles on the back of the thigh are the hamstring group, which flexes the knee. These are the biceps femoris, semitendinosus, and semimembranosus. The tendons of these muscles form the upper border of the popliteal fossa, the diamond-shaped space at the back of the knee.",True,"Thigh Muscles That Move the Femur, Tibia, and Fibula",,,,
+24f1f13e-90ec-486f-8f28-047158b3cd78,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,Muscles That Move the Feet and Toes,False,Muscles That Move the Feet and Toes,,,,
+c4569256-1582-480a-8e00-b9971e815394,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"Similar to the thigh muscles, the muscles of the leg are divided by deep fascia into compartments, although the leg has three: anterior, lateral, and posterior.",True,Muscles That Move the Feet and Toes,,,,
+0fc7435f-677c-42c5-9eeb-208c2ac38de9,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The muscles in the anterior compartment of the leg all contribute to dorsiflexion: the tibialis anterior, a long and thick muscle on the lateral surface of the tibia, the extensor hallucis longus, deep under it, and the extensor digitorum longus, lateral to it. The fibularis tertius, a small muscle that originates on the anterior surface of the fibula, is associated with the extensor digitorum longus and sometimes fused to it, but is not present in all people. Thick bands of connective tissue called the superior extensor retinaculum (transverse ligament of the ankle) and the inferior extensor retinaculum, hold the tendons of these muscles in place during dorsiflexion.",True,Muscles That Move the Feet and Toes,,,,
+091b671b-bab1-40c9-a19a-94bfa41bbe64,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The lateral compartment of the leg includes two muscles which contribute to eversion and plantar flexion: the fibularis longus (peroneus longus) and the fibularis brevis (peroneus brevis). The superficial muscles in the posterior compartment of the leg all insert onto the calcaneal tendon (Achilles tendon), a strong tendon that inserts into the calcaneal bone of the ankle, all contribute to plantar flexion. The muscles in this compartment are large and strong and keep humans upright. The most superficial and visible muscle of the calf is the gastrocnemius. Deep to the gastrocnemius is the wide, flat soleus. The plantaris runs obliquely between the two; some people may have two of these muscles, whereas no plantaris is observed in about seven percent of other cadaver dissections. The plantaris tendon is a desirable substitute for the fascia lata in hernia repair, tendon transplants, and repair of ligaments. There are four deep muscles in the posterior compartment of the leg as well: the popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior all contribute to plantar flexion or inversion of the foot.",True,Muscles That Move the Feet and Toes,,,,
+16b61677-31a7-4b8f-b5bd-30df0fdc4546,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,"The foot also has intrinsic muscles, which originate and insert within it (similar to the intrinsic muscles of the hand). These muscles primarily provide support for the foot and its arch, and contribute to movements of the toes (Figure 11.4.27 and Figure 11.4.28). The principal support for the longitudinal arch of the foot is a deep fascia called plantar aponeurosis, which runs from the calcaneus bone to the toes (inflammation of this tissue is the cause of “plantar fasciitis,” which can affect runners. The intrinsic muscles of the foot include the extensor digitorum brevis on the dorsal aspect and a plantar group, which consists of four layers.",True,Muscles That Move the Feet and Toes,Figure 11.4.27,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1124_Intrinsic_Muscles_of_the_Foot.jpg,"Figure 11.4.27 – Intrinsic Muscles of the Foot: The muscles along the dorsal side of the foot (a) generally extend the toes while the muscles of the plantar side of the foot (b, c, d) generally flex the toes. The plantar muscles exist in three layers, providing the foot the strength to counterbalance the weight of the body. In this diagram, these three layers are shown from a plantar view beginning with the bottom-most layer just under the plantar skin of the foot (b) and ending with the top-most layer (d) located just inferior to the foot and toe bones."
+09b611b0-3828-4ebc-bdcf-dc622a7173e0,https://open.oregonstate.education/aandp/,11.7 Appendicular Muscles of the Pelvic Girdle and Lower Limbs,https://open.oregonstate.education/aandp/chapter/11-7-appendicular-muscles-of-the-pelvic-girdle-and-lower-limbs/,Glossary,False,Glossary,,,,
+dacf6725-71e3-473c-bffe-12612e49b595,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,"Identify the following muscles and give their origins, insertions, actions and innervations:",True,Glossary,,,,
+606995ce-0b1c-4bec-b8de-5edcce9ddd1f,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,"Muscles of the shoulder and upper limb can be divided into four groups: muscles that stabilize and position the pectoral girdle, muscles that move the arm, muscles that move the forearm, and muscles that move the wrists, hands, and fingers.",True,Glossary,,,,
+583e6d97-4295-4fd2-a955-8047c5503db9,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,Muscles That Position the Pectoral Girdle,False,Muscles That Position the Pectoral Girdle,,,,
+14a3fc80-228e-4f23-a52b-e7db4eb4e2dc,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,Muscles That Move the Humerus,False,Muscles That Move the Humerus,,,,
+2d7d15f5-d2e1-4482-8317-081e54c5fecf,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,Muscles That Move the Forearm,False,Muscles That Move the Forearm,,,,
+66e9017e-0285-496e-962a-5385eb1b42c0,https://open.oregonstate.education/aandp/,11.6 Muscles of the Pectoral Girdle and Upper Limbs,https://open.oregonstate.education/aandp/chapter/11-6-muscles-of-the-pectoral-girdle-and-upper-limbs/,"Muscles That Move the Wrist, Hand, and Fingers",False,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+0b08244d-3532-4c31-8b17-fe84ffa26ed9,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,"Identify the following muscles and give their origins, insertions, actions and innervations:",True,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+825ec467-72f4-4dee-9a31-5beedfd4fd6f,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,"It is a complex job to balance the body on two feet and walk upright. The muscles of the vertebral column, thorax, and abdominal wall extend, flex, and stabilize different parts of the body’s trunk. The deep muscles of the body’s core help maintain posture as well as provide stability for movement of the limbs.",True,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+168efb4a-e26c-4adb-9628-0bf0cf95738d,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,"Those who have a muscle or joint injury will most likely be sent to a physical therapist (PT) after seeing their regular doctor. PTs have a master’s degree or doctorate, and are highly trained experts in the mechanics of body movements. Many PTs also specialize in sports injuries.",True,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+2293fae7-3501-4506-a422-0cc532e1c288,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,"If you injured your shoulder while you were kayaking, the first thing a physical therapist would do during your first visit is assess the functionality of the joint. The range of motion of a particular joint refers to the normal movements the joint performs. The PT will ask you to abduct and adduct, circumduct, and flex and extend the arm. The PT will note the shoulder’s degree of function, and based on the assessment of the injury, will create an appropriate physical therapy plan.",True,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+69dfa534-0d5c-4c02-a03d-61ff7b3a9724,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,"The first step in physical therapy will probably be applying a heat pack to the injured site, which acts much like a warm-up to draw blood to the area, to enhance healing. You will be instructed to do a series of exercises to continue the therapy at home, followed by icing, to decrease inflammation and swelling, which will continue for several weeks. When physical therapy is complete, the PT will do an exit exam and send a detailed report on the improved range of motion and return of normal limb function to your doctor. Gradually, as the injury heals, the shoulder will begin to function correctly. A PT works closely with patients to help them get back to their normal level of physical activity.",True,"Muscles That Move the Wrist, Hand, and Fingers",,,,
+0fc6d639-56ea-4234-ab77-99c6e729ef6c,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,Muscles of the Thorax,False,Muscles of the Thorax,,,,
+39db0604-fb5c-403f-b820-b162da8739fa,https://open.oregonstate.education/aandp/,11.5 Axial muscles of the abdominal wall and thorax,https://open.oregonstate.education/aandp/chapter/11-5-axial-muscles-of-the-abdominal-wall-and-thorax/,Muscles of the Pelvic Floor and Perineum,False,Muscles of the Pelvic Floor and Perineum,,,,
+ef8d0db4-1c2e-4af8-aaeb-14529b4053d9,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"Identify the following muscles and give their origins, insertions, actions and innervations:",True,Muscles of the Pelvic Floor and Perineum,,,,
+2314677c-4283-4d2f-b76e-2e6ecde6a297,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The skeletal muscles are divided into axial (muscles of the trunk and head) and appendicular (muscles of the arms and legs) categories. This system reflects the bones of the skeleton system, which are also arranged in this manner. Some of the axial muscles may seem to blur the boundaries because they cross over to the appendicular skeleton. The first grouping of the axial muscles you will review includes the muscles of the head and neck, then you will review the muscles of the vertebral column, and finally you will review the oblique and rectus muscles.",True,Muscles of the Pelvic Floor and Perineum,,,,
+12e30885-0a08-48aa-ba11-8588175dd220,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles of Facial Expression,False,Muscles of Facial Expression,,,,
+12062e7e-b32a-4195-9d35-6f8204164a8b,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression (Figure 11.4.1).",True,Muscles of Facial Expression,Figure 11.4.1,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1106_Front_and_Side_Views_of_the_Muscles_of_Facial_Expressions.jpg,"Figure 11.4.1 – Muscles of Facial Expression: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones."
+3e273c97-0c8f-4fee-9e3a-9df558287ba8,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye. The occipitofrontalis muscle elevates the scalp and eyebrows. The muscle has a frontal belly and an occipital belly (near the occipital bone on the posterior part of the skull). In other words, there is a muscle on the forehead (frontalis) and one on the back of the head (occipitals). The two bellies are connected by a broad tendon called the epicranial aponeurosis, or galea aponeurosis (galea = “apple”). The physicians originally studying human anatomy thought the skull looked like an apple.",True,Muscles of Facial Expression,,,,
+ff036b0b-ccee-41a3-926e-aeb43249dc0d,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The buccinator muscle compresses the cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of chewing. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. With these movements, you can feel the action of the corrugator supercilli. Additional muscles of facial expression are presented in Figure 11.4.2.",True,Muscles of Facial Expression,Figure 11.4.2,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1125_Muscles_in_Facial_Expression_revised.png,Figure 11.4.2 Muscles in Facial Expression
+45596785-883e-4431-9028-68b338b57245,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles That Move the Eyes,False,Muscles That Move the Eyes,,,,
+cc9d83bf-4168-4862-9e55-29d9258d59a7,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles That Move the Lower Jaw,False,Muscles That Move the Lower Jaw,,,,
+2136adb2-c02c-4999-aeb6-ae8ba42426d4,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles That Move the Tongue,False,Muscles That Move the Tongue,,,,
+ea2f43f0-3b2b-4f57-a842-b06366e277a2,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"Tongue muscles can be extrinsic or intrinsic. Extrinsic tongue muscles insert into the tongue from outside origins, and the intrinsic tongue muscles insert into the tongue from origins within it. The extrinsic muscles move the whole tongue in different directions, whereas the intrinsic muscles allow the tongue to change its shape (such as, curling the tongue in a loop or flattening it).",True,Muscles That Move the Tongue,,,,
+c7e15577-155d-467c-82b5-1da29d70f1ed,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The extrinsic muscles all include the word root glossus (glossus = “tongue”), and the muscle names are derived from where the muscle originates. The genioglossus (genio = “chin”) originates on the mandible and allows the tongue to move downward and forward. The styloglossus originates on the styloid process of the temporal bone, and allows upward and backward motion. The palatoglossus originates on the soft palate to elevate the back of the tongue, and the hyoglossus originates on the hyoid bone to move the tongue downward and flatten it.",True,Muscles That Move the Tongue,,,,
+e63a8418-018a-40a2-84dd-eca23bbd2a38,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles of the Anterior Neck,False,Muscles of the Anterior Neck,,,,
+94d24439-ce65-4e2a-bb5a-b8338c339dc0,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The muscles of the anterior neck assist in deglutition (swallowing) and speech by controlling the positions of the larynx (voice box), and the hyoid bone, a horseshoe-shaped bone that functions as a foundation on which the tongue can move. The muscles of the neck are categorized according to their position relative to the hyoid bone (Figure 11.4.7). Suprahyoid muscles are superior to it, and the infrahyoid muscles are located inferiorly.",True,Muscles of the Anterior Neck,Figure 11.4.7,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1110_Muscle_of_the_Anterior_Neck_revised.png,Figure 11.4.7 – Muscles of the Anterior Neck: The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.
+920f59d0-6d6d-433b-b25d-9a2628e726ca,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The suprahyoid muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition. These include the digastric muscle, which has anterior and posterior bellies that work to elevate the hyoid bone and larynx when one swallows; it also depresses the mandible. The stylohyoid muscle moves the hyoid bone posteriorly, elevating the larynx, and the mylohyoid muscle lifts it and helps press the tongue to the top of the mouth. The geniohyoid depresses the mandible in addition to raising and pulling the hyoid bone anteriorly.",True,Muscles of the Anterior Neck,,,,
+68437a56-042a-499f-8b24-d9b9a604113d,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The strap-like infrahyoid muscles generally depress the hyoid bone and control the position of the larynx. The omohyoid muscle, which has superior and inferior bellies, depresses the hyoid bone in conjunction with the sternohyoid and thyrohyoid muscles. The thyrohyoid muscle also elevates the larynx’s thyroid cartilage, whereas the sternothyroid depresses it.",True,Muscles of the Anterior Neck,,,,
+b6ad5c48-7b16-4a55-bccf-e24e93232067,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles That Move the Head,False,Muscles That Move the Head,,,,
+87629787-b1d2-48e0-b511-8dad0909579a,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The head is balanced, moved and rotated by the neck muscles (Table 11.5). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid. In addition, both muscles working together are the flexors of the head. Place your fingers on both sides of the neck and turn your head to the left and to the right. You will feel the movement originate there. This muscle divides the neck into anterior and posterior triangles when viewed from the side (Figure 11.4.8).",True,Muscles That Move the Head,Figure 11.4.8,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1117_Muscles_of_the_Neck_and_Back-scaled.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column."
+fa2b595b-4ee5-43b9-a8a7-d614ea064611,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,Muscles of the Posterior Neck and the Back,False,Muscles of the Posterior Neck and the Back,,,,
+98a0a71b-b052-46a7-999c-b8e0c73c9629,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The posterior muscles of the neck are primarily concerned with head movements, like extension. The back muscles stabilize and move the vertebral column, and are grouped according to the lengths and direction of the fascicles.",True,Muscles of the Posterior Neck and the Back,,,,
+6bd8d13c-a71d-4b6f-8d85-d8c7c5cb9c4e,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The splenius muscles originate at the midline and run laterally and superiorly to their insertions. From the sides and the back of the neck, the splenius capitis inserts onto the head region, and the splenius cervicis extends onto the cervical region. These muscles can extend the head, laterally flex it, and rotate it (Figure 11.4.8).",True,Muscles of the Posterior Neck and the Back,Figure 11.4.8,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1117_Muscles_of_the_Neck_and_Back-scaled.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column."
+091c86eb-35b5-4da1-98a2-18c81b554c26,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The erector spinae group forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column. It controls extension, lateral flexion, and rotation of the vertebral column, and maintains the lumbar curve. The erector spinae comprises the iliocostalis (laterally placed) group, the longissimus (intermediately placed) group, and the spinalis (medially placed) group.",True,Muscles of the Posterior Neck and the Back,,,,
+f5e1155a-b3d1-4842-82b3-5f161f9d8ec4,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The iliocostalis group includes the iliocostalis cervicis, associated with the cervical region; the iliocostalis thoracis, associated with the thoracic region; and the iliocostalis lumborum, associated with the lumbar region. The three muscles of the longissimus group are the longissimus capitis, associated with the head region; the longissimus cervicis, associated with the cervical region; and the longissimus thoracis, associated with the thoracic region. The third group, the spinalis group, comprises the spinalis capitis (head region), the spinalis cervicis (cervical region), and the spinalis thoracis (thoracic region).",True,Muscles of the Posterior Neck and the Back,,,,
+188e589d-3948-4b04-adeb-879af20b57b8,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"The transversospinales muscles run from the transverse processes to the spinous processes of the vertebrae. Similar to the erector spinae muscles, the semispinalis muscles in this group are named for the areas of the body with which they are associated. The semispinalis muscles include the semispinalis capitis, the semispinalis cervicis, and the semispinalis thoracis. The multifidus muscle of the lumbar region helps extend and laterally flex the vertebral column.",True,Muscles of the Posterior Neck and the Back,,,,
+151c4b23-ec40-4d3e-bdd2-ec4ef496926f,https://open.oregonstate.education/aandp/,11.4 Axial Muscles of the Head Neck and Back,https://open.oregonstate.education/aandp/chapter/11-4-identify-the-skeletal-muscles-and-give-their-origins-insertions-actions-and-innervations/,"Important in the stabilization of the vertebral column is the segmental muscle group, which includes the interspinales and intertransversarii muscles. These muscles bring together the spinous and transverse processes of each consecutive vertebra. Finally, the scalene muscles work together to flex, laterally flex, and rotate the head. They also contribute to deep inhalation. The scalene muscles include the anterior scalene muscle (anterior to the middle scalene), the middle scalene muscle (the longest, intermediate between the anterior and posterior scalenes), and the posterior scalene muscle (the smallest, posterior to the middle scalene).",True,Muscles of the Posterior Neck and the Back,,,,
+06219326-3bb3-4ecf-b53e-bff939fe0603,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Describe the criteria used to name skeletal muscles
+
+Explain how understanding the muscle names helps describe shapes, location, and actions of various muscles",True,Muscles of the Posterior Neck and the Back,,,,
+f356011f-7111-46ab-be13-b608c5707f5e,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Taking the time to learn the Latin and Greek roots of the words is crucial to understanding the vocabulary of anatomy and physiology. When you understand the names of muscles it will help you remember where the muscles are located and what they do (Figure 11.3.1, Figure 11.3.2, and Table 11.2).",True,Muscles of the Posterior Neck and the Back,Figure 11.3.1,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1105_Anterior_and_Posterior_Views_of_Muscles-scaled.jpg,"Figure 11.3.1 – Overview of the Muscular System: On the anterior and posterior views of the muscular system above, superficial muscles (those at the surface) are shown on the right side of the body while deep muscles (those underneath the superficial muscles) are shown on the left half of the body. For the legs, superficial muscles are shown in the anterior view while the posterior view shows both superficial and deep muscles."
+8cc6ab97-961f-4588-b921-1abf2bf1d31a,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Anatomists name the skeletal muscles according to a number of criteria, each of which describes the muscle in some way. These include naming the muscle after its shape, size, fiber direction, location, number of origins or its action.",True,Muscles of the Posterior Neck and the Back,,,,
+274949a6-64d8-4bbf-853f-3a6ccd3f5011,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Muscle Shape: The names of some muscles reflect their shape. For example, the deltoid is a large, triangular-shaped muscle that covers the shoulder. It is so-named because the Greek letter delta is a triangle.",True,Muscles of the Posterior Neck and the Back,,,,
+654c25bd-7301-4685-a546-4b13216c23da,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Muscle Location: The skeletal muscle’s anatomical location or its relationship to a particular bone often determines its name. For example, the frontalis muscle is located on top of the frontal bone of the skull. Other examples are muscles of the arm that include the term brachii (of the arm).
+
+Some muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).
+The location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.",True,Muscles of the Posterior Neck and the Back,,,,
+7414e005-fceb-433d-be45-8c60543471f4,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Some muscles indicate their positions relative to the midline, which is related to muscle location: lateralis (to the outside away from the midline), and medialis (toward the midline).",True,Muscles of the Posterior Neck and the Back,,,,
+c380ee65-0951-499f-95cf-475cdbcc1fc7,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"The location of a muscle’s attachment can also appear in its name. When the name of a muscle is based on the attachments, the origin is always named first. For instance, the sternocleidomastoid muscle of the neck has a dual origin on the sternum (sterno) and clavicle (cleido), and it inserts on the mastoid process of the temporal bone.",True,Muscles of the Posterior Neck and the Back,,,,
+0ff4e862-2e02-4d7f-affe-e7c487358ddf,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Muscle Size: For the buttocks, the size of the muscles influences the names: gluteus maximus (largest), gluteus medius (medium), and the gluteus minimus (smallest). Another example are the pectoral muscles including major or minor.
+
+Names are often used to indicate length, which is related to muscle size. For example, brevis (short), longus (long).",True,Muscles of the Posterior Neck and the Back,,,,
+3bae7ff4-ecd0-4cb4-b8eb-3ce959545be9,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Names are often used to indicate length, which is related to muscle size. For example, brevis (short), longus (long).",True,Muscles of the Posterior Neck and the Back,,,,
+34e391ca-808e-43a2-ad77-9dca778f2960,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Muscle Fiber Direction: The direction of the muscle fibers and fascicles are used to describe muscles. For example, the abdominal muscles all indicate (remove indicated) the direction of the fibers such as the rectus (straight), the obliques (at an angle) and the transverse (horizontal) muscles of the abdomen.",True,Muscles of the Posterior Neck and the Back,,,,
+a2b80e6d-fc80-47ac-91ce-4170ca4cb64b,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"Number of Muscle Origins (or muscles in a group): Some muscle names indicate the number of muscles origins, or number of muscles in a group, depending upon one’s perspective. For example, when considering the anterior thigh muscle(s), known as the quadriceps, some consider it to be a single muscle with four heads (origins) and others consider the quadriceps to be a group of four muscles. In either case, the prefix quad- refers to four. One example of this is the quadriceps, a group of four muscles located on the anterior (front) thigh. Other examples include the biceps brachii and the triceps brachii. The prefix bi indicates that the muscle has two origins and tri indicates three origins.",True,Muscles of the Posterior Neck and the Back,,,,
+b9665524-a30f-4031-8fc5-6dee34f11483,https://open.oregonstate.education/aandp/,11.3 Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/aandp/chapter/11-3-explain-the-criteria-used-to-name-skeletal-muscles/,"The last feature by which to name a muscle is its action. When muscles are named for the movement they produce, one can find action words in their name. Some examples are flexors (decrease the angle at the joint), extensors (increase the angle at the joint), abductors (move the bone away from the midline), or adductors (move the bone toward the midline).",True,Muscles of the Posterior Neck and the Back,,,,
+32a363ca-138e-4e1e-996d-1664d038ce9a,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,Describe how fascicles are arranged within a skeletal muscle,False,Describe how fascicles are arranged within a skeletal muscle,,,,
+5f6333ac-3ce0-4535-b2a5-8664db72ff4e,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,Patterns of Fascicle Organization,False,Patterns of Fascicle Organization,,,,
+93100b76-a6bc-4d13-b5d0-831dbe9d069f,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"Skeletal muscle is enclosed in connective tissue scaffolding at three levels. Each muscle fiber (cell) is covered by endomysium and the entire muscle is covered by epimysium. When a group of muscle fibers is “bundled” as a unit within the whole muscle it is called a fascicle. Fascicles are covered by a layer of connective tissue called perimysium (see Figure 10.2.1). Fascicle arrangement is correlated to the force generated by a muscle and affects the muscle’s range of motion. Based on the patterns of fascicle arrangement, skeletal muscles can be classified in several ways. What follows are the most common fascicle arrangements.",True,Patterns of Fascicle Organization,Figure 10.2.1,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2019/07/1001_Muscle_Tissue_revised.png,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium."
+72a24f4d-c9b4-4af3-b7ee-fbff975786e9,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,Parallel muscles have fascicles that are arranged in the same direction as the long axis of the muscle (Figure 11.2.1). The majority of skeletal muscles in the body have this type of organization. Some parallel muscles are flat sheets that expand at the ends to make broad attachments such as the sartorius (see Figure 11.2.2). Other parallel muscles have a larger central region called a muscle belly tapering to tendons on each end. This arrangement is called fusiform such as the biceps brachii (see Figure 11.2.2).,True,Patterns of Fascicle Organization,Figure 11.2.1,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1102_Fascicle_Muscle_Shapes.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.
+835b0cd7-579c-494f-8471-e43454702b86,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"Circular muscles are also called sphincters (see Figure 11.2.1). When they relax, the sphincters’ concentrically arranged bundles of muscle fibers increase the size of the opening, and when they contract, the size of the opening shrinks to the point of closure. The orbicularis oris muscle is a circular muscle that goes around the mouth. When it contracts, the oral opening becomes smaller, as when puckering the lips for whistling. Another example is the orbicularis oculi, one of which surrounds each eye. Consider, for example, the names of the two orbicularis muscles (orbicularis oris and oribicularis oculi), where part of the first name of both muscles is the same. The first part of orbicularis, orb (orb = “circular”), is a reference to a round or circular structure; it may also make one think of orbit, such as the moon’s path around the earth. The word oris (oris = “oral”) refers to the oral cavity, or the mouth. The word oculi (ocular = “eye”) refers to the eye.",True,Patterns of Fascicle Organization,Figure 11.2.1,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1102_Fascicle_Muscle_Shapes.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.
+47cd1715-24ac-4184-a95b-73a77cb50730,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"When a muscle has a widespread expansion over a sizable area and the fascicles come to a single, common attachment point, the muscle is called convergent. The attachment point for a convergent muscle could be a tendon, an aponeurosis (a flat, broad tendon), or a raphe (a very slender tendon). The large muscle on the chest, the pectoralis major, is an example of a convergent muscle because it converges on the intertubercular groove and greater tubercle of the humerus via a tendon (see image 11.3).",True,Patterns of Fascicle Organization,,,,
+8dcee826-9929-4df5-aa56-f8a9f66ac5af,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"Pennate muscles (penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle fascicles arranged similar to the feathers. Due to this design, the muscle fibers in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far. However, because a pennate muscle generally can hold more muscle fibers within it, it can produce relatively more tension for its size, compared to non-pennate muscles. There are three subtypes of pennate muscles.",True,Patterns of Fascicle Organization,,,,
+c13fc478-b376-4e72-a57a-819f0a5fd2a1,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"In a unipennate muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A bipennate muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons tapering towards a common tendon, like multiple feathers converging on a central point. A common example is the deltoid muscle of the shoulder, which covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus.",True,Patterns of Fascicle Organization,,,,
+974dc21d-bbb7-4b19-99de-344e8580d4a6,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,The Lever System of Muscle and Bone Interactions,False,The Lever System of Muscle and Bone Interactions,,,,
+53381045-b3f1-4412-a23b-0db7fbd5d62a,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"Skeletal muscles do not work by themselves. Muscles are arranged in pairs based on their functions. For muscles attached to the bones of the skeleton, the connection determines the force, speed, and range of movement. These characteristics depend on each other and can explain the general organization of the muscular and skeletal systems.",True,The Lever System of Muscle and Bone Interactions,,,,
+df7c2c1d-69a8-49be-a65c-15407a0188f2,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"The skeleton and muscles act together to move the body. Have you ever used the back of a hammer to remove a nail from wood? The handle acts as a lever and the head of the hammer acts as a fulcrum, the fixed point that the force is applied to when you pull back or push down on the handle. The effort applied to this system is the pulling or pushing on the handle to remove the nail, which is the load, or “resistance” to the movement of the handle in the system. Our musculoskeletal system works in a similar manner, with bones being stiff levers and the articular endings of the bones—encased in synovial joints—acting as fulcrums. The load would be an object being lifted or any resistance to a movement (your head is a load when you are lifting it), and the effort, or applied force, comes from contracting skeletal muscle.",True,The Lever System of Muscle and Bone Interactions,,,,
+760f1b62-ed76-4f57-9fcc-2b80aee98208,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"In the human body, most lever systems include the following components:  the rigid lever arm (A) , which is a bone in the body, the fulcrum (F) (or axis of rotation), which is the joint, and the load (L), which is the center of mass or weight of the body part being moved, and the effort (E), which is the force exerted by the muscle at its point of attachment to the bone.",True,The Lever System of Muscle and Bone Interactions,,,,
+3ef9693d-bdee-47da-8a46-e53c32171d8c,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"There are two factors that can influence the overall function of a lever system. The first is the order of arrangement of the fulcrum, load, and effort, which influences the function of the lever and whether it will be best at moving a heavy load a short distance or at moving a light load quickly over a long distance.  The second factor is whether the effort arm or the load arm is the longest.  The effort arm (EA) is the distance between the fulcrum (joint) and the effort (muscle insertion). The load arm (LA) is the distance between the fulcrum (joint) and the load (center of mass).",True,The Lever System of Muscle and Bone Interactions,,,,
+eca72b8d-ab21-436c-a9b1-0750dbe689a8,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"If the effort arm is longer than the load arm, the lever is referred to as a power lever that operates at a mechanical advantage.  Levers with a mechanical advantage are well-suited for moving heavy loads over a short distance with less of an effort than would be required to move the object without the lever.  One example of a power lever is a car jack that is used to change a tire. The car, which is a heavy load, is moved a small distance upward with each crank of the effort arm, which requires a minimal effort.  Another example is a wheelbarrow.",True,The Lever System of Muscle and Bone Interactions,,,,
+06f246bf-b703-4fad-8120-52e48daee294,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"If the load arm is longer than the effort arm, the lever is referred to as a speed lever that operates at a mechanical disadvantage. Levers with a mechanical disadvantage are well-suited for moving a smaller load quickly over a larger distance.  Examples of a speed lever include a baseball bat hitting a ball (load) or a shovel moving dirt.",True,The Lever System of Muscle and Bone Interactions,,,,
+4cfb2982-af80-494c-8c54-31d99ed81926,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"There are three main classes of levers, which differ according to how the load, fulcrum, and effort are arranged.  The first-class lever is arranged so that the fulcrum (joint) is between the load and the effort. The first-class lever can be written as load, fulcrum, effort (LFE) or as effort, fulcrum load (EFL).  A first-class lever can be a speed lever or a power lever, depending on whether the fulcrum in the middle is closer to the load or closer to the effort.  Scissors and seesaws are examples of first-class levers. When the posterior neck muscles raise your head off or your chest, your head and neck are acting as a first-class lever. The muscles provide the effort, the joint between the head and the neck acts as the fulcrum, and the mass of the face serves as the load.",True,The Lever System of Muscle and Bone Interactions,,,,
+888ab36f-b673-4ba9-b0bc-b95ddfeff093,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"The second-class lever is arranged so that the load is between the fulcrum (joint) and the effort. The second-class lever can be written as fulcrum, load, effort (FLE) or as effort, load, fulcrum (ELF). A second-class lever is a power lever (with a mechanical advantage) because the effort arm is longer than the load arm. There are few examples of second-class levers in the human body. One example is if you raise your heels off the ground while seated in a chair with your feet in front of you and your knees at a 90-degree angle.  This class of lever is efficient at moving large loads. With a second-class lever, a small effort is exerted over a relatively large distance, and it manages to move a large load over a small distance.",True,The Lever System of Muscle and Bone Interactions,,,,
+e04e16de-ad08-458a-b452-fd8819b255f8,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"The third-class lever is arranged so that the effort is between the load and the fulcrum and can be written as load, effort, fulcrum (LEF) or as fulcrum, effort, load (FEL). The third-class lever is a speed lever that operates at a mechanical disadvantage.  A shovel moving dirt and tweezers moving an object are examples of third-class lever systems. In the human body, flexing the forearm with the biceps brachii muscle is an example of a third-class lever. The third-class lever is the most common class of lever found in the human body. When considering this, one can conclude that the body is mostly made up of speed levers that are efficient at moving a smaller load (body parts) rapidly over a large distance with a large range of motion.   This is what allows humans to move their limbs quickly to run and avoid immediate danger.",True,The Lever System of Muscle and Bone Interactions,,,,
+5b5cdba9-1ce1-4886-94cf-86b98f874001,https://open.oregonstate.education/aandp/,11.2 Explain the organization of muscle fascicles and their role in generating force,https://open.oregonstate.education/aandp/chapter/11-2-explain-the-organization-of-muscle-fascicles-and-their-role-in-generating-force/,"There is one other type of lever within the human body that uses a pulley system. One example of a muscle that operates using a pulley is the extraocular muscle of the eye called the superior oblique. This muscle extends along the inner wall of the eye orbit (socket) and travels through the trochlea, which is a loop composed of fibrocartilage that is attached to the frontal bone of the skull. The muscle tendon turns at a sharp angle and then attaches to the eyeball. This muscle uses the trochlea as a pulley to depress the eye and to turn it laterally. Another example is the long head of the biceps brachii muscle, which originates at the glenoid labrum and supraglenoid tubercle, forms an angle to track through the intertubercular sulculs (bicipital groove), and inserts into the radial tuberosity. The bicipital groove holds the muscle in place and serves as a pulley.",True,The Lever System of Muscle and Bone Interactions,,,,
+e1970153-febc-411e-bb52-8fc81e1b3654,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,Compare and contrast agonist and antagonist muscles,False,Compare and contrast agonist and antagonist muscles,,,,
+0ede28f4-6dbd-4f91-8ce9-eb6d9d3d54d3,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"The moveable end of the muscle that attaches to the bone being pulled is called the muscle’s insertion, and the end of the muscle attached to a fixed (stabilized) bone is called the origin. Muscle pull rather than push. Upon activation, the muscle pulls the insertion toward the origin.",True,Compare and contrast agonist and antagonist muscles,,,,
+53d6e0d9-e525-47a7-bc69-74ed0369b2f6,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"Although a number of muscles may be involved in an action, the principal muscle involved is called the prime mover, or agonist. During forearm flexion, for example lifting a cup, a muscle called the biceps brachii is the prime mover. Because it can be assisted by the brachialis, the brachialis is called a synergist in this action (Figure 11.1.1). A synergist can also be a fixator that stabilizes the muscle’s origin.",True,Compare and contrast agonist and antagonist muscles,Figure 11.1.1,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/app/uploads/sites/157/2019/07/1101_Biceps_Muscle.jpg,"Figure 11.1.1 – Prime Movers and Synergists: The biceps brachii flex the lower arm. The brachoradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion."
+bbba3dbd-6c34-4d6e-a158-9d3bb1436fd0,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"A muscle with the opposite action of the prime mover is called an antagonist. Antagonists play two important roles in muscle function: (1) they maintain body or limb position, such as holding the arm out or standing erect; and (2) they control rapid movement, as in shadow boxing without landing a punch or the ability to check the motion of a limb.",True,Compare and contrast agonist and antagonist muscles,,,,
+3b512ae6-0304-4d40-8f8f-f63ae9573e58,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"For example, to extend the leg at the knee, a group of four muscles called the quadriceps femoris in the anterior compartment of the thigh are activated (and would be called the agonists of leg extension at the knee). A set of antagonists called the hamstrings in the posterior compartment of the thigh are activated to slow or stop the movement.",True,Compare and contrast agonist and antagonist muscles,,,,
+6df07e5d-c6a1-47ef-a5f2-6089ce9b4ca9,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"These terms are reversed for the opposite action, flexion of the leg at the knee. In this case the hamstrings would be called the agonists and the quadriceps femoris would be called the antagonists.",True,Compare and contrast agonist and antagonist muscles,,,,
+c2b770c3-d2d5-41e9-95ca-f06179607c6c,https://open.oregonstate.education/aandp/,"11.1 Describe the roles of agonists, antagonists and synergists",https://open.oregonstate.education/aandp/chapter/11-1-describe-the-roles-of-agonists-antagonists-and-synergists/,"There are also muscles that do not pull against the skeleton for movements such as the muscles of facial expressions. The insertions and origins of facial muscles are in the skin, so that certain individual muscles contract to form a smile or frown, form sounds or words, and raise the eyebrows. There also are skeletal muscles in the tongue, and the external urinary and anal sphincters that allow for voluntary regulation of urination and defecation, respectively. There are four helpful rules that can be applied to all major joints except the ankle and knee because the lower extremity is rotated during development. For example, in the case of the knee, muscles of the posterior thigh cause knee flexion and anterior thigh muscles cause knee extension, which is opposite of the rules stated below for most other joints.",True,Compare and contrast agonist and antagonist muscles,,,,
+1e0c3bcb-81a4-4c98-b1df-3ad0c80c1b28,https://open.oregonstate.education/aandp/,11.0 Introduction,https://open.oregonstate.education/aandp/chapter/11-0-introduction/,Describe the actions and roles of agonists and antagonists,False,Describe the actions and roles of agonists and antagonists,,,,
+caadbf09-a132-4224-8cfa-9b2bf2786ca5,https://open.oregonstate.education/aandp/,11.0 Introduction,https://open.oregonstate.education/aandp/chapter/11-0-introduction/,Explain the structure and organization of muscle fascicles and their role in generating force,True,Describe the actions and roles of agonists and antagonists,,,,
+33058eb8-471a-49b4-a732-68937241746d,https://open.oregonstate.education/aandp/,11.0 Introduction,https://open.oregonstate.education/aandp/chapter/11-0-introduction/,Explain the criteria used to name skeletal muscles,False,Explain the criteria used to name skeletal muscles,,,,
+c7bd6d53-a2bc-4b91-b273-de0d5d429ec5,https://open.oregonstate.education/aandp/,11.0 Introduction,https://open.oregonstate.education/aandp/chapter/11-0-introduction/,Identify the skeletal muscles and their actions on the skeleton and soft tissues of the body,True,Explain the criteria used to name skeletal muscles,,,,
+818499bd-df71-49a3-9744-d41aab0ff4dd,https://open.oregonstate.education/aandp/,11.0 Introduction,https://open.oregonstate.education/aandp/chapter/11-0-introduction/,Identify the origins and insertions of skeletal muscles and the prime movements,True,Explain the criteria used to name skeletal muscles,,,,
+8916e9e8-7bdf-4d4c-82a4-a201ebb7c256,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"Most muscle tissue of the body arises from embryonic mesoderm. Paraxial mesodermal cells adjacent to the neural tube form blocks of cells called somites. Skeletal muscles, excluding those of the head and limbs, develop from mesodermal somites, whereas skeletal muscle in the head and limbs develop from general mesoderm. Somites give rise to myoblasts. A myoblast is a muscle-forming stem cell that migrates to different regions in the body and then fuse(s) to form a syncytium, or myotube. As a myotube is formed from many different myoblast cells, it contains many nuclei, but has a continuous cytoplasm. This is why skeletal muscle cells are multinucleate, as the nucleus of each contributing myoblast remains intact in the mature skeletal muscle cell. However, cardiac and smooth muscle cells are not multinucleate because the myoblasts that form their cells do not fuse.",True,Explain the criteria used to name skeletal muscles,,,,
+3e7cee4b-6793-484b-8fb5-5fedffe21537,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"Gap junctions develop in the cardiac and single-unit smooth muscle in the early stages of development. In skeletal muscles, ACh receptors are initially present along most of the surface of the myoblasts, but spinal nerve innervation causes the release of growth factors that stimulate the formation of motor end-plates and NMJs. As neurons become active, electrical signals that are sent through the muscle influence the distribution of slow and fast fibers in the muscle.",True,Explain the criteria used to name skeletal muscles,,,,
+d515d5b7-f21a-49c4-a004-b96d505c9fe8,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"Although the number of muscle cells is set during development, satellite cells help to repair skeletal muscle cells. A satellite cell is similar to a myoblast because it is a type of stem cell; however, satellite cells are incorporated into muscle cells and facilitate the protein synthesis required for repair and growth. These cells are located outside the sarcolemma and are stimulated to grow and fuse with muscle cells by growth factors that are released by muscle fibers under certain forms of stress. Satellite cells can regenerate muscle fibers to a very limited extent, but they primarily help to repair damage in living cells. If a cell is damaged to a greater extent than can be repaired by satellite cells, the muscle fibers are replaced by scar tissue in a process called fibrosis. Because scar tissue cannot contract, muscle that has sustained significant damage loses strength and cannot produce the same amount of power or endurance as it could before being damaged.",True,Explain the criteria used to name skeletal muscles,,,,
+87a6600e-a30d-4a65-b805-42e4ee9d46f8,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"Smooth muscle tissue can regenerate from a type of stem cell called a pericyte, which is found in some small blood vessels. Pericytes allow smooth muscle cells to regenerate and repair much more readily than skeletal and cardiac muscle tissue. Similar to skeletal muscle tissue, cardiac muscle does not regenerate to a great extent. Dead cardiac muscle tissue is replaced by scar tissue, which cannot contract. As scar tissue accumulates, the heart loses its ability to pump because of the loss of contractile power. However, some minor regeneration may occur due to stem cells found in the blood that occasionally enter cardiac tissue.",True,Explain the criteria used to name skeletal muscles,,,,
+58c87578-675e-41f2-88fd-05061ee09305,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"As muscle cells die, they are not regenerated but instead are replaced by connective tissue and adipose tissue, which do not possess the contractile abilities of muscle tissue. Muscles atrophy when they are not used, and over time if atrophy is prolonged, muscle cells die. It is therefore important that those who are susceptible to muscle atrophy exercise to maintain muscle function and prevent the complete loss of muscle tissue. In extreme cases, when movement is not possible, electrical stimulation can be introduced to a muscle from an external source. This acts as a substitute for endogenous neural stimulation, stimulating the muscle to contract and preventing the loss of proteins that occurs with a lack of use.",True,Explain the criteria used to name skeletal muscles,,,,
+036fe217-d23a-49a2-b4e8-1c66ccd22211,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"Physiotherapists work with patients to maintain muscles. They are trained to target muscles susceptible to atrophy, and to prescribe and monitor exercises designed to stimulate those muscles. There are various causes of atrophy, including mechanical injury, disease, and age. After breaking a limb or undergoing surgery, muscle use is impaired and can lead to disuse atrophy. If the muscles are not exercised, this atrophy can lead to long-term muscle weakness. A stroke can also cause muscle impairment by interrupting neural stimulation to certain muscles. Without neural inputs, these muscles do not contract and thus begin to lose structural proteins. Exercising these muscles can help to restore muscle function and minimize functional impairments. Age-related muscle loss is also a target of physical therapy, as exercise can reduce the effects of age-related atrophy and improve muscle function.",True,Explain the criteria used to name skeletal muscles,,,,
+1f3dc75f-0460-4c13-8189-0283d393834c,https://open.oregonstate.education/aandp/,10.8 Development and Regeneration of Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-8-development-and-regeneration-of-muscle-tissue/,"The goal of a physiotherapist is to improve physical functioning and reduce functional impairments; this is achieved by understanding the cause of muscle impairment and assessing the capabilities of a patient, after which a program to enhance these capabilities is designed. Some factors that are assessed include strength, balance, and endurance, which are continually monitored as exercises are introduced to track improvements in muscle function. Physiotherapists can also instruct patients on the proper use of equipment, such as crutches, and assess whether someone has sufficient strength to use the equipment and when they can function without it.",True,Explain the criteria used to name skeletal muscles,,,,
+44ea4cc6-d0db-4eb7-895c-652db87ca1c5,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Smooth muscle, so-named because the cells do not have visible striations, is present in the walls of hollow organs (e.g., urinary bladder), lining the blood vessels, and in the eye (e.g., iris) and skin (e.g., erector pili muscle).  Smooth muscle displays involuntary control and can be triggered via hormones, neural stimulation by the ANS, and local factors. In certain locations, such as the walls of visceral organs, stretching the muscle can trigger its contraction).",True,Explain the criteria used to name skeletal muscles,,,,
+72b3b0c0-4f33-40c4-8195-a527fea7f636,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Smooth muscle fibers are spindle-shaped and, unlike skeletal muscle fibers, have a single nucleus; individual cells range in size from  30 to 200 μm.  Smooth muscle fibers are often found forming sheets of tissue and function in a coordinated fashion due to the presence of gap junctions between the cells.  Termed unitary smooth muscle or visceral muscle, this type of smooth muscle is the most common observed in the human body, forming the walls of hollow organs. Single-unit smooth muscle produces slow, steady contractions that allow substances, such as food in the digestive tract, to move through the body.",True,Explain the criteria used to name skeletal muscles,,,,
+682605d9-0a4a-4f70-8e78-f4f874fe2d50,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Multi-unit smooth muscle, the second type of smooth muscle observed, are composed of cells that rarely possess gap junctions, and thus are not electrically coupled. As a result, contraction does not spread from one cell to the next, but is instead confined to the cell that was originally stimulated. This type of smooth muscle is observed in the large airways to the lungs, in the large arteries, the arrector pili muscles associated with hair follicles, and the internal eye muscles which regulate light entry and lens shape.",True,Explain the criteria used to name skeletal muscles,,,,
+fc1257bc-0219-4a61-b996-38dea9a7b143,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Although smooth muscle cells do not have striations, smooth muscle fibers do have actin and myosin contractile proteins which interact to generate tension. These fibers are not arranged in orderly sarcomeres (hence, no striations) but instead are anchored to dense bodies which are scattered throughout the cytoplasm and anchored to the sarcolemma.   A network of intermediate fibers run between the dense bodies providing an internal framework for contractile proteins to work against.",True,Explain the criteria used to name skeletal muscles,,,,
+1804d239-c25e-4478-8c39-050257ae9d9b,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"A dense body is analogous to the Z-discs of skeletal muscle, anchoring the thin filaments in position. Calcium ions are supplied primarily from the extracellular environment.  T-tubules are absent but small indentations, called calveoli, in the sarcolemma represent locations where there are a high density of calcium channels present to facilitate calcium entry.  Sarcoplasmic reticulum is present in the fibers but is less developed than that observed in skeletal muscle.",True,Explain the criteria used to name skeletal muscles,,,,
+d0e360db-9852-4c39-8798-988324cbe490,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Because smooth muscle cells do not contain troponin, cross-bridge formation is not regulated by the troponin-tropomyosin complex but instead by the regulatory protein calmodulin. When a smooth muscle cell is stimulated, external Ca++ ions passing through opened calcium channels in the sarcolemma, with additional Ca++ released by the sarcoplasmic reticulum.  Calcium binds to calmodulin in the cytoplasm with the Ca++-calmodulin complex then activating an enzyme called myosin (light chain) kinase.  Myosin light chain kinase in turn, activates the myosin heads by phosphorylating them (converting ATP to ADP and Pi, with the Pi attaching to the head). The heads can then attach to actin-binding sites and pull on the thin filaments.",True,Explain the criteria used to name skeletal muscles,,,,
+63412cdf-0ac8-4b51-83be-9466e230eeab,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"When the thin filaments slide past the thick filaments, they pull on the dense bodies, which then pull on the intermediate filaments networks throughout the sarcoplasm. This arrangement causes the entire muscle fiber to contract in a manner whereby the ends are pulled toward the center, causing the midsection to bulge in a corkscrew motion (Figure 10.7.2).",True,Explain the criteria used to name skeletal muscles,Figure 10.7.2,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1028_Smooth_Muscle_Contraction.jpg,"Figure 10.7.2 – Muscle Contraction: The dense bodies and intermediate filaments are networked through the sarcoplasm, which cause the muscle fiber to contract."
+6121bc3d-e599-4ba7-a951-2df155a88556,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Muscle contraction continues until ATP-dependent calcium pumps actively transport Ca++ ions out of the cell or back into the sarcoplasmic reticulum.  However, a low concentration of calcium remains in the sarcoplasm to maintain muscle tone. This remaining calcium keeps the muscle slightly contracted, which is important in  certain functions, such as maintaining pressure in blood vessels.",True,Explain the criteria used to name skeletal muscles,,,,
+9ead590a-c914-49a3-b9d8-0c742eb036d4,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Because most smooth muscles must function for long periods without rest, their power output is relatively low to minimize energy needs. Some smooth muscle can also maintain contractions even as Ca++ is removed and myosin kinase is inactivated/dephosphorylated. This can happen as a subset of cross-bridges between myosin heads and actin, called latch-bridges, keep the thick and thin filaments linked together for a prolonged period, without the need for ATP. This allows for the maintaining of muscle “tone” in smooth muscle that lines arterioles and other visceral organs with very little energy expenditure.",True,Explain the criteria used to name skeletal muscles,,,,
+7bd4939d-51bd-4e76-9f28-985dbbdb5ff5,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"For smooth muscle stimulated by neurons, the axons from autonomic nervous system neurons do not form the highly organized neuromuscular junctions as observed in skeletal muscle. Instead, there is a series of neurotransmitter-filled bulges, called varicosities, along the axon of the neuron feeding the smooth muscle that release neurotransmitters over a wide synaptic cleft.  Also, visceral muscle in the walls of the hollow organs (except the heart) contains pacesetter cells. A pacesetter cell can spontaneously trigger action potentials and contractions in the muscle.",True,Explain the criteria used to name skeletal muscles,,,,
+13614187-3a1f-49e5-b05a-3faaf1ed6060,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,Hyperplasia in Smooth Muscle,False,Hyperplasia in Smooth Muscle,,,,
+d2ade987-dc1e-4fdd-9aaa-a9e29afe2886,https://open.oregonstate.education/aandp/,10.7 Smooth Muscle Tissue,https://open.oregonstate.education/aandp/chapter/10-7-smooth-muscle-tissue/,"Similar to skeletal muscle cells, smooth muscle can undergo hypertrophy to increase in size. Unlike other muscle, smooth muscle will also divide quite readily to produce more cells, a process called hyperplasia. This can most evidently be observed in the uterus at puberty, which responds to increased estrogen levels by producing more uterine smooth muscle fibers.",True,Hyperplasia in Smooth Muscle,,,,
+da039d46-9f6e-4492-abd4-cc43a2666414,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"Physical training can alter the appearance of skeletal muscles and produce changes in muscle performance. Conversely, a lack of use can result in decreased muscle mass and performance. Although muscle cells can change in size, new cells are rarely formed when muscles grow. Instead, structural proteins are added to a muscle fiber in a process called muscle hypertrophy, resulting in an increase in fiber diameter. The reverse, when structural proteins are lost and muscle mass decreases, is called muscle atrophy.",True,Hyperplasia in Smooth Muscle,,,,
+5b808b39-ad78-4283-9c24-94c5507964e6,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,Endurance Exercise,False,Endurance Exercise,,,,
+44272320-3cac-4a56-9c59-0efd983e32b5,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"Slow fibers are predominantly used in endurance exercises that require limited force generation but involve numerous repetitions. The aerobic metabolism used by slow oxidative fibers allows them to maintain contractions over long periods. Endurance training modifies these slow fibers to make them even more efficient by producing more mitochondria and synthesizing more myoglobin, both which lead to an increase in ATP production by increasing the rate of aerobic metabolism.",True,Endurance Exercise,,,,
+85610bdb-1e86-427d-b0f8-27fff81a817f,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"The training can trigger the formation of more extensive capillary networks around the fiber, a process called angiogenesis, to supply oxygen to the fibers and remove metabolic waste. To allow these capillary networks to supply the deep portions of the muscle, muscle mass does not greatly increase in order to maintain a smaller area for the diffusion of nutrients and gases.",True,Endurance Exercise,,,,
+d7a57ef7-1c78-400f-a9d7-20d08f2acc88,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"The proportion of slow oxidative muscle fibers in muscle determines the suitability of a muscle for endurance, and may benefit those participating in endurance activities (Figure 10.6.1). Postural muscles have a large number of slow oxidative fibers as they are continually contracting to keep the body erect.  Endurance athletes benefit greatly from having muscles containing a larger proportion of slow oxidative fibers compared to fast oxidative fibers.  Studies suggest that genetics play a critical role in determining the overall fiber proportions of slow oxidative to fast glycolytic fibers in muscles with repetitive training having its greatest influence on the fast oxidative fibers.",True,Endurance Exercise,Figure 10.6.1,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1026_Marathoners.jpg,Figure 10.6.1 – Marathoners: Long-distance runners have a large number of slow oxidative fibers and relatively few fast oxidative and fast glycolytic fibers. (credit: “Tseo2”/Wikimedia Commons)
+f3aa7ebc-355b-4b32-a993-413c36936bce,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,Resistance Exercise,False,Resistance Exercise,,,,
+abb5006c-f485-4f36-9dbc-eacdffcfe848,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"Resistance exercises, as opposed to endurance exercise, target fast glycolytic fibers by focusing on short, powerful movements that are not repeated over long periods. The high rates of ATP hydrolysis and cross-bridge formation in fast glycolytic fibers is responsible for such powerful muscle contractions. Thus, muscles used for power often have a higher ratio of fast glycolytic fibers compared to slow oxidative fibers. Resistance exercise affects muscles by increasing the formation of myofibrils, thereby increasing the diameter of muscle fibers (Figure 10.6.2). Because this muscular enlargement is achieved by the addition of structural proteins, athletes trying to build muscle mass often ingest large amounts of protein.",True,Resistance Exercise,Figure 10.6.2,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1027_Hypertrophy.jpg,Figure 10.6.2 – Muscle hypertrophy: Body builders work on increasing the size of the fast glycolytic fibers through resistance training. (credit: Lin Mei/flickr)
+ae18ebae-e6eb-4c3e-9b03-cb6ab0a4ad4d,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"In addition to the increase in muscle fiber diameter, resistance training also increases the development of connective tissue, adding to the overall mass of the muscle.  Increases in connective tissue help to contain muscles as they produce increasingly powerful contractions. Tendons also become stronger to prevent tendon damage, as the force produced by muscles is transferred to tendons that attach the muscle to bone.",True,Resistance Exercise,,,,
+919e5c77-f9d4-426c-8163-136b4fc9b01f,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"For effective strength training, the intensity of the exercise must continually be increased. For instance, continued weight lifting without increasing the weight of the load does not increase muscle size. To produce ever-greater results, the weights lifted must become increasingly heavier, making it more difficult for muscles to move the load. The muscle then adapts to this heavier load, and an even heavier load must be used if even greater muscle mass is desired.",True,Resistance Exercise,,,,
+02e38507-e159-4ce0-b528-8ac4bc01422b,https://open.oregonstate.education/aandp/,10.6 Exercise and Muscle Performance,https://open.oregonstate.education/aandp/chapter/10-6-exercise-and-muscle-performance/,"If done improperly, resistance training can lead to overuse injuries of the muscle, tendon, or bone. These injuries can occur if the load is too heavy, or if the muscles are not given sufficient time between workouts to recover, or if joints are not aligned properly during the exercises. Cellular damage to muscle fibers that occurs after intense exercise includes damage to the sarcolemma and myofibrils. This muscle damage contributes to the feeling of soreness after strenuous exercise, but muscles gain mass as this damage is repaired, and additional structural proteins are added to replace the damaged ones.",True,Resistance Exercise,,,,
+d2080423-6276-4df8-b956-91987d0134b4,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"Skeletal muscle fibers can be classified based on two criteria: 1) how fast do fibers contract relative to others, and 2) how do fibers regenerate ATP.  Using these criteria, there are three main types of skeletal muscle fibers recognized (Table 10.5.1). Slow oxidative (also called slow twitch or Type I) fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP. Fast oxidative (also called fast twitch or Type IIa) fibers have relatively fast contractions and primarily use aerobic respiration to generate ATP. Lastly, fast glycolytic (also called fast twitch or Type IIx) fibers have relatively fast contractions and primarily use anaerobic glycolysis. Most skeletal muscles in a human body contain all three types, although in varying proportions.",True,Resistance Exercise,,,,
+620d5fa4-24ec-4fb8-a9a6-486a4a83eceb,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"The speed of contraction is dependent on how quickly myosin’s ATPase hydrolyzes ATP to produce cross-bridge action. Fast fibers hydrolyze ATP approximately twice as rapidly as slow fibers, resulting in much quicker cross-bridge cycling (which pulls the thin filaments toward the center of the sarcomeres at a faster rate).",True,Resistance Exercise,,,,
+473c89b6-bfbc-4064-b1ba-c0d1d1f93fa6,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"The primary metabolic pathway used by a muscle fiber determines whether the fiber is classified as oxidative or glycolytic. If a fiber primarily produces ATP through aerobic pathways, then it is classified as oxidative. More ATP can be produced during each metabolic cycle, making the fiber more resistant to fatigue. Glycolytic fibers primarily create ATP through anaerobic glycolysis, which produces less ATP per cycle. As a result, glycolytic fibers fatigue at a quicker rate.",True,Resistance Exercise,,,,
+0b8050d6-e60b-4fd5-8f44-33c465ec66e3,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"Slow oxidative fibers have structural elements that maximize their ability to generate ATP through aerobic metabolism.  These fibers contain many more mitochondria than the glycolytic fibers, as aerobic metabolism, which uses oxygen (O2) in the metabolic pathway, occurs in the mitochondria. This allows slow oxidative fibers to contract for longer periods because of the large amount of ATP they can produce, but they have a relatively small diameter and thus do not produce a large amount of tension.",True,Resistance Exercise,,,,
+d347434e-6216-49d1-afe6-8e088c86b383,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"In addition to increased numbers of mitochondria, slow oxidative fibers are extensively supplied with blood capillaries to supply O2 from the bloodstream.  They also possess myoglobin, an O2-binding molecule similar to hemoglobin in the red blood cells. The myoglobin stores some of the needed O2 within the fibers themselves and is partially responsible for giving oxidative fibers a dark red color.",True,Resistance Exercise,,,,
+e6d97658-736e-4b79-9584-01911c3ff60b,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"The ability of slow oxidative fibers to function for long periods without fatiguing makes them useful in maintaining posture, producing isometric contractions, and stabilizing bones and joints.  Because they do not produce high tension, they are not used for powerful, fast movements that require high amounts of energy and rapid cross-bridge cycling.",True,Resistance Exercise,,,,
+778e9d55-3e12-4736-bf3a-917daa1a84cf,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"Fast glycolytic fibers primarily use anaerobic glycolysis as their ATP source.  They have a large diameter and possess large volumes of glycogen which is used in glycolysis to generate ATP quickly.  Because of their reliance on anaerobic metabolism, these fibers do not possess substantial numbers of mitochondria, a limited capillary supply, or significant amounts of myoglobin, resulting in a white coloration for muscles containing large numbers of these fibers.",True,Resistance Exercise,,,,
+8a55c2b4-2636-4b29-a891-22c4e77a479a,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"Fast glycolytic fibers fatigue quickly, permitting them to only be used for short periods.  However, during these short periods, the fibers are able to produce rapid, forceful contractions associated with quick, powerful movements.",True,Resistance Exercise,,,,
+55222a02-1bde-4d5d-8b3a-8c92451e7963,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"These different fiber types can be easily identified in poultry. Imagine a turkey. The legs and thighs of the turkey are dark meat, due to their slow oxidative fibers and robust supply of blood vessels and myoglobin. Turkeys spend most of their days walking around looking for food, so their legs must be able to work all day without fatiguing. Alternately, turkey breast is white meat, due to its fast glycolytic fibers and relatively insubstantial supply of myoglobin and lesser blood supply. Turkeys do not fly long distances, but only need to get into trees to roost. Their breast tissue produces strong, rapid contractions, but only for very brief flights.",True,Resistance Exercise,,,,
+b288a8ba-264f-49e6-8551-a9a16b116654,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,"Fast oxidative fibers are sometimes called intermediate fibers because they possess characteristics that are intermediate between slow oxidative fibers and fast glycolytic fibers. These fibers produce ATP relatively quickly, and thus can produce relatively high amounts of tension, but because they are oxidative, they do not fatigue quickly.  Fast oxidative fibers are used primarily for movements, such as walking, that require more energy than postural control but less energy than an explosive movement.",True,Resistance Exercise,,,,
+14b536d7-66be-4cd3-8045-5c72da99c8e5,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,What changes occur at the cellular level in response to endurance training?,True,Resistance Exercise,,,,
+69bc05ee-9056-4b7f-9d5f-362cdf54b568,https://open.oregonstate.education/aandp/,10.5 Types of Muscle Fibers,https://open.oregonstate.education/aandp/chapter/10-5-types-of-muscle-fibers/,What changes occur at the cellular level in response to resistance training?,True,Resistance Exercise,,,,
+f39dd778-055f-4169-ba8d-381fc5fe11f0,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"To move an object, referred to as a load, the muscle fibers of a skeletal muscle must shorten. The force generated by a contracting muscle is called muscle tension. Muscle tension can also be generated when the muscle is contracting against a load that does not move, resulting in two main types of skeletal muscle contractions: isotonic contractions and isometric contractions (Figure 10.4.1).",True,Resistance Exercise,Figure 10.4.1,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1015_Types_of_Contraction_new.jpg,"Figure 10.4.1- Types of Muscle Contractions: During isotonic contractions (concentric and eccentric contractions), muscle length changes to move a load. During isometric contractions, muscle length does not change because the load equals the tension the muscle generates."
+3be094e5-53db-4c8a-bdfa-7740bcee8ac4,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"In isotonic contractions, where the tension in the muscle stays relatively constant, a load is moved as the length of the muscle changes. A concentric contraction involves the muscle producing tension and shortening to move a load. An example of this is the contraction of the biceps brachii muscle when a hand weight is brought upward toward the body. An eccentric contraction occurs when the muscle tension produced is less than the load and a muscle lengthens while under tension. This type of contraction is observed when the same hand weight is lowered in a slow and controlled manner by the biceps brachii. Both concentric and eccentric contractions involve force production by the muscle and crossbridge cycling with the myosin heads pulling toward the M-line. The only difference between the two is whether the muscle length is shortening or elongating during the contraction.",True,Resistance Exercise,,,,
+55b5945f-38e9-4b5c-a2cf-2e8d761c869e,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"An isometric contraction occurs when a muscle produces tension without a change in muscle length. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load. For example, if one attempts to lift a hand weight that is too heavy, there will be sarcomere activation and shortening to a point, and ever-increasing muscle tension, but no change in the position of the hand weight. In everyday living, isometric contractions are active in maintaining posture and maintaining bone and joint stability.",True,Resistance Exercise,,,,
+5e84b3fe-7c3f-4cf1-b9bd-41f97b55ceed,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,Most actions of the body are the result of a combination of isotonic and isometric contractions working together to produce a wide range of outcomes.  These muscle activities are under the control of the nervous system. A crucial aspect of nervous system control of skeletal muscles is the role of motor units.,True,Resistance Exercise,,,,
+38bbdfd5-f79b-47aa-88b9-ffaf40a0ae13,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,Motor Units,False,Motor Units,,,,
+8dd0a52d-7325-4019-a336-2f926d571eba,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"As previously discussed, the contraction of skeletal muscle fibers is triggered by  signaling from a motor neuron.  Each muscle fiber is innervated by only one motor neuron but a single motor neuron can innervate multiple muscle fibers.  A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).",True,Motor Units,Figure 10.4.2,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.2.-new.png,Figure 10.4.2 – Skeletal Muscle Contractions
+8dd0a52d-7325-4019-a336-2f926d571eba,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"As previously discussed, the contraction of skeletal muscle fibers is triggered by  signaling from a motor neuron.  Each muscle fiber is innervated by only one motor neuron but a single motor neuron can innervate multiple muscle fibers.  A motor unit is defined a single motor neuron and all of the muscle fibers innervated by it (Figure 10.4.2b and Figure 10.4.2c).",True,Motor Units,Figure 10.4.2,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1029_Smooth_Muscle_Motor_Units_noLeaders.png,Figure 10.4.2b
+475209dc-8518-499b-bbee-747b856ccd7f,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"The size of a motor unit dictates its function.  A small motor unit, composed of a motor neuron and only a few muscle fibers, permits very fine motor control of a muscle. For example, the extraocular eye muscles have thousands of muscle fibers with every 5 – 10 fibers supplied by a single motor neuron; this allows for exquisite control of eye movements so that both eyes can quickly focus on an object. Small motor units are also involved in the many fine movements of the fingers and thumb of the hand for grasping, texting, etc.",True,Motor Units,,,,
+e55afe46-ab6c-44c5-9bdb-d0da6a457c1e,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Large motor units have more muscle fibers per neuron than small motor units. Larger motor units are concerned with simple, or “gross,” movements, such as moving parts of the body against gravity. The large motor units of the thigh muscles or back muscles, where a single motor neuron will supply thousands of muscle fibers in a muscle, are representative of this type of activity.",True,Motor Units,,,,
+a0700068-545a-41bc-b858-93d60c9f7269,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Most muscles in the human body have a mixture of small and large motor units which gives the nervous system a wide range of control over the muscle. The smaller motor units in a muscle have motor neurons that are more excitable.  Initial activation of these smaller motor units results in a relatively small degree of tension generated in a muscle. As more strength is needed, larger motor units are enlisted to generate more tension. This  process of bringing on additional motor units to produce more tension is known as recruitment.  This process allows a muscle such as the biceps brachii to pick up a feather with minimal force generation versus picking up a heavy weight which requires a much greater amount of force generation.",True,Motor Units,,,,
+c864fea4-d9b4-482d-8410-d2581430b9e1,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"When necessary, the maximal number of motor units in a muscle can be recruited simultaneously, producing the maximum force of contraction for that muscle, but this cannot last for very long because of the energy requirements to sustain the contraction. To prevent complete muscle fatigue, motor units are generally not all simultaneously active, but instead some motor units rest while others are active, which allows for longer muscle contractions. The nervous system thus uses recruitment as a mechanism to efficiently utilize a skeletal muscle.",True,Motor Units,,,,
+93a39035-45cf-4ce4-8f3a-bd808eb1305b,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,The Length-Tension Range of a Sarcomere,False,The Length-Tension Range of a Sarcomere,,,,
+1ff0329a-f95a-4f3e-a05d-841422f84ac3,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"As discussed previously, when a skeletal muscle fiber contracts, myosin heads attach to actin to form cross-bridges followed by the thin filaments sliding over the thick filaments as the heads pull the actin, and this results in sarcomere shortening, creating the tension of the muscle contraction. The cross-bridges can only form where thin and thick filaments overlap; thus, the length of the sarcomere has a direct influence on the force generated when the sarcomere shortens. This is called the length-tension relationship.",True,The Length-Tension Range of a Sarcomere,,,,
+3dd0506e-3993-44ba-8fa9-916966d660b9,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"The ideal length of a sarcomere to produce maximal tension occurs at 80 percent to 120 percent of its resting length, with 100 percent being the state where the medial edges of the thin filaments are just at the most-medial myosin heads of the thick filaments (Figure 10.4.4). This length maximizes the overlap of actin-binding sites and myosin heads.",True,The Length-Tension Range of a Sarcomere,Figure 10.4.4,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1012_Muscle_Twitch_Myogram.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops."
+4783fac0-2434-4a51-bbb0-f1209dfa22f9,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"If a sarcomere is stretched past the ideal length (beyond 120 percent), thick and thin filaments do not fully overlap, which results in less tension produced. If the muscle is stretched to the point where the thick and thin filaments do not overlap at all, no cross-bridges can be formed, and no tension is generated.  This amount of stretching does not usually occur as accessory proteins and connective tissue oppose extreme stretching.",True,The Length-Tension Range of a Sarcomere,,,,
+d140e82c-8f8c-4b04-96f5-3c0b56c6b8e8,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"If a sarcomere is shortened beyond 80 percent, the zone of overlap is reduced with the thin filaments jutting beyond the last of the myosin heads. Eventually, there is nowhere else for the thin filaments to go and the amount of tension is diminished.",True,The Length-Tension Range of a Sarcomere,,,,
+547ede9b-f190-4884-a9b8-775365a1c2d6,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,The Frequency of Motor Neuron Stimulation,False,The Frequency of Motor Neuron Stimulation,,,,
+d1934205-ce04-47d1-a520-44d14cd93a70,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"A single action potential from a motor neuron will produce a single contraction in the muscle fibers innervated by the motor neuron. This isolated contraction is called a twitch. A twitch can last anywhere from a few milliseconds to 100 milliseconds, depending on the muscle fiber type. The tension produced by a single twitch can be measured by a myogram, an instrument that measures the amount of tension produced over time (Figure 10.4.4).",True,The Frequency of Motor Neuron Stimulation,Figure 10.4.4,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1012_Muscle_Twitch_Myogram.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops."
+b1d5c6ca-3759-4b71-86ed-6affa921734a,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Three phases are recognized for a muscle twitch.  The first phase is the latent period, during which the action potential is being propagated along the sarcolemma and Ca++ ions are released from the sarcoplasmic reticulum. This is the phase during which excitation and contraction are being coupled but contraction has yet to occur. The contraction phase occurs as the muscle generates increasing levels of tension; the Ca++ ions in the sarcoplasm have bound to troponin, tropomyosin has shifted away from actin-binding sites, cross-bridges have formed, and sarcomeres are actively shortening. The last phase is the relaxation phase, when tension decreases as Ca++ ions are pumped out of the sarcoplasm back into the sarcoplasmic reticulum,  returning the muscle fibers to their resting state.",True,The Frequency of Motor Neuron Stimulation,,,,
+dfb9b009-eeee-4ec6-b40f-4f8fba4116e5,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Although a person can experience a skeletal muscle “twitch,” a single twitch does not produce ‘useful’ activity in a living body. Instead, a rapid series of action potentials sent to the muscle fibers is necessary for a muscle contraction that can produce work. By varying the rate at which a motor neuron fires action potentials, the amount of tension generated by the innervated muscle fibers can be modified; this is called a graded muscle response.",True,The Frequency of Motor Neuron Stimulation,,,,
+a21696df-dcef-47f5-ba2f-1e5a53024f2a,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"A graded muscle response works as follows:  if the fibers are stimulated while a previous twitch is still occurring, the second twitch will be stronger. This response is called wave summation, because the excitation-contraction coupling effects of successive motor neuron signaling is summed, or added together (Figure 10.4.5a). At the molecular level, summation occurs because the second stimulus triggers the release of more Ca++ ions, which become available to activate more cross-bridging while the muscle is still contracting from the first stimulus. Summation results in greater contraction of the motor unit.",True,The Frequency of Motor Neuron Stimulation,Figure 10.4.5,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+2e765358-f944-4b5d-b03f-f90a7a1b7602,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"If the frequency of motor neuron signaling increases, summation and subsequent muscle tension in the motor unit continues to rise until it reaches a peak point. The tension at this point is about three to four times greater than the tension of a single twitch, a state referred to as incomplete tetanus. During incomplete tetanus, the muscle goes through quick cycles of contraction followed by a short relaxation phase. If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus (Figure 10.4.5b).",True,The Frequency of Motor Neuron Stimulation,Figure 10.4.5,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+6d731dd7-7264-48c5-9aa3-6fe4020511bd,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"During complete tetanus, the concentration of Ca++ ions in the sarcoplasm allows virtually all of the sarcomeres to form cross-bridges and shorten, so that a contraction can continue uninterrupted (until the muscle fatigues and can no longer produce tension).",True,The Frequency of Motor Neuron Stimulation,,,,
+0ddc94e7-36ab-4b06-9c4a-3e7ba6232c48,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,Treppe,False,Treppe,,,,
+1df7d399-9d74-4003-8dc4-6c9ba4a77897,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"When a skeletal muscle has been dormant for an extended period and then stimulated to contract, with all other things being equal, the initial contractions generate about one-half the force of later contractions. The muscle tension increases in a graded manner that to some looks like a set of stairs. This tension increase is called treppe, a condition where muscle contractions become more efficient. It’s also known as the “staircase effect” (Figure 10.4.5).",True,Treppe,Figure 10.4.5,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+c6749fa0-4b26-4c3c-9f04-8e6a0bb2cd34,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,It is believed that treppe results from a higher concentration of Ca++ in the sarcoplasm resulting from the steady stream of signals from the motor neuron. It can only be maintained with adequate ATP.,True,Treppe,,,,
+8451d191-293c-4ae6-b0fc-23155792a0a1,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,Muscle Tone,False,Muscle Tone,,,,
+0fd3d45f-c6cc-4211-8880-4f56a332f1dd,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Skeletal muscles are rarely completely relaxed, or flaccid. Even if a muscle is not producing movement, it is contracted a small amount to maintain its contractile proteins and produce muscle tone. The tension produced by muscle tone allows muscles to continually stabilize joints and maintain posture.",True,Muscle Tone,,,,
+48f03b08-1ec2-49ad-8d1a-122030c00f60,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,"Muscle tone is accomplished by a complex interaction between the nervous system and skeletal muscles that results in the activation of a few motor units at a time, most likely in a cyclical manner. In this manner, muscles never fatigue completely, as some motor units are in a state of recovery while others are actively generating tension.",True,Muscle Tone,,,,
+a5d4435b-1e6c-4a28-b69d-1c641df9dc61,https://open.oregonstate.education/aandp/,10.4 Nervous System Control of Muscle Tension,https://open.oregonstate.education/aandp/chapter/10-4-nervous-system-control-of-muscle-tension/,hypotonia,False,hypotonia,,,,
+afd5f00f-0bbc-4ec0-97f5-9adb2864899e,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,The Neuromuscular Junction,False,The Neuromuscular Junction,,,,
+9b1a151e-1834-4d3d-87b1-85247252d0cf,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,The process of muscle contraction begins at the site where a motor neuron’s terminal meets the muscle fiber—called the neuromuscular junction (NMJ). Every skeletal muscle fiber in every skeletal muscle is innervated by a motor neuron at a NMJ. Excitation signals from the motor neuron are the only way to functionally activate skeletal muscle fibers to contract.,True,The Neuromuscular Junction,,,,
+c0794e91-6446-4447-b0dd-7aff1aceeda5,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,Excitation-Contraction Coupling,False,Excitation-Contraction Coupling,,,,
+f432cee9-eb50-4b89-a54d-ba5e86d142ad,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"All living cells have membrane potentials, or electrical gradients across their membranes based on the distribution of positively and negatively charged ions. The inside of the membrane is usually around -60 to -90 mV, relative to the outside. Neurons and muscle cells can use their membrane potentials to generate and conduct electrical signals by controlling the movement of charged ions across their membranes to create electrical currents. This movement is controlled by selective opening and closing of specialized proteins in the membrane called ion channels. Although the currents generated by ions moving through these channel proteins are very small, they form the basis of both neural signaling and muscle contraction.",True,Excitation-Contraction Coupling,,,,
+7e390b38-412c-42ff-af16-0a8b1442350d,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Both neurons and skeletal muscle cells are electrically excitable, meaning that they are able to generate action potentials. An action potential is a special type of electrical signal that can travel along a cell membrane as a wave. This allows a signal to be transmitted quickly over long distances.",True,Excitation-Contraction Coupling,,,,
+0b758a94-d4f1-4093-b9eb-48d51fc3c0c1,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"In skeletal muscle, cross-bridge formation and contraction requires the presence of calcium (Ca++) inside the muscle cell. Excitation signalling of action potentials from the motor neuron are coupled with calcium release. Thus, the excitation-contraction coupling process begins with signaling from the nervous system at the neuromuscular junction (Figure 10.3.1) and ends with calcium release for muscle contraction.",True,Excitation-Contraction Coupling,Figure 10.3.1,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/app/uploads/sites/157/2021/02/1009_Motor_End_Plate_and_Innervation_revised-1024x735.png,"Figure 10.3.1 – Motor End-Plate and Innervation: At the NMJ, the axon terminal releases acetylcholine (ACh). The motor end-plate is the location of the ACh-receptors in the muscle fiber sarcolemma. When ACh molecules are released, they diffuse across a minute space called the synaptic cleft and bind to the receptors."
+d8afa98b-d09b-4629-b8ec-99d58877eaeb,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Most motor neurons that tell the skeletal muscle fibers to contract originate in the spinal cord. A smaller number of motor neurons are located in the brainstem for activation of skeletal muscles of the face, head, and neck. These neurons have long processes, called axons, which are specialized to transmit action potentials long distances— in this case, all the way from the spinal cord to the muscle itself (which may be up to three feet away). The axons of multiple neurons bundle together to form nerves, like wires bundled together in a cable.",True,Excitation-Contraction Coupling,,,,
+02d019ee-cb60-4598-946e-709c7d68a36b,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Signaling begins when a neuronal action potential travels along the axon of a motor neuron to the axon terminals at the NMJ. The ACh molecules diffuse across a minute space called the synaptic cleft and bind to ACh receptors on chemically-gated or ligand-gated channels located within the motor end-plate of the sarcolemma on the other side of the synapse. Once ACh binds, the chemically gated channel opens and positively charged ions can pass through into the muscle fiber, causing it to depolarize, meaning that the membrane potential of the muscle fiber becomes less negative (closer to zero.)",True,Excitation-Contraction Coupling,,,,
+dffe1aa3-b5eb-4f28-8b73-a7fd7672afe8,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"The membrane depolarization at the synaptic cleft triggers nearby voltage-gated sodium channels to open. Sodium ions enter the muscle fiber further depolarizing the membrane, and an action potential rapidly spreads (or “fires”) along the entire membrane to initiate excitation-contraction coupling.",True,Excitation-Contraction Coupling,,,,
+ffef1268-8767-4b01-b11c-68fb999076dd,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Things happen very quickly in the world of excitable membranes (just think about how quickly you can snap your fingers as soon as you decide to do it). Immediately following depolarization of the membrane, repolarization occurs. Depolarization causes voltage-gated potassium channels open and allow potassium to leave the cell which returns the cell membrane to a negative membrane potential. The concentration gradients of sodium and potassium are then re-established by the sodium-potassium pump. Meanwhile, the ACh in the synaptic cleft is degraded by the enzyme acetylcholinesterase (AChE) so that the ACh cannot rebind to a receptor and reopen its channel, which would cause unwanted extended muscle excitation and contraction.",True,Excitation-Contraction Coupling,,,,
+83b9d915-7c56-4252-a414-d808d04c6d60,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling and must be coupled to the release of calcium ions for contraction. High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap.  The excitation of the muscle membrane is coupled to the SR release of calcium through invaginations in the sarcolemma called T-Tubules (“T” stands for “transverse”). Because the diameter of a muscle fiber can be up to 100 μm, the T-tubules ensure that the action potential on the membrane can get to the interior of the cell and close to the SR throughout the sarcoplasm. The arrangement of a T-tubule with the membranes of SR on either side is called a triad (Figure 10.3.2).",True,Excitation-Contraction Coupling,Figure 10.3.2,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/app/uploads/sites/157/2021/02/1023_T-tubule.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them."
+5700d629-407b-4f8a-89bf-5f609525d3b0,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Voltage-sensitive dihydropyridine receptors (DHPR) on the sarcolemma are mechanically linked to calcium channels in the adjacent SR membrane called ryanadine receptors (RyR).  Through the DHPR, the action potential in the sarcolemma triggers the opening of RyR, allowing Ca++ to diffuse out of the SR and into the sarcoplasm. It is the arrival of Ca++ in the sarcoplasm that allows for the binding of actin and myosin and thus initiates contraction and shortening of sarcomeres.",True,Excitation-Contraction Coupling,,,,
+91663431-8cec-45e8-99f8-ec5f5a379780,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,Sources of ATP,False,Sources of ATP,,,,
+2c5b3336-dd1f-4c24-a82f-1feef1766b15,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,Contraction and Relaxation,False,Contraction and Relaxation,,,,
+7860dd9c-4646-4865-bd61-ca1422f51115,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"The sequence of events that result in the contraction of an individual muscle fiber begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fiber. The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR). The Ca++ then initiates contraction, which is sustained by ATP (Figure 10.3.5). As long as Ca++ ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites “unshielded,” and as long as ATP is available to drive the cross-bridge cycling and the pulling of actin strands by myosin, the muscle fiber will continue to shorten to an anatomical limit.",True,Contraction and Relaxation,Figure 10.3.5,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/app/uploads/sites/157/2021/02/1010a_Contraction-and-Relaxation-1024x751.png,"Figure 10.3.5 – Contraction of a Muscle Fiber: A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten. Relaxation of a Muscle Fiber: Ca++ ions are pumped back into the SR, which causes the tropomyosin to reshield the binding sites on the actin strands. A muscle may also stop contracting when it runs out of ATP and becomes fatigued."
+14076bc4-cc3e-4070-9a07-6d1bade5b878,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Muscle contraction usually stops when signaling from the motor neuron ends, which repolarizes the sarcolemma and T-tubules, and closes the calcium channels in the SR. Ca++ ions are then pumped back into the SR, which causes the tropomyosin to re-cover the binding sites on actin (Figure 10.3.2).",True,Contraction and Relaxation,Figure 10.3.2,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/app/uploads/sites/157/2021/02/1023_T-tubule.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them."
+ba7ee1a5-2199-4fb1-936d-038e43b3b37c,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,Relaxation of a Skeletal Muscle,False,Relaxation of a Skeletal Muscle,,,,
+de356928-af54-4d7f-b0be-0772fba73f66,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"Relaxing skeletal muscle fibers, and ultimately, the skeletal muscle, begins with the motor neuron, which stops releasing its chemical signal, ACh, into the synapse at the NMJ. The muscle fiber will repolarize, which closes the gates in the SR where Ca++ was being released. ATP-driven pumps will move Ca++ out of the sarcoplasm back into the SR. This results in the “reshielding” of the actin-binding sites on the thin filaments. Without the ability to form cross-bridges between the thin and thick filaments, the muscle fiber loses its tension and relaxes.",True,Relaxation of a Skeletal Muscle,,,,
+6e8469c0-9bce-4b30-9a58-28c49ed2b40c,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,Muscle Strength,False,Muscle Strength,,,,
+ffee369e-025d-4ab2-84fb-bf63784c1bc9,https://open.oregonstate.education/aandp/,"10.3 Muscle Fiber Excitation, Contraction, and Relaxation",https://open.oregonstate.education/aandp/chapter/10-3-muscle-fiber-excitation-contraction-and-relaxation/,"The number of skeletal muscle fibers in a given muscle is genetically determined and does not change. Muscle strength is directly related to the amount of myofibrils and sarcomeres within each fiber. Factors, such as hormones and stress (and artificial anabolic steroids), acting on the muscle can increase the production of sarcomeres and myofibrils within the muscle fibers, a change called hypertrophy, which results in the increased mass and bulk in a skeletal muscle. Likewise, decreased use of a skeletal muscle results in atrophy, where the number of sarcomeres and myofibrils disappear (but not the number of muscle fibers). It is common for a limb in a cast to show atrophied muscles when the cast is removed, and certain diseases, such as polio, show atrophied muscles.",True,Muscle Strength,,,,
+50e165f4-aeea-4b4c-adc6-56aee9a55e8b,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Each skeletal muscle is an organ that consists of various integrated tissues. These tissues include the skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue. Each skeletal muscle has three layers of connective tissue (called mysia) that enclose it, provide structure to the muscle, and compartmentalize the muscle fibers within the muscle (Figure 10.2.1). Each muscle is wrapped in a sheath of dense, irregular connective tissue called the epimysium, which allows a muscle to contract and move powerfully while maintaining its structural integrity. The epimysium also separates muscle from other tissues and organs in the area, allowing the muscle to move independently.",True,Muscle Strength,Figure 10.2.1,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2019/07/1001_Muscle_Tissue_revised.png,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium."
+038727e5-093f-425f-8b8a-c7e7d7f34145,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, surrounded by a middle layer of connective tissue called the perimysium. This fascicular organization is common in muscles of the limbs; it allows the nervous system to trigger a specific movement of a muscle by activating a subset of muscle fibers within a fascicle of the muscle. Inside each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular fibers called the endomysium. The endomysium surrounds the extracellular matrix of the cells and plays a role in transferring force produced by the muscle fibers to the tendons.",True,Muscle Strength,,,,
+e4e68d03-03ba-42b5-8930-1282a8c96792,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"In skeletal muscles that work with tendons to pull on bones, the collagen in the three connective tissue layers intertwines with the collagen of a tendon. At the other end of the tendon, it fuses with the periosteum coating the bone. The tension created by contraction of the muscle fibers is then transferred though the connective tissue layers, to the tendon, and then to the periosteum to pull on the bone for movement of the skeleton. In other places, the mysia may fuse with a broad, tendon-like sheet called an aponeurosis, or to fascia, the connective tissue between skin and bones. The broad sheet of connective tissue in the lower back that the latissimus dorsi muscles (the “lats”) fuse into is an example of an aponeurosis.",True,Muscle Strength,,,,
+996ede2a-7ae9-450a-a6eb-7bcdec4684f9,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Every skeletal muscle is also richly supplied by blood vessels for nourishment, oxygen delivery, and waste removal. In addition, every muscle fiber in a skeletal muscle is supplied by the axon branch of a somatic motor neuron, which signals the fiber to contract. Unlike cardiac and smooth muscle, the only way to functionally contract a skeletal muscle is through signaling from the nervous system.",True,Muscle Strength,,,,
+1f70cefd-d54d-4f18-a7d2-f8206835b142,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,Skeletal Muscle Fibers,False,Skeletal Muscle Fibers,,,,
+926e255d-353c-4760-aad9-2fd0b112943f,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Because skeletal muscle cells are long and cylindrical, they are commonly referred to as muscle fibers (or myofibers). Skeletal muscle fibers can be quite large compared to other cells, with diameters up to 100 μm and lengths up to 30 cm (11.8 in) in the Sartorius of the upper leg. Having many nuclei allows for production of the large amounts of proteins and enzymes needed for maintaining normal function of these large protein dense cells.  In addition to nuclei, skeletal muscle fibers also contain cellular organelles found in other cells, such as mitochondria and endoplasmic reticulum.  However, some of these structures are specialized in muscle fibers.  The specialized smooth endoplasmic reticulum, called the sarcoplasmic reticulum (SR), stores, releases, and retrieves calcium ions (Ca++).",True,Skeletal Muscle Fibers,,,,
+884363d1-4dbf-4215-be36-e931835f641e,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"The plasma membrane of muscle fibers is called the sarcolemma (from the Greek sarco, which means “flesh”) and the cytoplasm is referred to as sarcoplasm (Figure 10.2.2). Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 μm in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber.  The sarcomere is the smallest functional unit of a skeletal muscle fiber and is a highly organized arrangement of contractile, regulatory, and structural proteins. It is the shortening of these individual sarcomeres that lead to the contraction of individual skeletal muscle fibers (and ultimately the whole muscle).",True,Skeletal Muscle Fibers,Figure 10.2.2,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+635ddbe1-c6b3-4dad-8b7e-b836cce466bb,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,The Sarcomere,False,The Sarcomere,,,,
+c192b758-f9f2-4392-9710-1d83ead9624f,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"A sarcomere is defined as the region of a myofibril contained between two cytoskeletal structures called Z-discs (also called Z-lines or Z-bands), and the striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere (Figure 10.2.2).  The dark striated A band is composed of the thick filaments containing myosin, which span the center of the sarcomere extending toward the Z-dics.  The thick filaments are anchored at the middle of the sarcomere (the M-line) by a protein called myomesin.  The lighter I band regions contain thin actin filaments anchored at the Z-discs by a protein called α-actinin.  The thin filaments extend into the A band toward the M-line and overlap with regions of the thick filament.  The A band is dark because of the thicker myosin filaments as well as overlap with the actin filaments. The H zone in the middle of the A band is a little lighter in color because it only contain the portion of the thick filaments that does not overlap with the thin filaments (i.e. the thin filaments do not extend into the H zone).",True,The Sarcomere,Figure 10.2.2,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+6612eb2b-9404-4925-bb02-ab85c82e4b13,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Because a sarcomere is defined by Z-discs, a single sarcomere contains one dark A band with half of the lighter I band on each end (Figure 10.2.2).  During contraction the myofilaments themselves do not change length, but actually slide across each other so the distance between the Z-discs shortens resulting in the shortening of the sarcomere. The length of the A band does not change (the thick myosin filament remains a constant length), but the H zone and I band regions shrink.  These regions represent areas where the filaments do not overlap, and as filament overlap increases during contraction these regions of no overlap decrease.",True,The Sarcomere,Figure 10.2.2,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+33f9062e-18a0-4fef-8c24-cc052bab4744,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"The thin filaments are composed of two filamentous actin chains (F-actin) comprised of individual actin proteins (Figure 10.2.3).  These thin filaments are anchored at the Z-disc and extend toward the center of the sarcomere.  Within the filament, each globular actin monomer (G-actin) contains a myosin binding site and is also associated with the regulatory proteins, troponin and tropomyosin.  The troponin protein complex consists of three polypeptides.  Troponin I (TnI) binds to actin, troponin T (TnT) binds to tropomyosin, and troponin C (TnC) binds to calcium ions.  Troponin and tropomyosin run along the actin filaments and control when the actin binding sites will be exposed for binding to myosin.",True,The Sarcomere,Figure 10.2.3,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1003_Thick_and_Thin_Filaments_revised.png,"Figure 10.2.3 – The Sarcomere: The sarcomere, the region from one Z-disc to the next Z-disc, is the functional unit of a skeletal muscle fiber."
+f23f1a7f-a7a8-4470-9c68-294886aa6a70,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Thick myofilaments are composed of myosin protein complexes, which are composed of six proteins: two myosin heavy chains and four light chain molecules.  The heavy chains consist of a tail region, flexible hinge region, and globular head which contains an Actin-binding site and a binding site for the high energy molecule ATP.  The light chains play a regulatory role at the hinge region, but the heavy chain head region interacts with actin and is the most important factor for generating force.  Hundreds of myosin proteins are arranged into each thick filament with tails toward the M-line and heads extending toward the Z-discs.",True,The Sarcomere,,,,
+793ac47b-20e5-41f1-9342-caba34e94a62,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"Other structural proteins are associated with the sarcomere but do not play a direct role in active force production.  Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere.  Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc.  The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments.",True,The Sarcomere,,,,
+60ad84ec-1982-495e-8144-170ad63e5483,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,The Sliding Filament Model of Contraction,False,The Sliding Filament Model of Contraction,,,,
+38c4b674-1ccc-46f6-9f4b-60306ffc4833,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"The arrangement and interactions between thin and thick filaments allows for the sarcomeres to generates force. When signaled by a motor neuron, a skeletal muscle fiber is activated. Cross bridges form between the thick and thin filaments and the thin filaments are pulled which slide past the thick filaments within the fiber’s sarcomeres. It is important to note that while the sarcomere shortens, the individual proteins and filaments do not change length but simply slide next to each other. This process is known as the sliding filament model of muscle contraction (Figure 10.2.4).",True,The Sliding Filament Model of Contraction,Figure 10.2.4,10.2 Skeletal Muscle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.2.4-replacement.png,"Figure 10.2.4 – The Sliding Filament Model of Muscle Contraction: When a sarcomere shortens, the Z-discs move closer together, and the I band becomes smaller. The A band stays the same width. At full contraction, the thin and thick filaments have the most amount of overlap."
+39d0edf5-da75-447c-badc-dc438a044fca,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,"The filament sliding process of contraction can only occur when myosin-binding sites on the actin filaments are exposed by a series of steps that begins with Ca++ entry into the sarcoplasm.  Tropomyosin winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The troponin-tropomyosin complex uses calcium ion binding to TnC to regulate when the myosin heads form cross-bridges to the actin filaments.  Cross-bridge formation and filament sliding will occur when calcium is present, and the signaling process leading to calcium release and muscle contraction is known as Excitation-Contraction Coupling.",True,The Sliding Filament Model of Contraction,,,,
+90ce172a-b5f2-4cd1-92df-63af849c496e,https://open.oregonstate.education/aandp/,10.2 Skeletal Muscle,https://open.oregonstate.education/aandp/chapter/10-2-skeletal-muscle/,Answers for Critical Thinking Questions,False,Answers for Critical Thinking Questions,,,,
+535b8abb-5a6e-4c96-a28d-2f4f781a63c4,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"Describe structural and functional differences of skeletal, cardiac, and smooth muscle tissue",True,Answers for Critical Thinking Questions,,,,
+1b4d95d8-5492-46db-aad8-a65c586e4233,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"Muscle is one of the four primary tissue types of the body (along with epithelial, nervous, and connective tissues), and the body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle (Figure 10.1.1). All three muscle tissues have some properties in common; they all exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane. While the nervous system can influence the excitability of cardiac and smooth muscle to some degree, skeletal muscle completely depends on signaling from the nervous system to work properly. On the other hand, both cardiac muscle and smooth muscle can respond to other stimuli, such as hormones and local stimuli.",True,Answers for Critical Thinking Questions,Figure 10.1.1,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.1.1.-replacement.png,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+069a73e3-7426-4a39-9941-c2f6e90737f2,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"A unique property common to all three types of muscle is contractility, which is the ability of the cells to shorten and generate force.  While muscle tissue can shorten with contractions, it also displays extensibility or the ability to stretch and extend beyond the resting length of the cells.  After being stretched, the elasticity of muscle allows it to recoil back to its original length.",True,Answers for Critical Thinking Questions,,,,
+74637967-9cc6-445c-b01c-1083803def1b,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"The muscles all begin the mechanical process of contracting (shortening) when a protein called actin is pulled by a protein called myosin, and differences in the microscopic organization of these contractile proteins exist among the three muscle types.  In both skeletal and cardiac muscle, the actin and myosin proteins are arranged very regularly in the cytoplasm of individual muscle cells, which creates an alternating light and dark striped pattern called striations. The striations are visible with a light microscope under high magnification (see Figure 10.1.1).  Smooth muscle (named for it’s lack of striations), does not produce this striped pattern because the contractile proteins are not arranged in such regular fashion.",True,Answers for Critical Thinking Questions,Figure 10.1.1,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.1.1.-replacement.png,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+4eaded9d-9d7d-4c33-b204-2507c8b91b08,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"Skeletal muscle cells (also called muscle fibers) are unique in that they are multinucleated with the nuclei located on the periphery of the cell under the cell plasma membrane (also called sarcolemma in muscle).  During early development, embryonic myoblasts, each with its own nucleus, fuse with hundreds of other myoblasts to form long multinucleated skeletal muscle fibers. Cardiac muscle cells each generally have one nucleus centrally located in the cell, but the cells are physically and electrically connected to each other so that the contraction signals spread through cells and the entire heart contracts as one unit.  Smooth muscle cells contain a single nucleus and can exist in electrically linked units contracting together as a single-unit or as multi-unit smooth muscle where cells are not electrically linked.",True,Answers for Critical Thinking Questions,,,,
+83607dca-c2a9-41f7-bd6e-f99a9c2c0954,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"The best-known feature of skeletal muscle is its ability to contract and cause movement. Skeletal muscles act not only to produce movement but also to stop movement, such as resisting gravity to maintain posture. Small, constant adjustments of the skeletal muscles are needed to hold a body upright or balanced in any position. Muscles also prevent excess movement of the bones and joints, maintaining skeletal stability and preventing skeletal structure damage or deformation.  Skeletal muscles are located throughout the body at the openings of internal tracts to control the movement of various substances. These muscles allow functions, such as swallowing, urination, and defecation, to be under voluntary control. Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external barrier or shield to external trauma and by supporting the weight of the organs.",True,Answers for Critical Thinking Questions,,,,
+b8d405e5-666f-400c-b736-9f516acb3e36,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"Skeletal muscles contribute to the maintenance of homeostasis in the body by generating heat. Muscle contraction requires energy, and when ATP is broken down, heat is produced. This heat is very noticeable during exercise, when sustained muscle movement causes body temperature to rise, and in cases of extreme cold, when shivering produces random skeletal muscle contractions to generate heat.",True,Answers for Critical Thinking Questions,,,,
+981a9036-67c6-4a72-a4c0-44e6778734ed,https://open.oregonstate.education/aandp/,10.1 Overview of Muscle Tissues,https://open.oregonstate.education/aandp/chapter/10-1-overview-of-muscle-tissues/,"Cardiac muscle is only found in the heart and functions to generate force and build pressure gradients to drive blood flow throughout the body. Smooth muscle in the walls of arteries is a critical component that regulates blood pressure and blood flow through the circulatory system.  Smooth muscle in the skin, visceral organs, and internal passageways is also essential for moving materials through the body. Neither cardiac nor smooth muscle connect to bone and therefore they cannot produce the gross movements we associate with skeletal muscle.",True,Answers for Critical Thinking Questions,,,,
+d86919ae-8f74-4ed3-98ed-fdfe9173e989,https://open.oregonstate.education/aandp/,10.0 Introduction,https://open.oregonstate.education/aandp/chapter/10-0-introduction/,"When most people think of muscles, they think of the muscles that are visible just under the skin, particularly of the limbs. These are skeletal muscles, so-named because most of them move the skeleton. But there are two other types of muscle in the body, with distinctly different jobs. Cardiac muscle, found in the heart, is concerned with pumping blood through the circulatory system. Smooth muscle is concerned with various involuntary movements, such as having one’s hair stand on end when cold or frightened, or moving food through the digestive system. This chapter will examine the structure and function of these three types of muscles.",True,Answers for Critical Thinking Questions,,,,
+deb68e56-fd37-4dd2-bbc0-de0fd6b0cc3e,https://open.oregonstate.education/aandp/,9.7 Development of Joints,https://open.oregonstate.education/aandp/chapter/9-7-development-of-joints/,Explain the development of body joints,False,Explain the development of body joints,,,,
+5a1483e2-6991-4dfe-a2f6-aec9032dd968,https://open.oregonstate.education/aandp/,9.7 Development of Joints,https://open.oregonstate.education/aandp/chapter/9-7-development-of-joints/,"Joints form during embryonic development in conjunction with the formation and growth of the associated bones. The embryonic tissue that gives rise to all bones, cartilages, and connective tissues of the body is called mesenchyme. In the head, mesenchyme will accumulate at those areas that will become the bones that form the top and sides of the skull. The mesenchyme in these areas will develop directly into bone through the process of intramembranous ossification, in which mesenchymal cells differentiate into bone-producing cells that then generate bone tissue. The mesenchyme between the areas of bone production will become the fibrous connective tissue that fills the spaces between the developing bones. Initially, the connective tissue-filled gaps between the bones are wide, and are called fontanelles. After birth, as the skull bones grow and enlarge, the gaps between them decrease in width and the fontanelles are reduced to suture joints in which the bones are united by a narrow layer of fibrous connective tissue.",True,Explain the development of body joints,,,,
+4f64f84c-6ed4-409a-aac6-00916a3acfdb,https://open.oregonstate.education/aandp/,9.7 Development of Joints,https://open.oregonstate.education/aandp/chapter/9-7-development-of-joints/,"The bones that form the base and facial regions of the skull develop through the process of endochondral ossification. In this process, mesenchyme accumulates and differentiates into hyaline cartilage, which forms a model of the future bone. The hyaline cartilage model is then gradually, over a period of many years, displaced by bone. The mesenchyme between these developing bones becomes the fibrous connective tissue of the suture joints between the bones in these regions of the skull.",True,Explain the development of body joints,,,,
+5a5e2091-b024-4982-87aa-c61233e0a416,https://open.oregonstate.education/aandp/,9.7 Development of Joints,https://open.oregonstate.education/aandp/chapter/9-7-development-of-joints/,"A similar process of endochondral ossification gives rises to the bones and joints of the limbs. The limbs initially develop as small limb buds that appear on the sides of the embryo around the end of the fourth week of development. Starting during the sixth week, as each limb bud continues to grow and elongate, areas of mesenchyme within the bud begin to differentiate into the hyaline cartilage that will form models for of each of the future bones. The synovial joints will form between the adjacent cartilage models, in an area called the joint interzone. Cells at the center of this interzone region undergo cell death to form the joint cavity, while surrounding mesenchyme cells will form the articular capsule and supporting ligaments. The process of endochondral ossification, which converts the cartilage models into bone, begins by the twelfth week of embryonic development. At birth, ossification of much of the bone has occurred, but the hyaline cartilage of the epiphyseal plate will remain throughout childhood and adolescence to allow for bone lengthening. Hyaline cartilage is also retained as the articular cartilage that covers the surfaces of the bones at synovial joints.",True,Explain the development of body joints,,,,
+be23c55b-bca9-4c76-856a-cd7c71d00808,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Discuss the structure of specific body joints and the movements allowed by each,True,Explain the development of body joints,,,,
+6b8b09eb-f7d9-485c-9b4e-5e09d31f4916,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Each synovial joint of the body is specialized to perform certain movements. The movements that are allowed are determined by the structural classification for each joint. For example, a multiaxial ball-and-socket joint is capable of more actions than a uniaxial hinge joint. However, the ligaments and muscles that support a joint may place restrictions on the total range of motion available. The ball-and-socket joint of the shoulder has little in the way of ligament support, which gives the shoulder a very large range of motion. In contrast, movements at the hip joint are restricted by tight ligaments, which reduce its range of motion but confer stability during standing and weight bearing.",True,Explain the development of body joints,,,,
+c3fbd21f-0f99-46f4-ac16-c8436e90778b,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"This section will examine the anatomy of selected synovial joints of the body. Anatomical names for most joints are derived from the names of the bones that articulate at that joint, although some joints, such as the elbow, hip, and knee joints are exceptions to this general naming scheme.",True,Explain the development of body joints,,,,
+5f7ece5e-8e5c-4f9b-967e-efa1a0f462c0,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Articulations of the Vertebral Column,False,Articulations of the Vertebral Column,,,,
+c1454f9a-293a-4f2d-9ca6-8899b939ad27,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"In addition to being held together by symphyses at the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called zygapophysial joints (facet joints) (see Chapter 9.1 Figure 9.1.2). These are plane joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the range of motion available in each vertebral region; the cervical and lumbar regions have the greatest ranges of motions.",True,Articulations of the Vertebral Column,Figure 9.1.2,9.1 Classification of Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/902_Intervertebral_Disk-02.jpg,Figure 9.1.2 – Intervertebral Disc: An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint.
+30debed4-82d2-48c0-9b93-c5b4fe9ff8d2,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"In the neck, the articular processes of cervical vertebrae are flattened and generally face upward or downward. This orientation provides the cervical vertebral column with extensive ranges of motion for flexion, extension, lateral flexion, and rotation. In the thoracic region, the downward projecting and overlapping spinous processes, along with the attached thoracic cage, greatly limit flexion, extension, and lateral flexion. However, the flattened and vertically positioned thoracic articular processes allow for the greatest range of rotation within the vertebral column. The lumbar region allows for considerable extension, flexion, and lateral flexion, but the orientation of the articular processes largely prohibits rotation.",True,Articulations of the Vertebral Column,,,,
+e34a6d4e-263b-452f-910b-970956f8a5ba,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The articulations formed between the skull, the atlas (C1 vertebra), and the axis (C2 vertebra) differ from the articulations in other vertebral areas and play important roles in movement of the head. The atlanto-occipital joint is formed by the articulations between the superior articular processes of the atlas and the occipital condyles on the base of the skull. This articulation has a pronounced U-shaped curvature, oriented along the anterior-posterior axis. This allows the skull to rock forward and backward, producing flexion and extension of the head. This moves the head up and down, as when shaking your head “yes.”",True,Articulations of the Vertebral Column,,,,
+e5c8bf6d-2d1a-4e09-9ad0-4c46b539ff61,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The atlantoaxial joint, between the atlas and axis, consists of three articulations. The paired superior articular processes of the axis articulate with the inferior articular processes of the atlas. These articulating surfaces are relatively flat and oriented horizontally. The third articulation is the pivot joint formed between the dens, which projects upward from the body of the axis, and the inner aspect of the anterior arch of the atlas (Figure 9.6.1). A strong ligament passes posterior to the dens to hold it in position against the anterior arch. These articulations allow the atlas to rotate on top of the axis, moving the head toward the right or left, as when shaking your head “no.”",True,Articulations of the Vertebral Column,Figure 9.6.1,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/912_Atlantoaxial_Joint.jpg,"Figure 9.6.1 – Atlantoaxial Joint: The atlantoaxial joint is a pivot type of joint between the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament."
+663de1b1-afc4-4325-8efc-975f5a352f19,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Temporomandibular Joint,False,Temporomandibular Joint,,,,
+ff16de58-6fc1-4688-bd50-9a8b7e23aeaa,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The temporomandibular joint (TMJ) is the modified hinge joint that allows for mandibular depression and elevation, as well as excursion, and protraction/retraction of the lower jaw. This joint involves the articulation between the mandibular fossa and articular tubercle of the temporal bone, with the condyle (head) of the mandible. Located between these bony structures, filling the gap between the skull and mandible, is a flexible articular disc (Figure 9.6.2). This disc serves to smooth the movements between the temporal bone and mandibular condyle.",True,Temporomandibular Joint,Figure 9.6.2,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/913_Tempomandibular_Joint.jpg,"Figure 9.6.2 – Temporomandibular Joint: The temporomandibular joint is the articulation between the temporal bone of the skull and the condyle of the mandible, with an articular disc located between these bones. During depression of the mandible (opening of the mouth), the mandibular condyle moves both forward and hinges downward as it travels from the mandibular fossa onto the articular tubercle."
+8fbdf673-f4ca-4104-8438-b2c34eed900d,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Movement at the TMJ during opening and closing of the mouth involves both gliding and hinge motions of the mandible. With the mouth closed, the mandibular condyle and articular disc are located within the mandibular fossa of the temporal bone. During opening of the mouth, the mandible hinges downward and at the same time is pulled anteriorly, causing both the condyle and the articular disc to glide forward from the mandibular fossa onto the downward projecting articular tubercle. The net result is a forward and downward motion of the condyle and mandibular depression. The temporomandibular joint is supported by an extrinsic ligament that anchors the mandible to the skull.",True,Temporomandibular Joint,,,,
+152005ef-d95c-4819-92c5-f017e07cbe7f,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Dislocation of the TMJ may occur when opening the mouth too wide (such as when taking a large bite) or following a blow to the jaw, resulting in the mandibular condyle moving beyond (anterior to) the articular tubercle. In this case, the individual would not be able to close his or her mouth. Temporomandibular joint disorder is a painful condition that may arise due to arthritis, wearing of the articular cartilage covering the bony surfaces of the joint, muscle fatigue from overuse or grinding of the teeth, damage to the articular disc within the joint, or jaw injury. Temporomandibular joint disorders can also cause headache, difficulty chewing, or even the inability to move the jaw (lock jaw). Pharmacologic agents for pain or other therapies, including bite guards, are used as treatments.",True,Temporomandibular Joint,,,,
+c06087ad-bd3e-45a8-9a02-6c61a20024f3,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Shoulder Joint,False,Shoulder Joint,,,,
+031a95c0-d797-4849-8ddf-463c4af73eae,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The shoulder joint is called the glenohumeral joint. This is a ball-and-socket joint formed by the articulation between the head of the humerus and the glenoid cavity of the scapula (Figure 9.6.3). This joint has the largest range of motion of any joint in the body. However, this freedom of movement is due to the minimal structural support and thus the enhanced mobility is offset by a loss of stability.",True,Shoulder Joint,Figure 9.6.3,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0914_Shoulder_Joint_revised-1024x757.png,Figure 9.6.3 – Glenohumeral Joint: The glenohumeral (shoulder) joint is a ball-and-socket joint that provides the widest range of motions. It has a loose articular capsule and is supported by ligaments and the rotator cuff muscles.
+228256f0-1da1-4e85-9dda-1b88453ae0b0,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The large range of motions at the shoulder joint is provided by the articulation of the large, rounded humeral head with the small and shallow glenoid cavity, which is only about one third of the size of the humeral head. The socket formed by the glenoid cavity is deepened slightly by a small lip of fibrocartilage called the glenoid labrum, which extends around the outer margin of the cavity. The articular capsule that surrounds the glenohumeral joint is relatively thin and loose to allow for large motions of the upper limb. Some structural support for the joint is provided by thickenings of the articular capsule wall that form weak intrinsic ligaments. These include the coracohumeral ligament, running from the coracoid process of the scapula to the anterior humerus, and three ligaments, each called a glenohumeral ligament, located on the anterior side of the articular capsule. These ligaments help to strengthen the superior and anterior capsule walls.",True,Shoulder Joint,,,,
+779d48b6-8099-4811-92b2-577750548f40,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"However, the primary support for the shoulder joint is provided by muscles crossing the joint, particularly the four rotator cuff muscles. These muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) arise from the scapula and attach to the greater or lesser tubercles of the humerus. As these muscles cross the shoulder joint, their tendons encircle the head of the humerus and become fused to the anterior, superior, and posterior walls of the articular capsule. The thickening of the capsule formed by the fusion of these four muscle tendons is called the rotator cuff. Two bursae, the subacromial bursa and the subscapular bursa, help to prevent friction between the rotator cuff muscle tendons and the scapula as these tendons cross the glenohumeral joint. In addition to their individual actions of moving the upper limb, the rotator cuff muscles also serve to hold the head of the humerus in position within the glenoid cavity. By constantly adjusting their strength of contraction to resist forces acting on the shoulder, these muscles serve as “dynamic ligaments” and thus provide the primary structural support for the glenohumeral joint.",True,Shoulder Joint,,,,
+5815042a-a163-4e85-aa1f-69a2d799b8a0,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Injuries to the shoulder joint are common. Repetitive use of the upper limb, particularly in abduction such as during throwing, swimming, or racquet sports, may lead to acute or chronic inflammation of the bursa or muscle tendons, a tear of the glenoid labrum, or degeneration or tears of the rotator cuff. Because the humeral head is strongly supported by the biceps brachii anteriorly, the acromion process of the scapula superiorly, and other tendons and ligaments on the anterior, superior and posterior aspects, most dislocations of the humerus occur in an inferior direction. This can occur when force is applied to the humerus when the upper limb is fully abducted, as when diving to catch a baseball and landing on your hand or elbow. Inflammatory responses to any shoulder injury can lead to the formation of scar tissue between the articular capsule and surrounding structures, thus reducing shoulder mobility, a condition called adhesive capsulitis (“frozen shoulder”).",True,Shoulder Joint,,,,
+a97c5be0-ba4a-4ded-a5f9-d96b6ada28c8,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Elbow Joint,False,Elbow Joint,,,,
+108a8810-0466-4ab8-8b30-15b0beb83b11,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The elbow joint is a uniaxial hinge joint formed by the humeroulnar joint, the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Also associated with the elbow are the humeroradial joint and the proximal radioulnar joint. All three of these joints are enclosed within a single articular capsule (Figure 9.6.4).",True,Elbow Joint,Figure 9.6.4,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0915_Elbow_Joint_revised-1024x842.png,"Figure 9.6.4 – Elbow Joint: (a) The elbow is a hinge joint that allows only for flexion and extension of the forearm. (b) It is supported by the ulnar and radial collateral ligaments. (c) The annular ligament supports the head of the radius at the proximal radioulnar joint, the pivot joint that allows for rotation of the radius"
+45228966-9c9f-4a82-bd0a-fbbc27f4c568,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The articular capsule of the elbow is thin on its anterior and posterior aspects, but is thickened along its outside margins by strong intrinsic ligaments. These ligaments prevent side-to-side movements and hyperextension. On the medial side is the triangular ulnar collateral ligament. This arises from the medial epicondyle of the humerus and attaches to the medial side of the proximal ulna. The strongest part of this ligament is the anterior portion, which resists hyperextension of the elbow. The ulnar collateral ligament may be injured by frequent, forceful extensions of the forearm, as is seen in baseball pitchers. Reconstructive surgical repair of this ligament is referred to as Tommy John surgery, named for the former major league pitcher who was the first person to have this treatment.",True,Elbow Joint,,,,
+c112b3c8-7730-4646-878d-79c894ebc164,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,The lateral side of the elbow is supported by the radial collateral ligament. This arises from the lateral epicondyle of the humerus and then blends into the lateral side of the annular ligament. The annular ligament encircles the head of the radius. This ligament supports the head of the radius as it articulates with the radial notch of the ulna at the proximal radioulnar joint. This is a pivot joint that allows for rotation of the radius during supination and pronation of the forearm.,True,Elbow Joint,,,,
+b02fb656-c9c7-4e9b-827b-2942661a2285,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Hip Joint,False,Hip Joint,,,,
+87fcdc42-017f-4ed5-b196-ba5a153f5836,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The hip joint is a multiaxial ball-and-socket joint between the head of the femur and the acetabulum of the hip bone (Figure 9.6.5). The hip carries the weight of the body and thus requires strength and stability during standing and walking. For these reasons, its range of motion is more limited than at the shoulder joint, though it is capable of  the same actions as the shoulder.",True,Hip Joint,Figure 9.6.5,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0916_Hip_Joint_revised-761x1024.png,"Figure 9.6.5 – Hip Joint: (a) The ball-and-socket joint of the hip is a multiaxial joint that provides both stability and a wide range of motion. (b–c) When standing, the supporting ligaments are tight, pulling the head of the femur into the acetabulum."
+c731536f-1719-4793-ac06-757a0bea57c1,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The acetabulum is the socket portion of the hip joint. This space is deep and has a large articulation area for the femoral head, thus giving stability and weight bearing ability to the joint. The acetabulum is further deepened by the acetabular labrum, a fibrocartilage lip attached to the outer margin of the acetabulum. The surrounding articular capsule is strong, with several thickened areas forming intrinsic ligaments. These ligaments arise from the hip bone, at the margins of the acetabulum, and attach to the femur at the base of the neck. The ligaments are the iliofemoral ligament, pubofemoral ligament, and ischiofemoral ligament, all of which spiral around the head and neck of the femur. The ligaments are tightened by extension at the hip, thus pulling the head of the femur tightly into the acetabulum when in the upright, standing position. Very little additional extension of the thigh is permitted beyond this vertical position. These ligaments thus stabilize the hip joint and allow you to maintain an upright standing position with only minimal muscle contraction. Inside of the articular capsule, the ligament of the head of the femur (ligamentum teres) spans between the acetabulum and femoral head. This intracapsular ligament is normally slack and does not provide any significant joint support, but it does provide a pathway for an important artery that supplies the head of the femur.",True,Hip Joint,,,,
+3102c917-130f-41ce-b657-2d3b147297b6,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The hip is prone to osteoarthritis, and thus was the first joint for which a replacement prosthesis was developed. A common injury in elderly individuals, particularly those with weakened bones due to osteoporosis, is a “broken hip,” which is actually a fracture of the femoral neck. This may result from a fall, or it may cause the fall. This can happen as one lower limb is taking a step and all of the body weight is placed on the other limb, causing the femoral neck to break and producing a fall. Any accompanying disruption of the blood supply to the femoral neck or head can lead to necrosis of these areas, resulting in bone and cartilage death. Femoral fractures usually require surgical treatment, after which the patient will need mobility assistance for a prolonged period. Consequentially, the associated health care costs of “broken hips” are substantial. In addition, hip fractures are associated with increased rates of morbidity (incidences of disease) and mortality (death). Surgery for a hip fracture followed by prolonged bed rest may lead to life-threatening complications, including pneumonia, infection of pressure ulcers (bedsores), and thrombophlebitis (deep vein thrombosis; blood clot formation) that can result in a pulmonary embolism (blood clot within the lung).",True,Hip Joint,,,,
+474f201f-6032-4a96-acb3-cca1e3ddda10,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Knee Joint,False,Knee Joint,,,,
+82ebe0b0-2067-4983-8f7e-502809d9c0a2,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The knee joint is the largest joint of the body (Figure 9.6.6). It actually consists of three articulations. The femoropatellar joint is found between the patella and the distal femur. The medial tibiofemoral joint and lateral tibiofemoral joint are located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a modified hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed, but not when fully extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.",True,Knee Joint,Figure 9.6.6,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+eeeb86bf-3572-47f7-965c-dbe33871bc0c,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"At the femoropatellar joint, the patella slides vertically within a groove on the distal femur. The patella is a sesamoid bone incorporated into the tendon of the quadriceps femoris group, which are four large muscles of the anterior thigh. The patella serves to protect the quadriceps tendon from friction against the distal femur. Continuing from the patella to the anterior tibia just below the knee is the patellar ligament. Acting via the patella and patellar ligament, the quadriceps are powerful muscles that act to extend the leg at the knee. It also serves as a “dynamic ligament” to provide very important support and stabilization for the knee joint.",True,Knee Joint,,,,
+d5dff95f-97aa-49a3-b31b-c8d21f50715c,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The medial and lateral tibiofemoral joints are the articulations between the rounded condyles of the femur and the relatively flat condyles of the tibia. During flexion and extension motions, the condyles of the femur both roll and glide over the surfaces of the tibia. The rolling action produces flexion or extension, while the gliding action serves to maintain the femoral condyles centered over the tibial condyles, thus ensuring maximal bony, weight-bearing support for the femur in all knee positions. As the knee comes into full extension, the femur undergoes a slight medial rotation in relation to tibia. The rotation results because the lateral condyle of the femur is slightly smaller than the medial condyle. Thus, the lateral condyle finishes its rolling motion first, followed by the medial condyle. The resulting small medial rotation of the femur serves to “lock” the knee into its fully extended and most stable position. Flexion of the knee is initiated by a slight lateral rotation of the femur on the tibia, which “unlocks” the knee. This lateral rotation motion is produced by the popliteus muscle of the posterior leg. This slight rotation of the knee is why it is referred to as a modified hinge, as opposed to a true hinge which is only capable of flexion and extension.",True,Knee Joint,,,,
+19dde259-82a2-4351-9254-51fdb43d000b,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Located between the articulating surfaces of the femur and tibia are two articular discs, the medial meniscus and lateral meniscus (see Figure 9.6.6b). Each is a C-shaped fibrocartilage structure that is thin along its inside margin and thick along the outer margin. They are attached to their tibial condyles, but do not attach to the femur. The menisci provide padding between the bones and help to fill the gap between the round femoral condyles and flattened tibial condyles. Some areas of each meniscus lack an arterial blood supply and thus these areas heal poorly if damaged.",True,Knee Joint,Figure 9.6.6,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+c8f5d53f-4fb4-4cd5-9bc3-537b22fe6e29,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The knee joint has multiple ligaments that provide support, particularly in the extended position (see Figure 9.6.6c). Outside of the articular capsule, located at the sides of the knee, are two extrinsic ligaments. The fibular collateral ligament (lateral collateral ligament) is on the lateral side and spans from the lateral epicondyle of the femur to the head of the fibula. The tibial collateral ligament (medial collateral ligament) of the medial knee runs from the medial epicondyle of the femur to the medial tibia. As it crosses the knee, the tibial collateral ligament is firmly attached on its internal surface to the articular capsule and to the medial meniscus, an important factor when considering knee injuries. In the fully extended knee position, both collateral ligaments are taut (tight), thus serving to stabilize and support the extended knee and preventing side-to-side or rotational motions between the femur and tibia.",True,Knee Joint,Figure 9.6.6,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+a3deb882-2b07-4873-96c2-155be31635dc,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The articular capsule of the posterior knee is thickened by intrinsic ligaments that help to resist knee hyperextension. Inside the knee are two intracapsular ligaments, the anterior cruciate ligament and posterior cruciate ligament. These ligaments are anchored inferiorly to the tibia at the intercondylar eminence, the roughened area between the tibial condyles. The cruciate ligaments are named for whether they are attached anteriorly or posteriorly to this tibial region. Each ligament runs diagonally upward to attach to the inner aspect of a femoral condyle. The cruciate ligaments are named for the X-shape formed as they pass each other (cruciate means “cross”). The posterior cruciate ligament is the stronger ligament. It serves to support the knee when it is flexed and weight bearing, as when walking downhill. In this position, the posterior cruciate ligament prevents the femur from sliding anteriorly off the top of the tibia. The anterior cruciate ligament becomes tight when the knee is extended, and thus resists hyperextension.",True,Knee Joint,,,,
+7ef1e0b8-0240-4c98-9e25-7f7a7db3974d,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,Ankle and Foot Joints,False,Ankle and Foot Joints,,,,
+0f0aeda9-8d5e-4887-8692-79fd4a6b9ba5,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"The ankle is formed by the talocrural joint (Figure 9.6.8). It consists of the articulations between the talus bone of the foot and the distal ends of the tibia and fibula of the leg (crural = “leg”). The superior aspect of the talus bone is square-shaped and has three areas of articulation. The top of the talus articulates with the inferior tibia. This is the portion of the ankle joint that carries the body weight between the leg and foot. The sides of the talus are firmly held in position by the articulations with the medial malleolus of the tibia and the lateral malleolus of the fibula, which prevent any side-to-side motion of the talus. The ankle is a true hinge joint that allows only for dorsiflexion and plantar flexion of the foot.",True,Ankle and Foot Joints,Figure 9.6.8,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/919_Ankle_Feet_Joints.jpg,"Figure 9.6.8 – Ankle Joint: The talocrural (ankle) joint is a uniaxial hinge joint that only allows for dorsiflexion or plantar flexion of the foot. Movements at the subtalar joint, between the talus and calcaneus bones, combined with motions at other intertarsal joints, enables eversion/inversion movements of the foot. Ligaments that unite the medial or lateral malleolus with the talus and calcaneus bones serve to support the talocrural joint and to resist excess eversion or inversion of the foot."
+4768773d-8999-4d44-a654-246d6abb14e7,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Additional joints between the tarsal bones of the posterior foot allow for the movements of foot inversion and eversion. Most important for these movements is the subtalar joint, located between the talus and calcaneus bones. The joints between the talus and navicular bones and the calcaneus and cuboid bones are also important contributors to these movements. All of the joints between tarsal bones are plane joints. Together, the small motions that take place at these joints all contribute to the production of inversion and eversion foot motions.",True,Ankle and Foot Joints,,,,
+acd5ee06-1222-4b2e-a58f-08da1d1461c7,https://open.oregonstate.education/aandp/,9.6 Anatomy of Selected Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-6-anatomy-of-selected-synovial-joints/,"Like the hinge joints of the elbow and knee, the talocrural joint of the ankle is supported by several strong ligaments located on the sides of the joint. These ligaments extend from the medial malleolus of the tibia or lateral malleolus of the fibula and anchor to the talus and calcaneus bones. Since they are located on the sides of the ankle joint, they allow for dorsiflexion and plantar flexion of the foot. They also prevent abnormal side-to-side and twisting movements of the talus and calcaneus bones during eversion and inversion of the foot. On the medial side is the broad deltoid ligament. The deltoid ligament supports the ankle joint and also resists excessive eversion of the foot. The lateral side of the ankle has several smaller ligaments. These include the anterior talofibular ligament and the posterior talofibular ligament, both of which span between the talus bone and the lateral malleolus of the fibula, and the calcaneofibular ligament, located between the calcaneus bone and fibula. These ligaments support the ankle and also resist excess inversion of the foot.",True,Ankle and Foot Joints,,,,
+442c5ce9-9e6a-4fe0-96c1-e1c3730ffd18,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Define and identify the different body movements,False,Define and identify the different body movements,,,,
+b54fedbf-dafd-4e64-a9f2-de08f2e7f5b9,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The degree and type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one directly opposing the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.5.1 as you go through this section.",True,Define and identify the different body movements,Figure 9.5.1,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+8d178411-ad0e-4e67-ad7a-a5826b56f206,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Flexion and Extension,False,Flexion and Extension,,,,
+09f72c4e-4abd-4867-95a7-468b082a41b6,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Flexion and extension are movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward. Lateral flexion is the bending of the neck or body toward the right or left side. These movements of the vertebral column involve both the symphysis joint formed by each intervertebral disc, as well as the plane type of synovial joint formed between the inferior articular processes of one vertebra and the superior articular processes of the next lower vertebra.",True,Flexion and Extension,,,,
+e034a39b-764c-42b5-86a0-205d9dd1885c,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"In the limbs, flexion decreases the angle between the bones (bending of the joint), while extension increases the angle and straightens the joint. For the upper limb, all anterior motions are flexion and all posterior motions are extension. These include anterior-posterior movements of the arm at the shoulder, the forearm at the elbow, the hand at the wrist, and the fingers at the metacarpophalangeal and interphalangeal joints. For the thumb, extension moves the thumb away from the palm of the hand, within the same plane as the palm, while flexion brings the thumb back against the index finger or into the palm. These motions take place at the first carpometacarpal joint. In the lower limb, bringing the thigh forward and upward is flexion at the hip joint, while any posterior-going motion of the thigh is extension. Note that extension of the thigh beyond the anatomical (standing) position is greatly limited by the ligaments that support the hip joint. Knee flexion is the bending of the knee to bring the foot toward the posterior thigh, and extension is the straightening of the knee. Flexion and extension movements are seen at the hinge, condyloid, saddle, and ball-and-socket joints of the limbs (see Figure 9.5.1a-d).",True,Flexion and Extension,Figure 9.5.1,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+abeb041e-ac9e-4fd5-b475-995a6c8b2433,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Hyperextension is the abnormal or excessive extension of a joint beyond its normal range of motion, thus resulting in injury. Similarly, hyperflexion is excessive flexion at a joint. Hyperextension injuries are common at hinge joints such as the knee or elbow. In cases of “whiplash” in which the head is suddenly moved backward and then forward, a patient may experience both hyperextension and hyperflexion of the cervical region.",True,Flexion and Extension,,,,
+d4c760ea-479d-4ed5-95e2-536d5ab17ebd,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Abduction and Adduction,False,Abduction and Adduction,,,,
+0bb7c08e-793b-4a8a-a434-4e45e4fa5dcc,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Abduction and adduction motions occur within the coronal plane and involve medial-lateral motions of the limbs, fingers, toes, or thumb. Abduction moves the limb laterally away from the midline of the body, while adduction is the opposing movement that brings the limb toward the body or across the midline. For example, abduction is raising the arm at the shoulder joint, moving it laterally away from the body, while adduction brings the arm down to the side of the body. Similarly, abduction and adduction at the wrist moves the hand away from or toward the midline of the body. Spreading the fingers or toes apart is also abduction, while bringing the fingers or toes together is adduction. For the thumb, abduction is the anterior movement that brings the thumb to a 90° perpendicular position, pointing straight out from the palm. Adduction moves the thumb back to the anatomical position, next to the index finger. Abduction and adduction movements are seen at condyloid, saddle, and ball-and-socket joints (see Figure 9.5.1e).",True,Abduction and Adduction,Figure 9.5.1,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+cdb47ba2-20a6-4f21-ac50-3ad046a0d410,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Circumduction,False,Circumduction,,,,
+8e3ea142-ccbb-41e5-badf-a36dc5d2e607,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Circumduction is the movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle. It involves the sequential combination of flexion, adduction, extension, and abduction at a joint. This type of motion is found at biaxial condyloid and saddle joints, and at multiaxial ball-and-sockets joints (see Figure 9.5.1e).",True,Circumduction,Figure 9.5.1,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+ed1fdcf2-b441-4a7d-8a75-b1e4bd73b662,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Rotation,False,Rotation,,,,
+8a75dbcb-42e3-4233-8a2d-18dd756aa6ed,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint. Rotation of the neck or body is the twisting movement produced by the summation of the small rotational movements available between adjacent vertebrae. At a pivot joint, one bone rotates in relation to another bone. This is a uniaxial joint, and thus rotation is the only motion allowed at a pivot joint. For example, at the atlantoaxial joint, the first cervical (C1) vertebra (atlas) rotates around the dens, the upward projection from the second cervical (C2) vertebra (axis). This allows the head to rotate from side to side as when shaking the head “no.” The proximal radioulnar joint is a pivot joint formed by the head of the radius and its articulation with the ulna. This joint allows for the radius to rotate along its length during pronation and supination movements of the forearm.",True,Rotation,,,,
+061c3599-4a25-4c5a-a2d6-bb222b4b15ee,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Rotation can also occur at the ball-and-socket joints of the shoulder and hip. Here, the humerus and femur rotate around their long axis, which moves the anterior surface of the arm or thigh either toward or away from the midline of the body. Movement that brings the anterior surface of the limb toward the midline of the body is called medial (internal) rotation. Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 9.5.1f). Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints.",True,Rotation,Figure 9.5.1,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+33f2d17d-d919-47e8-a0b2-54e16cd00b5b,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Supination and Pronation,False,Supination and Pronation,,,,
+193115a3-0d0a-4750-8e2d-0a3d449bf4dd,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Supination and pronation are movements of the forearm. In the anatomical position, the upper limb is held next to the body with the palm facing forward. This is the supinated position of the forearm. In this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape.",True,Supination and Pronation,,,,
+8b655d5d-9a06-4b66-8f51-bb253dd6f6dd,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Supination and pronation are the movements of the forearm that go between these two positions. Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position. This motion is produced by rotation of the radius at the proximal radioulnar joint, accompanied by movement of the radius at the distal radioulnar joint. The proximal radioulnar joint is a pivot joint that allows for rotation of the head of the radius. Because of the slight curvature of the shaft of the radius, this rotation causes the distal end of the radius to cross over the distal ulna at the distal radioulnar joint. This crossing over brings the radius and ulna into an X-shape position. Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position. It helps to remember that supination is the motion you use when scooping up soup with a spoon (see Figure 9.5.2g).",True,Supination and Pronation,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+54c1e649-292b-4370-9fd4-281492ec716b,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Dorsiflexion and Plantar Flexion,False,Dorsiflexion and Plantar Flexion,,,,
+c9169291-eb22-4ef7-acb0-4b5194f55f41,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint. Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion. These are the only movements available at the ankle joint (see Figure 9.5.2h).",True,Dorsiflexion and Plantar Flexion,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+b49ea74a-012c-4646-aaec-1f3a223c6b3f,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Inversion and Eversion,False,Inversion and Eversion,,,,
+edd85379-1849-47b4-bcfc-adba48a8ab39,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Inversion and eversion are complex movements that involve the multiple plane joints among the tarsal bones of the posterior foot (intertarsal joints) and thus are not motions that take place at the ankle joint. Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline. The foot has a greater range of inversion than eversion motion. These are important motions that help to stabilize the foot when walking or running on an uneven surface and aid in the quick side-to-side changes in direction used during active sports such as basketball, racquetball, or soccer (see Figure 9.5.2i).",True,Inversion and Eversion,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+d97b6554-3e7e-42be-8381-e5db4cf5508a,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Protraction and Retraction,False,Protraction and Retraction,,,,
+13d7460e-3500-4848-a40c-592817813782,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Protraction and retraction are anterior-posterior movements of the scapula or mandible. Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball. Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column. For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward. (See Figure 9.5.2j.)",True,Protraction and Retraction,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+8591d62b-51cf-43f1-95dd-1c2f9c5e67e8,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Depression and Elevation,False,Depression and Elevation,,,,
+f24d0f73-cf47-494d-beaa-61168957a776,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Depression and elevation are downward and upward movements of the scapula or mandible. The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders. Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (see Figure 9.5.2k).",True,Depression and Elevation,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+c11b7382-cd01-49c5-b5be-b94e6ccb046a,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Excursion,False,Excursion,,,,
+65244620-70fa-4a55-a5f4-c6491994dea7,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Excursion is the side to side movement of the mandible. Lateral excursion moves the mandible away from the midline, toward either the right or left side. Medial excursion returns the mandible to its resting position at the midline.",True,Excursion,,,,
+770c530d-dd1c-4438-9e2a-abbcb4d30730,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Superior Rotation and Inferior Rotation,False,Superior Rotation and Inferior Rotation,,,,
+caefbeb8-876b-4951-95a0-5c2312d8411f,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Superior and inferior rotation are movements of the scapula and are defined by the direction of movement of the glenoid cavity. These motions involve rotation of the scapula around a point inferior to the scapular spine and are produced by combinations of muscles acting on the scapula. During superior rotation, the glenoid cavity moves upward as the medial end of the scapular spine moves downward. This is a very important motion that contributes to upper limb abduction. Without superior rotation of the scapula, the greater tubercle of the humerus would hit the acromion of the scapula, thus preventing any abduction of the arm above shoulder height. Superior rotation of the scapula is thus required for full abduction of the upper limb. Superior rotation is also used without arm abduction when carrying a heavy load with your hand or on your shoulder. You can feel this rotation when you pick up a load, such as a heavy book bag and carry it on only one shoulder. To increase its weight-bearing support for the bag, the shoulder lifts as the scapula superiorly rotates. Inferior rotation occurs during limb adduction and involves the downward motion of the glenoid cavity with upward movement of the medial end of the scapular spine.",True,Superior Rotation and Inferior Rotation,,,,
+58b681b0-90ff-4424-b207-8776afcb05b3,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,Opposition and Reposition,False,Opposition and Reposition,,,,
+ffe49292-19b2-488b-a4e4-61de84b163e5,https://open.oregonstate.education/aandp/,9.5 Types of Body Movements,https://open.oregonstate.education/aandp/chapter/9-5-types-of-body-movements/,"Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. This movement is produced at the first carpometacarpal joint, which is a saddle joint formed between the trapezium carpal bone and the first metacarpal bone. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint. Returning the thumb to its anatomical position next to the index finger is called reposition (see Figure 9.5.2l).",True,Opposition and Reposition,Figure 9.5.2,9.5 Types of Body Movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+5b2b4445-9e5f-4c89-b35a-66dc5f558fd0,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Describe the characteristic features for synovial joints and give examples,False,Describe the characteristic features for synovial joints and give examples,,,,
+606c70ef-ae85-4f12-b4cc-66ba16f1431f,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Synovial joints are the most common type of joint in the body (Figure 9.4.1). A key structural characteristic for a synovial joint that is not seen at fibrous or cartilaginous joints is the presence of a joint cavity. This fluid-filled space is the site at which the articulating surfaces of the bones contact each other. At synovial joints, the articular surfaces of bones are covered with smooth articular cartilage. This gives the bones of a synovial joint the ability to move smoothly against each other, allowing for increased joint mobility.",True,Describe the characteristic features for synovial joints and give examples,Figure 9.4.1,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/907_Synovial_Joints.jpg,Figure 9.4.1 – Synovial Joints: Synovial joints allow for smooth movements between the adjacent bones. The joint is surrounded by an articular capsule that defines a joint cavity filled with synovial fluid. The articulating surfaces of the bones are covered by a thin layer of articular cartilage. Ligaments support the joint by holding the bones together and resisting excess or abnormal joint motions.
+055e345a-04c8-4589-922e-20ae1bed8bae,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Structural Features of Synovial Joints,False,Structural Features of Synovial Joints,,,,
+4e4eea7d-402a-4b3b-bd7d-5b35a10d469c,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Synovial joints are characterized by the presence of a joint cavity. The walls of this space are formed by the articular capsule, a fibrous connective tissue structure that is attached to each bone just outside the area of the bone’s articulating surface. The bones of the joint articulate with each other within the joint cavity.",True,Structural Features of Synovial Joints,,,,
+97086d51-f64c-4b4b-9795-0e9ef54aabcf,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Friction between the bones at a synovial joint is prevented by the presence of the articular cartilage, a thin layer of hyaline cartilage that covers the entire articulating surface of each bone. However, unlike at a cartilaginous joint, the articular cartilages of each bone are not continuous with each other. Instead, the articular cartilage acts like a Teflon® coating over the bone surface, allowing the articulating bones to move smoothly against each other without damaging the underlying bone tissue. Lining the inner surface of the articular capsule is a thin synovial membrane. The cells of this membrane secrete synovial fluid (synovia = “a thick fluid”), a thick, slimy fluid that provides lubrication to further reduce friction between the bones of the joint. This fluid also provides nourishment to the articular cartilage, which does not contain blood vessels. The ability of the bones to move smoothly against each other within the joint cavity, and the freedom of joint movement this provides, means that each synovial joint is functionally classified as a diarthrosis.",True,Structural Features of Synovial Joints,,,,
+441d7430-1b2d-4733-8625-3d3810709cf3,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Outside of their articulating surfaces, the bones are connected together by ligaments, which are strong bands of fibrous connective tissue. These strengthen and support the joint by anchoring the bones together and preventing their separation. Ligaments allow for normal movements at a joint, but limit the range of these motions, thus preventing excessive or abnormal joint movements. Ligaments are classified based on their relationship to the fibrous articular capsule. An extrinsic ligament is located outside of the articular capsule, an intrinsic ligament is fused to or incorporated into the wall of the articular capsule, and an intracapsular ligament is located inside of the articular capsule.",True,Structural Features of Synovial Joints,,,,
+5a72a52f-1fae-40fe-a6da-1e6757de6744,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"At many synovial joints, additional support is provided by the muscles and their tendons that act across the joint. A tendon is the dense connective tissue structure that attaches a muscle to bone. As forces acting on a joint increase, the body will automatically increase the overall strength of contraction of the muscles crossing that joint, thus allowing the muscle and its tendon to serve as a “dynamic ligament” to resist forces and support the joint. This type of indirect support by muscles is very important at the shoulder joint, for example, where the ligaments are relatively weak.",True,Structural Features of Synovial Joints,,,,
+7350e335-d7c5-4d5a-bf57-10421a4f49bf,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Additional Structures Associated with Synovial Joints,False,Additional Structures Associated with Synovial Joints,,,,
+b9583703-1799-4f7c-bb62-dd073f65f1d0,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"A few synovial joints of the body have a fibrocartilage structure located between the articulating bones. This is called an articular disc, which is generally small and oval-shaped, or a meniscus, which is larger and C-shaped. These structures can serve several functions, depending on the specific joint. In some places, an articular disc may act to strongly unite the bones of the joint to each other. Examples of this include the articular discs found at the sternoclavicular joint or between the distal ends of the radius and ulna bones. At other synovial joints, the disc can provide shock absorption and cushioning between the bones, which is the function of each meniscus within the knee joint. Finally, an articular disc can serve to smooth the movements between the articulating bones, as seen at the temporomandibular joint. Some synovial joints also have a fat pad, which can serve as a cushion between the bones.",True,Additional Structures Associated with Synovial Joints,,,,
+ec912e68-0731-498b-8b49-a24cd76a3ae0,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Additional structures located outside of a synovial joint serve to prevent friction between the bones of the joint and the overlying muscle tendons or skin. A bursa (plural = bursae) is a thin connective tissue sac filled with lubricating liquid. They are located in regions where skin, ligaments, muscles, or muscle tendons can rub against each other, usually near a body joint (Figure 9.4.2). Bursae reduce friction by separating the adjacent structures, preventing them from rubbing directly against each other. Bursae are classified by their location. A subcutaneous bursa is located between the skin and an underlying bone. It allows skin to move smoothly over the bone. Examples include the prepatellar bursa located over the kneecap and the olecranon bursa at the tip of the elbow. A submuscular bursa is found between a muscle and an underlying bone, or between adjacent muscles. These prevent rubbing of the muscle during movements. A large submuscular bursa, the trochanteric bursa, is found at the lateral hip, between the greater trochanter of the femur and the overlying gluteus maximus muscle. A subtendinous bursa is found between a tendon and a bone. Examples include the subacromial bursa that protects the tendon of shoulder muscle as it passes under the acromion of the scapula, and the suprapatellar bursa that separates the tendon of the large anterior thigh muscle from the distal femur just above the knee.",True,Additional Structures Associated with Synovial Joints,Figure 9.4.2,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/908_Bursa_revised-e1568231910936.png,"Figure 9.4.2 – Bursae: Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg"
+b24d79b4-0302-41ad-87f1-e40677ab4ed0,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"A tendon sheath is similar in structure to a bursa, but smaller. It is a connective tissue sac that surrounds a muscle tendon at places where the tendon crosses a joint. It contains a lubricating fluid that allows for smooth motions of the tendon during muscle contraction and joint movements.",True,Additional Structures Associated with Synovial Joints,,,,
+987b9a26-a543-4ff3-b36c-5446875065e4,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Types of Synovial Joints,False,Types of Synovial Joints,,,,
+c5caa4d6-97f5-4287-8934-f2cd47a2b040,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Synovial joints are subdivided based on the shapes of the articulating surfaces of the bones that form each joint. The six types of synovial joints are pivot, hinge, condyloid, saddle, plane, and ball-and socket-joints (Figure 9.4.3).",True,Types of Synovial Joints,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+6bd0f846-81fb-428c-9420-8b7f28b70db4,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Pivot Joint,False,Pivot Joint,,,,
+c12df6db-a815-47d7-9dc8-380de6510172,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (see Figure 9.4.3a). The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Here, the upward projecting dens of the axis articulates with the inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the radial notch of the ulna. Rotation of the radius allows for forearm movements.",True,Pivot Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+50266113-c010-401e-901d-3c901a7b51e3,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Hinge Joint,False,Hinge Joint,,,,
+866a2109-44e1-4c1d-88b4-603dac876cd9,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone (see Figure 9.4.3b). This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Other hinge joints of the body include the knee, ankle, and interphalangeal joints between the phalanges of the fingers and toes.",True,Hinge Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+e7fbe7fb-49fa-44cb-8570-4fb1e1c8e492,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Condyloid Joint,False,Condyloid Joint,,,,
+e406ecfc-3f3f-4fc6-8dc6-6f86fe203c64,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"At a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (see Figure 9.4.3e). The knuckle (metacarpophalangeal) joints of the hand between the distal end of a metacarpal bone and the proximal phalanx are condyloid joints. Another example is the radiocarpal joint of the wrist, between the shallow depression at the distal end of the radius bone and the rounded scaphoid, lunate, and triquetrum carpal bones. In this case, the articulation area has a more oval (elliptical) shape. Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial or lateral direction.",True,Condyloid Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+f0e11cdd-3d02-43d8-86cd-162440c58934,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Saddle Joint,False,Saddle Joint,,,,
+e0c0b690-db27-4122-bc0c-e126f425860d,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure 9.4.3c). This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb. This joint provides the thumb the ability to move away from the palm of the hand along two planes. Thus, the thumb can move within the same plane as the palm of the hand, or it can jut out anteriorly, perpendicular to the palm. This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. The sternoclavicular joint is also classified as a saddle joint.",True,Saddle Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+c3fb2eba-befa-44c8-a380-0462b97f7962,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Plane Joint,False,Plane Joint,,,,
+87587173-a70e-4e0e-af94-033ed46fe4d6,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other (see Figure 9.4.3d). The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation and can be functionally classified as a multiaxial joint. However, not all of these movements are available to every plane joint due to limitations placed on it by ligaments or neighboring bones. Depending upon the specific joint of the body, a plane joint may exhibit movement in a single plane or in multiple planes. Plane joints are found between the carpal bones (intercarpal joints) of the wrist or tarsal bones (intertarsal joints) of the foot, between the clavicle and acromion of the scapula (acromioclavicular joint), and between the superior and inferior articular processes of adjacent vertebrae (zygapophysial joints).",True,Plane Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+f4faf3d0-2a90-4a17-86a6-16a2d27d7181,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,Ball-and-Socket Joint,False,Ball-and-Socket Joint,,,,
+5567414a-7be0-4af0-9683-75b85b809a76,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone (see Figure 9.4.3f). The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula.",True,Ball-and-Socket Joint,Figure 9.4.3,9.4 Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+263409d4-f18d-4419-b36a-85941b614055,https://open.oregonstate.education/aandp/,9.4 Synovial Joints,https://open.oregonstate.education/aandp/chapter/9-4-synovial-joints/,"Ball-and-socket joints are classified functionally as multiaxial joints. The femur and the humerus are able to move in both anterior-posterior and medial-lateral directions and they can also rotate around their long axis. The shallow socket formed by the glenoid cavity allows the shoulder joint an extensive range of motion. In contrast, the deep socket of the acetabulum and the strong supporting ligaments of the hip joint serve to constrain movements of the femur, reflecting the need for stability and weight-bearing ability at the hip.",True,Ball-and-Socket Joint,,,,
+e940cbc5-cdef-45e8-94a0-56eee7c7f80f,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,Describe the characteristic features for fibrous joints and give examples,False,Describe the characteristic features for fibrous joints and give examples,,,,
+f52703d1-68c3-408b-a57a-61bd4693ffa6,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage (Figure 9.3.1). There are two types of cartilaginous joints. A synchondrosis is a cartilaginous joint where the bones are joined by hyaline cartilage, or where a bone is united to hyaline cartilage. The second type of cartilaginous joint is a symphysis, where the bones are joined by fibrocartilage.",True,Describe the characteristic features for fibrous joints and give examples,Figure 9.3.1,9.3 Cartilaginous Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/906_Cartiliginous_Joints.jpg,"Figure 9.3.1 – Cartiliginous Joints: At cartilaginous joints, bones are united by hyaline cartilage to form a synchondrosis or by fibrocartilage to form a symphysis. (a) The hyaline cartilage of the epiphyseal plate (growth plate) forms a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length. (b) The pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage, forming the pubic symphysis."
+6e69829d-dd7f-435e-91a8-d30e46a6ba72,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,Synchondrosis,False,Synchondrosis,,,,
+629232fe-717c-4985-92d8-e0d8c7a23c3e,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"A synchondrosis (“joined by cartilage”) is a cartilaginous joint where bones are joined together by hyaline cartilage, or where bone is united to hyaline cartilage. A synchondrosis may be temporary or permanent. A temporary synchondrosis is the epiphyseal plate (growth plate) of a growing long bone. The epiphyseal plate is the region of growing hyaline cartilage that unites the diaphysis (shaft) of a long bone to the epiphysis (end of the bone). Bone lengthening involves growth of the epiphyseal plate cartilage and its replacement by bone, which adds to the diaphysis (see section 6.4). For many years during childhood growth, the rates of cartilage growth and bone formation are equal and thus the epiphyseal plate does not change in overall thickness as the bone lengthens. During the late teens and early 20s, growth of the cartilage slows and eventually stops. The epiphyseal plate is then completely replaced by bone, and the diaphyseal and epiphyseal portions of the bone fuse together to form a single adult bone. This fusion of the diaphysis and epiphysis forms a synostosis and once this occurs, bone lengthening ceases. For this reason, the epiphyseal plate is considered to be a temporary synchondrosis. Because cartilage is softer than bone tissue, injury to a growing long bone can damage the epiphyseal plate cartilage, thus stopping bone growth and preventing additional bone lengthening.",True,Synchondrosis,,,,
+66da25a2-41d2-4a87-84d3-77f275430579,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"Growing layers of cartilage also form synchondroses that join together the ilium, ischium, and pubic portions of the hip bone during childhood and adolescence. When body growth stops, the cartilage disappears and is replaced by bone, forming synostoses and fusing the bony components together into the single hip bone of the adult. Similarly, synostoses unite the sacral vertebrae that fuse together to form the adult sacrum.",True,Synchondrosis,,,,
+6946c131-b192-4a8e-8a91-80753dc51f0b,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"Examples of permanent synchondroses are found in the thoracic cage. One example is the first sternocostal joint, where the first rib is anchored to the manubrium by its costal cartilage. (The articulations of the remaining costal cartilages to the sternum are all synovial joints.) Additional synchondroses are formed where the anterior ends of the other 11 ribs are joined to their costal cartilage. Unlike the temporary synchondroses of the epiphyseal plate, these permanent synchondroses retain their hyaline cartilage and do not ossify with age. Due to the lack of movement between the bone and cartilage, both temporary and permanent synchondroses are functionally classified as synarthroses.",True,Synchondrosis,,,,
+17b9f552-2a8c-48ce-8050-d594d8d72fb3,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,Symphysis,False,Symphysis,,,,
+b4639c5e-a058-4d39-acbb-d7fcdd5908b0,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"A cartilaginous joint where the bones are joined by fibrocartilage is called a symphysis (“growing together”). Fibrocartilage contains numerous bundles of thick collagen fibers, thus giving it a much greater ability to resist pulling and bending forces when compared with hyaline cartilage. This gives symphyses the ability to strongly unite the adjacent bones, but can still allow for limited movement to occur. Thus, symphyses are functionally classified as amphiarthroses.",True,Symphysis,,,,
+9ea7f23d-2913-49d7-acdd-8dc883c24243,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"A thick pad of fibrocartilage called an intervertebral disc strongly unites adjacent vertebral bodies at the intervertebral symphysis. The intervertebral symphysis is important because it allows for small movements between adjacent vertebrae. Small movements at many intervertebral joints combine to allow greater mobility of the vertebral column as a whole. In addition, the thick intervertebral disc provides cushioning between the vertebrae, which is important when carrying heavy objects or during high-impact activities such as running or jumping.",True,Symphysis,,,,
+565ad7e8-1415-433e-ac67-fab3592435eb,https://open.oregonstate.education/aandp/,9.3 Cartilaginous Joints,https://open.oregonstate.education/aandp/chapter/9-3-cartilaginous-joints/,"At the pubic symphysis, the pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage pad. This fibrocartilage provides cushioning similar to the intervertebral disc, thus providing both shock absorption and stability to the pelvis. During pregnancy, increased levels of the hormone relaxin lead to increased mobility at the pubic symphysis which allows for expansion of the pelvic cavity during childbirth.",True,Symphysis,,,,
+57577751-a9fa-4b91-9d08-8b6261937f10,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,Describe the characteristic features for fibrous joints and give examples,False,Describe the characteristic features for fibrous joints and give examples,,,,
+38521220-23b7-4852-acf0-423e4ba5f27a,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"At a fibrous joint, the adjacent bones are directly connected to each other by fibrous connective tissue, and thus the bones do not have a joint cavity between them (Figure 9.2.1). The fibers joining the bones may be short or long, thus the gap between bones at fibrous joints vary from narrow to wide. There are three types of fibrous joints. A suture is the narrow fibrous joint found between most bones of the skull. At a syndesmosis, the bones are more widely separated but are held together by a strap of fibrous connective tissue called a ligament or a wide sheet of connective tissue called an interosseous membrane. This type of fibrous joint is found between the shaft regions of the long bones in the forearm and in the leg. Lastly, a gomphosis is the narrow fibrous joint between the roots of a tooth and the bony socket in the jaw into which the tooth fits.",True,Describe the characteristic features for fibrous joints and give examples,Figure 9.2.1,9.2 Fibrous Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+17187a41-9ae7-4f15-b648-ac34c2d855aa,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,Suture,False,Suture,,,,
+c29499c4-0b81-4c39-a64e-6460ca6700d0,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"All the bones of the skull, except for the mandible, are joined to each other by fibrous joints called sutures. The fibrous connective tissue found at a suture (“to bind or sew”) strongly unites the adjacent skull bones and thus helps to protect the brain and form the face. In adults, the skull bones articulate closely and fibrous connective tissue fills the narrow gap between the bones. The suture is frequently convoluted, forming a tight union that prevents most movement between the bones. (See Figure 9.2.1a) Thus, skull sutures in the adult are functionally classified as a synarthrosis.",True,Suture,Figure 9.2.1,9.2 Fibrous Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+53b7e019-aac7-4381-b0a5-5f755d007dc6,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"In newborns and infants, the areas of connective tissue between the bones are much wider, especially in those areas on the top and sides of the skull that will become the sagittal, coronal, squamous, and lambdoid sutures. These broad areas of connective tissue are called fontanelles (Figure 9.2.2). During birth, the fontanelles provide flexibility to the skull, allowing the bones to push closer together or to overlap slightly, thus aiding movement of the infant’s head through the birth canal. After birth, these expanded regions of connective tissue allow for rapid growth of the skull and enlargement of the brain. The fontanelles greatly decrease in width during the first year after birth as the skull bones enlarge. When the connective tissue between the adjacent bones is reduced to a narrow layer, these fibrous joints are now called sutures. At some sutures, the connective tissue will ossify and be converted into bone, causing the adjacent bones to fuse to each other. This fusion between bones is called a synostosis (“joined by bone”). Examples of synostosis fusions between cranial bones are found both early and late in life. At the time of birth, the frontal and maxillary bones consist of right and left halves joined together by sutures, which disappear by the eighth year as the halves fuse together to form a single bone. Late in life, the sagittal, coronal, and lambdoid sutures of the skull will begin to ossify and fuse, causing the suture line to gradually disappear.",True,Suture,Figure 9.2.2,9.2 Fibrous Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/905_The_Newborn_Skull.jpg,Figure 9.2.2 – The Newborn Skull: The fontanelles of a newborn’s skull are broad areas of fibrous connective tissue that form fibrous joints between the bones of the skull.
+71472405-3bba-45c3-953b-36c6852bd75e,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,Syndesmosis,False,Syndesmosis,,,,
+5be9873d-3348-4a7d-aec6-3b9c30fc52bd,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"A syndesmosis (“fastened with a band”, plural = syndesmoses) is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane.",True,Syndesmosis,,,,
+e8e24c7f-64ef-4677-a687-d66d7556f935,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"In the forearm, the wide gap between the shaft portions of the radius and ulna bones are strongly united by an interosseous membrane (see Figure 9.2.1b). Similarly, in the leg, the shafts of the tibia and fibula are also united by an interosseous membrane. In addition, at the distal tibiofibular joint, the narrow gap between the bones is anchored by fibrous connective tissue and ligaments on both the anterior and posterior aspects of the joint. Together, the interosseous membrane and these ligaments form the tibiofibular syndesmosis.",True,Syndesmosis,Figure 9.2.1,9.2 Fibrous Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+6e73008b-458c-4075-ad3f-5de29eebe1cf,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation. However, a syndesmosis does not prevent all movement between the bones, and thus this type of fibrous joint is functionally classified as an amphiarthrosis. In the leg, the syndesmosis between the tibia and fibula strongly unites the bones, allows for little movement, and firmly locks the talus bone in place between the tibia and fibula at the ankle joint. This provides strength and stability to the leg and ankle, which are important during weight bearing. In the forearm, the interosseous membrane is flexible enough to allow for rotation of the radius bone during forearm movements. Thus in contrast to the stability provided by the tibiofibular syndesmosis, the flexibility of the antebrachial (forearm) interosseous membrane allows for the much greater mobility of the forearm.",True,Syndesmosis,,,,
+2b408eb3-4c1c-4abd-96d1-f4042be434d8,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"The interosseous membranes of the leg and forearm also provide areas for muscle attachment. Damage to a syndesmotic joint, which usually results from a fracture of the bone with an accompanying tear of the interosseous membrane, will produce pain, loss of stability of the bones, and may damage the muscles attached to the interosseous membrane. If the fracture site is not properly immobilized with a cast or splint, contractile activity by these muscles can cause improper alignment of the broken bones during healing.",True,Syndesmosis,,,,
+a10b9b32-4f31-45fd-bb65-781c449ba3fc,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,Gomphosis,False,Gomphosis,,,,
+516f84ae-b08e-47f9-be84-a79cee61df73,https://open.oregonstate.education/aandp/,9.2 Fibrous Joints,https://open.oregonstate.education/aandp/chapter/9-2-fibrous-joints/,"A gomphosis (“fastened with bolts”, plural = gomphoses) is the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull. A gomphosis is also known as a peg-and-socket joint and is considered a joint even though teeth are not bones. Spanning between the bony walls of the socket and the root of the tooth are numerous short bands of dense connective tissue, each of which is called a periodontal ligament (see Figure 9.2.1c). Due to the immobility of a gomphosis, this type of joint is functionally classified as a synarthrosis.",True,Gomphosis,Figure 9.2.1,9.2 Fibrous Joints,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+eedb6f00-8a06-41dc-8f86-172ef3274991,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,Discuss both functional and structural classifications for body joints,False,Discuss both functional and structural classifications for body joints,,,,
+163be4df-af49-4104-be22-82d7e610543e,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,"A joint, also called an articulation, is any place where adjacent bones or bone and cartilage come together (articulate with each other) to form a connection. Joints are classified both structurally and functionally. Structural classifications of joints take into account whether the adjacent bones are strongly anchored to each other by fibrous connective tissue or cartilage, or whether the adjacent bones articulate with each other within a fluid-filled space called a joint cavity. Functional classifications describe the degree of movement available between the bones, ranging from immobile, to slightly mobile, to freely moveable joints. The amount of movement available at a particular joint of the body is related to the functional requirements for that joint. Thus immobile or slightly moveable joints serve to protect internal organs, give stability to the body, and allow for limited body movement. In contrast, freely moveable joints allow for much more extensive movements of the body and limbs.",True,Discuss both functional and structural classifications for body joints,,,,
+ea845bb6-c86c-46b2-bf53-6914761efb9f,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,Structural Classification of Joints,False,Structural Classification of Joints,,,,
+cbb9bd42-d7d9-4e6f-9d7a-a95d1f40e8bb,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,"The structural classification of joints is based on whether the articulating surfaces of the adjacent bones are directly connected by fibrous connective tissue or cartilage, or whether the articulating surfaces contact each other within a fluid-filled joint cavity. These differences serve to divide the joints of the body into three structural classifications. A fibrous joint is where the adjacent bones are united by fibrous connective tissue. At a cartilaginous joint, the bones are joined by hyaline cartilage or fibrocartilage. At a synovial joint, the articulating surfaces of the bones are not directly connected, but instead come into contact with each other within a joint cavity that is filled with a lubricating fluid. Synovial joints allow for free movement between the bones and are the most common joints of the body.",True,Structural Classification of Joints,,,,
+60200c07-5363-492c-ad79-03d2e112278d,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,Functional Classification of Joints,False,Functional Classification of Joints,,,,
+f7f3cd2e-390c-44ef-885b-78984f964623,https://open.oregonstate.education/aandp/,9.1 Classification of Joints,https://open.oregonstate.education/aandp/chapter/9-1-classification-of-joints/,"The functional classification of joints is determined by the amount of mobility found between the adjacent bones. Joints are thus functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, which is a freely moveable joint (arthroun = “to fasten by a joint”). Depending on their location, fibrous joints may be functionally classified as a synarthrosis (immobile joint) or an amphiarthrosis (slightly mobile joint). Cartilaginous joints are also functionally classified as either a synarthrosis or an amphiarthrosis joint. All synovial joints are functionally classified as a diarthrosis joint.",True,Functional Classification of Joints,,,,
+bfe21794-8494-4fb5-a1c6-140c34b3468a,https://open.oregonstate.education/aandp/,9.0 Introduction,https://open.oregonstate.education/aandp/chapter/9-0-introduction/,"The adult human body has 206 named bones, and with the exception of the hyoid bone in the neck, each bone is connected to at least one other bone. Joints are the location where bones come together. Many joints allow for movement between the bones. At these joints, the articulating surfaces of the adjacent bones can move smoothly against each other. However, the bones of other joints may be joined to each other by connective tissue or cartilage. These joints are designed for stability and provide for little or no movement. Importantly, joint stability and movement are related to each other. This means that stable joints allow for little or no mobility between the adjacent bones. Conversely, joints that provide the most movement between bones are the least stable. Understanding the relationship between joint structure and function will help to explain why particular types of joints are found in certain areas of the body.",True,Functional Classification of Joints,,,,
+dc963827-10b3-40ab-9379-336305283728,https://open.oregonstate.education/aandp/,9.0 Introduction,https://open.oregonstate.education/aandp/chapter/9-0-introduction/,"The articulating surfaces of bones at stable types of joints, with little or no mobility, are strongly united to each other. For example, most of the joints of the skull are held together by fibrous connective tissue and do not allow for movement between the adjacent bones. This lack of mobility is important, because the skull bones serve to protect the brain. Similarly, other joints united by fibrous connective tissue allow for very little movement, which provides stability and weight-bearing support for the body. For example, the tibia and fibula of the leg are tightly united to give stability to the body when standing. At other joints, the bones are held together by cartilage, which permits limited movements between the bones. Thus, the joints of the vertebral column only allow for small movements between adjacent vertebrae, but when added together, these movements provide the flexibility that allows your body to twist, or bend to the front, back, or side. In contrast, at joints that allow for wide ranges of motion, the articulating surfaces of the bones are not directly united to each other. Instead, these surfaces are enclosed within a space filled with lubricating fluid, which allows the bones to move smoothly against each other. These joints provide greater mobility, but since the bones are free to move in relation to each other, the joint is less stable. Most of the joints between the bones of the appendicular skeleton are this freely moveable type of joint. These joints allow the muscles of the body to pull on a bone and thereby produce movement of that body region. Your ability to kick a soccer ball, pick up a fork, and dance the tango depend on mobility at these types of joints.",True,Functional Classification of Joints,,,,
+55fd9fd5-32ca-4afd-ad03-eba6afcad40f,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,Describe the embryonic formation and growth of the limb bones,False,Describe the embryonic formation and growth of the limb bones,,,,
+eec00aea-a008-42fd-bd58-8fbc7b1263a6,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"Embryologically, the appendicular skeleton arises from mesenchyme, a type of embryonic tissue that can differentiate into many types of tissues, including bone or muscle tissue. Mesenchyme gives rise to the bones of the upper and lower limbs, as well as to the pectoral and pelvic girdles. Development of the limbs begins near the end of the fourth embryonic week, with the upper limbs appearing first. Thereafter, the development of the upper and lower limbs follows similar patterns, with the lower limbs lagging behind the upper limbs by a few days.",True,Describe the embryonic formation and growth of the limb bones,,,,
+efe53c24-5276-433f-8a1a-264bc84ec90e,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,Limb Growth,False,Limb Growth,,,,
+23913e26-751a-47a3-8ecf-43e26b1852e4,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"Each upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after (Figure 8.5.1).",True,Limb Growth,Figure 8.5.1,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2914_Photo_of_Embryo-02.jpg,Figure 8.5.1 – Embryo at Seven Weeks: Limb buds are visible in an embryo at the end of the seventh week of development (embryo derived from an ectopic pregnancy). (credit: Ed Uthman/flickr)
+ac0fe9c2-c689-4e30-9676-0dbf36333883,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying mesenchyme to rapidly proliferate, producing the outgrowth of the developing limb. As the limb bud elongates, cells located farther from the apical ectodermal ridge slow their rates of cell division and begin to differentiate. In this way, the limb develops along a proximal-to-distal axis.",True,Limb Growth,,,,
+484c3b7f-c31a-445f-bfbb-ec248066f9f2,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"During the sixth week of development, the distal ends of the upper and lower limb buds expand and flatten into a paddle shape. This region will become the hand or foot. The wrist or ankle areas then appear as a constriction that develops at the base of the paddle. Shortly after this, a second constriction on the limb bud appears at the future site of the elbow or knee. Within the paddle, areas of tissue undergo cell death, producing separations between the growing fingers and toes. Also during the sixth week of development, mesenchyme within the limb buds begins to differentiate into hyaline cartilage that will form models of the future limb bones.",True,Limb Growth,,,,
+7066bdce-ff65-4864-8e12-986217047423,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"The early outgrowth of the upper and lower limb buds initially has the limbs positioned so that the regions that will become the palm of the hand or the bottom of the foot are facing medially toward the body, with the future thumb or big toe both oriented toward the head. During the seventh week of development, the upper limb rotates laterally by 90 degrees, so that the palm of the hand faces anteriorly and the thumb points laterally. In contrast, the lower limb undergoes a 90-degree medial rotation, thus bringing the big toe to the medial side of the foot.",True,Limb Growth,,,,
+b5be384f-2aa4-48ff-badd-abf3fe87c3d4,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,Ossification of Appendicular Bones,False,Ossification of Appendicular Bones,,,,
+92b76e9e-5ce1-4736-ba0f-fae9cd7ffb3e,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"All of the girdle and limb bones, except for the clavicle, develop by the process of endochondral ossification. This process begins as the mesenchyme within the limb bud differentiates into hyaline cartilage to form cartilage models for future bones. By the twelfth week, a primary ossification center will have appeared in the diaphysis (shaft) region of the long bones, initiating the process that converts the cartilage model into bone. A secondary ossification center will appear in each epiphysis (expanded end) of these bones at a later time, usually after birth. The primary and secondary ossification centers are separated by the epiphyseal plate, a layer of growing hyaline cartilage. This plate is located between the diaphysis and each epiphysis. It continues to grow and is responsible for the lengthening of the bone. The epiphyseal plate is retained for many years, until the bone reaches its final, adult size, at which time the epiphyseal plate disappears and the epiphysis fuses to the diaphysis. (Seek additional content on ossification in the chapter on bone tissue.)",True,Ossification of Appendicular Bones,,,,
+ced74f88-2998-46fb-9ed5-5cad1233fe14,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"Small bones, such as the phalanges, will develop only one secondary ossification center and will thus have only a single epiphyseal plate. Large bones, such as the femur, will develop several secondary ossification centers, with an epiphyseal plate associated with each secondary center. Thus, ossification of the femur begins at the end of the seventh week with the appearance of the primary ossification center in the diaphysis, which rapidly expands to ossify the shaft of the bone prior to birth. Secondary ossification centers develop at later times. Ossification of the distal end of the femur, to form the condyles and epicondyles, begins shortly before birth. Secondary ossification centers also appear in the femoral head late in the first year after birth, in the greater trochanter during the fourth year, and in the lesser trochanter between the ages of 9 and 10 years. Once these areas have ossified, their fusion to the diaphysis and the disappearance of each epiphyseal plate follow a reversed sequence. Thus, the lesser trochanter is the first to fuse, doing so at the onset of puberty (around 11 years of age), followed by the greater trochanter approximately 1 year later. The femoral head fuses between the ages of 14–17 years, whereas the distal condyles of the femur are the last to fuse, between the ages of 16–19 years. Knowledge of the age at which different epiphyseal plates disappear is important when interpreting radiographs taken of children. Since the cartilage of an epiphyseal plate is less dense than bone, the plate will appear dark in a radiograph image. Thus, a normal epiphyseal plate may be mistaken for a bone fracture.",True,Ossification of Appendicular Bones,,,,
+2f9f1fbe-8f7c-4081-8371-e431d83dbb31,https://open.oregonstate.education/aandp/,8.5 Development of the Appendicular Skeleton,https://open.oregonstate.education/aandp/chapter/8-5-development-of-the-appendicular-skeleton/,"The clavicle is the one appendicular skeleton bone that does not develop via endochondral ossification. Instead, the clavicle develops through the process of intramembranous ossification. During this process, mesenchymal cells differentiate directly into bone-producing cells, which produce the clavicle directly, without first making a cartilage model. Because of this early production of bone, the clavicle is the first bone of the body to begin ossification, with ossification centers appearing during the fifth week of development. However, ossification of the clavicle is not complete until age 25.",True,Ossification of Appendicular Bones,,,,
+46289042-3207-4286-ae05-132633443384,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"Describe the bones of the lower limb, including the bones of the thigh, leg, ankle, and foot",True,Ossification of Appendicular Bones,,,,
+3ae59c1e-b0c2-4125-b6f6-d7ab305ec3ee,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"Like the upper limb, the lower limb is divided into three regions. The thigh is that portion of the lower limb located between the hip joint and knee joint. The leg is specifically the region between the knee joint and the ankle joint. Distal to the ankle is the foot. The lower limb contains 30 bones. These are the femur, patella, tibia, fibula, tarsal bones, metatarsal bones, and phalanges (see Chapter 8.1 Figure 8.2). The femur is the single bone of the thigh. The patella is the kneecap and articulates with the distal femur. The tibia is the larger, weight-bearing bone located on the medial side of the leg, and the fibula is the thin bone of the lateral leg. The bones of the foot are divided into three groups. The posterior portion of the foot is formed by a group of seven tarsal bones, whereas the mid-foot contains five elongated metatarsal bones. The toes contain 14 small phalanges.",True,Ossification of Appendicular Bones,,,,
+72928cf4-4938-490a-8e5e-fe7643905cbe,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Femur,False,Femur,,,,
+43a01d40-92d6-4d5b-a408-c1959be58531,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The femur, or thigh bone, is the single bone of the thigh region (Figure 8.4.1). It is the longest and strongest bone of the body, and accounts for approximately one-quarter of a person’s total height. The rounded, proximal end is the head of the femur, which articulates with the acetabulum of the hip bone to form the hip joint. The fovea capitis is a minor indentation on the medial side of the femoral head that serves as the site of attachment for the ligament of the head of the femur. This ligament spans the femur and acetabulum, but is weak and provides little support for the hip joint. It does, however, carry an important artery that supplies the head of the femur.",True,Femur,Figure 8.4.1,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2019/07/810_Femur_and_Patella.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur."
+308fe489-bbc7-41a3-8011-a5450f9f4587,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,EDITORS NOTES: FOVEA CAPITIS IS NOT VISUALIZED IN THIS IMAGE,False,EDITORS NOTES: FOVEA CAPITIS IS NOT VISUALIZED IN THIS IMAGE,,,,
+977d122c-9698-48bb-a7bb-cb297327a198,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The narrowed region below the head is the neck of the femur. This is a common area for fractures of the femur. The greater trochanter is the large, upward, bony projection located above the base of the neck. Multiple muscles that act across the hip joint attach to the greater trochanter, which, because of its projection from the femur, gives additional leverage to these muscles. The greater trochanter can be felt just under the skin on the lateral side of your upper thigh. The lesser trochanter is a small, bony prominence that lies on the medial aspect of the femur, just below the neck. A single, powerful muscle attaches to the lesser trochanter. Running between the greater and lesser trochanters on the anterior side of the femur is the roughened intertrochanteric line. The trochanters are also connected on the posterior side of the femur by the larger intertrochanteric crest.",True,EDITORS NOTES: FOVEA CAPITIS IS NOT VISUALIZED IN THIS IMAGE,,,,
+bb8fc131-9314-4687-a07c-94e062e145e9,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The elongated shaft of the femur has a slight anterior bowing or curvature. At its proximal end, the posterior shaft has the gluteal tuberosity, a roughened area extending inferiorly from the greater trochanter. More inferiorly, the gluteal tuberosity becomes continuous with the linea aspera (“rough line”). This is the roughened ridge that passes distally along the posterior side of the mid-femur. Multiple muscles of the hip and thigh regions make long, thin attachments to the femur along the linea aspera.",True,EDITORS NOTES: FOVEA CAPITIS IS NOT VISUALIZED IN THIS IMAGE,,,,
+7679de4f-04fb-4e44-9b88-a90eb40a0259,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The distal end of the femur has medial and lateral bony expansions. On the lateral side, the smooth portion that covers the distal and posterior aspects of the lateral expansion is the lateral condyle of the femur. The roughened area on the outer, lateral side of the condyle is the lateral epicondyle of the femur. Similarly, the smooth region of the distal and posterior medial femur is the medial condyle of the femur, and the irregular outer, medial side of this is the medial epicondyle of the femur. The lateral and medial condyles articulate with the tibia to form the knee joint. The epicondyles provide attachment for muscles and supporting ligaments of the knee. The adductor tubercle is a small bump located at the superior margin of the medial epicondyle. Posteriorly, the medial and lateral condyles are separated by a deep depression called the intercondylar fossa. Anteriorly, the smooth surfaces of the condyles join together to form a wide groove called the patellar surface (not shown), which provides for articulation with the patella bone. The combination of the medial and lateral condyles with the patellar surface gives the distal end of the femur a horseshoe (U) shape.",True,EDITORS NOTES: FOVEA CAPITIS IS NOT VISUALIZED IN THIS IMAGE,,,,
+7f2f8b93-c232-4e05-98e3-12ccc61fd33f,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Patella,False,Patella,,,,
+0f85e347-9e42-4411-a965-07a16ca307f5,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The patella (kneecap) is largest sesamoid bone of the body (see Figure 8.4.1). A sesamoid bone is a bone that is incorporated into the tendon of a muscle where that tendon crosses a joint. The sesamoid bone articulates with the underlying bones to prevent damage to the muscle tendon due to rubbing against the bones during movements of the joint. The patella is found in the tendon of the quadriceps femoris muscle, the large muscle of the anterior thigh that passes across the anterior knee to attach to the tibia. The patella articulates with the patellar surface of the femur and thus prevents rubbing of the muscle tendon against the distal femur. The patella also lifts the tendon away from the knee joint, which increases the leverage power of the quadriceps femoris muscle as it acts across the knee. The patella does not articulate with the tibia.",True,Patella,Figure 8.4.1,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2019/07/810_Femur_and_Patella.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur."
+fad77a89-2e57-4517-ae64-edeeca508c97,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Tibia,False,Tibia,,,,
+ba9834ae-f20d-4a61-9b9e-fbeaa39d754a,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The tibia (shin bone) is the medial bone of the leg and is larger than the fibula, with which it is paired (Figure 8.4.3). The tibia is the main weight-bearing bone of the leg and the second longest bone of the body, after the femur. The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg.",True,Tibia,Figure 8.4.3,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/811_Tibia_and_fibula_revised-793x1024.png,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight."
+37a12053-f824-4c26-b466-2e833309c9b3,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The proximal end of the tibia is greatly expanded. The two sides of this expansion form the medial and lateral condyles of the tibia. The tibia does not have epicondyles. The top surface of each condyle is smooth and flattened. These areas articulate with the medial and lateral condyles of the femur to form the knee joint. Between the articulating surfaces of the tibial condyles is the intercondylar eminence, an irregular, elevated area that serves as the inferior attachment point for two supporting ligaments of the knee.",True,Tibia,,,,
+de31ef6c-a36a-41e8-8583-30fd2958c03b,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The tibial tuberosity is an elevated area on the anterior side of the tibia, near its proximal end. It is the final site of attachment for the muscle tendon associated with the patella. More inferiorly, the shaft of the tibia becomes triangular in shape. The anterior apex of this triangle forms the anterior border of the tibia, which begins at the tibial tuberosity and runs inferiorly along the length of the tibia. Both the anterior border and the medial side of the triangular shaft are located immediately under the skin and can be easily palpated along the entire length of the tibia. A small ridge running down the lateral side of the tibial shaft is the interosseous border of the tibia (not shown). This is for the attachment of the interosseous membrane of the leg, the sheet of dense connective tissue that unites the tibia and fibula bones. Located on the posterior side of the tibia is the soleal line, a diagonally running, roughened ridge that begins below the base of the lateral condyle, and runs down and medially across the proximal third of the posterior tibia. Muscles of the posterior leg attach to this line.",True,Tibia,,,,
+6431780f-2c0b-40e0-99da-29da3d2e70f6,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The large expansion found on the medial side of the distal tibia is the medial malleolus (“little hammer”). This forms the large bony bump found on the medial side of the ankle region. Both the smooth surface on the inside of the medial malleolus and the smooth area at the distal end of the tibia articulate with the talus bone of the foot as part of the ankle joint. On the lateral side of the distal tibia is a wide groove called the fibular notch (not shown). This area articulates with the distal end of the fibula, forming the distal tibiofibular joint.",True,Tibia,,,,
+e9b86cbd-6817-44e4-a562-9366efec8ba3,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Fibula,False,Fibula,,,,
+8aa3b945-0708-4c6a-a40b-e9f9aa9b469a,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,The fibula is the slender bone located on the lateral side of the leg (see Figure 8.4.3). The fibula does not bear weight. It serves primarily for muscle attachments and thus is largely surrounded by muscles. Only the proximal and distal ends of the fibula can be easily palpated.,True,Fibula,Figure 8.4.3,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/811_Tibia_and_fibula_revised-793x1024.png,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight."
+f5fa3ca5-16ad-4217-a418-33ae8924d76c,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The head of the fibula is the small, knob-like, proximal end of the fibula. It articulates with the inferior aspect of the lateral tibial condyle, forming the proximal tibiofibular joint. The thin shaft of the fibula has the interosseous border of the fibula (not shown), a narrow ridge running down its medial side for the attachment of the interosseous membrane that spans the fibula and tibia. The distal end of the fibula forms the lateral malleolus, which forms the easily palpated bony bump on the lateral side of the ankle. The deep (medial) side of the lateral malleolus articulates with the talus bone of the foot as part of the ankle joint. The distal fibula also articulates with the fibular notch of the tibia.",True,Fibula,,,,
+7f23c179-7a4a-41a1-8f0f-1685361afc84,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Tarsal Bones,False,Tarsal Bones,,,,
+9d3193b8-63ad-41b0-8219-934f02d696d5,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The posterior half of the foot is formed by seven tarsal bones (Figure 8.4.4). The most superior bone is the talus. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. Body weight is transferred from the tibia to the talus to the calcaneus, which rests on the ground. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone.",True,Tarsal Bones,Figure 8.4.4,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+cb1b6411-91ce-44a7-9b17-c3210388eef6,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The cuboid bone articulates with the anterior end of the calcaneus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. These bones are the medial cuneiform, the intermediate cuneiform, and the lateral cuneiform. Each of these bones has a broad superior surface and a narrow inferior surface, which together produce the transverse (medial-lateral) curvature of the foot. The navicular and lateral cuneiform bones also articulate with the medial side of the cuboid bone.",True,Tarsal Bones,,,,
+48703e28-00eb-43ae-bab2-fdcdd72b553e,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Metatarsal Bones,False,Metatarsal Bones,,,,
+b60cb96a-5070-4500-8890-ba12b2525540,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.4.4). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot.",True,Metatarsal Bones,Figure 8.4.4,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+70460c2c-e5d7-4793-aa7e-5f80b502c5b0,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Phalanges,False,Phalanges,,,,
+dc469763-113a-45e5-a355-35c9f373fb06,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8.4.4). The toes are numbered 1–5, starting with the big toe (hallux). The big toe has two phalanx bones, the proximal and distal phalanges. The remaining toes all have proximal, middle, and distal phalanges. A joint between adjacent phalanx bones is called an interphalangeal joint.",True,Phalanges,Figure 8.4.4,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+7f86bd83-baba-4800-a028-f80ce0c658cf,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,Arches of the Foot,False,Arches of the Foot,,,,
+034279ea-b9d6-4e05-a940-e7d23637d82c,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body weight puts a tremendous amount of pressure and force on the foot. During running, the force applied to each foot as it contacts the ground can be up to 2.5 times your body weight. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The arches of the foot play an important role in this shock-absorbing ability. When weight is applied to the foot, these arches will flatten somewhat, thus absorbing energy. When the weight is removed, the arch rebounds, giving “spring” to the step.",True,Arches of the Foot,,,,
+185a649a-fe1d-4541-82e3-efd358327066,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8.4.4). The transverse arch forms the medial-lateral curvature of the mid-foot. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain.",True,Arches of the Foot,Figure 8.4.4,8.4 Bones of the Lower Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+c460ae07-4ba6-401b-aeb1-f215f7c337ee,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"The longitudinal arches run down the length of the foot. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. These arches are supported at either end, where they contact the ground. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. Contraction of the foot muscles also plays an important role in this energy absorption. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This recovery of the arches releases the stored energy and improves the energy efficiency of walking.",True,Arches of the Foot,,,,
+1fc2d251-ab8a-4c8b-8a13-706ce8140c37,https://open.oregonstate.education/aandp/,8.4 Bones of the Lower Limb,https://open.oregonstate.education/aandp/chapter/8-4-bones-of-the-lower-limb/,"Stretching of the ligaments that support the longitudinal arches can lead to pain. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. This condition is called pes planus (“flat foot” or “fallen arches”).",True,Arches of the Foot,,,,
+26899a0f-b044-41c5-bddc-5079ebb42ae4,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"Describe the bones of the pelvic girdle, and describe how the pelvis unites the lower limbs with the axial skeleton.",True,Arches of the Foot,,,,
+a63fa321-7f25-4643-9b9e-60aa88fedd4d,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The two hip bones (also called coxal bones or os coxae) are together called the pelvic girdle (hip girdle) and serve as the attachment point for each lower limb. When the two hip bones are combined with the sacrum and coccyx of the axial skeleton, they are referred to as the pelvis. The right and left hip bones also converge anteriorly to attach to each other at the pubic symphysis (Figure 8.3.1).",True,Arches of the Foot,Figure 8.3.1,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+ef05eed8-6350-4f4c-bc92-87e0b7d12502,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"Unlike the bones of the pectoral girdle, which are highly mobile to enhance the range of upper limb movements, the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure. This is important for stability because it enables the weight of the body to be easily transferred laterally from the vertebral column, through the pelvic girdle and hip joints, and into the weight bearing lower limb(s). Thus, the immobility of the pelvis provides a strong foundation for the upper body as it rests on top of the mobile lower limbs.",True,Arches of the Foot,,,,
+7ba002e3-5bff-4cbc-9d5d-b58ba86f23bb,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,Hip Bone,False,Hip Bone,,,,
+7ada0d60-838b-4419-9631-688f40d9b7d0,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The hip (or coxal) bones form the pelvic girdle portion of the pelvis. The hip bones are large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis (Figure 8.3.2). These names are retained and used to define the three regions of the adult hip bone.",True,Hip Bone,Figure 8.3.2,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/808_Hip_Bone.jpg,"Figure 8.3.2 – The Hip Bone: Each adult hip bone consists of three regions. The ilium forms the large, fan-shaped superior portion, the ischium forms the posteroinferior portion, and the pubis forms the anteromedial portion."
+bdde0a6e-f55e-4b3e-896a-1b4105c2edc2,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The ilium is the fan-like, superior region that forms the largest part of the hip bone. It is firmly united to the sacrum at the largely immobile sacroiliac joint (see Figure 8.3.1). The ischium forms the posteroinferior region of each hip bone. It supports the body when sitting. The pubis forms the anterior portion of the hip bone. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.",True,Hip Bone,Figure 8.3.1,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+14b69627-abd9-4e1c-a8d1-ed8c91490e45,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,Pelvis,False,Pelvis,,,,
+8037649d-4111-4eaa-9e47-e988546e7873,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx (see Figure 8.3.1). The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. It serves as an attachment point for trunk and lower limb muscles, and also protects the internal pelvic organs. When standing in the anatomical position, the pelvis is tilted anteriorly. In this position, the anterior superior iliac spines and the pubic tubercles lie in the same vertical plane, and the anterior (internal) surface of the sacrum faces forward and downward.",True,Pelvis,Figure 8.3.1,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+1880ed16-c491-471c-abd7-97bb9e34bf15,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The three areas of each hip bone, the ilium, pubis, and ischium, converge centrally to form a deep, cup-shaped cavity called the acetabulum. This is located on the lateral side of the hip bone and is part of the hip joint. The large opening in the anteroinferior hip bone between the ischium and pubis is the obturator foramen. This space is largely filled in by a layer of connective tissue and serves for the attachment of muscles on both its internal and external surfaces.",True,Pelvis,,,,
+246376b0-4722-4cb4-8b32-b8b63d3098f6,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"Several ligaments unite the bones of the pelvis (Figure 8.3.3). The largely immobile sacroiliac joint is supported by a pair of strong ligaments that are attached between the sacrum and ilium portions of the hip bone. These are the anterior sacroiliac ligament on the anterior side of the joint and the posterior sacroiliac ligament on the posterior side. Also spanning the sacrum and hip bone are two additional ligaments. The sacrospinous ligament runs from the sacrum to the ischial spine, and the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These ligaments help to support and immobilize the sacrum as it carries the weight of the body.",True,Pelvis,Figure 8.3.3,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/817_Ligaments_of_Pelvis.jpg,"Figure 8.3.3 – Ligaments of the Pelvis: The posterior sacroiliac ligament supports the sacroiliac joint. The sacrospinous ligament spans the sacrum to the ischial spine, and the sacrotuberous ligament spans the sacrum to the ischial tuberosity. The sacrospinous and sacrotuberous ligaments contribute to the formation of the greater and lesser sciatic foramens."
+f938e00a-6ccc-47da-b478-b68e20d825c2,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The sacrospinous and sacrotuberous ligaments also help to define two openings on the posterolateral sides of the pelvis through which muscles, nerves, and blood vessels for the lower limb exit. The superior opening is the greater sciatic foramen. This large opening is formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament. The smaller, more inferior lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone, together with the sacrospinous and sacrotuberous ligaments.",True,Pelvis,,,,
+185368d9-42a5-4d20-96c8-246a19fe8185,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"The space enclosed by the bony pelvis is divided into two regions (Figure 8.3.4). The broad, superior region, defined laterally by the large, fan-like portion of the upper hip bone, is called the greater pelvis (greater pelvic cavity). This broad area is occupied by portions of the small and large intestines, and because it is more closely associated with the abdominal cavity, it is sometimes referred to as the false pelvis. More inferiorly, the narrow, rounded space of the lesser pelvis (lesser pelvic cavity) contains the bladder and other pelvic organs, and thus is also known as the true pelvis. The pelvic brim (also known as the pelvic inlet) forms the superior margin of the lesser pelvis, separating it from the greater pelvis. The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. The inferior limit of the lesser pelvic cavity is called the pelvic outlet. This large opening is defined by the inferior margin of the pubic symphysis anteriorly, and the ischiopubic ramus, the ischial tuberosity, the sacrotuberous ligament, and the inferior tip of the coccyx posteriorly. Because of the anterior tilt of the pelvis, the lesser pelvis is also angled, giving it an anterosuperior (pelvic inlet) to posteroinferior (pelvic outlet) orientation.",True,Pelvis,Figure 8.3.4,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/809_Male_Female_Pelvic_Girdle.jpg,"Figure 8.3.4 – Male and Female Pelvis: The female pelvis is adapted for childbirth and is broader, with a larger subpubic angle, a rounder pelvic brim, and a wider and more shallow lesser pelvic cavity than the male pelvis."
+461941b4-9d91-4bf7-9555-fa565640831a,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"A forensic pathologist (also known as a medical examiner) is a medically trained physician who has been specifically trained in pathology to examine the bodies of the deceased to determine the cause of death. A forensic pathologist applies his or her understanding of disease as well as toxins, blood and DNA analysis, firearms and ballistics, and other factors to assess the cause and manner of death. At times, a forensic pathologist will be called to testify under oath in situations that involve a possible crime. Forensic pathology is a field that has received much media attention on television shows or following a high-profile death.",True,Pelvis,,,,
+35c3d1bf-6b05-41c5-b005-43d6f762d64e,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"While forensic pathologists are responsible for determining whether the cause of someone’s death was natural, a suicide, accidental, or a homicide, there are times when uncovering the cause of death is more complex, and other skills are needed. Forensic anthropology brings the tools and knowledge of physical anthropology and human osteology (the study of the skeleton) to the task of investigating a death. A forensic anthropologist assists medical and legal professionals in identifying human remains. The science behind forensic anthropology involves the study of archaeological excavation; the examination of hair; an understanding of plants, insects, and footprints; the ability to determine how much time has elapsed since the person died; the analysis of past medical history and toxicology; the ability to determine whether there are any postmortem injuries or alterations of the skeleton; and the identification of the decedent (deceased person) using skeletal and dental evidence.",True,Pelvis,,,,
+9b497150-91cd-407f-8372-871f72331c36,https://open.oregonstate.education/aandp/,8.3 The Pelvic Girdle and Pelvis,https://open.oregonstate.education/aandp/chapter/8-3-the-pelvic-girdle-and-pelvis/,"Due to the extensive knowledge and understanding of excavation techniques, a forensic anthropologist is an integral and invaluable team member to have on-site when investigating a crime scene, especially when the recovery of human skeletal remains is involved. When remains are bought to a forensic anthropologist for examination, he or she must first determine whether the remains are in fact human. Once the remains have been identified as belonging to a person and not to an animal, the next step is to approximate the individual’s age, sex, race, and height. The differences in the male and female pelvis aid in this identification process. The forensic anthropologist does not determine the cause of death, but rather provides information to the forensic pathologist, who will use all of the data collected to make a final determination regarding the cause of death.",True,Pelvis,,,,
+e1856c95-7ce7-4d41-8379-7fe4a63e8f20,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"Describe the bones of the upper limb, including the bones of the arm, forearm, wrist, and hand",True,Pelvis,,,,
+c9667f1a-5582-4b8f-9c72-de35ce8b82a3,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The upper limb is divided into three regions. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. There are 30 bones in each upper limb. The humerus is the single bone of the arm, and the ulna (medially) and the radius (laterally) are the paired bones of the forearm. The base of the hand contains eight carpal bones, and the palm of the hand is formed by five metacarpal bones. The fingers and thumb contain a total of 14 phalanges.",True,Pelvis,,,,
+c481b669-a4d3-41f2-b4ea-d946800cf607,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Humerus,False,Humerus,,,,
+3b92b8a2-36fc-4e90-a611-fac73f4276fd,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The humerus is the single bone of the arm region (Figure 8.2.1). At its proximal end is the head of the humerus. This is the large, round, smooth region that faces medially. The head articulates with the glenoid cavity of the scapula to form the glenohumeral (shoulder) joint (see Chapter 9). The margin of the smooth area of the head is the anatomical neck of the humerus. Located on the lateral side of the proximal humerus is an expanded bony area called the greater tubercle. The smaller lesser tubercle of the humerus is found on the anterior aspect of the humerus. Both the greater and lesser tubercles serve as attachment sites for muscles that act across the shoulder joint (see Chapter 11). Passing between the greater and lesser tubercles is the narrow intertubercular groove (sulcus), which is also known as the bicipital groove because it provides passage for a tendon of the biceps brachii muscle. The surgical neck is located where the proximal end of the humerus joins the narrow shaft of the humerus, and is a common site of arm fractures. The deltoid tuberosity is a roughened, V-shaped region located on the lateral side in the middle of the humerus shaft. As its name indicates, it is the site of attachment for the deltoid muscle.",True,Humerus,Figure 8.2.1,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Humerus__elbow_joint-872x1024.png,Figure 8.2.1 – Humerus and Elbow Joint: The humerus is the single bone of the arm region. It articulates with the radius and ulna bones of the forearm to form the elbow joint.
+3842fba8-afce-41a2-8127-64e15fa97c61,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"Distally, the humerus becomes flattened. The prominent bony projection on the medial side is the medial epicondyle of the humerus. The much smaller lateral epicondyle of the humerus is found on the lateral side of the distal humerus. The roughened ridge of bone above the lateral epicondyle is the lateral supracondylar ridge. All of these areas are attachment points for muscles that act on the forearm, wrist, and hand. The powerful grasping muscles of the anterior forearm arise from the medial epicondyle, which is thus larger and more robust than the lateral epicondyle that gives rise to the weaker posterior forearm muscles (see Chapter 11).",True,Humerus,,,,
+dc97b34c-1fdb-4ae8-bdf7-315010b00aa8,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The distal end of the humerus has two articulation areas, which join the ulna and radius bones of the forearm to form the elbow joint. The more medial of these areas is the trochlea, a spindle- or pulley-shaped region (trochlea = “pulley”), which articulates with the ulna bone. Immediately lateral to the trochlea is the capitulum (“small head”), a knob-like structure located on the anterior surface of the distal humerus. The capitulum articulates with the radius bone of the forearm. Just above these bony areas are two small depressions. These spaces accommodate the forearm bones when the elbow is fully bent (flexed). Superior to the trochlea is the coronoid fossa, which receives the coronoid process of the ulna, and superior to the capitulum is the radial fossa, which receives the head of the radius when the elbow is flexed. Similarly, the posterior humerus has the olecranon fossa, a larger depression that receives the olecranon process of the ulna when the forearm is fully extended.",True,Humerus,,,,
+6d1ad1bc-2d0b-406d-8a58-0940afba0646,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Ulna,False,Ulna,,,,
+af8da4b3-0c57-4a6f-8b7d-b6b8a033d313,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The ulna is the medial bone of the forearm. It runs parallel to the radius, which is the lateral bone of the forearm (Figure 8.2.2). The proximal end of the ulna resembles a crescent wrench with its large, C-shaped, trochlear notch. This region articulates with the trochlea of the humerus as part of the elbow joint. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. Just below this on the anterior ulna is a roughened area called the ulnar tuberosity. To the lateral side and slightly inferior to the trochlear notch is a small, smooth area called the radial notch of the ulna. This area is the site of articulation between the proximal ends of the radius and ulna, forming the proximal radioulnar joint. The posterior and superior portions of the proximal ulna make up the olecranon process, which forms the bony tip of the elbow.",True,Ulna,Figure 8.2.2,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Forearm_-1024x989.png,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane."
+e0b1e2cb-cbba-4024-a6a3-5395a15ae6e1,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"More distal is the shaft of the ulna. The lateral side of the shaft forms a ridge called the interosseous border of the ulna. This is the line of attachment for the interosseous membrane of the forearm, a sheet of dense connective tissue that unites the ulna and radius bones. The small, rounded area that forms the distal end is the head of the ulna. Projecting from the posterior side of the ulnar head is the styloid process of the ulna, a short bony projection. This serves as an attachment point for connective tissues that unite the distal end of the ulna with the carpal bones of the wrist joint.",True,Ulna,,,,
+a2b8ab75-d5fc-4009-9eb0-a4a27626a956,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"In the anatomical position, with the elbow fully extended and the palms facing forward, the arm and forearm do not form a straight line. Instead, the forearm deviates laterally by 5–15 degrees from the line of the arm. This deviation is called the carrying angle. It allows the forearm and hand to swing freely or to carry an object without hitting the hip. The carrying angle is larger in females.",True,Ulna,,,,
+120e7a5b-c76a-40d9-9db0-95bf87cf836e,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Radius,False,Radius,,,,
+13601fee-40c1-4a86-a154-5ea4a5e97be1,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The radius runs parallel to the ulna, on the lateral (thumb) side of the forearm (see Figure 8.2.2). The head of the radius is a disc-shaped structure that forms the proximal end. The small depression on the surface of the head articulates with the capitulum of the humerus as part of the elbow joint, whereas the smooth, outer margin of the head articulates with the radial notch of the ulna at the proximal radioulnar joint. The neck of the radius is the narrowed region immediately below the expanded head. Inferior to this point on the medial side is the radial tuberosity, an oval-shaped, bony protuberance that serves as a muscle attachment point. The shaft of the radius is slightly curved and has a small ridge along its medial side. This ridge forms the interosseous border of the radius, which, like the similar border of the ulna, is the line of attachment for the interosseous membrane that unites the two forearm bones. The distal end of the radius has a smooth surface for articulation with two carpal bones to form the radiocarpal joint or wrist joint (Figure 8.2.3 and Figure 8.2.4). On the medial side of the distal radius is the ulnar notch of the radius. This shallow depression articulates with the head of the ulna, which together form the distal radioulnar joint. The lateral end of the radius has a pointed projection called the styloid process of the radius. This provides attachment for ligaments that support the lateral side of the wrist joint. Compared to the styloid process of the ulna, the styloid process of the radius projects more distally, thereby limiting the range of movement for lateral deviations of the hand at the wrist joint.",True,Radius,Figure 8.2.2,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Forearm_-1024x989.png,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane."
+a5c21850-328b-42ef-b009-84d4ef3ae63d,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Carpal Bones,False,Carpal Bones,,,,
+f67e6e5a-4baf-4f4d-be01-85183966bffd,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The wrist and base of the hand are formed by a series of eight small carpal bones (see Figure 8.2.3). The carpal bones are arranged in two rows, forming a proximal row of four carpal bones and a distal row of four carpal bones. The bones in the proximal row, running from the lateral (thumb) side to the medial side, are the scaphoid (“boat-shaped”), lunate (“moon-shaped”), triquetrum (“three-cornered”), and pisiform (“pea-shaped”) bones. The small, rounded pisiform bone articulates with the anterior surface of the triquetrum bone. The pisiform thus projects anteriorly, where it forms the bony bump that can be felt at the medial base of your hand. The distal bones (lateral to medial) are the trapezium (“table”), trapezoid (“resembles a table”), capitate (“head-shaped”), and hamate (“hooked bone”) bones. The hamate bone is characterized by a prominent bony extension on its anterior side called the hook of the hamate bone.",True,Carpal Bones,Figure 8.2.3,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+4e97e85d-db81-4a3e-9fa9-32aad8a86011,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"A helpful mnemonic for remembering the arrangement of the carpal bones is “So Long To Pinky, Here Comes The Thumb.” This mnemonic starts on the lateral side and names the proximal bones from lateral to medial (scaphoid, lunate, triquetrum, pisiform), then makes a U-turn to name the distal bones from medial to lateral (hamate, capitate, trapezoid, trapezium). Thus, it starts and finishes on the lateral side.",True,Carpal Bones,,,,
+8df2c9d2-f811-4a02-b7b9-e49543990009,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The carpal bones form the base of the hand. This can be seen in the radiograph (X-ray image) of the hand that shows the relationships of the hand bones to the skin creases of the hand (see Figure 8.2.4). Within the carpal bones, the four proximal bones are united to each other by ligaments to form a unit. Only three of these bones, the scaphoid, lunate, and triquetrum, contribute to the radiocarpal joint. The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad (creating a space in the X-ray in Figure 8.2.4 between the ulna and the triquetrum). The distal end of the ulna thus does not directly articulate with any of the carpal bones.",True,Carpal Bones,Figure 8.2.4,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/814_Radiograph_of_Hand.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek
+24904c00-574e-4139-bdc7-cd5961cffe25,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The four distal carpal bones are also held together as a group by ligaments. The proximal and distal rows of carpal bones articulate with each other to form the midcarpal joint (see Figure 8.2.4). Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The distal carpal bones also articulate with the metacarpal bones of the hand.",True,Carpal Bones,Figure 8.2.4,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/814_Radiograph_of_Hand.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek
+e898b77a-7031-453a-a72b-3eedabc9531f,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"In the articulated hand, the carpal bones form a U-shaped grouping. A strong ligament called the flexor retinaculum spans the top of this U-shaped area to maintain this grouping of the carpal bones (Figure 8.2.5). The flexor retinaculum is attached laterally to the trapezium and scaphoid bones, and medially to the hamate and pisiform bones. Together, the carpal bones and the flexor retinaculum form a passageway called the carpal tunnel, with the carpal bones forming the walls and floor, and the flexor retinaculum forming the roof of this space. The tendons of nine muscles of the anterior forearm and an important nerve (the median nerve) pass through this narrow tunnel to enter the hand. Overuse of the muscle tendons or wrist injury can produce inflammation and swelling within this space. This produces compression of the nerve, resulting in carpal tunnel syndrome, which is characterized by pain or numbness, and muscle weakness in those areas of the hand supplied by this nerve.",True,Carpal Bones,Figure 8.2.5,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/815_The_Carpal_Tunnel.jpg,"Figure 8.2.5 – Carpal Tunnel: The carpal tunnel is the passageway by which nine muscle tendons and the median nerve enter the hand from the anterior forearm. The walls and floor of the carpal tunnel are formed by the U-shaped grouping of the carpal bones, and the roof is formed by the flexor retinaculum, a strong ligament that anteriorly unites the bones."
+0ba09c92-6aea-4f0c-90c2-4a86d23d4f98,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Metacarpal Bones,False,Metacarpal Bones,,,,
+358b0607-30f9-4d2d-a5bb-f31caac8c56f,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The palm of the hand contains five elongated metacarpal bones. These bones lie between the carpal bones of the wrist and the bones of the fingers and thumb (see Figure 8.2.3). The proximal end of each metacarpal bone articulates with one of the distal carpal bones. Each of these articulations is a carpometacarpal joint (see Figure 8.2.4). The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers. The distal end also forms the knuckles of the hand, at the base of the fingers. The metacarpal bones are numbered 1–5, beginning at the thumb.",True,Metacarpal Bones,Figure 8.2.3,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+ef0565af-aaf6-4061-b8f1-d847ccd45dcc,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. This allows it a freedom of motion that is independent of the other metacarpal bones, which is very important for thumb mobility. The remaining metacarpal bones are united together to form the palm of the hand. The second and third metacarpal bones are firmly anchored in place and are immobile. However, the fourth and fifth metacarpal bones have limited anterior-posterior mobility, a motion that is greater for the fifth bone. This mobility is important during power gripping with the hand (Figure 8.2.6). The anterior movement of these bones, particularly the fifth metacarpal bone, increases the strength of contact for the medial hand during gripping actions.",True,Metacarpal Bones,Figure 8.2.6,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/816_Hand_Gripping.jpg,"Figure 8.2.6 – Hand During Gripping: During tight gripping—compare (b) to (a)—the fourth and, particularly, the fifth metatarsal bones are pulled anteriorly. This increases the contact between the object and the medial side of the hand, thus improving the firmness of the grip."
+d6ce531f-78d0-4ae5-8dff-901f6cd6e710,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,Phalanx Bones,False,Phalanx Bones,,,,
+ef2ce10d-3190-4d8c-bffc-6ae415faab04,https://open.oregonstate.education/aandp/,8.2 Bones of the Upper Limb,https://open.oregonstate.education/aandp/chapter/8-2-bones-of-the-upper-limb/,"The fingers and thumb contain 14 bones, each of which is called a phalanx bone (plural = phalanges), named after the ancient Greek phalanx (a rectangular block of soldiers). The thumb (pollex) is digit number 1 and has two phalanges, a proximal phalanx, and a distal phalanx bone (see Figure 8.2.3). Digits 2 (index finger) through 5 (little finger) have three phalanges each, called the proximal, middle, and distal phalanx bones. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits (see Figure 8.2.4).",True,Phalanx Bones,Figure 8.2.3,8.2 Bones of the Upper Limb,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+7dc3fabe-b855-4f5e-a8a9-3f48cd15b4f0,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"Describe the bones of the pectoral girdle, and describe how the girdle unites the upper limbs with the axial skeleton",True,Phalanx Bones,,,,
+17d87bb1-51f4-46c7-a66d-2008b267e2ea,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The bones that attach each upper limb to the axial skeleton form the pectoral girdle (shoulder girdle). This consists of two bones, the scapula and clavicle (Figure 8.1.1). The clavicle (collarbone) is an S-shaped bone located on the anterior side of the shoulder. It is attached on its medial end to the sternum of the thoracic cage, which is part of the axial skeleton. The lateral end of the clavicle articulates (joins) with the scapula just above the shoulder joint. You can easily palpate, or feel with your fingers, the entire length of your clavicle.",True,Phalanx Bones,Figure 8.1.1,8.1 The Pectoral Girdle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+762f8479-d10a-4a62-a91b-59efc231f5a6,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The scapula (shoulder blade) lies on the posterior aspect of the shoulder. It articulates with the humerus (arm bone) to form the shoulder joint (the glenohumeral joint). The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface. This ridge extends out laterally, where it forms the bony tip of the shoulder and joins with the lateral end of the clavicle. By following along the clavicle, you can palpate out to the bony tip of the shoulder, and from there, you can move back across your posterior shoulder to follow the ridge of the scapula. Move your shoulder around and feel how the clavicle and scapula move together as a unit. Both of these bones serve as important attachment sites for muscles that aid with movements of the shoulder and arm.",True,Phalanx Bones,,,,
+a3c5b6fb-f052-49fe-a185-ddc0a198d444,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The right and left pectoral girdles are not joined to each other, allowing each to operate independently. In addition, the clavicle of each pectoral girdle is anchored to the axial skeleton by a single, highly mobile joint (the sternoclavicular joint). This allows for the extensive mobility of the entire pectoral girdle, which in turn enhances movements of the shoulder and upper limb.",True,Phalanx Bones,,,,
+08bba117-0082-4dca-8d0b-1fb16239ad36,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,Clavicle,False,Clavicle,,,,
+5111dc21-8b2f-42df-9789-3863ce7c9e65,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The clavicle is the only long bone that lies in a horizontal position in the body (see Figure 8.1.1). The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb. The clavicle also transmits forces acting on the upper limb to the sternum and axial skeleton. Finally, it serves to protect the underlying nerves and blood vessels as they pass between the trunk of the body and the upper limb.",True,Clavicle,Figure 8.1.1,8.1 The Pectoral Girdle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+2106c9f8-d0f7-4913-9f92-9ef114193a7c,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The clavicle has three regions: the medial end, the lateral end, and the shaft. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. This forms the sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. This joint allows considerable mobility, enabling the clavicle and scapula to move in upward/downward and anterior/posterior directions during shoulder movements. The sternoclavicular joint is indirectly supported by the costoclavicular ligament (costo- = “rib”), which spans the sternal end of the clavicle and the underlying first rib. The lateral or acromial end of the clavicle articulates with the acromion of the scapula, the portion of the scapula that forms the bony tip of the shoulder. There are some sex differences in the morphology of the clavicle. In women, the clavicle tends to be shorter, thinner, and less curved. In men, the clavicle is heavier and longer, and has a greater curvature and rougher surfaces where muscles attach.",True,Clavicle,,,,
+d53d5a6b-e213-48b5-9485-e11c3bdabf8e,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The clavicle is the most commonly fractured bone in the body. Such breaks often occur because of the force exerted on the clavicle when a person falls onto his or her outstretched arm, or when the lateral shoulder receives a strong blow. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. If the fracture is complete, the shoulder and lateral clavicle fragment will drop due to the weight of the upper limb, causing the person to support the sagging limb with their other hand. Muscles acting across the shoulder will also pull the shoulder and lateral clavicle anteriorly and medially, causing the clavicle fragments to overlap. The clavicle overlies many important blood vessels and nerves for the upper limb, but fortunately, due to the anterior displacement of a broken clavicle, these structures are rarely affected when the clavicle is fractured.",True,Clavicle,,,,
+0e062ad7-ba72-4413-a3a8-925c4181a803,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,Scapula,False,Scapula,,,,
+2ee245a4-d917-428b-b484-5db504719766,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The scapula is also part of the pectoral girdle and thus plays an important role in anchoring the upper limb to the body. The scapula is located on the posterior side of the shoulder. It is surrounded by muscles on both its anterior (deep) and posterior (superficial) sides, and it does not directly articulate with the ribs of the thoracic cage.",True,Scapula,,,,
+ab46ea20-07c0-4f82-97e0-a9cc5fddc31c,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The scapula has several important landmarks (Figure 8.1.2). The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. The suprascapular notch is located lateral to the midpoint of the superior border. The corners of the triangular scapula, at either end of the medial border, are the superior angle of the scapula, located between the medial and superior borders, and the inferior angle of the scapula, located between the medial and lateral borders. The inferior angle is the most inferior portion of the scapula, and is particularly important because it serves as the attachment point for several powerful muscles involved in shoulder and upper limb movements. The remaining corner of the scapula, between the superior and lateral borders, is the location of the glenoid cavity (glenoid fossa). This shallow depression articulates with the humerus bone of the arm to form the glenohumeral joint (shoulder joint, see Chapter 9). The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. These provide attachments for muscles of the arm.",True,Scapula,Figure 8.1.2,8.1 The Pectoral Girdle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/803_The_Scapula_revised-1024x438.png,"Figure 8.1.2 – Scapula: The isolated scapula is shown here from its anterior (deep) side, lateral side and its posterior (superficial) side."
+037776e6-f1cf-4f56-96a6-0978898704e0,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The scapula also has two prominent projections. Toward the lateral end of the superior border, between the suprascapular notch and glenoid cavity, is the hook-like coracoid process (coracoid = “shaped like a crow’s beak”). This process projects anteriorly and curves laterally. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle. It is anchored to the clavicle by a strong ligament, and serves as the attachment site for muscles of the anterior chest and arm. On the posterior aspect, the spine of the scapula is a long and prominent ridge that runs across its upper portion. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. The acromion forms the bony tip of the superior shoulder region and articulates with the lateral end of the clavicle, forming the acromioclavicular joint (see Figure 8.1.1). When visualized from above, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.",True,Scapula,Figure 8.1.1,8.1 The Pectoral Girdle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+c31379f0-7935-45a7-a13f-b76fc203dbc6,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The scapula has three depressions, each of which is called a fossa (plural = fossae). Two of these are found on the posterior scapula, above and below the scapular spine. Superior to the spine is the narrow supraspinous fossa, and inferior to the spine is the broad infraspinous fossa. The anterior (deep) surface of the scapula forms the broad subscapular fossa. All of these fossae provide large surface areas for the attachment of muscles that cross the shoulder joint to act on the humerus.",True,Scapula,,,,
+7683f56e-7a54-4597-8ae1-52c348a71da9,https://open.oregonstate.education/aandp/,8.1 The Pectoral Girdle,https://open.oregonstate.education/aandp/chapter/8-1-the-pectoral-girdle/,"The acromioclavicular joint transmits forces from the upper limb to the clavicle. The ligaments around this joint are relatively weak. A hard fall onto the elbow or outstretched hand can stretch or tear the acromioclavicular ligaments, resulting in a moderate injury to the joint. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament (see Figure 8.1.1). This connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle and thus provides important indirect support for the acromioclavicular joint. Following a strong blow to the lateral shoulder, such as when a hockey player is driven into the boards, a complete dislocation of the acromioclavicular joint can result. In this case, the acromion is thrust under the acromial end of the clavicle, resulting in ruptures of both the acromioclavicular and coracoclavicular ligaments. The scapula then separates from the clavicle, with the weight of the upper limb pulling the shoulder downward. This dislocation injury of the acromioclavicular joint is known as a “shoulder separation” and is common following a bicycle accident, or during contact sports.",True,Scapula,Figure 8.1.1,8.1 The Pectoral Girdle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+da493b69-07e0-47f7-9b0c-239033f6343b,https://open.oregonstate.education/aandp/,8.0 Introduction,https://open.oregonstate.education/aandp/chapter/8-0-introduction/,"Your skeleton provides the internal supporting structure of the body. The adult axial skeleton consists of 80 bones that form the head and body trunk. Attached to this are the limbs, whose 126 bones constitute the appendicular skeleton (Figure 8.0.2). These bones are divided into two groups: the bones that are located within the limbs themselves, and the girdle bones that attach the limbs to the axial skeleton. The bones of the shoulder region form the pectoral girdle, which anchors the upper limb to the thoracic cage of the axial skeleton. The lower limb is attached to the vertebral column by the pelvic girdle.",True,Scapula,Figure 8.0.2,8.0 Introduction,https://open.oregonstate.education/app/uploads/sites/157/2021/02/801_Appendicular_Skeleton.jpg,"Figure 8.0.2 – Axial and Appendicular Skeletons: The axial skeleton forms the central axis of the body and consists of the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of the pectoral and pelvic girdles, the limb bones, and the bones of the hands and feet."
+a9e366bc-4332-4501-90ad-1b584289bb1b,https://open.oregonstate.education/aandp/,8.0 Introduction,https://open.oregonstate.education/aandp/chapter/8-0-introduction/,"Because of our upright stance, different functional demands are placed upon the upper and lower limbs. Thus, the bones of the lower limbs are adapted for weight-bearing support and stability, as well as for body locomotion via walking or running. In contrast, our upper limbs are not required for these functions. Instead, our upper limbs are highly mobile and can be utilized for a wide variety of activities. The large range of upper limb movements, coupled with the ability to easily manipulate objects with our hands and opposable thumbs, has allowed humans to construct the modern world in which we live.",True,Scapula,,,,
+534ec173-1e3b-4aa2-9acf-5a0ca0757955,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,Discuss the embryonic development of the axial skeleton,False,Discuss the embryonic development of the axial skeleton,,,,
+c95111b3-5390-4c76-88ce-1bfd17defa83,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"The axial skeleton begins to form during early embryonic development. However, growth, remodeling, and ossification (bone formation) continue for several decades after birth before the adult skeleton is fully formed. Knowledge of the developmental processes that give rise to the skeleton is important for understanding the abnormalities that may arise in skeletal structures.",True,Discuss the embryonic development of the axial skeleton,,,,
+c55c128e-14b9-44b2-a879-763bebea49bd,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,Development of the Skull,False,Development of the Skull,,,,
+e50e70fc-9467-4831-b74a-7713ace13a25,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"During the third week of embryonic development, a rod-like structure called the notochord develops dorsally along the length of the embryo. The tissue overlying the notochord enlarges and forms the neural tube, which will give rise to the brain and spinal cord. By the fourth week, mesoderm tissue located on either side of the notochord thickens and separates into a repeating series of block-like tissue structures, each of which is called a somite. As the somites enlarge, each one will split into several parts. The most medial of these parts is called a sclerotome. The sclerotomes consist of an embryonic tissue called mesenchyme, which will give rise to the fibrous connective tissues, cartilages, and bones of the body.",True,Development of the Skull,,,,
+cd62ae65-0027-4d22-8a22-0115b9fde011,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"The bones of the skull arise from mesenchyme during embryonic development in two different ways. The first mechanism produces the bones that form the top and sides of the brain case. This involves the local accumulation of mesenchymal cells at the site of the future bone. These cells then differentiate directly into bone producing cells, which form the skull bones through the process of intramembranous ossification. As the cranial bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle (Figure 7.6.1). The fontanelles are the soft spots on an infant’s head. They are important during birth because these areas allow the skull to change shape as it squeezes through the birth canal. As part of the newborn exam, fontanelles are palpated for bulging which indicates increased intracranial pressure often associated with hydrocephalus. After birth, the fontanelles allow for continued growth and expansion of the skull as the brain enlarges. The largest fontanelle is located on the anterior head, at the junction of the frontal and parietal bones. The fontanelles decrease in size and disappear by age 2. However, the skull bones remained separated from each other at the sutures, which contain dense fibrous connective tissue that unites the adjacent bones. The connective tissue of the sutures allows for continued growth of the skull bones as the brain enlarges during childhood growth.",True,Development of the Skull,Figure 7.6.1,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/702_Newborn_Skull-01.jpg,"Figure 7.6.1 – Newborn Skull: The bones of the newborn skull are not fully ossified and are separated by large areas called fontanelles, which are filled with fibrous connective tissue. The fontanelles allow for continued growth of the brain and skull after birth. At the time of birth, the facial bones are small and underdeveloped, and the mastoid process has not yet formed."
+02ce616a-c52a-4bf3-b366-3200c826b8fa,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"The second mechanism for bone development in the skull produces the facial bones and floor of the brain case. This also begins with the localized accumulation of mesenchymal cells. However, these cells differentiate into cartilage cells, which produce a hyaline cartilage model of the future bone. As this cartilage model grows, it is gradually converted into bone through the process of endochondral ossification. This is a slow process and the cartilage is not completely converted to bone until the skull achieves its full adult size.",True,Development of the Skull,,,,
+154455e9-3ac9-4ceb-85e7-471e2e5c408e,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"At birth, the brain case and orbits of the skull are disproportionally large compared to the bones of the jaws and lower face. This reflects the relative underdevelopment of the maxilla and mandible, which lack teeth, and the small sizes of the paranasal sinuses and nasal cavity. During early childhood, the mastoid process enlarges, the two halves of the mandible and frontal bone fuse together to form single bones, and the paranasal sinuses enlarge. The jaws also expand as the teeth begin to appear. These changes all contribute to the rapid growth and enlargement of the face during childhood.",True,Development of the Skull,,,,
+e3c720e5-1252-4580-a382-1a4facd054b1,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,Development of the Vertebral Column and Thoracic cage,False,Development of the Vertebral Column and Thoracic cage,,,,
+f91e2c94-1106-4c39-a50f-52349523e012,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"Development of the vertebrae begins with the accumulation of mesenchyme cells from each sclerotome around the notochord. These cells differentiate into a hyaline cartilage model for each vertebra, which then grow and eventually ossify into bone through the process of endochondral ossification. As the developing vertebrae grow, the notochord largely disappears. However, small areas of notochord tissue persist between the adjacent vertebrae as the nucleus pulposus and this contributes to the formation of each intervertebral disc.",True,Development of the Vertebral Column and Thoracic cage,,,,
+188f0d91-8567-4c6f-8c87-7c13fd4814f2,https://open.oregonstate.education/aandp/,7.6 Embryonic Development of the Axial Skeleton,https://open.oregonstate.education/aandp/chapter/7-6-embryonic-development-of-the-axial-skeleton/,"The ribs and sternum also develop from mesenchyme. The ribs initially develop as part of the cartilage model for each vertebra, but in the thorax region, the rib portion separates from the vertebra by the eighth week. The cartilage model of the rib then ossifies, except for the anterior portion, which remains as the costal cartilage. The sternum initially forms as paired hyaline cartilage models on either side of the anterior midline, beginning during the fifth week of development. The cartilage models of the ribs become attached to the lateral sides of the developing sternum. Eventually, the two halves of the cartilaginous sternum fuse together along the midline and then ossify into bone. The manubrium and body of the sternum are converted into bone first, with the xiphoid process remaining as cartilage until late in life.",True,Development of the Vertebral Column and Thoracic cage,,,,
+163c34e4-9249-4834-9621-cfefbd774543,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,Describe the components of the thoracic cage,False,Describe the components of the thoracic cage,,,,
+fdf3a0b3-e9f4-4b80-98f2-6b33db56a689,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,The thoracic cage (rib cage) forms the thorax (chest) portion of the body. It consists of the 12 pairs of ribs with their costal cartilages and the sternum (Figure 7.5.1). The ribs are anchored posteriorly to the 12 thoracic vertebrae (T1–T12). The thoracic cage protects the heart and lungs.,True,Describe the components of the thoracic cage,Figure 7.5.1,7.5 The Thoracic Cage,https://open.oregonstate.education/app/uploads/sites/157/2019/07/721_Rib_Cage.jpg,"Figure 7.5.1 – Thoracic Cage: The thoracic cage is formed by the (a) sternum and (b) 12 pairs of ribs with their costal cartilages. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The ribs are classified as true ribs (1–7) and false ribs (8–12). The last two pairs of false ribs are also known as floating ribs (11–12)."
+f0cc8805-ddf0-4989-8b64-fb64b8f5d10e,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,Sternum,False,Sternum,,,,
+49487449-909c-4910-aa64-5e148eec43ca,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,"The sternum is the elongated bony structure that anchors the anterior thoracic cage. It consists of three parts: the manubrium, body, and xiphoid process. The manubrium is the wider, superior portion of the sternum. The top of the manubrium has a shallow, U-shaped border called the jugular (suprasternal) notch. This can be easily felt at the anterior base of the neck, between the medial ends of the clavicles. The clavicular notch is the shallow depression located on either side at the superior-lateral margins of the manubrium. This is the site of the sternoclavicular joint, between the sternum and clavicle. The first ribs also attach to the manubrium.",True,Sternum,,,,
+853d7fc3-95be-435e-8022-8329baa9b925,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,"The elongated, central portion of the sternum is the body. The manubrium and body join together at the sternal angle, so called because the junction between these two components is not flat, but forms a slight bend. The second rib attaches to the sternum at the sternal angle. Since the first rib is hidden behind the clavicle, the second rib is the highest rib that can be identified by palpation. Thus, the sternal angle and second rib are important landmarks for the identification and counting of the lower ribs. Ribs 3–7 attach to the sternal body. When assessing a patient’s level of alertness sometimes a sternal rub is performed with the knuckles to see if they respond to pain.",True,Sternum,,,,
+1ed1b2e8-0216-4e3c-bbe0-f33d2a98de93,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,"The inferior tip of the sternum is the xiphoid process. This small structure is cartilaginous early in life, but gradually becomes ossified starting during middle age.",True,Sternum,,,,
+45f4feea-4aa6-45df-b2ac-4b4c86e9e350,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,Ribs,False,Ribs,,,,
+e00387ea-a967-4201-b242-1030d418a6b7,https://open.oregonstate.education/aandp/,7.5 The Thoracic Cage,https://open.oregonstate.education/aandp/chapter/7-5-the-thoracic-cage/,"Each rib is a curved, flattened bone that contributes to the wall of the thorax. The ribs articulate posteriorly with the T1–T12 thoracic vertebrae, and most attach anteriorly via their costal cartilages to the sternum. There are 12 pairs of ribs. The ribs are numbered 1–12 in accordance with the thoracic vertebrae.",True,Ribs,,,,
+7f9a7599-81cb-446e-bbf6-4026a5e51ef9,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,Discuss the vertebral column and regional variations in its bony components and curvatures,True,Ribs,,,,
+c3292362-673c-4105-a01b-4237b1463b69,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The vertebral column is also known as the spinal column (Figure 7.4.1). It consists of a sequence of vertebrae (singular = vertebra), each of which is separated and united by a cartilaginous intervertebral disc. Together, the vertebrae and intervertebral discs form the vertebral column. It is a flexible column that supports the head, neck, and body and allows for their movements. It also protects the spinal cord, which passes through openings in the vertebrae.",True,Ribs,Figure 7.4.1,7.4 The Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2019/07/715_Vertebral_Column.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves)."
+c207ba96-bca1-40bc-b984-80ce7274c591,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,Regions of the Vertebral Column,False,Regions of the Vertebral Column,,,,
+46625fe8-a901-4d92-be6d-a42d3c9eb0c2,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The vertebral column originally develops as a series of 33 vertebrae, but this number is eventually reduced to 24 vertebrae, plus the fused vertebrae comprising the sacrum and coccyx. The vertebral column is subdivided into five regions, with the vertebrae in each area named for that region and numbered in descending order. In the neck, there are seven cervical vertebrae, each designated with the letter “C” followed by its number. Superiorly, the C1 vertebra articulates (forms a joint) with the occipital condyles of the skull. Inferiorly, C1 articulates with the C2 vertebra, and so on. Below these are the 12 thoracic vertebrae, designated T1–T12. The lower back contains the L1–L5 lumbar vertebrae. The single sacrum, which is also part of the pelvis, is formed by the fusion of five sacral vertebrae, though in about 33% percent of the population T12 is fused to the sacrum or S1 remains unfused. This is called transitional anatomy. Similarly, the coccyx, or tailbone, results from the fusion of four (or in some cases 3 or 5) small coccygeal vertebrae. However, the sacral and coccygeal fusions do not start until age 20 and are not completed until middle age.",True,Regions of the Vertebral Column,,,,
+a7a75be7-53c4-429f-8331-efeac9ccae2a,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"An interesting anatomical fact is that almost all mammals have seven cervical vertebrae, regardless of body size. This means that there are large variations in the size of cervical vertebrae, ranging from the very small cervical vertebrae of a shrew to the greatly elongated vertebrae in the neck of a giraffe. In a full-grown giraffe, each cervical vertebra is 11 inches tall.",True,Regions of the Vertebral Column,,,,
+4b2ce4f4-9c13-4fc4-8989-5307a3c8e819,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,Curvatures of the Vertebral Column,False,Curvatures of the Vertebral Column,,,,
+f6cd8fc5-07dc-487e-b51c-9826d94cbb04,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The adult vertebral column does not form a straight line, but instead has four curvatures along its length (see Figure 7.4.1). These curves increase the vertebral column’s strength, flexibility, and ability to absorb shock. When the load on the spine is increased, by carrying a heavy backpack for example, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spring back when the weight is removed. The four adult curvatures are classified as either primary or secondary curvatures. Primary curvatures are retained from the original fetal curvature, while secondary curvatures develop after birth.",True,Curvatures of the Vertebral Column,Figure 7.4.1,7.4 The Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2019/07/715_Vertebral_Column.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves)."
+f21d27c0-d54f-4499-9d8b-6e6a0cfd5b24,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"During fetal development, the body is flexed anteriorly into the fetal position, giving the entire vertebral column a single curvature that is concave anteriorly. In the adult, this primary curvature is retained in two regions of the vertebral column as the thoracic curve, which involves the thoracic vertebrae, and the sacrococcygeal curve, formed by the sacrum and coccyx.",True,Curvatures of the Vertebral Column,,,,
+ec24854a-92e4-4611-bc1c-8838397a4c89,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"A secondary curve develops gradually after birth as the child learns to sit upright, stand, and walk. Secondary curves are concave posteriorly, opposite in direction to the original fetal curvature. The cervical curve of the neck region develops as the infant begins to hold their head upright when sitting. Later, as the child begins to stand and then to walk, the lumbar curve of the lower back develops. In adults, the lumbar curve is generally deeper in females.",True,Curvatures of the Vertebral Column,,,,
+9d736e9d-3dd4-467d-beb2-73dd2ff7558a,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"Disorders associated with the curvature of the spine include kyphosis (an excessive posterior curvature of the thoracic region), lordosis (an excessive anterior curvature of the lumbar region), and scoliosis (an abnormal, lateral curvature, accompanied by twisting of the vertebral column).",True,Curvatures of the Vertebral Column,,,,
+22710eb7-05cf-469e-8657-def6407e5790,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,General Structure of a Vertebra,False,General Structure of a Vertebra,,,,
+576b209b-80f7-46d2-9917-24e66d6053d7,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"Within the different regions of the vertebral column, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral arch, and seven processes (Figure 7.4.4).",True,General Structure of a Vertebra,Figure 7.4.4,7.4 The Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2021/02/718_Vertebra.jpg,"Figure 7.4.4 – Parts of a Typical Vertebra: A typical vertebra consists of a body and a vertebral arch. The arch is formed by the paired pedicles and paired laminae. Arising from the vertebral arch are the transverse, spinous, superior articular, and inferior articular processes. The vertebral foramen provides for passage of the spinal cord. Each spinal nerve exits through an intervertebral foramen, located between adjacent vertebrae. Intervertebral discs unite the bodies of adjacent vertebrae."
+320b9033-4dca-420f-87b9-9cd5f6eddfaa,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The body is the anterior portion of each vertebra and is the part that supports the body weight. Because of this, the vertebral bodies progressively increase in size and thickness going down the vertebral column. The bodies of adjacent vertebrae are separated and strongly united by an intervertebral disc.",True,General Structure of a Vertebra,,,,
+671c508c-25df-4a21-a4ca-98c94d5041c6,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The vertebral arch forms the posterior portion of each vertebra. It consists of four parts, the right and left pedicles and the right and left laminae. Each pedicle forms one of the lateral sides of the vertebral arch. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms part of the posterior roof of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen, which contains the spinal cord. In the intact vertebral column, the vertebral foramina of all of the vertebrae align to form the vertebral (spinal) canal, which serves as the bony protection and passageway for the spinal cord down the back. When the vertebrae are aligned together in the vertebral column, notches in the margins of the pedicles of adjacent vertebrae together form an intervertebral foramen, the opening through which a spinal nerve exits from the vertebral column (Figure 7.4.5).",True,General Structure of a Vertebra,Figure 7.4.5,7.4 The Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2021/02/716_Intervertebral_Disk.jpg,"Figure 7.4.5 – Intervertebral Disc: The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The intervertebral foramen is the opening formed between adjacent vertebrae for the exit of a spinal nerve."
+aead9cd7-7ad7-43ae-b7e4-185092e24129,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"Seven processes arise from the vertebral arch. Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina. The single spinous process (vertebral spine) projects posteriorly at the midline of the back. The vertebral spines can easily be felt as a series of bumps just under the skin down the middle of the back. The transverse and spinous processes serve as important muscle attachment sites. A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of a vertebrae. Facets of the paired superior articular processes of one vertebra articulate with corresponding facets of the paired inferior articular processes from the next higher vertebra. These junctions form slightly moveable joints between the adjacent vertebrae. The shape and orientation of the articular processes vary in different regions of the vertebral column and play a major role in determining the type and range of motion available in each region.",True,General Structure of a Vertebra,,,,
+42674ca5-7f82-4edb-9a13-b8eee7db025d,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,Regional Modifications of Vertebrae,False,Regional Modifications of Vertebrae,,,,
+8df6b76a-4c2e-417d-b013-090c7340786f,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"In addition to the general characteristics of a typical vertebra described above, vertebrae also display characteristic size and structural features that vary between the different vertebral column regions. Thus, cervical vertebrae are smaller than lumbar vertebrae due to differences in the proportion of body weight that each supports. Thoracic vertebrae have sites for rib attachment, and the vertebrae that give rise to the sacrum and coccyx are fused together into single bones.",True,Regional Modifications of Vertebrae,,,,
+99a7df0c-f3cd-4dd2-a7a4-4a63cb70c178,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,Intervertebral Discs and Ligaments of the Vertebral Column,False,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+58f3d82c-8e19-41a5-98cf-624a62fddcd8,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"The bodies of adjacent vertebrae are strongly anchored to each other by an intervertebral disc. This structure provides padding between the bones during weight bearing, and because it can change shape, also allows for movement between the vertebrae. Although the total amount of movement available between any two adjacent vertebrae is small, when these movements are summed together along the entire length of the vertebral column, large body movements can be produced. Ligaments that extend along the length of the vertebral column also contribute to its overall support and stability.",True,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+978ef113-66ff-451e-af44-1bd6d0b703e9,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"Chiropractors are health professionals who use nonsurgical techniques to help patients with musculoskeletal system problems that involve the bones, muscles, ligaments, tendons, or nervous system. They treat problems such as neck pain, back pain, joint pain, or headaches. Chiropractors focus on the patient’s overall health and can also provide counseling related to lifestyle issues, such as diet, exercise, or sleep problems. If needed, they will refer the patient to other medical specialists.",True,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+bc3951e7-2ad3-4dcd-8f22-204c45f33fc4,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"Chiropractors use a drug-free, hands-on approach for patient diagnosis and treatment. They will perform a physical exam, assess the patient’s posture and spine, and may perform additional diagnostic tests, including taking X-ray images. They primarily use manual techniques, such as spinal manipulation, to adjust the patient’s spine or other joints. They can recommend therapeutic or rehabilitative exercises, and some also include acupuncture, massage therapy, or ultrasound as part of the treatment program. In addition to those in general practice, some chiropractors specialize in sport injuries, neurology, orthopaedics, pediatrics, nutrition, internal disorders, or diagnostic imaging.",True,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+5a5e5d8d-8436-4808-b962-87931a0e70f8,https://open.oregonstate.education/aandp/,7.4 The Vertebral Column,https://open.oregonstate.education/aandp/chapter/7-4-the-vertebral-column/,"To become a chiropractor, students must have 3–4 years of undergraduate education, attend an accredited, four-year Doctor of Chiropractic (D.C.) degree program, and pass a licensure examination to be licensed for practice in their state. With the aging of the baby-boom generation, employment for chiropractors is expected to increase.",True,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+25672b6c-44f3-4424-a9b7-ff193aebfb04,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The skull is the skeletal structure of the head that supports the face and protects the brain. It is subdivided into the facial bones and the cranium, or cranial vault (Figure 7.3.1). The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. The rounded cranium surrounds and protects the brain and houses the middle and inner ear structures.",True,Intervertebral Discs and Ligaments of the Vertebral Column,Figure 7.3.1,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2019/07/703_Parts_of_Skull_revised-1024x842.png,"Figure 7.3.1 – Parts of the Skull: The skull consists of the rounded cranium that houses the brain and the facial bones that form the upper and lower jaws, nose, orbits, and other facial structures."
+8117acc1-39bd-4345-a318-a207fccfa77d,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"In the adult, the skull consists of 22 individual bones, 21 of which are immobile and united into a single unit. The 22nd bone is the mandible (lower jaw), which is the only moveable bone of the skull.",True,Intervertebral Discs and Ligaments of the Vertebral Column,,,,
+7eb60bb4-c757-4db3-980d-4b8c7b7fc422,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Anterior View of Skull,False,Anterior View of Skull,,,,
+beaf244e-0b36-4bfc-9056-880d85529297,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The anterior skull consists of the facial bones and provides the bony support for the eyes, teeth and structures of the face and provides openings for eating and breathing. This view of the skull is dominated by the openings of the orbits and the nasal cavity. Also seen are the upper and lower jaws, with their respective teeth (Figure 7.3.2).",True,Anterior View of Skull,Figure 7.3.2,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/704_Skull-01.jpg,"Figure 7.3.2 – Anterior View of Skull: An anterior view of the skull shows the bones that form the forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws."
+3beb88f5-aba6-4804-9e87-c66bb03cbb80,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The orbit is the bony socket that houses the eyeball and muscles that move the eyeball or open the upper eyelid. The upper margin of the anterior orbit is the supraorbital margin. Located near the midpoint of the supraorbital margin is a small opening called the supraorbital foramen. This provides for passage of a sensory nerve to the skin of the forehead. Below the orbit is the infraorbital foramen, which is the point of emergence for a sensory nerve that supplies the anterior face below the orbit.",True,Anterior View of Skull,,,,
+43dc065c-9a33-4c25-9ecc-2ca4cc496962,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"Inside the nasal area of the skull, the nasal cavity is divided into halves by the nasal septum. The upper portion of the nasal septum is formed by the perpendicular plate of the ethmoid bone and the lower portion is the vomer bone. When looking into the nasal cavity from the front of the skull, two bony plates are seen projecting from each lateral wall. The larger of these is the inferior nasal concha, an independent bone of the skull. Located just above the inferior concha is the middle nasal concha, which is part of the ethmoid bone. A third bony plate, also part of the ethmoid bone, is the superior nasal concha. It is much smaller and out of sight, above the middle concha. The superior nasal concha is located just lateral to the perpendicular plate, in the upper nasal cavity.",True,Anterior View of Skull,,,,
+07232571-8d40-4500-9d54-8703478d8659,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Lateral View of Skull,False,Lateral View of Skull,,,,
+57df196b-b112-4539-a5ab-16728fc92241,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"A view of the lateral skull is dominated by the large, rounded cranium above and the upper and lower jaws with their teeth below (Figure 7.3.3). Separating these areas is the bridge of bone called the zygomatic arch. The zygomatic arch (cheekbone) is the bony arch on the side of skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes: a short anterior component, the temporal process of the zygomatic bone and a longer posterior portion, the zygomatic process of the temporal bone, extending forward from the temporal bone. Thus the temporal process (anteriorly) and the zygomatic process (posteriorly) join together, like the two ends of a drawbridge, to form the zygomatic arch. One of the major muscles that pulls the mandible upward during biting and chewing, the masseter, arises from the zygomatic arch.",True,Lateral View of Skull,Figure 7.3.3,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lateral-sagittal_skull-795x1024.png,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum."
+066b7070-59c3-4f32-acf4-298959fca1a9,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"On the lateral side of the cranium, above the level of the zygomatic arch, is a shallow space called the temporal fossa. Arising from the temporal fossa and passing deep to the zygomatic arch is another muscle that acts on the mandible during chewing, the temporalis.",True,Lateral View of Skull,,,,
+c0904f4d-9fdf-428e-8bc9-d72f0f0677d1,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Bones of the Cranium,False,Bones of the Cranium,,,,
+684e7888-0257-4221-ad0a-dee2929a565a,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The cranium contains and protects the brain. The interior space that is almost completely occupied by the brain is called the cranial cavity. This cavity is bounded superiorly by the rounded top of the skull, which is called the calvaria (skullcap), and the lateral and posterior sides of the skull. The bones that form the top and sides of the cranium are usually referred to as the “flat” bones of the skull.",True,Bones of the Cranium,,,,
+95bcc992-26c0-4f08-85ba-d673e07ed01e,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The floor of the brain case is referred to as the base of the skull or cranial floor. This is a complex area that varies in depth and has numerous openings for the passage of cranial nerves, blood vessels, and the spinal cord. Inside the skull, the base is subdivided into three large spaces, called the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa (fossa = “trench or ditch”) (Figure 7.3.4). From anterior to posterior, the fossae increase in depth. The shape and depth of each fossa correspond to the shape and size of the brain region that each houses.",True,Bones of the Cranium,Figure 7.3.4,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/727_Cranial_Fossae_revised.png,"Figure 7.3.4 – Cranial Fossae: The bones of the brain case surround and protect the brain, which occupies the cranial cavity. The base of the brain case, which forms the floor of cranial cavity, is subdivided into the shallow anterior cranial fossa, the middle cranial fossa, and the deep posterior cranial fossa."
+cb0602db-a65f-4a2c-8438-021b7f9a6ca3,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The cranium consists of eight bones. These include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones.",True,Bones of the Cranium,,,,
+61cc38f0-6c55-4aba-b4be-008de9ccf990,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Sutures of the Skull,False,Sutures of the Skull,,,,
+f5e8911a-336c-44ab-b73f-2e022c78fcd1,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"A suture is an immobile joint between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the bones of the cranium are not straight, but instead follow irregular, tightly twisting paths. These twisting lines serve to tightly interlock the adjacent bones, thus adding strength to the skull to protect the brain.",True,Sutures of the Skull,,,,
+c2f6d7ea-8d0f-4cb9-8524-03ba511164d4,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The two suture lines seen on the top of the skull are the coronal and sagittal sutures. The coronal suture runs from side to side across the skull, within the coronal plane of section (see Figure 7.3.3). It joins the frontal bone to the right and left parietal bones. The sagittal suture extends posteriorly from the coronal suture at the intersection called bregma, running along the midline at the top of the skull in the sagittal plane of section (see Figure 7.3.8). It unites the right and left parietal bones. On the posterior skull, the sagittal suture terminates by joining the lambdoid suture at the intersection called lambda. The lambdoid suture extends downward and laterally to either side away from its junction with the sagittal suture. The lambdoid suture joins the occipital bone to the right and left parietal and temporal bones. This suture is named for its upside-down “V” shape, which resembles the capital letter version of the Greek letter lambda (Λ). The squamous suture is located on the lateral skull. It unites the squamous portion of the temporal bone with the parietal bone (see Figure 7.3.3). At the intersection of the frontal bone, parietal bone, squamous portion of the temporal bone, and greater wing of the sphenoid bone is the pterion, a small, capital-H-shaped suture line that unites the region. It is the weakest part of the skull. The pterion is located approximately two finger widths above the zygomatic arch and a thumb’s width posterior to the upward portion of the zygomatic bone.",True,Sutures of the Skull,Figure 7.3.3,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lateral-sagittal_skull-795x1024.png,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum."
+2d96efef-b39b-4017-9d64-1db15cadde0f,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Facial Bones of the Skull,False,Facial Bones of the Skull,,,,
+6ae9be01-9319-4891-bd2e-c56b7c818694,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The facial bones of the skull form the upper and lower jaws, the nose, nasal cavity and nasal septum, and the orbit. The facial bones include 14 bones, with six paired bones and two unpaired bones. The paired bones are the maxilla, palatine, zygomatic, nasal, lacrimal, and inferior nasal conchae bones. The unpaired bones are the vomer and mandible bones. Although classified with the cranial bones, the ethmoid bone also contributes to the nasal septum and the walls of the nasal cavity and orbit.",True,Facial Bones of the Skull,,,,
+f386b454-5e25-4d57-a300-f9230ff5b281,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,The Orbit,False,The Orbit,,,,
+fda04f14-e033-4126-890c-00b93b5994bb,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The orbit is the bony socket that houses the eyeball and contains the muscles that move the eyeball or open the upper eyelid. Each orbit is cone-shaped, with a narrow posterior region that widens toward the large anterior opening. To help protect the eye, the bony margins of the anterior opening are thickened and somewhat constricted. The medial walls of the two orbits are parallel to each other but each lateral wall diverges away from the midline at a 45° angle. This divergence provides greater lateral peripheral vision.",True,The Orbit,,,,
+0983328f-2bfe-4baa-8d08-4f964943c2ab,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The walls of each orbit include contributions from seven skull bones (Figure 7.3.15). The frontal bone forms the roof and the zygomatic bone forms the lateral wall and lateral floor. The medial floor is primarily formed by the maxilla, with a small contribution from the palatine bone. The ethmoid bone and lacrimal bone make up much of the medial wall and the sphenoid bone forms the posterior orbit.",True,The Orbit,Figure 7.3.15,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/713_Bones_Forming_Orbit.jpg,Figure 7.3.15 – Bones of the Orbit: Seven skull bones contribute to the walls of the orbit. Opening into the posterior orbit from the cranial cavity are the optic canal and superior orbital fissure.
+2e2ab4d1-0be4-498b-9b86-7bab936251d6,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"At the posterior apex of the orbit is the opening of the optic canal, which allows for passage of the optic nerve from the retina to the brain. Lateral to this is the elongated and irregularly shaped superior orbital fissure, which provides passage for the artery that supplies the eyeball, sensory nerves, and the nerves that supply the muscles involved in eye movements.",True,The Orbit,,,,
+c95d3352-2340-49cb-a63a-15856e2b61be,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,The Nasal Septum and Nasal Conchae,False,The Nasal Septum and Nasal Conchae,,,,
+504d8ad9-9a5d-4f62-9ae4-d6e5ae3b0daa,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The nasal septum consists of both bone and cartilage components (Figure 7.3.16; see also Figure 7.3.10). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils.",True,The Nasal Septum and Nasal Conchae,Figure 7.3.16,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/714_Bone_of_Nasal_Cavity.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.
+4cb7f1cd-f3a0-4fe1-ab0c-4cd013d5f196,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.3.12). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae are the inferior nasal conchae, which is an independent bone of the skull. The middle conchae and the superior conchae, which are the smallest, are all formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal conchae are well hidden above and behind the middle conchae.",True,The Nasal Septum and Nasal Conchae,Figure 7.3.12,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Sutures_of_the_skull-1009x1024.png,Figure 7.3.12 Sutures of the skull
+c84edbb7-6112-449a-bd9f-b1358a890d30,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Paranasal Sinuses,False,Paranasal Sinuses,,,,
+eb0a973e-f4d4-401b-8e4b-aa3201de1395,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.3.17). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion which causes swelling of the mucosa and excess mucus production, obstructing the narrow passageways between the sinuses and the nasal cavity and causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort.",True,Paranasal Sinuses,Figure 7.3.17,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/724_Paranasal_Sinuses.jpg,"Figure 7.3.17 – Paranasal Sinuses: The air-filled paranasal sinuses, each named for the bone in which it is found, drain into the nasal cavity."
+04fe0a3b-6222-4b0c-b584-99e0e6163eb9,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The paranasal sinuses are named for the skull bone that each occupies. The frontal sinus is located just above the eyebrows, within the frontal bone (see Figure 7.3.16). This irregular space may be divided at the midline into bilateral spaces, or these may be fused into a single sinus space. The frontal sinus is the most anterior of the paranasal sinuses. The largest sinus is the maxillary sinus. These are paired and located within the right and left maxillary bones, where they occupy the area just below the orbits. The maxillary sinuses are most commonly involved during sinus infections. Because their connection to the nasal cavity is located high on their medial wall, they are difficult to drain. The sphenoid sinus is a single, midline sinus. It is located within the body of the sphenoid bone, just anterior and inferior to the sella turcica, thus making it the most posterior of the paranasal sinuses. The lateral aspects of the ethmoid bone contain multiple small spaces separated by very thin bony walls. Each of these spaces is called an ethmoid air cell. These are located on both sides of the ethmoid bone, between the upper nasal cavity and medial orbit, just behind the superior nasal conchae.",True,Paranasal Sinuses,Figure 7.3.16,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/714_Bone_of_Nasal_Cavity.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.
+9758e270-ba4b-4f7b-aea9-5510148a9d38,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,Hyoid Bone,False,Hyoid Bone,,,,
+b51f023f-2f2b-4700-8bd6-4375ee78edc8,https://open.oregonstate.education/aandp/,7.3 The Skull,https://open.oregonstate.education/aandp/chapter/7-3-the-skull/,"The hyoid bone is an independent bone that does not contact any other bone and thus is not part of the skull (Figure 7.3.18). It is a small U-shaped bone located in the upper neck near the level of the inferior mandible, with the tips of the “U” pointing posteriorly. The hyoid serves as the base for the tongue above, and is attached to the larynx below and the pharynx posteriorly. The hyoid is held in position by a series of small muscles that attach to it either from above or below. These muscles act to move the hyoid up/down or forward/back. Movements of the hyoid are coordinated with movements of the tongue, larynx, and pharynx during swallowing and speaking.",True,Hyoid Bone,Figure 7.3.18,7.3 The Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/712_Hyoid_Bone_revised-805x1024.png,"Figure 7.3.18 – Hyoid Bone: The hyoid bone is located in the upper neck and does not join with any other bone. It provides attachments for muscles that act on the tongue, larynx, and pharynx."
+e3a05b2e-7842-48a7-9b82-39602c5aff7f,https://open.oregonstate.education/aandp/,7.2 Bone Markings,https://open.oregonstate.education/aandp/chapter/7-2-bone-markings/,Bone Markings,False,Bone Markings,,,,
+cb93fb2d-92bd-417e-96bf-bd8ac084bcec,https://open.oregonstate.education/aandp/,7.2 Bone Markings,https://open.oregonstate.education/aandp/chapter/7-2-bone-markings/,"The surface features of bones vary considerably, depending on the function and location in the body. Table 7.2 describes the bone markings, which are illustrated in (Figure 7.2.1). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.",True,Bone Markings,Figure 7.2.1,7.2 Bone Markings,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 7.2.1 – Bone Features: The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+b449bdd4-d7ec-410c-821f-f1ad424e3b77,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,Describe the functions of the skeletal system and define its two major subdivisions,True,Bone Markings,,,,
+36e81620-6109-46a0-a7e8-4d9c42b8bb2e,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,"The skeletal system includes all of the bones, cartilages, and ligaments of the body that support and give shape to the body and body structures, whereas the skeleton consists of the bones of the body. For adults, there are 206 named bones in the skeleton. Younger individuals have higher numbers of bones because some bones fuse together during childhood and adolescence. The primary functions of the skeleton are to provide a rigid, internal structure that protects internal organs and supports the weight of the body, and to provide a structure upon which muscles can act to produce movements of the body. The bones of the skeleton also serve as the primary storage site for important minerals such as calcium and phosphate. The bone marrow found within bones stores fat and houses the blood-cell producing tissue of the body.",True,Bone Markings,,,,
+cd30f384-7a01-44ce-bf00-a2ec6348a1be,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,The skeleton is subdivided into two major divisions—the axial and appendicular.,True,Bone Markings,,,,
+7e9da2b3-e2e3-4e23-ad38-aaf8ae6e5711,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,The Axial Skeleton,False,The Axial Skeleton,,,,
+726e8299-716f-4746-ad85-e18770c8b6c3,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,"The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 7.1.1). It serves to protect the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip joints to move their corresponding limbs.",True,The Axial Skeleton,Figure 7.1.1,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Ventral_skeleton_app-1024x803.png,"Figure 7.1.1 – Axial and Appendicular Skeleton: The axial skeleton supports the head, neck, back, and chest and thus forms the vertical axis of the body. It consists of the skull, vertebral column (including the sacrum and coccyx), and the thoracic cage, formed by the ribs and sternum. The appendicular skeleton is made up of all bones of the upper and lower limbs and the girdles which attach them to the axial skeleton."
+dc9a6048-5100-4a12-8bc3-07b8b8887949,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,"The axial skeleton of the adult consists of 80 bones, comprising the skull, the vertebral column, and the thoracic cage. The skull is formed by 22 bones. Also associated with the head are an additional seven bones, including the hyoid bone (found in the upper neck) and the ear ossicles (three small bones found in each middle ear). The vertebral column consists of 24 bones, each called a vertebra, plus the fused vertebrae of the sacrum and coccyx. The thoracic cage includes 12 pairs of ribs, and the sternum, the flattened bone of the anterior chest.",True,The Axial Skeleton,,,,
+5d5890f5-45f4-4ce8-b661-09b152318134,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,The Appendicular Skeleton,False,The Appendicular Skeleton,,,,
+6725184c-c21c-4436-b42c-6a18f648e8f7,https://open.oregonstate.education/aandp/,7.1 Divisions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/7-1-divisions-of-the-skeletal-system/,"The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones of the pectoral and pelvic girdles that attach each limb to the axial skeleton. There are 126 bones in the appendicular skeleton of an adult. The lower portion of the appendicular skeleton is specialized for stability during walking or running. In contrast, the upper portion of the appendicular skeleton has greater mobility and ranges of motion, features that allow you to lift and carry objects. The bones of the appendicular skeleton are covered in a separate chapter.",True,The Appendicular Skeleton,,,,
+0f9b3f56-507b-4732-ae15-a5e08f4ec836,https://open.oregonstate.education/aandp/,7.0 Introduction,https://open.oregonstate.education/aandp/chapter/introduction-3/,"The skeletal system forms the rigid internal framework of the body. It consists of the bones, cartilages, and ligaments. Bones support the weight of the body, allow for body movements, and protect internal organs. Cartilage provides flexible strength and support for body structures such as the thoracic cage, the external ear, and the trachea and larynx. At joints of the body, cartilage can also unite adjacent bones or provide cushioning between them. Ligaments are the strong connective tissue bands that hold the bones together at a moveable joint and serve to prevent excessive movements of the joint that would result in injury. Providing force to create movement of the skeleton are the skeletal muscles of the body, which are firmly attached to the skeleton via connective tissue structures called tendons. As muscles contract, they pull on the bones to produce movements of the body. Thus, without a skeleton, you would not be able to stand, run, or even feed yourself!",True,The Appendicular Skeleton,,,,
+d9c3412c-ce33-4a96-90f2-86a4ac54dda9,https://open.oregonstate.education/aandp/,7.0 Introduction,https://open.oregonstate.education/aandp/chapter/introduction-3/,"Each bone of the body serves a particular function, and therefore bones vary in size, shape, and strength based on these functions. For example, the bones of the lower back and lower limb are thick and strong to support your body weight. Similarly, the size of a bony landmark that serves as a muscle attachment site on an individual bone is related to the strength of this muscle. Muscles can apply very strong pulling forces to the bones of the skeleton. Due to these forces, bones develop enlarged bony landmarks at sites where powerful muscles attach. This means that not only the size of a bone, but also its shape, is related to its function. For this reason, the identification of bony landmarks is important during your study of the skeletal system.",True,The Appendicular Skeleton,,,,
+e8054b46-6bb8-4a69-a37b-84cdc67fdfcf,https://open.oregonstate.education/aandp/,7.0 Introduction,https://open.oregonstate.education/aandp/chapter/introduction-3/,"Bones are dynamic organs that can modify their density and thickness in response to application of forces and changes in body chemistry. Thus, muscle attachment sites on bones will thicken if you begin a workout program that increases muscle strength. Similarly, the walls of weight-bearing bones will thicken if you gain body weight or begin pounding the pavement as part of a new running regimen. In contrast, a reduction in muscle strength or body weight will cause bones to become thinner. This may happen during a prolonged hospital stay, following limb immobilization in a cast, or going into the weightlessness of outer space. Even a change in diet, such as eating only soft food due to the loss of teeth, will result in a noticeable decrease in the size and thickness of the jaw bones. Changes in hormones such as estrogen and testosterone also cause changes to bone mass as a normal part of development and aging.",True,The Appendicular Skeleton,,,,
+4c5f8dbb-93c1-4447-8485-11fce6ea3a52,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Calcium is not only the most abundant mineral in bone, it is also the most abundant mineral in the human body. Calcium ions are needed not only for bone mineralization but for tooth health, regulation of the heart rate and strength of contraction, blood coagulation, contraction of smooth and skeletal muscle cells, and regulation of nerve impulse conduction. The normal level of calcium in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo- or hypercalcemia.",True,The Appendicular Skeleton,,,,
+66dcdb56-03e5-4e7a-a9cb-1d62bc62b017,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Hypocalcemia, a condition characterized by abnormally low levels of calcium, can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone. Without adequate calcium, blood has difficulty coagulating, the heart may skip beats or stop beating altogether, muscles may have difficulty contracting, nerves may have difficulty functioning, and bones may become brittle. The causes of hypocalcemia can range from hormonal imbalances to an improper diet. Treatments vary according to the cause, but prognoses are generally good.",True,The Appendicular Skeleton,,,,
+fd330610-64bc-48df-9d64-8b3f2e6e22d0,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Conversely, in hypercalcemia, a condition characterized by abnormally high levels of calcium, the nervous system is underactive, which results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.",True,The Appendicular Skeleton,,,,
+471e5fb3-24c1-4fc7-b236-ab3394085747,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Obviously, calcium homeostasis is critical. The skeletal, endocrine, and digestive systems play a role in this, but the kidneys do, too. These body systems work together to maintain a normal calcium level in the blood (Figure 6.7.1).",True,The Appendicular Skeleton,Figure 6.7.1,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+439df380-b08f-4acb-819e-24bbd60551dc,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Calcium is a chemical element that cannot be produced by any biological processes. The only way it can enter the body is through the diet. The bones act as a storage site for calcium: The body deposits calcium in the bones when blood levels get too high, and it releases calcium when blood levels drop too low. This process is regulated by PTH, vitamin D, and calcitonin.",True,The Appendicular Skeleton,,,,
+9efdab46-6bc1-47b6-afab-64ca7ad57d21,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"Cells of the parathyroid gland have plasma membrane receptors for calcium. When calcium is not binding to these receptors, the cells release PTH, which stimulates osteoclast proliferation and resorption of bone by osteoclasts. This demineralization process releases calcium into the blood. PTH promotes reabsorption of calcium from the urine by the kidneys, so that the calcium returns to the blood. Finally, PTH stimulates the synthesis of vitamin D, which in turn, stimulates calcium absorption from any digested food in the small intestine.",True,The Appendicular Skeleton,,,,
+552b1283-90a2-4952-9068-75b6aaeaea2a,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"When all these processes return blood calcium levels to normal, there is enough calcium to bind with the receptors on the surface of the cells of the parathyroid glands, and this cycle of events is turned off (Figure 6.7.1).",True,The Appendicular Skeleton,Figure 6.7.1,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+28cc553c-c581-4d81-a9aa-38792722a0ff,https://open.oregonstate.education/aandp/,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/aandp/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/,"When blood levels of calcium get too high, the thyroid gland is stimulated to release calcitonin (Figure 6.7.1), which inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys. All of these actions lower blood levels of calcium. When blood calcium levels return to normal, the thyroid gland stops secreting calcitonin.",True,The Appendicular Skeleton,Figure 6.7.1,6.7 Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+ce760f78-4898-47e8-a4ea-eca0b9db4155,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"All of the organ systems of your body are interdependent, and the skeletal system is no exception. The food you take in via your digestive system and the hormones secreted by your endocrine system affect your bones. Even using your muscles to engage in exercise has an impact on your bones.",True,The Appendicular Skeleton,,,,
+311a990b-e05a-4bc4-9432-e82904ee2ade,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Exercise and Bone Tissue,False,Exercise and Bone Tissue,,,,
+3c06276a-2063-4be3-a3e2-4b1972efc491,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"During long space missions, astronauts can lose approximately 1 to 2 percent of their bone mass per month. This loss of bone mass is thought to be caused by the lack of mechanical stress on astronauts’ bones due to the low gravitational forces in space. Lack of mechanical stress causes bones to lose mineral salts and collagen fibers, and thus strength. Similarly, mechanical stress stimulates the deposition of mineral salts and collagen fibers. The internal and external structure of a bone will change as stress increases or decreases so that the bone is an ideal size and weight for the amount of activity it endures. That is why people who exercise regularly have thicker bones than people who are more sedentary. It is also why a broken bone in a cast atrophies while its contralateral mate maintains its concentration of mineral salts and collagen fibers. The bones undergo remodeling as a result of forces (or lack of forces) placed on them.",True,Exercise and Bone Tissue,,,,
+3d9e0dd3-f187-4ecf-abc5-cc18a821ca95,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Numerous, controlled studies have demonstrated that people who exercise regularly have greater bone density than those who are more sedentary. Any type of exercise will stimulate the deposition of more bone tissue, but resistance training has a greater effect than cardiovascular activities. Resistance training is especially important to slow down the eventual bone loss due to aging and for preventing osteoporosis.",True,Exercise and Bone Tissue,,,,
+7e62ad5b-5c24-4770-9ff3-7d3fb6d28711,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Nutrition and Bone Tissue,False,Nutrition and Bone Tissue,,,,
+667ff5c1-6024-4616-aec8-d06695f3c6e1,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"The vitamins and minerals contained in all of the food we consume are important for all of our organ systems. However, there are certain nutrients that affect bone health.",True,Nutrition and Bone Tissue,,,,
+4c316883-8aac-4059-bc77-b57894fd77a7,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Calcium and Vitamin D,False,Calcium and Vitamin D,,,,
+18f82ee0-afd3-48d5-904e-8c9066e30110,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"You already know that calcium is a critical component of bone, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without vitamin D. Therefore, intake of vitamin D is also critical to bone health. In addition to vitamin D’s role in calcium absorption, it also plays a role, though not as clearly understood, in bone remodeling.",True,Calcium and Vitamin D,,,,
+b1e68691-dc32-403e-b0c2-812f5324d819,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Milk and other dairy foods are not the only sources of calcium. This important nutrient is also found in green leafy vegetables, broccoli, and intact salmon and canned sardines with their soft bones. Nuts, beans, seeds, and shellfish provide calcium in smaller quantities.",True,Calcium and Vitamin D,,,,
+021df50c-fb0a-4b73-813e-8ac34a5f2dc3,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Except for fatty fish like salmon and tuna, or fortified milk or cereal, vitamin D is not found naturally in many foods. The action of sunlight on the skin triggers the body to produce its own vitamin D (Figure 6.6.1), but many people, especially those of darker complexion and those living in northern latitudes where the sun’s rays are not as strong, are deficient in vitamin D. In cases of deficiency, a doctor can prescribe a vitamin D supplement.",True,Calcium and Vitamin D,Figure 6.6.1,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/app/uploads/sites/157/2019/07/614_Synthesis_of_Vitamin_D.jpg,Figure 6.6.1 – Synthesis of Vitamin D: Sunlight is one source of vitamin D.
+c236891c-d787-46f2-afd9-ba85a6184d76,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Other Nutrients,False,Other Nutrients,,,,
+e01e65c4-7907-4510-b65f-20c62dcf1342,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Vitamin K also supports bone mineralization and may have a synergistic role with vitamin D in the regulation of bone growth. Green leafy vegetables are a good source of vitamin K.,True,Other Nutrients,,,,
+3d9dd26c-2a66-48fe-84f7-efb015edc6f7,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"The minerals magnesium and fluoride may also play a role in supporting bone health. While magnesium is only found in trace amounts in the human body, more than 60 percent of it is in the skeleton, suggesting it plays a role in the structure of bone. Fluoride can displace the hydroxyl group in bone’s hydroxyapatite crystals and form fluorapatite. Similar to its effect on dental enamel, fluorapatite helps stabilize and strengthen bone mineral. Fluoride can also enter spaces within hydroxyapatite crystals, thus increasing their density.",True,Other Nutrients,,,,
+fa882727-b55c-4182-92ac-48cc90bcf55c,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Omega-3 fatty acids have long been known to reduce inflammation in various parts of the body. Inflammation can interfere with the function of osteoblasts, so consuming omega-3 fatty acids, in the diet or in supplements, may also help enhance production of new osseous tissue. Table 6.5 summarizes the role of nutrients in bone health.",True,Other Nutrients,,,,
+c061b7b9-0e3a-4f48-8149-7a2c3185dba0,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Hormones and Bone Tissue,False,Hormones and Bone Tissue,,,,
+e4c38cb6-760f-48da-bfee-9c651bdc1024,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"The endocrine system produces and secretes hormones, many of which interact with the skeletal system. These hormones are involved in controlling bone growth, maintaining bone once it is formed, and remodeling it.",True,Hormones and Bone Tissue,,,,
+2fd035a3-14bf-472f-8f25-f28b9da04736,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Hormones That Influence Osteoblasts and/or Maintain the Matrix,False,Hormones That Influence Osteoblasts and/or Maintain the Matrix,,,,
+15a43db0-6288-4331-ace9-e2b0ed6e04c1,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth in several ways. It triggers chondrocyte proliferation in epiphyseal plates, resulting in the increasing length of long bones. GH also increases calcium retention, which enhances mineralization, and stimulates osteoblastic activity, which improves bone density.",True,Hormones That Influence Osteoblasts and/or Maintain the Matrix,,,,
+e082b57d-11c8-457e-9290-cf9f46c0aa5f,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"GH is not alone in stimulating bone growth and maintaining osseous tissue. Thyroxine, a hormone secreted by the thyroid gland promotes osteoblastic activity and the synthesis of bone matrix. During puberty, the sex hormones (estrogen in girls, testosterone in boys) also come into play. They too promote osteoblastic activity and production of bone matrix, and in addition, are responsible for the growth spurt that often occurs during adolescence. They also promote the conversion of the epiphyseal plate to the epiphyseal line (i.e., cartilage to its bony remnant), thus bringing an end to the longitudinal growth of bones. Additionally, calcitriol, the active form of vitamin D, is produced by the kidneys and stimulates the absorption of calcium and phosphate from the digestive tract.",True,Hormones That Influence Osteoblasts and/or Maintain the Matrix,,,,
+7f86d30d-4d41-4d01-bd52-4addb315dcdd,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Osteoporosis,False,Osteoporosis,,,,
+25c99d37-94c8-43fa-919c-ecc2d9b925a5,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Hormones That Influence Osteoclasts,False,Hormones That Influence Osteoclasts,,,,
+362a585c-58f8-4591-a3b3-a07d32116d93,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"Bone modeling and remodeling require osteoclasts to resorb unneeded, damaged, or old bone, and osteoblasts to lay down new bone. Two hormones that affect the osteoclasts are parathyroid hormone (PTH) and calcitonin.",True,Hormones That Influence Osteoclasts,,,,
+aeea1dc7-1205-4122-b358-1638d203e8b3,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"PTH stimulates osteoclast proliferation and activity. As a result, calcium is released from the bones into the circulation, thus increasing the calcium ion concentration in the blood. PTH also promotes the reabsorption of calcium by the kidney tubules, which can affect calcium homeostasis (see below).",True,Hormones That Influence Osteoclasts,,,,
+9b097673-a16e-495b-8468-e59aa2bab8af,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,"The small intestine is also affected by PTH, albeit indirectly. Because another function of PTH is to stimulate the synthesis of vitamin D, and because vitamin D promotes intestinal absorption of calcium, PTH indirectly increases calcium uptake by the small intestine. Calcitonin, a hormone secreted by the thyroid gland, has some effects that counteract those of PTH. Calcitonin inhibits osteoclast activity and stimulates calcium uptake by the bones, thus reducing the concentration of calcium ions in the blood. As evidenced by their opposing functions in maintaining calcium homeostasis, PTH and calcitonin are generally not secreted at the same time. Table 6.6 summarizes the hormones that influence the skeletal system.",True,Hormones That Influence Osteoclasts,,,,
+8c8d45ba-79e8-4306-90eb-e57ee0099776,https://open.oregonstate.education/aandp/,"6.6 Exercise, Nutrition, Hormones, and Bone Tissue",https://open.oregonstate.education/aandp/chapter/6-6-exercise-nutrition-hormones-and-bone-tissue/,Glossary,False,Glossary,,,,
+1175a888-9d04-412b-9408-15c08740b777,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"A fracture is a broken bone. It will heal whether or not a physician resets (places) it in its anatomical position. If the bone is not reset correctly, the healing process will rebuild new bone but keep the bone in its deformed position.",True,Glossary,,,,
+2b3734b3-5eb0-4196-83bc-6517faf42d60,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"When a broken bone is manipulated and set into its natural position without surgery, the procedure is called a closed reduction. Open reduction requires surgery to expose the fracture and reset the bone. While some fractures can be minor, others are quite severe and result in grave complications. For example, a fractured diaphysis of the femur has the potential to release fat globules into the bloodstream. These can become lodged in the capillary beds of the lungs, leading to respiratory distress and if not treated quickly, death (this is called a pulmonary embolism).",True,Glossary,,,,
+cff4f9e4-fef8-4051-baf2-075b8be1827b,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,Types of Fractures,False,Types of Fractures,,,,
+cdae035d-ec70-499f-8dd7-dd8f838b43b9,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"Fractures are classified by their complexity, location, and other features (Figure 6.5.1). Table 6.4 outlines common types of fractures. Some fractures may be described using more than one term because it may have the features of more than one type (e.g., an open transverse fracture).",True,Types of Fractures,Figure 6.5.1,6.5 Fractures: Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2019/07/612_Types_of_Fractures_revised-475x1024.png,"Figure 6.5.1 – Types of Fractures: Compare healthy bone with different types of fractures: (a) open fracture, (b) closed fracture, (c) oblique fracture, (d) comminuted fracture, (e) spiral fracture , (f) impacted fracture, (g) greenstick fracture, and (h) transverse fracture."
+8d45fb3a-cb3b-4b4d-b874-d77c588dd7ee,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,Bone Repair,False,Bone Repair,,,,
+fda9b11f-ed73-4b7a-af3a-6a4e177c3776,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Direct bone healing is essentially bone remodeling in which osteoblasts and osteoclasts unite broken structures. With indirect bone healing the process is more complicated and similar to endochondral bone formation in which broken bones form cartilaginous patches before regrowing new bone. In this process, blood released from broken or torn vessels in the periosteum, osteons, and/or medullary cavity clots into a fracture hematoma (Figure 6.5.2a). Though broken vessels promote an increase in nutrient delivery to the site of vessel injury (see inflammation process in blood vessel chapter), the disruption of blood flow to the bone results in the death of bone cells around the fracture.",True,Bone Repair,Figure 6.5.2,6.5 Fractures: Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+b19ec1a3-552c-4d81-9b64-8ae2c0eaedff,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"Within about 48 hours after the fracture, stem cells from the endosteum of the bone differentiate into chondrocytes which then secrete a fibrocartilaginous matrix between the two ends of the broken bone; gradually over several days to weeks, this matrix unites the opposite ends of the fracture into an internal callus (plural = calli or calluses). Additionally, the periosteal chondrocytes form and working with osteoblasts, create an external callus of cartilage and bone, respectively, around the outside of the break (Figure 6.5.2b). Together, these temporary soft calluses stabilize the fracture.",True,Bone Repair,Figure 6.5.2,6.5 Fractures: Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+ea802e5a-79ce-4875-bd09-f77b51f6d876,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"Over the next several weeks, osteoclasts resorb the dead bone while osteogenic cells become active, divide, and differentiate into more osteoblasts. The cartilage in the calluses is replaced by trabecular bone via endochondral ossification (destruction of cartilage and replacement by bone) (Figure 6.5.2c). This new bony callus is also called the hard callus.",True,Bone Repair,Figure 6.5.2,6.5 Fractures: Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+c88bcd92-f146-41e6-8fa8-04c6716bd5d9,https://open.oregonstate.education/aandp/,6.5 Fractures: Bone Repair,https://open.oregonstate.education/aandp/chapter/6-5-fractures-bone-repair/,"Over several more weeks or months, compact bone replaces spongy bone at the outer margins of the fracture and the bone is remodeled in response to strain (Figure 6.5.2d). Once healing and remodeling are complete a slight swelling may remain on the outer surface of the bone, but quite often, no external evidence of the fracture remains. This is why bone is said to be a regenerative tissue that can completely replace itself without scars.",True,Bone Repair,Figure 6.5.2,6.5 Fractures: Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+8b836a71-48d6-41b5-9edf-bf632e8c1950,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"In the early stages of embryonic development, the embryo’s skeleton consists of fibrous membranes and hyaline cartilage. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but in the end, mature bone is the same regardless of the pathway that produces it.",True,Bone Repair,,,,
+fe9c1f5e-fd39-4fee-8e63-3391d8df8a6a,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,Intramembranous Ossification,False,Intramembranous Ossification,,,,
+84e22a55-ff8a-49bb-be5d-ad3b98cf930f,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"During intramembranous ossification, compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue. The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via intramembranous ossification.",True,Intramembranous Ossification,,,,
+6ef298f9-656f-40d5-8bad-a7e0006bf27d,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"The process begins when mesenchymal cells in the embryonic skeleton gather together and begin to differentiate into specialized cells (Figure 6.4.1a). Some of these cells will differentiate into capillaries, while others will become osteogenic cells and then osteoblasts. Although they will ultimately be spread out by the formation of bone tissue, early osteoblasts appear in a cluster called an ossification center.",True,Intramembranous Ossification,Figure 6.4.1,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+af933738-c0c6-42f0-b49d-17dc87c6da53,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"The osteoblasts secrete osteoid, uncalcified matrix consisting of collagen precursors and other organic proteins, which calcifies (hardens) within a few days as mineral salts are deposited on it, thereby entrapping the osteoblasts within. Once entrapped, the osteoblasts become osteocytes (Figure 6.4.1b). As osteoblasts transform into osteocytes, osteogenic cells in the surrounding connective tissue differentiate into new osteoblasts at the edges of the growing bone.",True,Intramembranous Ossification,Figure 6.4.1,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+6b1ba284-802a-4b2d-884d-ccafb1c84dbc,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"Several clusters of osteoid unite around the capillaries to form a trabecular matrix, while osteoblasts on the surface of the newly formed spongy bone become the cellular layer of the periosteum (Figure 6.4.1c). The periosteum then secretes compact bone superficial to the spongy bone. The spongy bone crowds nearby blood vessels, which eventually condense into red bone marrow (Figure 6.4.1d). The new bone is constantly also remodeling under the action of osteoclasts (not shown).",True,Intramembranous Ossification,Figure 6.4.1,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+536b0772-f3ad-4262-9123-4c09f3b25c6c,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,Endochondral Ossification,False,Endochondral Ossification,,,,
+faebcdfd-e341-4a75-a0b3-07f359d072b6,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification. Bones at the base of the skull and long bones form via endochondral ossification.",True,Endochondral Ossification,,,,
+7438c93e-650d-4099-b375-bcabc46093b6,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"In a long bone, for example, at about 6 to 8 weeks after conception, some of the mesenchymal cells differentiate into chondroblasts (cartilage cells) that form the hyaline cartilaginous skeletal precursor of the bones (Figure 6.4.2a). This cartilage is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water. As the matrix surrounds and isolates chondroblasts, they are called chondrocytes. Unlike most connective tissues, cartilage is avascular, meaning that it has no blood vessels supplying nutrients and removing metabolic wastes. All of these functions are carried on by diffusion through the matrix from vessels in the surrounding perichondrium, a membrane that covers the cartilage,a).",True,Endochondral Ossification,Figure 6.4.2,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+5aef1f80-ad33-48d9-928c-427dd8d51ebf,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"As more and more matrix is produced, the cartilaginous model grow in size. Blood vessels in the perichondrium bring osteoblasts to the edges of the structure and these arriving osteoblasts deposit bone in a ring around the diaphysis – this is called a bone collar (Figure 6.4.2b). The bony edges of the developing structure prevent nutrients from diffusing into the center of the hyaline cartilage. This results in chondrocyte death and disintegration in the center of the structure. Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting spaces, not only enlarging the cavities but also carrying osteogenic cells with them, many of which will become osteoblasts. These enlarging spaces eventually combine to become the medullary cavity. Bone is now deposited within the structure creating the primary ossification center (Figure 6.4.2c).",True,Endochondral Ossification,Figure 6.4.2,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+bb307add-9d86-4898-b1ae-f0e6fbb9ffae,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"While these deep changes are occurring, chondrocytes and cartilage continue to grow at the ends of the structure (the future epiphyses), which increases the structure’s length at the same time bone is replacing cartilage in the diaphyses. This continued growth is accompanied by remodeling inside the medullary cavity (osteoclasts were also brought with invading blood vessels) and overall lengthening of the structure (Figure 6.4.2d). By the time the fetal skeleton is fully formed, cartilage remains at the epiphyses and at the joint surface as articular cartilage.",True,Endochondral Ossification,Figure 6.4.2,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+675ff3f9-0cae-46ac-9d44-e1ae58f359e4,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a secondary ossification center (Figure 6.4.2e). Throughout childhood and adolescence, there remains a thin plate of hyaline cartilage between the diaphysis and epiphysis known as the growth or epiphyseal plate (Figure 6.4.2f). Eventually, this hyaline cartilage will be removed and replaced by bone to become the epiphyseal line.",True,Endochondral Ossification,Figure 6.4.2,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+4575b5cb-e3a5-4a8d-bfdc-6609b3a29b7a,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,How Bones Grow in Length,False,How Bones Grow in Length,,,,
+40f3d5fb-b666-464d-94c3-122470ca2e7c,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"The epiphyseal plate is the area of elongation in a long bone. It includes a layer of hyaline cartilage where ossification can continue to occur in immature bones. We can divide the epiphyseal plate into a diaphyseal side (closer to the diaphysis) and an epiphyseal side (closer to the epiphysis). On the epiphyseal side of the epiphyseal plate, hyaline cartilage cells are active and are dividing and producing hyaline cartilage matrix. (figure 6.43, reserve and proliferative zones). On the diaphyseal side of the growth plate, cartilage calcifies and dies, then is replaced by bone (figure 6.43, zones of hypertrophy and maturation, calcification and ossification). As cartilage grows, the entire structure grows in length and then is turned into bone. Once cartilage cannot grow further, the structure cannot elongate more.",True,How Bones Grow in Length,,,,
+8623c072-03cd-4303-b016-0360a99552b0,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,The epiphyseal plate is composed of five zones of cells and activity (Figure 6.4.3). The reserve zone is the region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix. These chondrocytes do not participate in bone growth but secure the epiphyseal plate to the overlying osseous tissue of the epiphysis.,True,How Bones Grow in Length,Figure 6.4.3,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/622_Longitudinal_Bone_Growth_revised-657x1024.png,Figure 6.4.3 – Longitudinal Bone Growth: The epiphyseal plate is responsible for longitudinal bone growth.
+e2020a6f-5a68-4a43-8cd7-054461ba815c,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"The proliferative zone is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes. It makes new chondrocytes (via mitosis) to replace those that die at the diaphyseal end of the plate. Chondrocytes in the next layer, the zone of maturation and hypertrophy, are older and larger than those in the proliferative zone. The more mature cells are situated closer to the diaphyseal end of the plate. The longitudinal growth of bone is a result of cellular division in the proliferative zone and the maturation of cells in the zone of maturation and hypertrophy. This growth within a tissue is called interstitial growth.",True,How Bones Grow in Length,,,,
+e04e1e95-f2c6-4d33-99ae-9daa3279ecd0,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"Most of the chondrocytes in the zone of calcified matrix, the zone closest to the diaphysis, are dead because the matrix around them has calcified, restricting nutrient diffusion. Capillaries and osteoblasts from the diaphysis penetrate this zone, and the osteoblasts secrete bone tissue on the remaining calcified cartilage. Thus, the zone of calcified matrix connects the epiphyseal plate to the diaphysis. A bone grows in length when osseous tissue is added to the diaphysis.",True,How Bones Grow in Length,,,,
+76575189-ddc5-4df9-8420-66b242842f8a,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"Bones continue to grow in length until early adulthood. The rate of growth is controlled by hormones, which will be discussed later. When the chondrocytes in the epiphyseal plate cease their proliferation and bone replaces all the cartilage, longitudinal growth stops. All that remains of the epiphyseal plate is the ossified epiphyseal line (Figure 6.4.4).",True,How Bones Grow in Length,Figure 6.4.4,6.4 Bone Formation and Development,https://open.oregonstate.education/app/uploads/sites/157/2021/02/623_Epiphyseal_Plate-Line.jpg,"Figure 6.4.4 – Progression from Epiphyseal Plate to Epiphyseal Line: As a bone matures, the epiphyseal plate progresses to an epiphyseal line. (a) Epiphyseal plates are visible in a growing bone. (b) Epiphyseal lines are the remnants of epiphyseal plates in a mature bone."
+48b4a53c-ab04-4d2d-a401-2236bb36625a,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,How Bones Grow in Diameter,False,How Bones Grow in Diameter,,,,
+c8a3160c-957c-4b48-a38d-4ab0cabd1c86,https://open.oregonstate.education/aandp/,6.4 Bone Formation and Development,https://open.oregonstate.education/aandp/chapter/6-4-bone-formation-and-development/,"While bones are increasing in length, they are also increasing in diameter; growth in diameter can continue even after longitudinal growth ceases. This growth by adding to the free surface of bone is called appositional growth. Appositional growth can occur at the endosteum or peristeum where osteoclasts resorb old bone that lines the medullary cavity, while osteoblasts produce new bone tissue. The erosion of old bone along the medullary cavity and the deposition of new bone beneath the periosteum not only increase the diameter of the diaphysis but also increase the diameter of the medullary cavity. This remodeling of bone primarily takes place during a bone’s growth. However, in adult life, bone undergoes constant remodeling, in which resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed. Injury, exercise, and other activities lead to remodeling. Those influences are discussed later in the chapter, but even without injury or exercise, about 5 to 10 percent of the skeleton is remodeled annually just by destroying old bone and renewing it with fresh bone.",True,How Bones Grow in Diameter,,,,
+5c730b1d-d9cd-45c2-9cdc-bd689aa41f9b,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Describe the microscopic and gross anatomical structures of bones,False,Describe the microscopic and gross anatomical structures of bones,,,,
+39ee96f9-d281-40ce-9fc6-8fe7badda5b2,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Bone tissue (osseous tissue) differs greatly from other tissues in the body. Bone is hard and many of its functions depend on that characteristic hardness. Later discussions in this chapter will show that bone is also dynamic in that its shape adjusts to accommodate stresses. This section will examine the gross anatomy of bone first and then move on to its histology.,True,Describe the microscopic and gross anatomical structures of bones,,,,
+f6d2267a-663a-4db4-a119-074310ef9a7f,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Gross Anatomy of Bones,False,Gross Anatomy of Bones,,,,
+dbeb43dc-2a40-4abd-b4a4-73a0f5028a6b,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"A long bone has two main regions: the diaphysis and the epiphysis (Figure 6.3.1). The diaphysis is the hollow, tubular shaft that runs between the proximal and distal ends of the bone. Inside the diaphysis is the medullary cavity, which is filled with yellow bone marrow in an adult. The outer walls of the diaphysis (cortex, cortical bone) are composed of dense and hard compact bone, a form of osseous tissue.",True,Gross Anatomy of Bones,Figure 6.3.1,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2019/07/603_Anatomy_of_a_Long_Bone_revised-606x1024.png,Figure 6.3.1 – Anatomy of a Long Bone: A typical long bone showing gross anatomical features.
+2f96fa58-7911-4287-ac93-5faa704dce3e,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled internally with spongy bone, another type of osseous tissue. Red bone marrow fills the spaces between the spongy bone in some long bones. Each epiphysis meets the diaphysis at the metaphysis. During growth, the metaphysis contains the epiphyseal plate, the site of long bone elongation described later in the chapter. When the bone stops growing in early adulthood (approximately 18–21 years), the epiphyseal plate becomes an epiphyseal line seen in the figure.",True,Gross Anatomy of Bones,,,,
+970c5164-30e0-4ed5-9026-e3f7c2d46532,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.",True,Gross Anatomy of Bones,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lossy-page1-1280px-Bertazzo_S_-_SEM_deproteined_bone_-_wistar_rat_-_x10k.tif_-300x225-1.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)"
+970c5164-30e0-4ed5-9026-e3f7c2d46532,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.",True,Gross Anatomy of Bones,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Bone-matrices-300x146-1.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson"
+970c5164-30e0-4ed5-9026-e3f7c2d46532,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Lining the inside of the bone adjacent to the medullary cavity is a layer of bone cells called the endosteum (endo- = “inside”; osteo- = “bone”). These bone cells (described later) cause the bone to grow, repair, and remodel throughout life. On the outside of bones there is another layer of cells that grow, repair and remodel bone as well. These cells are part of the outer double layered structure called the periosteum (peri– = “around” or “surrounding”). The cellular layer is adjacent to the cortical bone and is covered by an outer fibrous layer of dense irregular connective tissue (see Figure 6.3.4a). The periosteum also contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 6.3.2). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber.",True,Gross Anatomy of Bones,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+00c2867c-b69b-4354-993c-665d678ce72f,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), covered on either side by a layer of compact bone (Figure 6.3.3). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.",True,Gross Anatomy of Bones,Figure 6.3.3,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/621_Anatomy_of_a_Flat_Bone.jpg,Figure 6.3.3 – Anatomy of a Flat Bone: This cross-section of a flat bone shows the spongy bone (diploë) covered on either side by a layer of compact bone.
+5dc09977-c926-4cd0-8f46-f55a079e86c0,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Osseous Tissue: Bone Matrix and Cells,False,Osseous Tissue: Bone Matrix and Cells,,,,
+607ce530-18f4-4257-9462-b5e84182d39c,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Bone Cells,False,Bone Cells,,,,
+945543bf-ea6f-469b-b2d4-8bc07029f7f0,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Although bone cells compose less than 2% of the bone mass, they are crucial to the function of bones. Four types of cells are found within bone tissue: osteoblasts, osteocytes, osteogenic cells, and osteoclasts (Figure 6.3.5).",True,Bone Cells,Figure 6.3.5,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/604_Bone_cells_revised.png,"Figure 6.3.5 – Bone Cells: Four types of cells are found within bone tissue. Osteogenic cells are undifferentiated and develop into osteoblasts. Osteoblasts deposit bone matrix. When osteoblasts get trapped within the calcified matrix, they become osteocytes. Osteoclasts develop from a different cell lineage and act to resorb bone."
+cafd3e67-d88d-48ce-beb3-4aa683f95b46,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The osteoblast is the bone cell responsible for forming new bone and is found in the growing portions of bone, including the endosteum and the cellular layer of the periosteum. Osteoblasts, which do not divide, synthesize and secrete the collagen matrix and other proteins. As the secreted matrix surrounding the osteoblast calcifies, the osteoblast become trapped within it; as a result, it changes in structure and becomes an osteocyte, the primary cell of mature bone and the most common type of bone cell. Each osteocyte is located in a small cavity in the bone tissue called a lacuna (lacunae for plural). Osteocytes maintain the mineral concentration of the matrix via the secretion of enzymes. Like osteoblasts, osteocytes lack mitotic activity. They can communicate with each other and receive nutrients via long cytoplasmic processes that extend through canaliculi (singular = canaliculus), channels within the bone matrix. Osteocytes are connected to one another within the canaliculi via gap junctions.",True,Bone Cells,,,,
+43607270-699a-492d-bbb6-a234a6e156c0,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"If osteoblasts and osteocytes are incapable of mitosis, then how are they replenished when old ones die? The answer lies in the properties of a third category of bone cells—the osteogenic (osteoprogenitor) cell. These osteogenic cells are undifferentiated with high mitotic activity and they are the only bone cells that divide. Immature osteogenic cells are found in the cellular layer of the periosteum and the endosteum. They differentiate and develop into osteoblasts.",True,Bone Cells,,,,
+f9918e7e-05dc-4b2e-9250-b1ad68df3773,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The dynamic nature of bone means that new tissue is constantly formed, and old, injured, or unnecessary bone is dissolved for repair or for calcium release. The cells responsible for bone resorption, or breakdown, are the osteoclasts. These multinucleated cells originate from monocytes and macrophages, two types of white blood cells, not from osteogenic cells. Osteoclasts are continually breaking down old bone while osteoblasts are continually forming new bone. The ongoing balance between osteoblasts and osteoclasts is responsible for the constant but subtle reshaping of bone. Table 6.3 reviews the bone cells, their functions, and locations.",True,Bone Cells,,,,
+79574164-a512-42ae-9a0a-76e7b8521ce2,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Compact and Spongy Bone,False,Compact and Spongy Bone,,,,
+1f457461-71ef-49ff-a5a5-28a4a37b689e,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Most bones contain compact and spongy osseous tissue, but their distribution and concentration vary based on the bone’s overall function. Although compact and spongy bone are made of the same matrix materials and cells, they are different in how they are organized. Compact bone is dense so that it can withstand compressive forces, while spongy bone (also called cancellous bone) has open spaces and is supportive, but also lightweight and can be readily remodeled to accommodate changing body needs.",True,Compact and Spongy Bone,,,,
+80079ab1-21fa-4c8a-9aa9-175b8e3f5361,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Compact Bone,False,Compact Bone,,,,
+50c565a1-13f7-4ed4-9c33-831d1d6df411,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Compact bone is the denser, stronger of the two types of osseous tissue (Figure 6.3.6). It makes up the outer cortex of all bones and is in immediate contact with the periosteum. In long bones, as you move from the outer cortical compact bone to the inner medullary cavity, the bone transitions to spongy bone.",True,Compact Bone,Figure 6.3.6,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/624_Diagram_of_Compact_Bone_revised.png,"Figure 6.3.6 – Diagram of Compact Bone: (a) This cross-sectional view of compact bone shows several osteons, the basic structural unit of compact bone. (b) In this micrograph of the osteon, you can see the concentric lamellae around the central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+e8d51f73-f6b5-4145-808f-9c2d124af481,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"If you look at compact bone under the microscope, you will observe a highly organized arrangement of concentric circles that look like tree trunks. Each group of concentric circles (each “tree”) makes up the microscopic structural unit of compact bone called an osteon (this is also called a Haversian system). Each ring of the osteon is made of collagen and calcified matrix and is called a lamella (plural = lamellae). The collagen fibers of adjacent lamallae run at perpendicular angles to each other, allowing osteons to resist twisting forces in multiple directions (see figure 6.34a). Running down the center of each osteon is the central canal, or Haversian canal, which contains blood vessels, nerves, and lymphatic vessels. These vessels and nerves branch off at right angles through a perforating canal, also known as Volkmann’s canals, to extend to the periosteum and endosteum. The endosteum also lines each central canal, allowing osteons to be removed, remodeled and rebuilt over time.",True,Compact Bone,,,,
+6d08d74a-71ea-4602-b1fb-53e28f1589ed,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The osteocytes are trapped within their lacuane, found at the borders of adjacent lamellae. As described earlier, canaliculi connect with the canaliculi of other lacunae and eventually with the central canal. This system allows nutrients to be transported to the osteocytes and wastes to be removed from them despite the impervious calcified matrix.",True,Compact Bone,,,,
+6b4cbdb4-116e-4471-8568-326110148bdb,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Spongy (Cancellous) Bone,False,Spongy (Cancellous) Bone,,,,
+10b59662-6640-4bab-a6f2-2ace0f0ed345,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"Like compact bone, spongy bone, also known as cancellous bone, contains osteocytes housed in lacunae, but they are not arranged in concentric circles. Instead, the lacunae and osteocytes are found in a lattice-like network of matrix spikes called trabeculae (singular = trabecula) (Figure 6.3.8). The trabeculae are covered by the endosteum, which can readily remodel them. The trabeculae may appear to be a random network, but each trabecula forms along lines of stress to direct forces out to the more solid compact bone providing strength to the bone. Spongy bone provides balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. In addition, the spaces in some spongy bones contain red bone marrow, protected by the trabeculae, where hematopoiesis occurs.",True,Spongy (Cancellous) Bone,Figure 6.3.8,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/606_Spongy_Bone.jpg,Figure 6.3.8 – Diagram of Spongy Bone: Spongy bone is composed of trabeculae that contain the osteocytes. Red marrow fills the spaces in some bones.
+d9b7b036-2690-4cdd-8559-bd161c55fee4,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Blood and Nerve Supply,False,Blood and Nerve Supply,,,,
+46c764b4-9e7c-4578-85af-ec43076e0f3d,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The spongy bone and medullary cavity receive nourishment from arteries that pass through the compact bone. The arteries enter through the nutrient foramen (plural = foramina), small openings in the diaphysis (Figure 6.3.10). The osteocytes in spongy bone are nourished by blood vessels of the periosteum that penetrate spongy bone and blood that circulates in the marrow cavities. As the blood passes through the marrow cavities, it is collected by veins, which then pass out of the bone through the foramina.",True,Blood and Nerve Supply,Figure 6.3.10,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/609_Body_Supply_to_the_Bone.jpg,Figure 6.3.10 – Diagram of Blood and Nerve Supply to Bone: Blood vessels and nerves enter the bone through the nutrient foramen.
+1c0befdc-9038-40bb-8125-ba17521b2cc8,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"In addition to the blood vessels, nerves follow the same paths into the bone where they tend to concentrate in the more metabolically active regions of the bone. The nerves sense pain, and it appears the nerves also play roles in regulating blood supplies and in bone growth, hence their concentrations in metabolically active sites of the bone.",True,Blood and Nerve Supply,,,,
+8f988c95-5c3d-48a3-8bd2-a354b2a88016,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Bone Markings,False,Bone Markings,,,,
+1bb6c035-45f5-4573-a64e-c0b59a30f32a,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,Define and list examples of bone markings,False,Define and list examples of bone markings,,,,
+d2e0f48c-3e6e-42ba-bb20-73d99a1723e2,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.",True,Define and list examples of bone markings,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lossy-page1-1280px-Bertazzo_S_-_SEM_deproteined_bone_-_wistar_rat_-_x10k.tif_-300x225-1.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)"
+d2e0f48c-3e6e-42ba-bb20-73d99a1723e2,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.",True,Define and list examples of bone markings,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Bone-matrices-300x146-1.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson"
+d2e0f48c-3e6e-42ba-bb20-73d99a1723e2,https://open.oregonstate.education/aandp/,6.3 Bone Structure,https://open.oregonstate.education/aandp/chapter/6-3-bone-structure/,"The surface features of bones vary considerably, depending on the function and location in the body. Table 6.2 describes the bone markings, which are illustrated in (Figure 6.3.4). There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.",True,Define and list examples of bone markings,Figure 6.3.4,6.3 Bone Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+7de5b0af-30f6-4985-9e83-d94e87605276,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Describe the classes of bones.,False,Describe the classes of bones.,,,,
+c9e61b83-6a9a-4fd7-b511-f1f1e4c7127e,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"The 206 bones that compose the adult skeleton are divided into five categories based on their shapes (Figure 6.2.1). Like other structure/function relationships in the body, their shapes and their functions are related such that each categorical shape of bone has a distinct function.",True,Describe the classes of bones.,Figure 6.2.1,6.2 Bone Classification,https://open.oregonstate.education/app/uploads/sites/157/2019/07/601_Bone_Classification_revised-874x1024.png,Figure 6.2.1 – Classifications of Bones: Bones are classified according to their shape.
+4f2c435c-bcd4-4a2a-b88c-6f356f53259b,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Long Bones,False,Long Bones,,,,
+a43e4d6a-04d2-4e52-90f7-f4b43f3b4e25,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"A long bone is one that is cylindrical in shape, being longer than it is wide. Keep in mind, however, that the term describes the shape of a bone, not its size. Long bones are found in the upper limbs (humerus, ulna, radius) and lower limbs (femur, tibia, fibula), as well as in the hands (metacarpals, phalanges) and feet (metatarsals, phalanges). Long bones function as rigid bars that move when muscles contract.",True,Long Bones,,,,
+1ca53218-b6d4-4cd3-bd09-01a4ac1f88f9,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Short Bones,False,Short Bones,,,,
+34453cd4-ccfd-4fd9-b4f9-5e05aa2076d9,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"A short bone is one that is cube-like in shape, being approximately equal in length, width, and thickness. The only short bones in the human skeleton are in the carpals of the wrists and the tarsals of the ankles. Short bones provide stability and support as well as some limited motion.",True,Short Bones,,,,
+d858e183-c248-4460-950c-3e3c1c95c3b5,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Flat Bones,False,Flat Bones,,,,
+760f5f22-bb6f-4a7c-aab5-28d677a0cefc,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"The term flat bone is somewhat of a misnomer because, although a flat bone is typically thin, it is also often curved. Examples include the cranial (skull) bones, the scapulae (shoulder blades), the sternum (breastbone), and the ribs. Flat bones serve as points of attachment for muscles and often protect internal organs.",True,Flat Bones,,,,
+0f33e007-69e8-4d90-b4e5-4a65c1014a83,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Irregular Bones,False,Irregular Bones,,,,
+89bccfe2-4c47-4012-9081-6eb205f335d6,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"An irregular bone is one that does not have any easily characterized shape and therefore does not fit any other classification. These bones tend to have more complex shapes, like the vertebrae that support the spinal cord and protect it from compressive forces. Many bones of the face, particularly the jaw bones that contain teeth, are classified as irregular bones.",True,Irregular Bones,,,,
+dafd8189-9002-49ef-b565-2e99a842ea7a,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,Sesamoid Bones,False,Sesamoid Bones,,,,
+d0f614fd-cf5c-4c62-85b7-d8c963d9039d,https://open.oregonstate.education/aandp/,6.2 Bone Classification,https://open.oregonstate.education/aandp/chapter/6-2-bone-classification/,"A sesamoid bone is a small, round bone that forms in tendons (sesamo- = “sesame” and -oid = “resembling”). Tendons are a dense connective tissue that connect bones to muscles and sesamoid bones form where a great deal of pressure is generated in a joint. The sesamoid bones protect tendons by helping them overcome excessive forces but also allow tendons and their attached muscles to be more effective. Sesamoid bones vary in number and placement from person to person but are typically found in tendons associated with the feet, hands, and knees. The patellae (singular = patella) are the only sesamoid bones found in common with every person. Table 6.1 reviews bone classifications with their associated features, functions, and examples.",True,Sesamoid Bones,,,,
+0d72fb70-db86-4189-b975-bec9dee02ac1,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,List and describe the functions of the skeletal system,False,List and describe the functions of the skeletal system,,,,
+31d4c6ff-7288-4f46-a2c1-39cf131ead1e,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"The skeletal system is the body system composed of bones, cartilages, ligaments and other tissues that perform essential functions for the human body. Bone tissue, or osseous tissue, is a hard, dense connective tissue that forms most of the adult skeleton, the internal support structure of the body. In the areas of the skeleton where whole bones move against each other (for example, joints like the shoulder or between the bones of the spine), cartilages, a semi-rigid form of connective tissue, provide flexibility and smooth surfaces for movement. Additionally, ligaments composed of dense connective tissue surround these joints, tying skeletal elements together (a ligament is the dense connective tissue that connect bones to other bones). Together, they perform the following functions:",True,List and describe the functions of the skeletal system,,,,
+13963fc2-382c-4601-b4a0-718c69c3505a,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Support, Movement, and Protection",False,"Support, Movement, and Protection",,,,
+e441ea0d-9739-4f7e-b39c-fd4bad8f6cbf,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Some functions of the skeletal system are more readily observable than others. When you move you can feel how your bones support you, facilitate your movement, and protect the soft organs of your body. Just as the steel beams of a building provide a scaffold to support its weight, the bones and cartilages of your skeletal system compose the scaffold that supports the rest of your body. Without the skeletal system, you would be a limp mass of organs, muscle, and skin. Bones facilitate movement by serving as points of attachment for your muscles. Bones also protect internal organs from injury by covering or surrounding them. For example, your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain (see Figure 6.1.1).",True,"Support, Movement, and Protection",Figure 6.1.1,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/mineral_storage_revised-838x1024.png,Figure 6.1.1 Functions of the skeletal system.
+0700ac2f-8a8a-43dd-a08c-b0aaba26adbf,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Mineral and Fat Storage, Blood Cell Formation",False,"Mineral and Fat Storage, Blood Cell Formation",,,,
+9f1122a9-1f6e-468a-9d5a-0b79f351555b,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"On a metabolic level, bone tissue performs several critical functions. For one, the bone tissue acts as a reservoir for a number of minerals important to the functioning of the body, especially calcium, and phosphorus. These minerals, incorporated into bone tissue, can be released back into the bloodstream to maintain levels needed to support physiological processes. Calcium ions, for example, are essential for muscle contractions and are involved in the transmission of nerve impulses.",True,"Mineral and Fat Storage, Blood Cell Formation",,,,
+4f63ce15-8166-4151-9f92-a497ff516ceb,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Bones also serve as a site for fat storage and blood cell production. The unique connective tissue that fills the interior of most bones is referred to as bone marrow. There are two types of bone marrow: yellow bone marrow and red bone marrow. Yellow bone marrow contains adipose tissue, and the triglycerides stored in the adipocytes of this tissue can be released to serve as a source of energy for other tissues of the body. Red bone marrow is where the production of blood cells (named hematopoiesis, hemato- = “blood”, -poiesis = “to make”) takes place. Red blood cells, white blood cells, and platelets are all produced in the red bone marrow. As we age, the distribution of red and yellow bone marrow changes as seen in the figure (Figure 6.1.2).",True,"Mineral and Fat Storage, Blood Cell Formation",Figure 6.1.2,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/marrow_skele-1024x920.png,Figure 6.1.2 – Bone Marrow: Bones contain variable amounts of yellow and/or red bone marrow. Yellow bone marrow stores fat and red bone marrow is responsible for producing blood cells (hematopoiesis).
+2579341a-92c8-4eb6-a5fd-32a901b8a4cb,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,bone marrow,False,bone marrow,,,,
+887638da-1622-4ea2-a5c1-78f40434863d,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"An orthopedist is a doctor who specializes in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery (Figure 6.1.3).",True,bone marrow,Figure 6.1.3,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/620_Arms_Brace.jpg,Figure 6.1.3 – Arm Brace: An orthopedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support. (credit: Juhan Sonin)
+01ce62ff-c6e9-4d15-ae2f-a3e310ebdb62,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"While the origin of the word “orthopedics” (ortho- = “straight”; paed- = “child”), literally means “straightening of the child,” orthopedists can have patients who range from pediatric to geriatric. In recent years, orthopedists have even performed prenatal surgery to correct spina bifida, a congenital defect in which the neural canal in the spine of the fetus fails to close completely during embryologic development.",True,bone marrow,,,,
+816004ba-87f8-4c10-a859-75dda27704fa,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Orthopedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine. Lateral curvatures (scoliosis) can be severe enough to slip under the shoulder blade (scapula) forcing it up as a hump. Spinal curvatures can also be excessive dorsoventrally (kyphosis) causing a hunch back and thoracic compression. These curvatures often appear in preteens as the result of poor posture, abnormal growth, or indeterminate causes. Mostly, they are readily treated by orthopedists. As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly.",True,bone marrow,,,,
+3fffdb02-6e41-4842-9bd6-b06f439d0179,https://open.oregonstate.education/aandp/,6.1 The Functions of the Skeletal System,https://open.oregonstate.education/aandp/chapter/6-1-the-functions-of-the-skeletal-system/,"Some orthopedists sub-specialize in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder. Treatment can range from exercise to surgery.",True,bone marrow,,,,
+74cb52e5-5e2a-43b2-b594-1274bce8c073,https://open.oregonstate.education/aandp/,6.0 Introduction,https://open.oregonstate.education/aandp/chapter/6-0-introduction/,"Bones make good fossils. While the soft tissue of a once living organism will decay and fall away over time, bone tissue will, under the right conditions, undergo a process of mineralization, effectively turning the bone to stone. A well-preserved fossil skeleton can give us a good sense of the size and shape of an organism, just as your skeleton helps to define your size and shape. Unlike a fossil skeleton, however, your skeleton is a structure of living tissue that grows, repairs, and renews itself. The bones within it are dynamic and complex organs that serve a number of important functions, including some necessary to maintain homeostasis.",True,bone marrow,,,,
+201b310c-1f39-438b-b473-a5675f682ada,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"The integumentary system is susceptible to a variety of diseases, disorders, and injuries. These range from annoying but relatively benign bacterial or fungal infections that are categorized as disorders, to skin cancer and severe burns, which can be fatal. In this section, you will learn several of the most common skin conditions.",True,bone marrow,,,,
+02c8a40a-c17f-48e3-9d83-64bac0f5c06e,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,Diseases,False,Diseases,,,,
+bf9f5d3f-c505-45c2-ade8-7639849bf469,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"One of the most talked about diseases is skin cancer. Cancer is a broad term that describes diseases caused by abnormal cells in the body dividing uncontrollably. Most cancers are identified by the organ or tissue in which the cancer originates. One common form of cancer is skin cancer. The Skin Cancer Foundation reports that one in five Americans will experience some type of skin cancer in their lifetime. The degradation of the ozone layer in the atmosphere and the resulting increase in exposure to UV radiation has contributed to its rise. Overexposure to UV radiation damages DNA, which can lead to the formation of cancerous lesions. Although melanin offers some protection against DNA damage from the sun, often it is not enough. The fact that cancers can also occur on areas of the body that are normally not exposed to UV radiation suggests that there are additional factors that can lead to cancerous lesions.",True,Diseases,,,,
+47654876-5580-45d0-97a4-0f23211a8911,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"In general, cancers result from an accumulation of DNA mutations. These mutations can result in cell populations that do not die when they should and uncontrolled cell proliferation that leads to tumors. Although many tumors are benign (harmless), some produce cells that can mobilize and establish tumors in other organs of the body; this process is referred to as metastasis. Cancers are characterized by their ability to metastasize.",True,Diseases,,,,
+cb801d18-1249-4457-b746-7506512679ca,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,Skin Disorders,False,Skin Disorders,,,,
+2223baac-9283-4f2a-a67c-8ed820d03d51,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Two common skin disorders are eczema and acne. Eczema is an inflammatory condition and occurs in individuals of all ages. Acne involves the clogging of pores, which can lead to infection and inflammation, and is often seen in adolescents. Other disorders, not discussed here, include seborrheic dermatitis (on the scalp), psoriasis, cold sores, impetigo, scabies, hives, and warts.",True,Skin Disorders,,,,
+5d65dab6-2f46-4a37-9996-b2ca6c9145c9,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Dermatologist
+
+Have you ever had a skin rash that did not respond to over-the-counter creams, or a mole that you were concerned about? Dermatologists help patients with these types of problems and more, on a daily basis. Dermatologists are medical doctors who specialize in diagnosing and treating skin disorders. Like all medical doctors, dermatologists earn a medical degree and then complete several years of residency training. In addition, dermatologists may then participate in a dermatology fellowship or complete additional, specialized training in a dermatology practice. If practicing in the United States, dermatologists must pass the United States Medical Licensing Exam (USMLE), become licensed in their state of practice, and be certified by the American Board of Dermatology.",True,Skin Disorders,,,,
+f3fa48c2-69a0-4829-8a8d-db63ba0d679b,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Most dermatologists work in a medical office or private-practice setting. They diagnose skin conditions and rashes, prescribe oral and topical medications to treat skin conditions, and may perform simple procedures, such as mole or wart removal. In addition, they may refer patients to an oncologist if skin cancer that has metastasized is suspected. Recently, cosmetic procedures have also become a prominent part of dermatology. Botox injections, laser treatments, and collagen and dermal filler injections are popular among patients, hoping to reduce the appearance of skin aging.",True,Skin Disorders,,,,
+9a76e5a3-049d-4746-be95-402cfc775218,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Dermatology is a competitive specialty in medicine. Limited openings in dermatology residency programs mean that many medical students compete for a few select spots. Dermatology is an appealing specialty to many prospective doctors, because unlike emergency room physicians or surgeons, dermatologists generally do not have to work excessive hours or be “on-call” weekends and holidays. Moreover, the popularity of cosmetic dermatology has made it a growing field with many lucrative opportunities. It is not unusual for dermatology clinics to market themselves exclusively as cosmetic dermatology centers, and for dermatologists to specialize exclusively in these procedures.",True,Skin Disorders,,,,
+a32cf432-2786-45e7-bf77-92a796a7e7be,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,Consider visiting a dermatologist to talk about why he or she entered the field and what the field of dermatology is like. Visit this site for additional information.,True,Skin Disorders,,,,
+8ee95e78-24e1-41f8-8559-aecd0b694486,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,Injuries,False,Injuries,,,,
+aa41a9dd-06d6-4baf-a136-711735ffe5e3,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Because the skin is the part of our bodies that meets the world most directly, it is especially vulnerable to injury. Injuries include burns and wounds, as well as scars and calluses. They can be caused by sharp objects, heat, or excessive pressure or friction to the skin.",True,Injuries,,,,
+4d7ea85e-6e32-455d-b558-fc7dd6651bc6,https://open.oregonstate.education/aandp/,"5.4 Diseases, Disorders, and Injuries of the Integumentary System",https://open.oregonstate.education/aandp/chapter/5-5-diseases-disorders-and-injuries-of-the-integumentary-system/,"Skin injuries set off a healing process that occurs in several overlapping stages. The first step to repairing damaged skin is the formation of a blood clot that helps stop the flow of blood and scabs over with time. Many different types of cells are involved in wound repair, especially if the surface area that needs repair is extensive. Before the basal stem cells of the stratum basale can recreate the epidermis, fibroblasts mobilize and divide rapidly to repair the damaged tissue by collagen deposition, forming granulation tissue. Blood capillaries follow the fibroblasts and help increase blood circulation and oxygen supply to the area. Immune cells, such as macrophages, roam the area and engulf any foreign matter to reduce the chance of infection.",True,Injuries,,,,
+69516819-c60b-48fd-87df-6f76b5d8f2d4,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The skin and accessory structures perform a variety of essential functions, such as protecting the body from invasion by microorganisms, chemicals, and other environmental factors; preventing dehydration; acting as a sensory organ; modulating body temperature and electrolyte balance; and synthesizing vitamin D. The underlying hypodermis has important roles in storing fats, forming a “cushion” over underlying structures, and providing insulation from cold temperatures.",True,Injuries,,,,
+211f32c6-8903-4420-85e2-9db80487db67,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,Protection,False,Protection,,,,
+a4ec1ba9-bb1f-4896-93d3-c3404fa52d39,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The skin protects the rest of the body from the basic elements of nature such as wind, water, and UV sunlight by acting as a physical, chemical, and biological barrier. It acts as a protective barrier against water loss, due to the presence of layers of keratin and glycolipids in the strata of the epidermis. It also is the first line of defense against abrasive activity due to contact with grit, microbes, or harmful chemicals. Sweat excreted from sweat glands deters microbes from over-colonizing the skin surface by generating dermicidin, which has antibiotic properties. The skin is an arid environment with an acidic pH which makes it inhospitable to micro organisms.",True,Protection,,,,
+b18f4a40-dcc2-4c7f-b532-279d77a4ebe8,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,Sensory Function,False,Sensory Function,,,,
+aef7ba32-37c9-4fce-9613-92f4eb2269f2,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment. The hair root plexus surrounding the base of the hair follicle senses a disturbance, and then transmits the information to the central nervous system (brain and spinal cord), which can then respond by activating the skeletal muscles of your eyes to see the ant and the skeletal muscles of the body to act against the ant.",True,Sensory Function,,,,
+26b0e0d0-3e94-45fe-8bac-468eee92bb6b,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the Meissner corpuscle (tactile corpuscle) (Figure 5.3.1), which responds to light touch, and the Pacinian corpuscle (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also touch receptors. In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our environment and react accordingly.",True,Sensory Function,Figure 5.3.1,5.3 Functions of the Integumentary System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/514_Light_Micrograph_of_a_Meissner_Corpuscle.jpg,"Figure 5.3.1 – Light Micrograph of a Meissner Corpuscle: In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM × 100. (credit: “Wbensmith”/Wikimedia Commons)"
+7c345e01-b119-4b2b-ac56-96c1e3d767a8,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,Thermoregulation,False,Thermoregulation,,,,
+61d4d139-47c1-44e8-a554-46b0ebc50b88,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (Figure 5.3.2ac), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.",True,Thermoregulation,Figure 5.3.2,5.3 Functions of the Integumentary System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/515_Thermoregulation.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)"
+4cf3291f-ace1-4544-b439-89857d72f795,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (Figure 5.3.2b). This accounts for the skin redness that many lighter skinned people experience when exercising.",True,Thermoregulation,Figure 5.3.2,5.3 Functions of the Integumentary System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/515_Thermoregulation.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)"
+b4bfce5e-97c1-4b24-b636-8f278df5f4e3,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"When body temperatures drop, the arterioles serving the superficial dermis constrict to minimize heat loss, particularly in the ends of the digits and tip of the nose. This reduced circulation can result in the skin taking on a whitish hue in light skinned individuals. Although the temperature of the skin drops as a result, passive heat loss is prevented, and internal organs and structures remain warm due to the warm blood remaining closer to the core. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of body core heat can result in the skin actually freezing, a condition called frostbite. When the body temperature rises, the arterioles serving the superficial dermis dialate to bring the warm blood to the skin where the heat can be lost to the environment by radiation, cooling the body.",True,Thermoregulation,,,,
+e793178b-2df3-4b72-808f-9078ffb7accc,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 5.3.3). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.",True,Thermoregulation,Figure 5.3.3,5.3 Functions of the Integumentary System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/516_Aging.jpg,"Figure 5.3.3 – Aging: Generally, skin, especially on the face and hands, starts to display the first noticeable signs of aging, as it loses its elasticity over time. (credit: Janet Ramsden)"
+50f6c8aa-e7b9-4e5e-ae92-0a642dfc4393,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The accessory structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating ability can cause some elderly to be intolerant to extreme heat. Other cells in the skin, such as melanocytes and dendritic cells, also become less active, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakdown of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the skin, and the inability of the skin to retain adequate moisture.",True,Thermoregulation,,,,
+577f7abf-9666-46cc-834e-44a9e257cadd,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"Many anti-aging products can be found in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate skin growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling.",True,Thermoregulation,,,,
+a6d79088-c62a-4bb5-b532-2c8e934e7fff,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,Vitamin D Synthesis,False,Vitamin D Synthesis,,,,
+44ae5275-83b1-4f09-9764-c3ab885c999b,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"The epidermal layer of human skin synthesizes vitamin D when exposed to UV radiation. In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized from a derivative of the steroid cholesterol in the skin. The liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys. Vitamin D is essential for normal absorption of calcium and phosphorous, which are required for healthy bones. The absence of sun exposure can lead to a lack of vitamin D in the body, leading to a condition called rickets, a painful condition in children where the bones are misshapen due to a lack of calcium, causing bowleggedness. Elderly individuals who suffer from vitamin D deficiency can develop a condition called osteomalacia, a softening of the bones. In present day society, vitamin D is added as a supplement to many foods, including milk and orange juice, attempting to compensate for the need for sun exposure.",True,Vitamin D Synthesis,,,,
+b35b5369-4fc0-439a-b043-34e9f0945e21,https://open.oregonstate.education/aandp/,5.3 Functions of the Integumentary System,https://open.oregonstate.education/aandp/chapter/5-3-functions-of-the-integumentary-system/,"In addition to its essential role in bone health, vitamin D is essential for general immunity against bacterial, viral, and fungal infections. Recent studies are also finding a link between insufficient vitamin D and cancer.",True,Vitamin D Synthesis,,,,
+e1027d09-66a1-4a34-977f-29cf80518494,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. These structures embryologically originate from the epidermis and can extend down through the dermis into the hypodermis.",True,Vitamin D Synthesis,,,,
+9e61500f-5a66-43d5-a05d-1ee0294e4e49,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,Hair,False,Hair,,,,
+4cc6eabc-0d99-472c-a306-cc25d69ae217,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Strands of hair originate in an epidermal penetration of the dermis called the hair follicle. The hair shaft is the part of the hair not anchored to the follicle, and much of this can be exposed at the skin’s surface. The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root. The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix. The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis (Figure 5.2.1).",True,Hair,Figure 5.2.1,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2019/07/506_Hair.jpg,Figure 5.2.1 – Hair: Hair follicles originate in the epidermis and have many different parts.
+11e0181b-8a0a-4339-a6da-fd0c682a7767,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows. The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle. These layers are depicted in a longitudinal cross-section of the hair follicle (Figure 5.2.2), although not all hair has a medullary layer. Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla. The shape and structure of these layers are, in turn, determined by the shape of the hair follicle. Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface. Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible. The external hair is completely dead and composed entirely of keratin. For this reason, our hair does not have sensation. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and plucking both attempt to destroy the hair bulb so hair cannot grow.",True,Hair,Figure 5.2.2,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/511_Hair_Follicle.jpg,Figure 5.2.2 – Hair Follicle: The slide shows a cross-section of a hair follicle. Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath. Basal cells at the base of the hair root form the outer root sheath. LM × 4. (credit: modification of work by “kilbad”/Wikimedia Commons)
+720253ea-7382-4bfd-ab8d-9026b856fc30,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"The wall of the hair follicle is made of three concentric layers of cells. The cells of the internal root sheath surround the root of the growing hair and extend just up to the hair shaft. They are derived from the basal cells of the hair matrix. The external root sheath, which is an extension of the epidermis, encloses the hair root. It is made of basal cells at the base of the hair root and tends to be more keratinous in the upper regions. The glassy membrane is a thick, clear connective tissue sheath covering the hair root, connecting it to the tissue of the dermis.",True,Hair,,,,
+d490756d-8482-4908-9615-20fe783e895b,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. For example, hair on the head protects the skull from the sun. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface. This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface. Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps and even more obvious in animals, such as when a frightened cat raises its fur. Of course, this is much more obvious in organisms with a heavier coat than most humans, such as dogs and cats.",True,Hair,,,,
+edd43fd3-10fd-493a-bea9-2f1ab01fbd30,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,Nails,False,Nails,,,,
+cf3ccf42-e034-4559-afb3-a969137bb457,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"The nail bed is a specialized structure of the epidermis that is found at the tips of our fingers and toes. The nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress (Figure 5.2.3). In addition, the nail body forms a back-support for picking up small objects with the fingers. The nail body is composed of densely packed dead keratinocytes. The epidermis in this part of the body has evolved a specialized structure upon which nails can form. The nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously. The lateral nail fold overlaps the nail on the sides, helping to anchor the nail body. The nail fold that meets the proximal end of the nail body forms the nail cuticle, also called the eponychium. The nail bed is rich in blood vessels, making it appear pink, except at the base, where a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the lunula (the “little moon”). The area beneath the free edge of the nail, furthest from the cuticle, is called the hyponychium. It consists of a thickened layer of stratum corneum.",True,Nails,Figure 5.2.3,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/507_Nails.jpg,Figure 5.2.3 – Nails: The nail is an accessory structure of the integumentary system.
+329283e2-92e3-432a-848e-a31c1c4545f8,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,Sweat Glands,False,Sweat Glands,,,,
+b0a85d53-52c7-43e8-b4d9-87a063fa6198,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"When the body becomes warm, sudoriferous glands  (sweat glands) produce sweat to cool the body. Sweat glands develop from epidermal projections into the dermis and are classified as merocrine glands; that is, the secretions are excreted by exocytosis through a duct without affecting the cells of the gland. There are two types of sweat glands, each secreting slightly different products.",True,Sweat Glands,,,,
+eacb1fb3-1e23-4736-96f9-80f21e150758,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"An eccrine sweat gland is type of gland that produces a hypotonic sweat for thermoregulation. These glands are found all over the skin’s surface, but are especially abundant on the palms of the hand, the soles of the feet, and the forehead (Figure 5.2.4). They are coiled glands lying deep in the dermis, with the duct rising up to a pore on the skin surface, where the sweat is released. This type of sweat, released by exocytosis, is hypotonic and composed mostly of water, with some salt, antibodies, traces of metabolic waste, and dermicidin, an antimicrobial peptide. Eccrine glands are a primary component of thermoregulation in humans and thus help to maintain homeostasis by producing sweat that evaporates and cools the body.",True,Sweat Glands,Figure 5.2.4,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/508_Eccrine_gland.jpg,Figure 5.2.4 – Eccrine Gland: Eccrine glands are coiled glands in the dermis that release sweat that is mostly water.
+2bc7e110-5b63-4193-8735-71f65144c45f,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control, and plays a role in the poorly understood human pheromone response. Most commercial antiperspirants use an aluminum-based compound as their primary active ingredient to stop sweat. When the antiperspirant enters the sweat gland duct, the aluminum-based compounds precipitate due to a change in pH and form a physical block in the duct, which prevents sweat from coming out of the pore.",True,Sweat Glands,,,,
+6360d1f3-1dd8-4f98-a537-942d8bc67272,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,Sebaceous Glands,False,Sebaceous Glands,,,,
+f8d748a3-8eb8-4eef-acd5-4714adb665f6,https://open.oregonstate.education/aandp/,5.2 Accessory Structures of the Skin,https://open.oregonstate.education/aandp/chapter/5-2-accessory-structures-of-the-skin/,"A sebaceous gland is a type of oil gland that is found all over the body and helps to lubricate and waterproof the skin and hair. Most sebaceous glands are associated with hair follicles. They generate and excrete sebum, a mixture of lipids, onto the skin surface, thereby naturally lubricating the dry and dead layer of keratinized cells of the stratum corneum, keeping it pliable. The fatty acids of sebum also have antibacterial properties, and prevent water loss from the skin in low-humidity environments. The secretion of sebum is stimulated by hormones, many of which do not become active until puberty. Thus, sebaceous glands are relatively inactive during childhood.",True,Sebaceous Glands,,,,
+3bc4be9d-ba9d-4544-bbe9-967327b9cd08,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"Although you may not typically think of the skin as an organ, it is in fact made of tissues that work together as a single structure to perform unique and critical functions. The skin and its accessory structures make up the integumentary system, which provides the body with overall protection. The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue (Figure 5.1.1). The most superficial layer of the skin is the epidermis which is attached to the deeper dermis. Accessory structures, hair, glands, and nails, are found associated with the skin. The deeper layer of skin is well vascularized (has numerous blood vessels) and is superficial to the hypodermics. It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain.",True,Sebaceous Glands,Figure 5.1.1,5.1 Layers of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2019/07/501_Structure_of_the_skin.jpg,"Figure 5.1.1 – Layers of Skin: The skin is composed of two main layers: the epidermis, made of closely packed epithelial cells, and the dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures. Beneath the dermis lies the hypodermis, which is composed mainly of loose connective and fatty tissues."
+ff751787-d264-4e73-8dec-b51f67002c3d,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,The Epidermis,False,The Epidermis,,,,
+40da5b91-04c2-4b69-a8a3-100614b2113f,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it (i.e., it is avascular). Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum (Figure 5.1.2).",True,The Epidermis,Figure 5.1.2,5.1 Layers of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/502ab_Thin_Skin_versus_Thick_Skin.jpg,"Figure 5.1.2 – Thin Skin versus Thick Skin: These slides show cross-sections of the epidermis and dermis of (a) thin and (b) thick skin. Note the significant difference in the thickness of the epithelial layer of the thick skin. From top, LM × 40, LM × 40. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+e8021626-5ca1-4aa1-a51e-b5a770c52f11,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"The cells in all of the layers except the stratum basale are called keratinocytes, which make up about 95% of all epidermal cells. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers (Figure 5.1.3).",True,The Epidermis,Figure 5.1.3,5.1 Layers of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/503_Epidermis.jpg,"Figure 5.1.3 – Epidermis: The epidermis is epithelium composed of multiple layers of cells. The basal layer consists of cuboidal cells, whereas the outer layers are squamous, keratinized cells, so the whole epithelium is often described as being keratinized stratified squamous epithelium. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+a94da52b-7118-4c99-babb-bec1b59ea091,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,Dermis,False,Dermis,,,,
+06b00cb2-67a9-483d-827f-e8d8d406b436,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"The dermis might be considered the “core” of the integumentary system (derma- = “skin”), as distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The epidermis is avascular and cells of this layer must get their oxygen and nutrients from capillaries in the dermis. The dermis is made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts (Figure 5.1.6). The more superficial papillary layer serves as an anchor point for the epidermis above and is intimately connected to the deeper reticular layer.",True,Dermis,Figure 5.1.6,5.1 Layers of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/506_Layers_of_the_Dermis.jpg,"Figure 5.1.6 – Layers of the Dermis: This stained slide shows the two components of the dermis—the papillary layer and the reticular layer. Both are made of connective tissue with fibers of collagen extending from one to the other, making the border between the two somewhat indistinct. The dermal papillae extending into the epidermis belong to the papillary layer, whereas the dense collagen fiber bundles below belong to the reticular layer. LM × 10. (credit: modification of work by “kilbad”/Wikimedia Commons)"
+87986f51-23db-465d-a4aa-3a6e51124807,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,Hypodermis,False,Hypodermis,,,,
+78e3c2dd-e589-4a1e-bffd-a0d236adc1bb,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"The hypodermis (also called the subcutaneous layer or superficial fascia) is a layer directly below the dermis and serves to connect the skin to the underlying fascia (fibrous tissue) surrounding the muscles. It is not strictly a part of the skin, although the border between the hypodermis and dermis can be difficult to distinguish. The hypodermis consists of well-vascularized, loose, areolar connective tissue and abundant adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument. Fascia is a thick connective tissue wrapping that surrounds skeletal muscles anchoring them to surrounding tissues and investing groups of muscles.",True,Hypodermis,,,,
+fa64a55b-69a8-45dd-965e-3b37763aff6f,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,Pigmentation,False,Pigmentation,,,,
+0a8ab4f3-5371-49f4-821e-d507151e3c67,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome (Figure 5.1.7).",True,Pigmentation,Figure 5.1.7,5.1 Layers of the Skin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/504_Melanocytes.jpg,Figure 5.1.7 – Skin Pigmentation: The relative coloration of the skin depends of the amount of melanin produced by melanocytes in the stratum basale and taken up by keratinocytes.
+c73e765d-36c0-49a8-a755-d191e4447e42,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"Melanin occurs in two primary forms. Eumelanin exists as black and brown, whereas pheomelanin provides a red color. Dark-skinned individuals produce more melanin than those with pale skin. Exposure to the UV rays of the sun or a tanning salon causes melanin to be manufactured and built up in keratinocytes, as sun exposure stimulates keratinocytes to secrete chemicals that stimulate melanocytes. The accumulation of melanin in keratinocytes results in the darkening of the skin, or a tan. This increased melanin accumulation protects the DNA of epidermal cells from UV ray damage and the breakdown of folic acid, a nutrient necessary for our health and well-being. In contrast, too much melanin can interfere with the production of vitamin D, an important nutrient involved in calcium absorption. There is a dynamic interplay between the amount of protection from UV radiation that melanin provides and the amount of vitamin D produced. The amount of melanin produced, and therefore UV protection, is directly correlated with the amount of sunlight exposure. The more sunlight, the more UV protection, but the compromise is that with increased melanin there is a decrease in vitamin D produced.",True,Pigmentation,,,,
+9826c79a-7717-4fb7-a26c-b8dde688d582,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"It requires about 10 days after initial sun exposure for melanin synthesis to peak, which is why pale-skinned individuals tend to suffer sunburns of the epidermis initially. Dark-skinned individuals can also get sunburns, but are more protected than are pale-skinned individuals. Melanosomes are temporary structures that are eventually destroyed by fusion with lysosomes; this fact, along with melanin-filled keratinocytes in the stratum corneum sloughing off, makes tanning impermanent.",True,Pigmentation,,,,
+5d657cec-dfb4-41a3-a772-8a431f7da5f6,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,"Too much sun exposure can eventually lead to wrinkling due to the destruction of the cellular structure of the skin, and in severe cases, can cause sufficient DNA damage to result in skin cancer. When there is an irregular accumulation of melanocytes in the skin, freckles appear. Moles are larger masses of melanocytes, and although most are benign, they should be monitored for changes that might indicate the presence of cancer (Figure 5.1.8). A total lack of melanin is caused by the genetic disorder called albinism (See Disorders of the…Integumentary System below)",True,Pigmentation,Figure 5.1.8,,,
+8468161f-2df3-4412-a95a-05f280eb4647,https://open.oregonstate.education/aandp/,5.1 Layers of the Skin,https://open.oregonstate.education/aandp/chapter/5-1-layers-of-the-skin/,Albinism,False,Albinism,,,,
+a404159e-dd9d-440f-a5fe-7504f79a4990,https://open.oregonstate.education/aandp/,5.0 Introduction,https://open.oregonstate.education/aandp/chapter/5-0-introduction/,"What do you think when you look at your skin in the mirror? Do you think about covering it with makeup, adding a tattoo, or maybe a body piercing? Or do you think about the fact that the skin belongs to one of the body’s most essential and dynamic systems: the integumentary system? The integumentary system refers to the skin and its accessory structures, and it is responsible for much more than simply lending to your outward appearance. In the adult human body, the skin makes up about 16 percent of body weight and covers an area of 1.5 to 2 m2. In fact, the skin and accessory structures are the largest organ system in the human body. As such, the skin protects your inner organs and it is in need of daily care and protection to maintain its health. This chapter will introduce the structure and functions of the integumentary system, as well as some of the diseases, disorders, and injuries that can affect this system.",True,Albinism,,,,
+9b1a2df8-8d33-4a74-ad6c-be0ce51daabd,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Tissues of all types are vulnerable to injury and, inevitably, aging. In the former case, understanding how tissues respond to damage can guide strategies to aid repair. In the latter case, understanding the impact of aging can help in the search for ways to diminish its effects.",True,Albinism,,,,
+8194a027-ce13-46da-b0a6-c030cb00fd04,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,Tissue Injury and Repair,False,Tissue Injury and Repair,,,,
+57287f1e-0718-478c-8894-7e774f11017c,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Inflammation is the standard, initial response of the body to injury. Whether biological, chemical, physical, or radiation burns, all injuries lead to the same sequence of physiological events. Inflammation limits the extent of injury, partially or fully eliminates the cause of injury, and initiates repair and regeneration of damaged tissue. Necrosis, or accidental cell death, causes inflammation. Apoptosis is programmed cell death, a normal step-by-step process that destroys cells no longer needed by the body. By mechanisms still under investigation, apoptosis does not initiate the inflammatory response. Acute inflammation resolves over time by the healing of tissue. If inflammation persists, it becomes chronic and leads to diseased conditions. Arthritis and tuberculosis are examples of chronic inflammation. The suffix “-itis” denotes inflammation of a specific organ or type. For example, peritonitis is the inflammation of the peritoneum, and meningitis refers to the inflammation of the meninges, the tough membranes that surround the central nervous system.",True,Tissue Injury and Repair,,,,
+1dbff0a6-f283-43a8-b797-7d166053fad4,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"The four cardinal signs of inflammation—redness (at least for people with light colored skin), swelling, pain, and local heat—were first recorded in antiquity. Cornelius Celsus is credited with documenting these signs during the days of the Roman Empire, as early as the first century AD. A fifth sign, loss of function, may also accompany inflammation.",True,Tissue Injury and Repair,,,,
+8eab2ce9-a651-4a0d-9b95-54dfd0fc2701,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Upon tissue injury, damaged cells release inflammatory chemical signals that evoke local vasodilation, the widening of the blood vessels. Increased blood flow can change the color of the integument and result in a localized temperature increase. In response to injury, mast cells present in tissue degranulate, releasing the potent vasodilator histamine. Increased blood flow and inflammatory mediators recruit white blood cells to the site of inflammation. The endothelium lining the local blood vessel becomes “leaky” under the influence of histamine and other inflammatory mediators allowing neutrophils, macrophages, and fluid to move from the blood into the interstitial tissue spaces. The excess liquid in tissue causes swelling, properly called edema. The swollen tissues stimulate mechanical receptors, which can cause the perception of pain. Prostaglandins released from injured cells also activate pain pathways. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce perceived pain because they inhibit the synthesis of prostaglandins. High levels of NSAIDs reduce inflammation. Antihistamines decrease allergies by blocking histamine receptors and as a result, the histamine response.",True,Tissue Injury and Repair,,,,
+8bede91b-18d9-466e-8e7e-23a95a27e7e2,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.6.1 – Tissue Healing).",True,Tissue Injury and Repair,Figure 4.6.1,4.6 Tissue Injury and Aging,https://open.oregonstate.education/app/uploads/sites/157/2019/07/417_Tissue_Repair.jpg,"Figure 4.6.1 – Tissue Healing: During wound repair, collagen fibers are laid down randomly by fibroblasts that move into repair the area."
+6894872a-32d6-4273-881c-270acd020f1a,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,Tissue and Aging,False,Tissue and Aging,,,,
+22bc30e7-f67f-45b4-9f69-e820c5ef7ece,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"According to poet Ralph Waldo Emerson, “The surest poison is time.” In fact, biology confirms that many functions of the body decline with age. All the cells, tissues, and organs are affected by senescence, with noticeable variability between individuals owing to different genetic makeup and lifestyles. The outward signs of aging are easily recognizable. The skin and other tissues become thinner and drier, reducing their elasticity, contributing to wrinkles and high blood pressure. Hair turns gray because follicles produce less melanin, the brown pigment of hair and the iris of the eye. The face looks flabby because elastic and collagen fibers decrease in connective tissue and muscle tone is lost. Glasses and hearing aids may become parts of life as the senses slowly deteriorate, all due to reduced elasticity. Overall height decreases as the bones lose calcium and other minerals. With age, fluid decreases in the fibrous cartilage disks intercalated between the vertebrae in the spine. Joints lose cartilage and stiffen. Many tissues, including those in muscles, lose mass through a process called atrophy. Lumps and rigidity become more widespread. As a consequence, the passageways, blood vessels, and airways become more rigid. The brain and spinal cord lose mass. Nerves do not transmit impulses with the same speed and frequency as in the past. Some loss of thought, clarity, and memory can accompany aging. More severe problems are not necessarily associated with the aging process and may be symptoms of an underlying illness.",True,Tissue and Aging,,,,
+1f2a4c19-25a4-4459-9d76-1c088f283901,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"As exterior signs of aging increase, so do the interior signs, which are not as noticeable. The incidence of heart diseases, respiratory syndromes, and type 2 diabetes increases with age, though these are not necessarily age-dependent effects. Wound healing is slower in the elderly, accompanied by a higher frequency of infection as the capacity of the immune system to fend off pathogens declines.",True,Tissue and Aging,,,,
+42ab2254-3936-45fe-a926-1fc8dfcfe68a,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Aging is also apparent at the cellular level because all cells experience changes with aging. Telomeres, regions of the chromosomes necessary for cell division, shorten each time cells divide. As they do, cells are less able to divide and regenerate. Because of alterations in cell membranes, transport of oxygen and nutrients into the cell and removal of carbon dioxide and waste products from the cell are not as efficient in the elderly. Cells may begin to function abnormally, which may lead to diseases associated with aging, including arthritis, memory issues, and some cancers.",True,Tissue and Aging,,,,
+49a0c198-2270-4a19-a3b2-ea74c4b6d533,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"The progressive impact of aging on the body varies considerably among individuals. However, studies indicate that exercise and healthy lifestyle choices can slow down the deterioration of the body that comes with old age.",True,Tissue and Aging,,,,
+daa3766b-3918-4b7d-bd7c-6ade8ae902c8,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,Homeostatic Imbalances: Tissues and Cancer,False,Homeostatic Imbalances: Tissues and Cancer,,,,
+bf3de8ec-7e4b-46ce-bd9d-8ccae5e8af39,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Cancer is a generic term for many diseases in which cells escape regulatory signals. Uncontrolled growth, invasion into adjacent tissues, and colonization of other organs, if not treated early enough, are its hallmarks. Health suffers when tumors “rob” blood supply from the “normal” organs.",True,Homeostatic Imbalances: Tissues and Cancer,,,,
+4c727b42-0f4a-456c-b048-d0f6e1b51647,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"A mutation is defined as a permanent change in the DNA of a cell. Epigenetic modifications, changes that do not affect the code of the DNA but alter how the DNA is decoded, are also known to generate abnormal cells. Alterations in the genetic material may be caused by environmental agents, infectious agents, or errors in the replication of DNA that accumulate with age. Many mutations do not cause any noticeable change in the functions of a cell, however, if the modification affects key proteins that have an impact on the cell’s ability to proliferate in an orderly fashion, the cell starts to divide abnormally. As changes in cells accumulate, they lose their ability to form regular tissues. A tumor, a mass of cells displaying abnormal architecture, forms in the tissue. Many tumors are benign, meaning they do not metastasize nor cause disease. A tumor becomes malignant, or cancerous, when it breaches the confines of its tissue, promotes angiogenesis, attracts the growth of capillaries, and metastasizes to other organs (Figure 4.6.2 Development of Cancer). The specific names of cancers reflect the tissue of origin. Cancers derived from epithelial cells are referred to as carcinomas. Cancer in myeloid tissue or blood cells form myelomas. Leukemias are cancers of white blood cells, whereas sarcomas derive from connective tissue. Cells in tumors differ both in structure and function. Some cells, called cancer stem cells, appear to be a subtype of cell responsible for uncontrolled growth. Recent research shows that contrary to what was previously assumed, tumors are not disorganized masses of cells, but have their own structures.",True,Homeostatic Imbalances: Tissues and Cancer,Figure 4.6.2,4.6 Tissue Injury and Aging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/418_Development_of_Cancer.png,"Figure 4.6.2 – Development of Cancer: Note the change in cell size, nucleus size, and organization in the tissue."
+3160d86b-ac63-4c82-b0e8-5b8132ebf42a,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Cancer treatments vary depending on the disease’s type and stage. Traditional approaches, including surgery, radiation, chemotherapy, and hormonal therapy. The aim is to remove or kill rapidly dividing cancer cells, but these strategies have their limitations. Depending on a tumor’s location, for example, cancer surgeons may be unable to remove it. Radiation and chemotherapy are difficult, and it is often impossible to target only the cancer cells. The treatments inevitably destroy healthy tissue as well. To address this, researchers are working on pharmaceuticals that can target specific proteins implicated in cancer-associated molecular pathways.",True,Homeostatic Imbalances: Tissues and Cancer,,,,
+b9675649-6b15-4ee1-8626-b787f09a4850,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,References,False,References,,,,
+a742e792-bc69-497f-ad54-11a26d6b7ad6,https://open.oregonstate.education/aandp/,4.6 Tissue Injury and Aging,https://open.oregonstate.education/aandp/chapter/4-6-tissue-injury-and-aging/,"Emerson, RW. Old age. Atlantic. 1862 [cited 2012 Dec 4]; 9(51):134–140.",True,References,,,,
+60edbc8a-829b-4b70-bc21-5bd5fa8a6ab4,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,"Nervous tissue is characterized as being excitable and capable of sending and receiving electrochemical signals that provide the body with information. Two main classes of cells make up nervous tissue: the neuron and neuroglia (Figure 4.5.1 The Neuron). Neurons propagate information via electrochemical impulses, called action potentials, which are biochemically linked to the release of chemical signals. Neuroglia play an essential role in supporting neurons.",True,References,Figure 4.5.1,4.5 Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/415_Neuron.jpg,"Figure 4.5.1 – The Neuron: The cell body of a neuron, also called the soma, contains the nucleus and mitochondria. The dendrites transfer the nerve impulse to the soma. The axon carries the action potential away to another excitable cell (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+4ac76e66-d898-4a8b-9642-a749d3794274,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,"Neurons display distinctive morphology, well suited to their role as conducting cells, with three main parts. The cell body includes most of the cytoplasm, organelles, and nucleus. Dendrites, which receive input from other neurons, branch off the cell body and appear as thin extensions. A long axon extends from the cell body and may be wrapped in an insulating layer known as myelin, which is formed by accessory cells. Axons transmit electrical signals traveling away from the cell body. The synapse is the gap between nerve cells, or between a nerve cell and its target. The signal is transmitted across the synapse by chemical compounds known as neurotransmitters. Neurons categorized as multipolar neurons have several dendrites and a single prominent axon. Bipolar neurons possess a single dendrite and axon with the cell body, while unipolar neurons have only a single process extending out from the cell body, which divides into a functional dendrite and into a functional axon. When a neuron is sufficiently stimulated, it generates an action potential that propagates down the axon towards the synapse. If enough neurotransmitters are released at the synapse to stimulate the next neuron (or muscle, or gland), a response is generated.",True,References,,,,
+5e50790b-1e83-4fe6-8394-0c39f16dea3e,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,"The second class of neural cells are the neuroglia or glial cells, which have been characterized as having a simple support role. The word “glia” comes from the Greek word for glue. Recent research is shedding light on the more complex role of neuroglia in the function of the brain and nervous system. Astrocyte cells, named for their distinctive star shape, are abundant in the central nervous system. The astrocytes have many functions, including regulation of ion concentration in the intercellular space, uptake and/or breakdown of some neurotransmitters, and formation of the blood-brain barrier, the membrane that separates the circulatory system from the brain. Microglia protect the nervous system against infection and are related to macrophages. Oligodendrocyte cells produce myelin in the central nervous system (brain and spinal cord) while the Schwann cell produces myelin in the peripheral nervous system (Figure 4.5.2 Nervous Tissue).",True,References,Figure 4.5.2,4.5 Nervous Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/416_Nervous_Tissue-new.jpg,Figure 4.5.2 – Nervous Tissue: Nervous tissue is made up of neurons and neuroglia. The cells of nervous tissue are specialized to transmit and receive impulses (LM × 872). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+160a932a-9085-4f99-bc79-2d248c89a674,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,References,False,References,,,,
+f888f32b-6be2-4777-a79f-bca258803f33,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,"Stern, P. Focus issue: getting excited about glia. Science [Internet]. 2010 [cited 2012 Dec 4]; 3(147):330-773. Available from:",True,References,,,,
+96c9ad69-da48-4b48-927f-e6907236016c,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,http://stke.sciencemag.org/cgi/content/abstract/sigtrans;3/147/eg11,True,References,,,,
+53a06bb0-8ab1-4329-a7ed-ef3c62bd066d,https://open.oregonstate.education/aandp/,4.5 Nervous Tissue,https://open.oregonstate.education/aandp/chapter/4-5-nervous-tissue/,"Ming GL, Song H. Adult neurogenesis in the mammalian central nervous system. Annu. Rev. Neurosci. 2005 [cited 2012 Dec 4]; 28:223–250.",True,References,,,,
+a15fe260-92a4-4156-bf31-8de9b1583de0,https://open.oregonstate.education/aandp/,4.4 Muscle Tissue,https://open.oregonstate.education/aandp/chapter/4-4-muscle-tissue/,"Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth (Table 4.2).",True,References,,,,
+5ff6a553-bd17-4c8d-9622-caa0b23f7ec2,https://open.oregonstate.education/aandp/,4.4 Muscle Tissue,https://open.oregonstate.education/aandp/chapter/4-4-muscle-tissue/,"Skeletal muscle is attached to bones and its contraction makes possible locomotion, facial expressions, posture, and other voluntary movements of the body. Forty percent of your body mass is made up of skeletal muscle. Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis. Shivering is an involuntary contraction of skeletal muscles in response to lower than normal body temperature. The muscle cell, or myocyte, develops from myoblasts derived from the mesoderm. Myocytes and their numbers remain relatively constant throughout life. Skeletal muscle tissue is arranged in bundles surrounded by connective tissue. Under the light microscope, muscle cells appear striated with many nuclei squeezed along the membranes. The striation is due to the regular alternation of the contractile proteins actin and myosin, along with the structural proteins that couple the contractile proteins to connective tissues. The cells are multinucleated as a result of the fusion of the many myoblasts that fuse to form each long muscle fiber.",True,References,,,,
+1173c4e0-9506-47d4-90cc-89eb7351f3e7,https://open.oregonstate.education/aandp/,4.4 Muscle Tissue,https://open.oregonstate.education/aandp/chapter/4-4-muscle-tissue/,"Cardiac muscle forms the contractile walls of the heart. The cells of cardiac muscle, known as cardiomyocytes, also appear striated under the microscope. Unlike skeletal muscle fibers, cardiomyocytes are single cells with a single centrally located nucleus. A principal characteristic of cardiomyocytes is that they contract on their own intrinsic rhythm without external stimulation. Cardiomyocytes attach to one another with specialized cell junctions called intercalated discs. Intercalated discs have both anchoring junctions and gap junctions. Attached cells form long, branching cardiac muscle fibers that act as a syncytium, allowing the cells to synchronize their actions. The cardiac muscle pumps blood through the body and is under involuntary control.",True,References,,,,
+f720e6c6-8d42-4921-a6cf-91363d7a7736,https://open.oregonstate.education/aandp/,4.4 Muscle Tissue,https://open.oregonstate.education/aandp/chapter/4-4-muscle-tissue/,"Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and blood vessels. Each cell is spindle shaped with a single nucleus and no visible striations (Figure 4.4.1 – Muscle Tissue).",True,References,Figure 4.4.1,4.4 Muscle Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/414_Skeletal_Smooth_Cardiac.jpg,"Figure 4.4.1 – Muscle Tissue: (a) Skeletal muscle cells have prominent striation and nuclei on their periphery. (b) Smooth muscle cells have a single nucleus and no visible striations. (c) Cardiac muscle cells appear striated and have a single nucleus. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+8a6f1e4f-81af-4a78-8b41-7a5ce63cf5a5,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Functions of Connective Tissues,False,Functions of Connective Tissues,,,,
+f88639b7-1ce0-4586-9293-38e9acfddc0f,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Connective tissues perform many functions in the body, most importantly, they support and connect other tissues: from the connective tissue sheath that surrounds a muscle, to the tendons that attach muscles to bones, and to the skeleton that supports the positions of the body. Protection is another major function of connective tissue, in the form of fibrous capsules and bones that protect delicate organs. Specialized cells in connective tissue defend the body from microorganisms that enter the body. Transport of gases, nutrients, waste, and chemical messengers is ensured by specialized fluid connective tissues, such as blood and lymph. Adipose cells store surplus energy in the form of fat and contribute to the thermal insulation of the body.",True,Functions of Connective Tissues,,,,
+24f9b1e5-cbab-4d65-9f0b-869b7dba1c0a,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Embryonic Connective Tissue,False,Embryonic Connective Tissue,,,,
+b36e9a62-990a-4410-a36e-af0c88a9fc90,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"All connective tissues derive from the mesodermal layer of the embryo (see Figure 4.2.2). The first connective tissue to develop in the embryo is mesenchyme, the stem cell line from which all connective tissues are later derived. Clusters of mesenchymal cells are scattered throughout adult tissue and supply the cells needed for replacement and repair after a connective tissue injury. A second type of embryonic connective tissue forms in the umbilical cord, called mucous connective tissue or Wharton’s jelly. This tissue is no longer present after birth, leaving only scattered mesenchymal cells throughout the body.",True,Embryonic Connective Tissue,Figure 4.2.2,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+a20a3c25-64a1-450d-a979-666445f51e92,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Structural Elements of Connective Tissue,False,Structural Elements of Connective Tissue,,,,
+6f6fbabd-2e20-4adf-a29a-d995870e52f6,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Connective tissues come in a vast variety of forms, yet they typically have in common three characteristic components: cells, large amounts of amorphous ground substance, and protein fibers. Unlike epithelial tissue, which is composed of cells closely packed together, cells of connective tissue are more widely dispersed within an extracellular matrix (ECM). The matrix plays a major role in the functioning of this tissue. The major component of the matrix is ground substance. This ground substance is usually a fluid, but it can also be mineralized and solid, as in bones.  The amount and structure of each component correlates with the function of the tissue, from the rigid ground substance in bones supporting the body to the inclusion of specialized cells; for example, a phagocytic cell that engulfs pathogens and also rids tissue of cellular debris.",True,Structural Elements of Connective Tissue,,,,
+593c6799-57bd-45b2-99f3-05208d1e255b,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Cell Types,False,Cell Types,,,,
+29087e61-1a0b-4df7-a901-fd03d2f69546,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Each class of connective tissue is formed by fundamental cell types. The cells can be found in both an active form (suffix –blast), where they are dividing and secreting the components of ground substance, and an in-active form (suffix –cyte).  The most abundant cell in connective tissue proper is the fibroblast. Polysaccharides and proteins secreted by fibroblasts combine with extra-cellular fluids to produce a viscous ground substance that, with embedded fibrous proteins and cells, forms the extra-cellular matrix. Chondroblasts and osteoblasts are the primary specialized cell type located in cartilage and bone, respectively.",True,Cell Types,,,,
+9c084ed1-fca4-4846-9966-3a92db16c9fa,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Adipocytes are cells that store lipids as droplets that fill most of the cytoplasm. There are two basic types of adipocytes: white and brown. The brown adipocytes store lipids as many droplets, and have high metabolic activity. In contrast, white fat adipocytes store lipids as a single large drop and are metabolically less active. Their effectiveness at storing large amounts of fat is witnessed in obese individuals. The number and type of adipocytes depends on the tissue and location, and vary among individuals in the population.",True,Cell Types,,,,
+06f24a06-7157-4721-a605-a0093edd44b2,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,The mesenchymal cell is a multipotent adult stem cell. These cells can differentiate into any type of connective tissue cells needed for repair and healing of damaged tissue.,True,Cell Types,,,,
+ec775b19-2726-40b3-8adb-a40c79961720,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The macrophage cell is a large cell derived from a monocyte, a type of blood cell, which enters the connective tissue matrix from the blood vessels. The macrophage cells are an essential component of the immune system, which is the body’s defense against potential pathogens and degraded host cells. When stimulated, macrophages release cytokines, small proteins that act as chemical messengers. Cytokines recruit other cells of the immune system to infected sites and stimulate their activities. Roaming, or free, macrophages move rapidly by amoeboid movement, engulfing infectious agents and cellular debris. In contrast, fixed macrophages are permanent residents of their tissues.",True,Cell Types,,,,
+6300755c-57aa-4d8d-95d5-06b43cd6f956,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The mast cell, found in connective tissue proper, has many cytoplasmic granules. These granules contain the chemical signals histamine and heparin. When irritated or damaged, mast cells release histamine, an inflammatory mediator, which causes vasodilation and increased blood flow at a site of injury or infection, along with itching, swelling, and redness (in people with light skin), recognized as an allergic response. Mast cells are derived from hematopoietic stem cells and are part of the immune system.",True,Cell Types,,,,
+a0b8dd81-e87c-4699-89c7-541120a16f37,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Connective Tissue Fibers and Ground Substance,False,Connective Tissue Fibers and Ground Substance,,,,
+b1dcf806-22cf-4c2f-a42c-4fc4dd02a615,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Three main types of fibers are secreted by fibroblasts: collagen fibers, elastic fibers, and reticular fibers. Collagen fiber is made from fibrous protein subunits linked together to form a long, straight fiber. Collagen fibers, while flexible, have great tensile strength, resist stretching, and give ligaments and tendons their characteristic resilience.",True,Connective Tissue Fibers and Ground Substance,,,,
+a8b60a26-415c-4054-8d62-95212f65168f,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"An elastic fiber contains the protein elastin along with lesser amounts of other proteins and glycoproteins. The main property of elastin is that after being stretched or compressed, it will return to its original shape. Elastic fibers are prominent in elastic tissues found in skin, the walls of large blood vessels, and in a few ligaments which support the spine.",True,Connective Tissue Fibers and Ground Substance,,,,
+253ab3a8-41c9-4241-97ea-e31e0f1ad830,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"A reticular fiber is formed from the same protein subunits as collagen fibers, however, these fibers remain narrow and are arranged in a branching network. They are found throughout the body, but are most abundant in the reticular tissue of soft organs, such as the liver and spleen, where they anchor and provide structural support to the parenchyma (the functional cells, blood vessels, and nerves of the organ).",True,Connective Tissue Fibers and Ground Substance,,,,
+3a87bb46-1e4f-4d9f-a4d1-6a13402d0cf8,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"All of these fiber types are embedded in ground substance. Secreted by fibroblasts, ground substance is made of polysaccharides, specifically hyaluronic acid, and proteins. These combine to form a proteoglycan with a protein core and polysaccharide branches. The proteoglycan attracts and traps available moisture forming the clear, viscous, colorless ground substance.",True,Connective Tissue Fibers and Ground Substance,,,,
+03676f6e-d69a-4a19-9ebd-c238d7eba566,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Classification of Connective Tissues,False,Classification of Connective Tissues,,,,
+3c0b278e-08f2-4a2b-9411-c8c4e20a8093,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The three broad categories of connective tissue are classified according to the characteristics of their ground substance and the types of fibers found within the matrix (Table 4.1). Connective tissue proper includes loose connective tissue and dense connective tissue. Both tissues have a variety of cell types and protein fibers suspended in a viscous ground substance. Dense connective tissue is reinforced by bundles of fibers that provide tensile strength, elasticity, and protection. In loose connective tissue, the fibers are loosely organized, leaving large spaces in between. Supportive connective tissue—bone and cartilage—provide structure and strength to the body and protect soft tissues. A few distinct cell types and densely packed fibers in a matrix characterize these tissues. In bone, the matrix is rigid and described as calcified because of the deposited calcium salts. In fluid connective tissue, lymph and blood, various specialized cells circulate in a watery fluid containing salts, nutrients, and dissolved proteins.",True,Classification of Connective Tissues,,,,
+a8093138-d8e5-4a2e-89e5-0f5b7fc46605,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Connective Tissue Proper,False,Connective Tissue Proper,,,,
+694637b6-5279-40b1-9e16-2f0db8d65a0f,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Fibroblasts are present in all connective tissue proper (Figure 4.3.1). Fibrocytes, adipocytes, and mesenchymal cells are fixed cells, which means they remain within the connective tissue. Other cells move in and out of the connective tissue in response to chemical signals. Macrophages, mast cells, lymphocytes, plasma cells, and phagocytic cells are found in connective tissue proper but are actually part of the immune system protecting the body.",True,Connective Tissue Proper,Figure 4.3.1,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/app/uploads/sites/157/2019/07/408_Connective_Tissue-1.jpg,"Figure 4.3.1 – Connective Tissue Proper: Fibroblasts produce this fibrous tissue. Connective tissue proper includes the fixed cells fibrocytes, adipocytes, and mesenchymal cells (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+74380f14-a46d-4df2-ab6e-2cf1a8305b4b,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Loose Connective Tissue,False,Loose Connective Tissue,,,,
+e94eacbe-2278-4670-a0b2-97f6d6cff70d,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Loose connective tissue is found between many organs where it acts both to absorb shock and bind tissues together. It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues.",True,Loose Connective Tissue,,,,
+505305bd-d7e8-4761-9131-6a0afe3e95f5,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.",True,Loose Connective Tissue,Figure 4.3.2,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/app/uploads/sites/157/2021/02/409_Adipose_Tissue-1.jpg,Figure 4.3.2 – Adipose Tissue: This is a loose connective tissue that consists of fat cells with little extracellular matrix. It stores fat for energy and provides insulation (LM × 800). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+505305bd-d7e8-4761-9131-6a0afe3e95f5,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Adipose tissue consists mostly of fat storage cells, with little extracellular matrix (Figure 4.3.2). A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries. White adipose tissue can be found protecting the kidneys, cushioning the back of the eye, within the abdomen, and in the hypodermis. Brown adipose tissue is more common in infants, hence the term “baby fat.” In adults, there is a reduced amount of brown fat and it is found mainly in the neck and clavicular regions of the body. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate (ATP), a key molecule used in metabolism.",True,Loose Connective Tissue,Figure 4.3.2,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/app/uploads/sites/157/2021/02/areolar1_enhanced.png,Figure 4.3.2a – Areolar tissue
+7ea231cc-b0c7-442d-8395-fbedbee2542f,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Areolar tissue shows relatively little specialization and is the most widely distributed connective tissue in the body. It contains all the cell types and fibers previously described and is structured in an apparently random, web-like fashion. It fills the spaces between muscle fibers, surrounds blood and lymph vessels, and supports organs in the abdominal cavity. Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes.",True,Loose Connective Tissue,,,,
+d526c639-7d91-46b7-ad84-28c30c5820a6,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Reticular tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver (Figure 4.3.3). The reticular fibers form the network onto which other cells attach. It derives its name from the Latin reticulus, which means “little net.”",True,Loose Connective Tissue,Figure 4.3.3,,,
+4af590ef-fba8-4535-9592-b2b3d0a9dad2,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Dense Connective Tissue,False,Dense Connective Tissue,,,,
+96736fc6-fdec-4216-aa4b-92c619c55ebf,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Dense connective tissue contains more collagen fibers than does loose connective tissue. As a consequence, it displays greater resistance to stretching and a higher tensile strength. There are three major categories of dense connective tissue: regular, irregular, and elastic. Dense regular connective tissue fibers are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fiber orientations. Ligaments and tendons are mostly formed from dense regular connective tissue.",True,Dense Connective Tissue,,,,
+a5e02c2e-54f8-43fd-93c9-48c990cb1fd0,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"In dense irregular connective tissue, the arrangement of proteins fibers is irregular and lacks the uniformity seen in dense regular . This arrangement gives the tissue greater strength in all directions and less strength in any one particular direction. In some tissues, fibers crisscross and form a mesh. In other tissues, stretching in several directions is achieved by alternating layers where fibers run in the same orientation in each layer, and it is the layers themselves that are stacked at an angle. The dermis of the skin is an example of dense irregular connective tissue rich in collagen fibers.",True,Dense Connective Tissue,,,,
+3045ba2e-4993-49fc-9783-9e82f7e64e29,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Dense elastic tissue contains elastin fibers in addition to collagen fibers, which allows the tissue to return to its original length after stretching. Dense elastic tissues give arterial walls the strength and the ability to regain original shape after stretching (dense CT figure).",True,Dense Connective Tissue,,,,
+80446511-8ed1-496f-8eca-8e26bc979743,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Disorders of the Connective Tissue: Tendinitis,False,Disorders of the Connective Tissue: Tendinitis,,,,
+5eec3361-830c-4cec-a18b-3909e2f49926,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Your opponent stands ready as you prepare to hit the serve, but you are confident that you will smash the ball past your opponent. As you toss the ball high in the air, a burning pain shoots across your wrist and you drop the tennis racket. That dull ache in the wrist that you ignored through the summer is now an unbearable pain. The game is over for now.",True,Disorders of the Connective Tissue: Tendinitis,,,,
+34750ab3-9289-4c8e-a4d7-b0b1d648355e,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"After examining your swollen wrist, the doctor in the emergency room announces that you have developed wrist tendinitis. She recommends icing the tender area, taking non-steroidal anti-inflammatory medication to ease the pain and to reduce swelling, and complete rest for a few weeks. She interrupts your protests that you cannot stop playing. She issues a stern warning about the risk of aggravating the condition and the possibility of surgery. She consoles you by mentioning that well known tennis players such as Venus and Serena Williams and Rafael Nadal have also suffered from tendinitis related injuries.",True,Disorders of the Connective Tissue: Tendinitis,,,,
+e23b513a-ac01-47a7-ab64-df5cfeb63103,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"What is tendinitis and how did it happen? Tendinitis is the inflammation of a tendon, the thick band of fibrous connective tissue that attaches a muscle to a bone. The condition causes pain and tenderness in the area around a joint. Most often, the condition results from repetitive motions over time that strain the tendons needed to perform the tasks.",True,Disorders of the Connective Tissue: Tendinitis,,,,
+36d0e5c6-dd00-4c1a-968b-cf8ee7929319,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Persons whose jobs and hobbies involve performing the same movements over and over again are often at the greatest risk of tendinitis. You hear of tennis and golfer’s elbow, jumper’s knee, and swimmer’s shoulder. In all cases, overuse of the joint causes a microtrauma that initiates the inflammatory response. Tendinitis is routinely diagnosed through a clinical examination. In case of severe pain, X-rays can be examined to rule out the possibility of a bone injury. Severe cases of tendinitis can even tear loose a tendon. Surgical repair of a tendon is painful. Connective tissue in the tendon does not have abundant blood supply and heals slowly.",True,Disorders of the Connective Tissue: Tendinitis,,,,
+ebb613e6-3579-4f87-a3a4-fcff2d78626a,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"While older adults are at risk for tendinitis because the elasticity of tendon tissue decreases with age, active people of all ages can develop tendinitis. Young athletes, dancers, and computer operators; anyone who performs the same movements constantly is at risk for tendinitis. Although repetitive motions are unavoidable in many activities and may lead to tendinitis, precautions can be taken that can lessen the probability of developing tendinitis. For active individuals, stretches before exercising and cross training or changing exercises are recommended. For the passionate athlete, it may be time to take some lessons to improve technique. All of the preventive measures aim to increase the strength of the tendon and decrease the stress put on it. With proper rest and managed care, you will be back on the court to hit that slice-spin serve over the net.",True,Disorders of the Connective Tissue: Tendinitis,,,,
+23b16984-903d-478a-b915-2fe772677dc9,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Supportive Connective Tissues,False,Supportive Connective Tissues,,,,
+e28775f1-8778-47c5-be2d-59e5661ed2c5,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Two major forms of supportive connective tissue, cartilage and bone, allow the body to maintain its posture and protect internal organs.",True,Supportive Connective Tissues,,,,
+ac6ae5b0-1cc9-4c82-97c8-b6fd560af92a,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Cartilage,False,Cartilage,,,,
+d6fa6f6b-3b4f-4801-8bd6-a2a541914481,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans. Embedded within the cartilage matrix are chondrocytes, or cartilage cells, and the space they occupy are called lacunae (singular = lacuna). A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus, all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues.",True,Cartilage,,,,
+f04f72be-bf23-4562-9f67-51d17f804504,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage (Figure 4.3.5 – Types of Cartilage). Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It forms the template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. The intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue provides support as well as elasticity. Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage.",True,Cartilage,Figure 4.3.5,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/app/uploads/sites/157/2021/02/412_Types_of_Cartilage-new-1.jpg,"Figure 4.3.5 – Types of Cartilage: Cartilage is a connective tissue consisting of collagenous fibers embedded in a firm matrix of chondroitin sulfates. (a) Hyaline cartilage provides support with some flexibility. The example is from dog tissue. (b) Fibrocartilage provides some compressibility and can absorb pressure. (c) Elastic cartilage provides firm but elastic support. From top, LM × 300, LM × 1200, LM × 1016. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+e233fa48-f59e-44a6-9155-b5b57d471141,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Bone,False,Bone,,,,
+66e77f4b-c0c5-4dc7-ac73-4c01c7554db9,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Bone is the hardest connective tissue. It provides protection to internal organs and supports the body. Bone’s rigid extracellular matrix contains mostly collagen fibers embedded in a mineralized ground substance containing hydroxyapatite, a form of calcium phosphate. Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone. Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support. Osteoblasts are the active bone forming cells, producing the organic part of the extracellular matrix. The mature bone cells, osteocytes, are located within lacunae.  Bone is a highly vascularized tissue. Unlike cartilage, bone tissue can recover from injuries in a relatively short time.",True,Bone,,,,
+5e037876-71e2-4a3a-956d-1557b04697d9,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"The histology of a cross sectional view of compact bone shows a typical arrangement of osteocytes in concentric circles around a central canal. This structural unit of compact bone is called the osteon. There is no such structural unit in cancellous bone, or spongy bone, which looks like a sponge under the microscope and contains empty spaces between trabeculae. It is lighter than compact bone and found in the interior of bones and at the end of long bones. Compact bone is solid and has greater structural strength.",True,Bone,,,,
+54216fc4-c55b-4d41-84d2-53d0f5306ec3,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,Fluid Connective Tissue,False,Fluid Connective Tissue,,,,
+e77a378b-02d2-41cc-9247-c2f6905f2b5a,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix. The formed elements circulating in blood are all derived from hematopoietic stem cells located in bone marrow (Figure 4.3.6 – Blood: A Fluid Connective Tissue). Erythrocytes, red blood cells, transport oxygen and carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body.",True,Fluid Connective Tissue,Figure 4.3.6,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/app/uploads/sites/157/2021/02/424_Blood_A_Fluid_Connective_Tissue-new-1024x541-1.jpg,Figure 4.3.6 – Blood: A Fluid Connective Tissue: Blood is a fluid connective tissue containing erythrocytes and various types of leukocytes that circulate in a liquid extracellular matrix (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+3785c2ce-b352-4e33-83ce-6e4454de1e6f,https://open.oregonstate.education/aandp/,4.3 Connective Tissue Supports and Protects,https://open.oregonstate.education/aandp/chapter/4-3-connective-tissue-supports-and-protects/,"Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are highly permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels. Lymph vessels return molecules and fluid to the venous blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood.",True,Fluid Connective Tissue,,,,
+c1768d56-8c3b-442f-8f81-224bd2092402,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial tissue primarily appears as large sheets of cells covering all surfaces of the body exposed to the external environment and lining internal body cavities.  In addition, epithelial tissue is responsible for forming a majority of glandular tissue found in the human body.",True,Fluid Connective Tissue,,,,
+ff1d00ec-18f1-4ed7-bbbd-00163244c4e8,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial tissue is derived from all three major embryonic layers. The epithelial tissue composing cutaneous membranes develops from the ectoderm.  Epithelial tissue composing a majority of the mucous membranes originate in the endoderm.  Epithelial tissue that lines vessels and open spaces within the body are derived from mesoderm.  Of particular note, epithelial tissue that lines vessels in the lymphatic and cardiovascular systems is called endothelium whereas epithelial tissue that forms the serous membranes lining the true cavities is called mesothelium.",True,Fluid Connective Tissue,,,,
+c0edc612-7a4e-43da-b532-28ce9475dd5e,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Regardless of its location and function, all epithelial tissue shares important structural features. First, epithelial tissue is highly cellular, with little or no extracellular material present between cells. Second, adjoining cells form specialized intercellular connections called cell junctions. Third, epithelial cells exhibit polarity with differences in structure and function between the exposed, or apical, facing cell surface and the basal surface closest to the underlying tissue.  Fourth, epithelial tissues are avascular;  nutrients must enter the tissue by diffusion or absorption from underlying tissues or the surface.  Last,  epithelial tissue is capable of rapidly replacing damaged and dead cells, necessary with respect to the harsh environment this tissue encounters.",True,Fluid Connective Tissue,,,,
+a0ca53fd-748e-43fa-8da0-91b5eacbf4ee,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Epithelial Tissue Function:,False,Epithelial Tissue Function:,,,,
+c0d765e8-d40b-4285-a6b4-6659d29f7344,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial tissues provide the body’s first line of protection from physical, chemical, and biological damage. The cells of an epithelium act as gatekeepers of the body, controlling permeability by allowing selective transfer of materials across its surface. All substances that enter the body must cross an epithelium.",True,Epithelial Tissue Function:,,,,
+176de245-90aa-48af-a99a-d8eea88ebb37,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Many epithelial cells are capable of secreting mucous and other specific chemical compounds onto their apical surfaces.  For example, the epithelium of the small intestine releases digestive enzymes and cells lining the respiratory tract secrete mucous that traps incoming microorganisms and particles.",True,Epithelial Tissue Function:,,,,
+28254d18-426d-449e-bcf5-18f084e826e5,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,The Epithelial Cell,False,The Epithelial Cell,,,,
+275dc159-b867-4f12-8acb-4e29a25444ce,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial cells are typically characterized by unequal distribution of organelles and membrane-bound proteins between their apical and basal surfaces.  Structures found on some epithelial cells are an adaptation to specific functions.  For example, cilia are extensions of the apical cell membrane that are supported by microtubules. These extensions beat in unison, allowing for the movement of fluids and particles along the surface.  Such ciliated epithelia line the ventricles of the brain where it helps circulate cerebrospinal fluid and line the respirtatory system where it helps sweep particles of dust and pathogens up and out of the respiratory tract.",True,The Epithelial Cell,,,,
+318613f5-8089-41fb-a36a-a2d9880a9470,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial cells in close contact with underlying connective tissues secrete glycoproteins and collagen from their basal surface which forms the basal lamina.  The basal lamina interacts with the reticular lamina secreted by the underlying connective tissue, forming a basement membrane that helps anchor the layers together.",True,The Epithelial Cell,,,,
+c499dd0f-d0e3-4255-be69-c28bb00930bc,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Cells of epithelia are closely connected with limited extracellular material present. Three basic types of connections may be present: tight junctions, anchoring junctions, and gap junctions (Figure 4.2.1).",True,The Epithelial Cell,Figure 4.2.1,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2019/07/402_Types_of_Cell_Junctions_new-scaled.jpg,"Figure 4.2.1 – Types of Cell Junctions: The three basic types of cell-to-cell junctions are tight junctions, gap junctions, and anchoring junctions."
+a92f7ff5-4f74-4334-9f22-ddce9af81555,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Types of Cell Junctions,False,Types of Cell Junctions,,,,
+a93dd0ef-4285-44c3-94dc-a6cdb23539b0,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial cells are held close together by cell junctions.  The three basic types of cell-to-cell junctions are tight junctions, gap junctions, and anchoring junctions.",True,Types of Cell Junctions,,,,
+1e5623c6-c143-4182-b5ee-ddfe1fc454b4,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"A Tight junction restricts the movement of fluids between adjacent cells due to the presence of integral proteins that fuse together to form a firm seal.  Tight junctions are observed in the epithelium of the urinary bladder, preventing the escape of fluids comprising the urine.",True,Types of Cell Junctions,,,,
+7e54c228-d9d7-4c5d-b43f-68e6dcd6fb3a,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"An anchoring junction provides a strong yet flexible connection between epithelial cells. There are three types of anchoring junctions: desmosomes, hemidesmosomes, and adherens. Desmosomes hold neighboring cells together by way of cadherin molecules which are embedded in protein plates in the cell membranes and link together between the adjacent cells.  Hemidesmosomes, which look like half a desmosome, link cells to components in the extracellular matrix, such as the basal lamina. While similar in appearance to desmosomes, hemidesmosomes use adhesion proteins called integrins rather than cadherins. Adherens use either cadherins or integrins depending on whether they are linking to other cells or matrix. These junctions are characterized by the presence of the contractile protein actin located on the cytoplasmic surface of the cell membrane.  These junctions influence the shape and folding of the epithelial tissue.",True,Types of Cell Junctions,,,,
+325f4bb2-f5cd-465e-b197-1480ac5e6b95,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"In contrast with the tight and anchoring junctions, a gap junction forms an intercellular passageway between the membranes of adjacent cells to facilitate the movement of small molecules and ions between cells. These junctions thus allow electrical and metabolic coupling of adjacent cells.",True,Types of Cell Junctions,,,,
+835794b4-89bc-4a96-97b2-d8c973876470,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Classification of Epithelial Tissues,False,Classification of Epithelial Tissues,,,,
+702d5ace-849a-4199-835d-d0809b936b9e,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Epithelial tissues are classified according to the shape of the cells composing the tissue and by the number of cell layers present in the tissue.(Figure 4.2.2) Cell shapes are classified as being either squamous (flattened and thin), cuboidal (boxy, as wide as it is tall), or columnar (rectangular, taller than it is wide). Similarly, cells in the tissue can be arranged in a single layer, which is called simple epithelium, or more than one layer, which is called stratified epithelium.  Pseudostratified (pseudo- = “false”) describes an epithelial tissue with a single layer of irregularly shaped cells that give the appearance of more than one layer.  Transitional describes a form of specialized stratified epithelium in which the shape of the cells, and the number of layers present, can vary depending on the degree of stretch within a tissue.",True,Classification of Epithelial Tissues,Figure 4.2.2,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+1f16231d-0eaa-402b-8d1c-569b6618dd66,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Epithelial tissue is classified based on the shape of the cells present and the number of cell layers present.  Figure 4.2.2 summarizes the different categories of epithelial cell tissue cells.,True,Classification of Epithelial Tissues,Figure 4.2.2,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+bdbc518c-0a93-4764-afeb-077e69a7e6e5,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Simple Epithelium,False,Simple Epithelium,,,,
+d7a7f1b0-30d9-425b-8bf6-bf6c06bca084,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"The cells in a simple squamous epithelium have the appearance of thin scales. The nuclei of squamous cells  tend to appear flat, horizontal, and elliptical, mirroring the form of the cell.   Simple squamous epithelium, because of the thinness of the cells, is present where rapid passage of chemical compounds is necessary such as the lining of capillaries and the small air sacs of the lung.  This epithelial type is also found composing the mesothelium which secretes serous fluid to lubricate the internal body cavities.",True,Simple Epithelium,,,,
+68d32801-fe3b-45e6-8a80-b2e41da1f7d0,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"In simple cuboidal epithelium, the nucleus of the box-like cells appears round and is generally located near the center of the cell. These epithelia are involved in the secretion and absorptions of molecules requiring active transport. Simple cuboidal epithelia are observed in the lining of the kidney tubules and in the ducts of glands.",True,Simple Epithelium,,,,
+ff960db9-53bf-4d5e-95ff-5a807416cd38,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"In simple columnar epithelium, the nucleus of the tall column-like cells tends to be elongated and located in the basal end of the cells. Like the cuboidal epithelia, this epithelium is active in the absorption and secretion of molecules using active transport. Simple columnar epithelium forms a majority of the digestive tract and some parts of the female reproductive tract. Ciliated columnar epithelium is composed of simple columnar epithelial cells with cilia on their apical surfaces. These epithelial cells are found in the lining of the fallopian tubes where the assist in the passage of the egg, and parts of the respiratory system, where the beating of the cilia helps remove particulate matter.",True,Simple Epithelium,,,,
+062e9854-94fd-405c-9723-d425ad6ff938,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Pseudostratified columnar epithelium is a type of epithelium that appears to be stratified but instead consists of a single layer of irregularly shaped and differently sized columnar cells. In pseudostratified epithelium, nuclei of neighboring cells appear at different levels rather than clustered in the basal end. The arrangement gives the appearance of stratification, but in fact, all the cells are in contact with the basal lamina, although some do not reach the apical surface. Pseudostratified columnar epithelium is found in the respiratory tract, where some of these cells have cilia.",True,Simple Epithelium,,,,
+bbc01339-882c-4c66-9cc7-6681e2f4a1b4,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Both simple and pseudostratified columnar epithelia are heterogeneous epithelia because they include additional types of cells interspersed among the epithelial cells. For example, a goblet cell is a mucous-secreting unicellular gland interspersed between the columnar epithelial cells of a mucous membrane (Figure 4.2.3).",True,Simple Epithelium,Figure 4.2.3,,,
+683876cc-a3c4-433b-b28a-c948432dc978,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Stratified Epithelium,False,Stratified Epithelium,,,,
+60be6b62-f72a-4d6a-b8f9-718f7e90233b,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"A stratified epithelium consists of multiple stacked layers of cells. This epithelium protects against physical and chemical damage. The stratified epithelium is named by the shape of the most apical layer of cells, closest to the free space.",True,Stratified Epithelium,,,,
+e65d39e3-763e-41c4-93e5-240285cd7079,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Stratified squamous epithelium is the most common type of stratified epithelium in the human body. The apical cells appear squamous, whereas the basal layer contains either columnar or cuboidal cells. The top layer may be covered with dead cells containing keratin. The skin is an example of a keratinized, stratified squamous epithelium. Alternatively, the lining of the oral cavity is an example of an unkeratinized, stratified squamous epithelium. Stratified cuboidal epithelium and stratified columnar epithelium can also be found in certain glands and ducts, but are relatively rare in the human body.",True,Stratified Epithelium,,,,
+f590e012-c6e1-434c-aac0-d7d6e7d2259f,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Another kind of stratified epithelium is transitional epithelium, so-called because of the gradual changes in the shapes and layering of the cells as the epithelium lining the expanding hollow organ is stretched.  Transitional epithelium is found only in the urinary system, specifically the ureters and urinary bladder. When the bladder is empty, this epithelium is convoluted and has cuboidal-shaped apical cells with convex, umbrella shaped,  surfaces. As the bladder fills with urine, this epithelium loses its convolutions and the apical cells transition in appearance from cuboidal to squamous. It appears thicker and more multi-layered when the bladder is empty, and more stretched out and less stratified when the bladder is full and distended.",True,Stratified Epithelium,,,,
+de950876-877a-4728-9c48-122da095fb4f,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Glandular Epithelium,False,Glandular Epithelium,,,,
+ac3ba501-545e-4af6-be52-6ad4d89a3709,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"A gland is a structure made up of one or more cells modified to synthesize and secrete chemical substances. Most glands consist of groups of epithelial cells. A gland can be classified as an endocrine gland, a ductless gland that releases secretions directly into surrounding tissues and fluids (endo- = “inside”), or an exocrine gland whose secretions leave through a duct that opens to the external environment (exo- = “outside”).",True,Glandular Epithelium,,,,
+0e791783-a631-4298-a2e1-5f43238a91c1,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Endocrine Glands,False,Endocrine Glands,,,,
+b3491e01-3b48-4217-9d66-2ade81d098fc,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"The secretions of endocrine glands are called hormones. Hormones are released into the interstitial fluid, diffuse into the bloodstream, and are delivered to cells that have receptors to bind the hormones. The endocrine system a major communication system coordinating the regulation and integration of body responses.  These glands will be discussed in much greater detail in a later chapter.",True,Endocrine Glands,,,,
+b2efce6d-343a-4b5a-a804-fe5f4cb2d884,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Exocrine Glands,False,Exocrine Glands,,,,
+7c47ed58-6c97-403b-b4fd-489e99a8f523,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Exocrine glands release their contents through a duct or duct system that ultimately leads to the external environment. Mucous, sweat, saliva, and breast milk are all examples of secretions released by exocrine glands.",True,Exocrine Glands,,,,
+8e2fd5d8-9d45-4407-a150-6c98babaf57f,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Glandular Structure,False,Glandular Structure,,,,
+d955cb2c-1280-4341-b36c-a3860f641d6d,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Exocrine glands are classified as either unicellular or multicellular. Unicellular glands are individual cells which are scattered throughout an epithelial lining.  Goblet cells are an example of a unicellular gland type found extensively in the mucous membranes of the small and large intestine.,True,Glandular Structure,,,,
+168ad969-0a30-40bd-b119-075a67211dc6,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Multicellular exocrine glands are composed of two or more cells which either secrete their contents directly into an inner body cavity (e.g., serous glands), or release their contents into a duct.  If there is a single duct carrying the contents to the external environment then the gland is referred to as a simple gland.  Multicellular glands that have ducts divided into one or more branches is called a compound gland (Figure 4.2.4).  In addition to the number of ducts present, multicellular glands are also classified based on the shape of the secretory portion of the gland.  Tubular glands have enlongated secretory regions (similar to a test tube in shape) while alveolar (acinar) glands have a secretory region that is spherical in shape.   Combinations of the two secretory regions are known as tubuloalveolar (tubuloacinar) glands.",True,Glandular Structure,Figure 4.2.4,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/406_Types_of_Glands.jpg,Figure 4.2.4 – Types of Exocrine Glands: Exocrine glands are classified by their structure.
+0de0dd56-7804-448b-a47e-759ebe7507ee,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,Exocrine glands are classified by the arrangement of ducts emptying the gland and the shape of the secretory region.,True,Glandular Structure,,,,
+7fdb37b5-4812-4e78-ba58-9de725f24f4c,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Methods and Types of Secretion
+
+In addition to the glandular structure, exocrine glands can be classified by their mode of secretion and the nature of the substances released (Figure 4.2.5). Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles that move to the apical surface of the cell where the contents are released by exocytosis. For example, saliva containing the glycoprotein mucin is a merocrine secretion.  The glands that produce and secrete sweat are another example of merocrine secretion.",True,Glandular Structure,Figure 4.2.5,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/405_Modes_of_Secretion_by_Glands_updated.jpg,"Figure 4.2.5 – Modes of Glandular Secretion: (a) In merocrine secretion, the cell remains intact. (b) In apocrine secretion, the apical portion of the cell is released, as well. (c) In holocrine secretion, the cell is destroyed as it releases its product and the cell itself becomes part of the secretion."
+ed21b3eb-1fef-4b35-b2a6-148c6d82e354,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Apocrine secretion occurs when secretions accumulate near the apical portion of a secretory cell. That portion of the cell and its secretory contents pinch off from the cell and are released. The sweat glands of the armpit are classified as apocrine glands. Like merocrine glands, apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and golgi regions remain intact after the secretory event.",True,Glandular Structure,,,,
+69cb1d32-8f59-4d89-b7dd-cd1c8bd7595d,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"In contrast, the process of holocrine secretion involves the rupture and destruction of the entire gland cell. The cell accumulates its secretory products and releases them only when the cell bursts. New gland cells differentiate from cells in the surrounding tissue to replace those lost by secretion. The sebaceous glands that produce the oils on the skin and hair are an example of a holocrine glands (Figure 4.2.6).",True,Glandular Structure,Figure 4.2.6,4.2 Epithelial Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/407_Sebaceous_Glands.jpg,Figure 4.2.6 – Sebaceous Glands: These glands secrete oils that lubricate and protect the skin. They are holocrine glands and they are destroyed after releasing their contents. New glandular cells form to replace the cells that are lost (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+099dbc78-e5a5-4b2c-806b-cd842dc8464e,https://open.oregonstate.education/aandp/,4.2 Epithelial Tissue,https://open.oregonstate.education/aandp/chapter/4-2-epithelial-tissue/,"Glands are also named based on the  products they produce. A serous gland produces watery, blood-plasma-like secretions rich in enzymes, whereas a mucous gland releases a more viscous product rich in the glycoprotein mucin. Both serous and mucous secretions are common in the salivary glands of the digestive system.  Such glands releasing both serous and mucous secretions are often referred to as seromucous glands.",True,Glandular Structure,,,,
+8e6add6a-a1e9-4ca6-a12c-1571b47e9040,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"The term tissue is used to describe a group of cells that are similar in structure and perform a specific function.   Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function.",True,Glandular Structure,,,,
+e2cb147a-9471-494b-96cb-a5eb6b6b1a31,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"Tissues are organized into four broad categories based on structural and functional similarities.  These categories are  epithelial, connective, muscle, and nervous.   The primary tissue types work together to contribute to the overall health and maintenance of the human body.   Thus, any disruption in the structure of a tissue can lead to injury or disease.",True,Glandular Structure,,,,
+176b1769-6abd-4a7f-b088-82ed96477389,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,The Four Primary Tissue Types,False,The Four Primary Tissue Types,,,,
+984ec6c3-464c-4974-bdb3-960c1cd373a9,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"Epithelial tissue refers to groups of cells that cover the exterior surfaces of the body, line internal cavities and passageways, and form certain glands. Connective tissue, as its name implies, binds the cells and organs of the body together. Muscle tissue contracts forcefully when excited, providing movement.  Nervous tissue is also excitable, allowing for the generation and propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body (Figure 4.1.1).",True,The Four Primary Tissue Types,Figure 4.1.1,4.1 Types of Tissues,https://open.oregonstate.education/app/uploads/sites/157/2019/07/401_Types_of_Tissue.jpg,"Figure 4.1.1 – The Four Primary Tissue Types: Examples of nervous tissue, epithelial tissue, muscle tissue, and connective tissue found throughout the human body. Clockwise from nervous tissue, LM × 872, LM × 282, LM × 460, LM × 800. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+2296d3c3-8c73-4f80-9cde-b5c72810592d,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,An understanding of the various primary tissue types present in the human body is essential for understanding the structure and function of organs which are composed of two or more primary tissue types.  This chapter will focus on examining epithelial and connective tissues.  Muscle and nervous tissue will be discussed in detail in future chapters.,True,The Four Primary Tissue Types,,,,
+3728ffd9-b0af-4f14-afdb-cf357922588e,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,Embryonic Origin of Tissues,False,Embryonic Origin of Tissues,,,,
+b9155d22-8128-42a6-b460-522439381f3f,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"The cells composing a tissue share a common embryonic origin. The zygote, or fertilized egg, is a single cell formed by the fusion of an egg and sperm cell. After fertilization, the zygote gives rise many cells to form the embryo. The first embryonic cells generated have the ability to differentiate into any type of cell in the body and, as such, are called omnipotent, meaning each has the capacity to divide, differentiate, and develop into a new organism. As cell proliferation progresses, three major cell lines are established within the embryo. Each of these lines of embryonic cells forms the distinct germ layers from which all the tissues and organs of the human body eventually form. Each germ layer is identified by its relative position: ectoderm (ecto- = “outer”), mesoderm (meso- = “middle”), and endoderm (endo- = “inner”). Figure 4.1.2 shows the types of tissues and organs associated with each of the three germ layers. Note that epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue derives from the mesoderm.",True,Embryonic Origin of Tissues,Figure 4.1.2,4.1 Types of Tissues,https://open.oregonstate.education/app/uploads/sites/157/2021/02/04-13_EmbryoTissue_1-copy-1024x777.png,Figure 4.1.2 – Embryonic Origin of Tissues and Major Organs: Embryonic germ layers and the resulting primary tissue types formed by each.
+2f5e6443-6a9b-4320-a0f6-bc10ee436c46,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,Tissue Membranes,False,Tissue Membranes,,,,
+c8723788-ca5c-42ca-a39b-98aac709ca96,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"A tissue membrane is a thin layer or sheet of cells that either covers the outside of the body (e.g., skin), lines an internal body cavity (e.g., peritoneal cavity),  lines a vessel (e.g., blood vessel),  or lines a movable joint cavity (e.g., synovial joint).   Two basic types of tissue membranes are recognized based on the primary tissue type composing each: connective tissue membranes and epithelial membranes (Figure 4.1.3).",True,Tissue Membranes,Figure 4.1.3,4.1 Types of Tissues,https://open.oregonstate.education/app/uploads/sites/157/2021/02/413_Types_of_Membranes.jpg,"Figure 4.1.3 – Tissue Membranes: The two broad categories of tissue membranes in the body are (1) connective tissue membranes, which include synovial membranes, and (2) epithelial membranes, which include mucous membranes, serous membranes, and the cutaneous membrane, in other words, the skin."
+09007598-afe5-48cc-a6de-5d53b448916d,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,Connective Tissue Membranes,False,Connective Tissue Membranes,,,,
+6933b67f-d6a5-48ad-8f0f-af075e0c3826,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"A connective tissue membrane is built entirely of connective tissue. This type of membrane may be found encapsulating an organ, such as the kidney, or lining the cavity of a freely movable joint (e.g., shoulder).  When lining a joint, this membrane is referred to as a synovial membrane.  Cells in the inner layer of the synovial membrane release synovial fluid, a natural lubricant that enables the bones of a joint to move freely against one another with reduced friction.",True,Connective Tissue Membranes,,,,
+fc8c34ac-1d8d-43cb-8f98-208ecf2d5b06,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,Epithelial Membranes,False,Epithelial Membranes,,,,
+d850cd06-c892-4e98-a4cf-350c31e36093,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"An epithelial membrane is composed of an epithelial layer attached to a layer of connective tissue. A mucous membrane, sometimes called a mucosa, lines a body cavity or hollow passageway that is open to the external environment.  This type of membrane can be found lining portions of the digestive, respiratory, excretory, and reproductive tracts. Mucus, produced by  uniglandular cells and glandular tissue, coats the epithelial layer. The underlying connective tissue, called the lamina propria (literally “own layer”), helps support the epithelial layer.",True,Epithelial Membranes,,,,
+e83ec6ce-9f1e-4b4a-ac53-023e4e4c1172,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"A serous membrane lines the cavities of the body that do not open to the external environment.  Serous fluid secreted by the cells of the epithelium lubricates the membrane and reduces abrasion and friction between organs.  Serous membranes are identified according to location. Three serous membranes are found lining the thoracic cavity; two membranes that cover the lungs (pleura) and one membrane that covers the heart (pericardium). A fourth serous membrane, the peritoneum, lines the peritoneal cavity, covering the abdominal organs and forming double sheets of mesenteries that suspend many of the digestive organs.",True,Epithelial Membranes,,,,
+42dd31bc-8dbb-4622-8137-3b72e2443d11,https://open.oregonstate.education/aandp/,4.1 Types of Tissues,https://open.oregonstate.education/aandp/chapter/4-1-types-of-tissues/,"A cutaneous membrane is a multi-layered membrane composed of epithelial and connective tissues.  The apical surface of this membrane exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens.  The skin is an example of a cutaneous membrane.",True,Epithelial Membranes,,,,
+b4975049-3b17-479c-8c4a-4d4e3ef12c3c,https://open.oregonstate.education/aandp/,4.0 Introduction,https://open.oregonstate.education/aandp/chapter/4-0-introduction/,"The cells found in the human body contain essentially the same internal structures yet they vary enormously in shape and function. The variation in cells is not randomly distributed throughout the body, rather, they occur in organized layers.  Such aggregations of cells that are similar in structure and work together to perform a specialized function are referred to as tissues.  The micrograph that opens this chapter shows the high degree of organization among different types of cells in the tissue of the cervix. You can also see how that organization breaks down when cancer takes over the regular mitotic functioning of a cell.",True,Epithelial Membranes,,,,
+00738a02-0f7d-417b-8020-9500528f0291,https://open.oregonstate.education/aandp/,4.0 Introduction,https://open.oregonstate.education/aandp/chapter/4-0-introduction/,"The human body starts as a single cell at fertilization. As this fertilized egg divides, it gives rise to trillions of cells, each built from the same blueprint, but organizing into tissues and becoming irreversibly committed to a developmental pathway.",True,Epithelial Membranes,,,,
+03a12af4-f1f6-410e-8ad4-72b7f4753636,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"How does a complex organism such as a human develop from a single cell—a fertilized egg—into the vast array of cell types such as nerve cells, muscle cells, and epithelial cells that characterize the adult? Throughout development and adulthood, the process of cellular differentiation leads cells to assume their final morphology and physiology. Differentiation is the process by which unspecialized cells become specialized to carry out distinct functions.",True,Epithelial Membranes,,,,
+745aaa18-6b31-403e-bd89-c0bf9ea9b8a7,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,Stem Cells,False,Stem Cells,,,,
+730329a1-d0d1-4994-aea6-fc3f7fd1ab29,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"A stem cell is an unspecialized cell that can divide without limit as needed and can, under specific conditions, differentiate into specialized cells. Stem cells are divided into several categories according to their potential to differentiate.",True,Stem Cells,,,,
+76294a8b-876f-47df-a71f-862b5685a1d8,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,The first embryonic cells that arise from the division of the zygote are the ultimate stem cells; these stems cells are described as totipotent because they have the potential to differentiate into any of the cells needed to enable an organism to grow and develop.,True,Stem Cells,,,,
+40c679ce-d910-4ea3-842f-1e22873367ad,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"The embryonic cells that develop from totipotent stem cells and are precursors to the fundamental tissue layers of the embryo are classified as pluripotent. A pluripotent stem cell is one that has the potential to differentiate into any type of human tissue but cannot support the full development of an organism. These cells then become slightly more specialized, and are referred to as multipotent cells.",True,Stem Cells,,,,
+ca4ef3b4-4a2d-46bd-9e1b-341d32f782cf,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"A multipotent stem cell has the potential to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell.",True,Stem Cells,,,,
+9483f1a8-e954-413d-af3d-a0e879542174,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"Finally, multipotent cells can become further specialized oligopotent cells. An oligopotent stem cell is limited to becoming one of a few different cell types. In contrast, a unipotent cell is fully specialized and can only reproduce to generate more of its own specific cell type.",True,Stem Cells,,,,
+55f297b0-13cc-4966-930e-e00d45aaf384,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"Stem cells are unique in that they can also continually divide and regenerate new stem cells instead of further specializing. There are different stem cells present at different stages of a human’s life. They include the embryonic stem cells of the embryo, fetal stem cells of the fetus, and adult stem cells in the adult. One type of adult stem cell is the epithelial stem cell, which gives rise to the keratinocytes in the multiple layers of epithelial cells in the epidermis of skin. Adult bone marrow has three distinct types of stem cells: hematopoietic stem cells (which give rise to red blood cells, white blood cells, and platelets), endothelial stem cells (which give rise to the endothelial cell types that line blood and lymph vessels), and mesenchymal stem cells (which give rise to the different types of muscle cells).",True,Stem Cells,,,,
+62562bb2-d352-4278-8055-d976cb2de640,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"The process of hematopoiesis involves the differentiation of multipotent cells into blood and immune cells. The multipotent hematopoietic stem cells give rise to many different cell types, including the cells of the immune system and red blood cells.",True,Stem Cells,,,,
+a54a73e9-b124-4dba-9d9b-aa1d7d471cee,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,Differentiation,False,Differentiation,,,,
+a895fd73-a591-4587-b53d-bbdf0d2fba34,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"When a cell differentiates (becomes more specialized), it may undertake major changes in its size, shape, metabolic activity, and overall function. Since all cells in the body, beginning with the fertilized egg, contain the same DNA, how do the different cell types come to be so different? The answer is analogous to a movie script. The different actors in a movie all read from the same script, however, they are each only reading their own part of the script. Similarly, all cells contain the same full complement of DNA, but each type of cell only “reads” the portions of DNA that are relevant to its own function. In biology, this is referred to as the unique genetic expression of each cell.",True,Differentiation,,,,
+5f04284a-3986-47a7-8cc3-0dd0883c7631,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"In order for a cell to differentiate into its specialized form and function, it need only manipulate those genes (and thus those proteins) that will be expressed, and not those that will remain silent. The primary mechanism by which genes are turned “on” or “off” is through transcription factors.",True,Differentiation,,,,
+fc1494e0-329e-42ea-bfd8-043a48565659,https://open.oregonstate.education/aandp/,3.6 Cellular Differentiation,https://open.oregonstate.education/aandp/chapter/3-6-cellular-differentiation/,"While each body cell contains the organism’s entire genome, different cells regulate gene expression with the use of various transcription factors. Transcription factors are proteins that affect the binding of RNA polymerase to a particular gene on the DNA molecule.",True,Differentiation,,,,
+3f0c0273-758c-46c6-8026-2d5335c5e25d,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"So far in this chapter, you have read numerous times of the importance and prevalence of cell division. While there are a few cells in the body that do not undergo cell division (such as gametes, red blood cells, most neurons, and some muscle cells), most somatic cells divide regularly. A somatic cell is a general term for a body cell, and all human cells, except for the cells that produce eggs and sperm (which are referred to as germ cells). Somatic cells contain two copies of each of their chromosomes (one copy received from each parent). A homologous pair of chromosomes are the two copies of a single chromosome found in each somatic cell. The human is a diploid organism, having 23 homologous pairs of chromosomes in each of the somatic cells. The condition of having pairs of chromosomes is known as diploidy.",True,Differentiation,,,,
+66a3b04d-3d3c-4aac-8efa-3bcc9c0cd155,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Cells in the body replace themselves over the lifetime of a person. For example, the cells lining the gastrointestinal tract must be frequently replaced when constantly “worn off” by the movement of food through the gut. But what triggers a cell to divide, and how does it prepare for and complete cell division? The cell cycle is the sequence of events in the life of the cell from the moment it is created at the end of a previous cycle of cell division until it then divides itself, generating two new cells.",True,Differentiation,,,,
+c3243a8a-fefc-4549-858e-7c85df811c20,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,The Cell Cycle,False,The Cell Cycle,,,,
+fd30e44b-1414-427a-acce-792dea2d40b3,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"One “turn” or cycle of the cell cycle consists of three general phases: interphase, followed by mitosis and cytokinesis. Interphase is the period of the cell cycle during which the cell is not dividing. The majority of cells are in interphase most of the time. Mitosis is the division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed. Cytokinesis divides the cytoplasm into two distinctive cells.",True,The Cell Cycle,,,,
+a04b2ada-252a-49f9-b309-1a610851c649,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,Interphase,False,Interphase,,,,
+534666a1-49f5-4dbf-9f6b-2e03d91dd96e,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"A cell grows and carries out all normal metabolic functions and processes in a period called G1 (Figure 3.5.1). G1 phase (gap 1 phase) is the first gap, or growth phase in the cell cycle. For cells that will divide again, G1 is followed by replication of the DNA, during the S phase. The S phase (synthesis phase) is the period during which a cell replicates its DNA.",True,Interphase,Figure 3.5.1,3.5 Cell Growth and Division,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0329_Cell_Cycle.jpg,"Figure 3.5.1 – Cell Cycle: The two major phases of the cell cycle include mitosis (cell division), and interphase, when the cell grows and performs all of its normal functions. Interphase is further subdivided into G1, S, and G2 phases."
+0115eda2-09dd-4f3b-a23f-abf6cb9edbc8,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"After the synthesis phase, the cell proceeds through the G2 phase. The G2 phase is a second gap phase, during which the cell continues to grow and makes the necessary preparations for mitosis. Between G1, S, and G2 phases, cells will vary the most in their duration of the G1 phase. It is here that a cell might spend a couple of hours, or many days. The S phase typically lasts between 8-10 hours and the G2 phase approximately 5 hours. In contrast to these phases, the G0 phase is a resting phase of the cell cycle. Cells that have temporarily stopped dividing and are resting (a common condition) and cells that have permanently ceased dividing (like nerve cells) are said to be in G0.",True,Interphase,,,,
+58b05159-5859-4e6a-847d-db29b6f9eafa,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,The Structure of Chromosomes,False,The Structure of Chromosomes,,,,
+45de81d3-f7db-4924-ae3e-bb477602aefa,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Billions of cells in the human body divide every day. During the synthesis phase (S, for DNA synthesis) of interphase, the amount of DNA within the cell precisely doubles. Therefore, after DNA replication, but before cell division, each cell actually contains two copies of each chromosome. Each copy of the chromosome is referred to as a sister chromatid and is physically bound to the other copy. The centromere is the structure that attaches one sister chromatid to another. Since a human cell has 46 chromosomes, during this phase, there are 92 chromatids (46 × 2) in the cell. Make sure not to confuse the concept of a pair of chromatids (one chromosome and its exact copy attached during mitosis) and a homologous pair of chromosomes (two paired chromosomes which were inherited separately, one from each parent) (Figure 3.52).",True,The Structure of Chromosomes,,,,
+699e07d7-f68a-44e3-a6c1-5949b61e338c,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,Mitosis and Cytokinesis,False,Mitosis and Cytokinesis,,,,
+1b9452b7-efa8-44ba-b1cf-adedc6674ed7,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"The mitotic phase of the cell typically takes between 1 and 2 hours. During this phase, a cell undergoes two major processes. First, it completes mitosis, during which the contents of the nucleus are equitably pulled apart and distributed between its two halves. Cytokinesis then occurs, dividing the cytoplasm and cell body into two new cells. Mitosis is divided into four major stages that take place after interphase (Figure 3.5.3) and in the following order: prophase, metaphase, anaphase, and telophase. The process is then followed by cytokinesis.",True,Mitosis and Cytokinesis,Figure 3.5.3,3.5 Cell Growth and Division,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0331_Stages_of-_Mitosis_and_Cytokinesis.jpg,"Figure 3.5.3 – Cell Division: Mitosis Followed by Cytokinesis: The stages of cell division oversee the separation of identical genetic material into two new nuclei, followed by the division of the cytoplasm."
+fcfe84a2-6701-436c-857c-45287824edb6,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Prophase is the first phase of mitosis, during which the loosely packed chromatin coils and condenses into visible chromosomes. During prophase, each chromosome becomes visible with its identical partner attached, forming the familiar X-shape of sister chromatids. The nucleolus disappears early during this phase, and the nuclear envelope also disintegrates.",True,Mitosis and Cytokinesis,,,,
+66a86e1c-d862-4f2b-8ebe-be90fdb117ca,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"A major occurrence during prophase concerns a very important structure that contains the origin site for microtubule growth. Recall the cellular structures called centrioles that serve as origin points from which microtubules extend. These tiny structures also play a very important role during mitosis. A centrosome is a pair of centrioles together. The cell contains two centrosomes side-by-side, which begin to move apart during prophase. As the centrosomes migrate to two different sides of the cell, microtubules begin to extend from each like long fingers from two hands extending toward each other. The mitotic spindle is the structure composed of the centrosomes and their emerging microtubules.",True,Mitosis and Cytokinesis,,,,
+eb5e08ad-869d-47d5-8c8d-7f86aa9171de,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Near the end of prophase there is an invasion of the nuclear area by microtubules from the mitotic spindle. The nuclear membrane has disintegrated, and the microtubules attach themselves to the centromeres that adjoin pairs of sister chromatids. The kinetochore is a protein structure on the centromere that is the point of attachment between the mitotic spindle and the sister chromatids. This stage is referred to as late prophase or “prometaphase” to indicate the transition between prophase and metaphase.",True,Mitosis and Cytokinesis,,,,
+4734a62d-04cc-4a25-8faa-bdea6fd961c2,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Metaphase is the second stage of mitosis. During this stage, the sister chromatids, with their attached microtubules, line up along a linear plane in the middle of the cell. A metaphase plate forms between the centrosomes that are now located at either end of the cell. The metaphase plate is the name for the plane through the center of the spindle on which the sister chromatids are positioned. The microtubules are now poised to pull apart the sister chromatids and bring one from each pair to each side of the cell.",True,Mitosis and Cytokinesis,,,,
+1268e8fb-3536-4503-9747-699126663ba5,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Anaphase is the third stage of mitosis. Anaphase takes place over a few minutes, when the pairs of sister chromatids are separated from one another, forming individual chromosomes once again. These chromosomes are pulled to opposite ends of the cell by their kinetochores, as the microtubules shorten. Each end of the cell receives one partner from each pair of sister chromatids, ensuring that the two new daughter cells will contain identical genetic material.",True,Mitosis and Cytokinesis,,,,
+bae2bbd8-3ab5-4692-af5c-03addaeb084a,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Telophase is the final stage of mitosis. Telophase is characterized by the formation of two new daughter nuclei at either end of the dividing cell. These newly formed nuclei surround the genetic material, which uncoils in such a way that the chromosomes return to loosely packed chromatin. Nucleoli also reappear within the new nuclei, and the mitotic spindle breaks apart, each new cell receiving its own complement of DNA, organelles, membranes, and centrioles. At this point, the cell is already beginning to split in half as cytokinesis begins.",True,Mitosis and Cytokinesis,,,,
+b7277274-5431-48b8-b32a-b5567654741f,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"The cleavage furrow is a contractile band made up of microfilaments that forms around the midline of the cell during cytokinesis. (Recall that microfilaments consist of actin). This contractile band squeezes the two cells apart until they finally separate. Two new cells are now formed. One of these cells (the “stem cell”) enters its own cell cycle; able to grow and divide again at some future time. The other cell transforms into the functional cell of the tissue, typically replacing an “old” cell there.",True,Mitosis and Cytokinesis,,,,
+426e6c52-f65a-4c23-94af-0abd58ab5120,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Imagine a cell that completed mitosis but never underwent cytokinesis. In some cases, a cell may divide its genetic material and grow in size, but fail to undergo cytokinesis. This results in larger cells with more than one nucleus. Usually this is an unwanted aberration and can be a sign of cancerous cells.",True,Mitosis and Cytokinesis,,,,
+6b127de7-dedc-4e07-aa8a-45ad66007e8f,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,Cell Cycle Control,False,Cell Cycle Control,,,,
+b07d3767-11a6-4ade-9384-26c0b4d75828,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"A very elaborate and precise system of regulation controls direct the way cells proceed from one phase to the next in the cell cycle and begin mitosis. The control system involves molecules within the cell as well as external triggers. These internal and external control triggers provide “stop” and “advance” signals for the cell. Precise regulation of the cell cycle is critical for maintaining the health of an organism, and loss of cell cycle control can lead to cancer.",True,Cell Cycle Control,,,,
+1761301a-e6d6-4df1-8f2c-87cd1fbd2746,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,Mechanisms of Cell Cycle Control,False,Mechanisms of Cell Cycle Control,,,,
+f64c3845-964c-47fe-91e0-0326b048c4d4,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"As the cell proceeds through its cycle, each phase involves certain processes that must be completed before the cell should advance to the next phase. A checkpoint is a point in the cell cycle at which the cycle can be signaled to move forward or stopped. At each of these checkpoints, different varieties of molecules provide the stop or go signals, depending on certain conditions within the cell. A cyclin is one of the primary classes of cell cycle control molecules (Figure 3.5.4). A cyclin-dependent kinase (CDK) is one of a group of molecules that work together with cyclins to determine progression past cell checkpoints. By interacting with many additional molecules, these triggers push the cell cycle forward (unless prevented from doing so by “stop” signals, if for some reason the cell is not ready). At the G1 checkpoint, the cell must be ready for DNA synthesis to occur. At the G2 checkpoint the cell must be fully prepared for mitosis. Even during mitosis, a crucial stop and go checkpoint in metaphase ensures that the cell is fully prepared to complete cell division. The metaphase checkpoint ensures that all sister chromatids are properly attached to their respective microtubules and lined up at the metaphase plate before the signal is given to separate them during anaphase.",True,Mechanisms of Cell Cycle Control,Figure 3.5.4,3.5 Cell Growth and Division,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0332_Cell_Cycle_With_Cyclins_and_Checkpoints.jpg,"Figure 3.5.4 – Control of the Cell Cycle: Cells proceed through the cell cycle under the control of a variety of molecules, such as cyclins and cyclin-dependent kinases. These control molecules determine whether or not the cell is prepared to move into the following stage."
+d61ce397-d3b9-4008-ae46-139d665718b4,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,The Cell Cycle Out of Control: Implications,False,The Cell Cycle Out of Control: Implications,,,,
+c10b85d6-7f76-41a3-82ed-961312debb04,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Most people understand that cancer or tumors are caused by abnormal cells that multiply continuously. If the abnormal cells continue to divide unstopped, they can damage the tissues around them, spread to other parts of the body, and eventually result in death. In healthy cells, the tight regulation mechanisms of the cell cycle prevent this from happening, while failures of the cell cycle control can cause unwanted and excessive cell division. Failures of control may be caused by inherited genetic abnormalities that compromise the function of certain “stop” and “go” signals. Environmental insult that damages DNA can also cause dysfunction in those signals. Often, a combination of both genetic predisposition and environmental factors lead to cancer.",True,The Cell Cycle Out of Control: Implications,,,,
+cd542e34-310f-429d-95c3-61b768fef7d3,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"The process of a cell escaping its normal control system and becoming cancerous may actually happen throughout the body quite frequently. Fortunately, certain cells of the immune system are capable of recognizing cells that have become cancerous and destroying them. However, in certain cases the cancerous cells remain undetected and continue to proliferate. If the resulting tumor does not pose a threat to surrounding tissues, it is said to be benign and can usually be easily removed. If capable of damage, the tumor is considered malignant and the patient is diagnosed with cancer.",True,The Cell Cycle Out of Control: Implications,,,,
+32c2e3c8-141e-451a-b2b6-3cabc40d6c6e,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,False,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+d0201333-b698-4320-aec2-5cb6c405e951,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"Cancer is an extremely complex condition, capable of arising from a wide variety of genetic and environmental causes. Typically, mutations or aberrations in a cell’s DNA that compromise normal cell cycle control systems lead to cancerous tumors. Cell cycle control is an example of a homeostatic mechanism that maintains proper cell function and health. While progressing through the phases of the cell cycle, a large variety of intracellular molecules provide stop and go signals to regulate movement forward to the next phase. These signals are maintained in an intricate balance so that the cell only proceeds to the next phase when it is ready. This homeostatic control of the cell cycle can be thought of like a car’s cruise control. Cruise control will continually apply just the right amount of acceleration to maintain a desired speed, unless the driver hits the brakes, in which case the car will slow down. Similarly, the cell includes molecular messengers, such as cyclins, that push the cell forward in its cycle.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+ae1b881b-005d-41ff-baef-24f80c7f0de7,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"In addition to cyclins, a class of proteins that are encoded by genes called proto-oncogenes provide important signals that regulate the cell cycle and move it forward. Examples of proto-oncogene products include cell-surface receptors for growth factors, or cell-signaling molecules, two classes of molecules that can promote DNA replication and cell division. In contrast, a second class of genes known as tumor suppressor genes sends stop signals during a cell cycle. For example, certain protein products of tumor suppressor genes signal potential problems with the DNA and thus stop the cell from dividing, while other proteins signal the cell to die if it is damaged beyond repair. Some tumor suppressor proteins also signal a sufficient surrounding cellular density, which indicates that the cell need not presently divide. The latter function is uniquely important in preventing tumor growth. Normal cells exhibit a phenomenon called “contact inhibition”, thus, extensive cellular contact with neighboring cells causes a signal that stops further cell division.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+b8e5b3b5-2f7c-45bc-97a0-721769fc95c4,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"These two contrasting classes of genes, proto-oncogenes and tumor suppressor genes, are like the accelerator and brake pedal of the cell’s own “cruise control system,” respectively. Under normal conditions, these stop and go signals are maintained in a homeostatic balance. Generally speaking, there are two ways that the cell’s cruise control can lose control: a malfunctioning (overactive) accelerator, or a malfunctioning (underactive) brake. When compromised through a mutation, or otherwise altered, proto-oncogenes can be converted to oncogenes, which produce oncoproteins that push a cell forward in its cycle and stimulate cell division even when it is undesirable to do so. For example, a cell that should be programmed to self-destruct (a process called apoptosis) due to extensive DNA damage might instead be triggered to proliferate by an oncoprotein. On the other hand, a dysfunctional tumor suppressor gene may fail to provide the cell with a necessary stop signal, also resulting in unwanted cell division and proliferation.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+1f96781d-ac03-417b-ad43-62862086c596,https://open.oregonstate.education/aandp/,3.5 Cell Growth and Division,https://open.oregonstate.education/aandp/chapter/3-5-cell-growth-and-division/,"A delicate homeostatic balance between the many proto-oncogenes and tumor suppressor genes delicately controls the cell cycle and ensures that only healthy cells replicate. Therefore, a disruption of this homeostatic balance can cause aberrant cell division and cancerous growths.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+12dc0b9a-bfdb-4b3b-a5e3-d369aafbdae8,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"It was mentioned earlier that DNA provides a “blueprint” for the cell structure and physiology. This refers to the fact that DNA contains the information necessary for the cell to build one very important type of molecule: the protein. Most structural components of the cell are made up, at least in part, by proteins and virtually all the functions that a cell carries out are completed with the help of proteins. One of the most important classes of proteins is enzymes, which help speed up necessary biochemical reactions that take place inside the cell. Some of these critical biochemical reactions include building larger molecules from smaller components (such as what occurs during DNA replication or synthesis of microtubules) and breaking down larger molecules into smaller components (such as when harvesting chemical energy from nutrient molecules). Whatever the cellular process may be, it is almost sure to involve proteins. Just as the cell’s genome describes its full complement of DNA, a cell’s proteome is its full complement of proteins. Protein synthesis begins with genes. A gene is a functional segment of DNA that provides the genetic information necessary to build a protein. Each particular gene provides the code necessary to construct a particular protein. Gene expression, which transforms the information coded in a gene to a final gene product, ultimately dictates the structure and function of a cell by determining which proteins are made.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,,,,
+3a636569-9360-4d5b-85bc-626ced4bf113,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"The interpretation of genes works in the following way. Recall that proteins are polymers, or chains, of many amino acid building blocks. The sequence of bases in a gene (that is, its sequence of A, T, C, G nucleotides) translates to an amino acid sequence. A triplet is a section of three DNA bases in a row that codes for a specific amino acid. For example, the DNA triplet CAC (cytosine, adenine, and cytosine) specifies the amino acid valine. Therefore, a gene, which is composed of multiple triplets in a unique sequence, provides the code to build an entire protein, with multiple amino acids in the proper sequence (Figure 3.4.1). The mechanism by which cells turn the DNA code into a protein product is a two-step process, with an RNA molecule as the intermediate.",True,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,Figure 3.4.1,3.4 Protein Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0324_DNA_Translation_and_Codons.jpg,Figure 3.4.1 – The Genetic Code: DNA holds all of the genetic information necessary to build a cell’s proteins. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein.
+088fcb87-3b27-499e-a9d6-0b073484cc92,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,From DNA to RNA: Transcription,False,From DNA to RNA: Transcription,,,,
+f205220f-e196-44c2-b58f-8769dd939fc9,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"DNA is housed within the nucleus, and protein synthesis takes place in the cytoplasm, thus there must be some sort of intermediate messenger that leaves the nucleus and manages protein synthesis. This intermediate messenger is messenger RNA (mRNA), (Figure 3.29), a single-stranded nucleic acid that carries a copy of the genetic code for a single gene out of the nucleus and into the cytoplasm where it is used to produce proteins.",True,From DNA to RNA: Transcription,,,,
+46049e2a-3524-45e0-a823-d42ac6b03d80,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"There are several different types of RNA, each having different functions in the cell. The structure of RNA is similar to DNA with a few small exceptions. For one thing, unlike DNA, most types of RNA, including mRNA, are single-stranded and contain no complementary strand. Second, the ribose sugar in RNA contains an additional oxygen atom compared with DNA. Finally, instead of the base thymine, RNA contains the base uracil. This means that adenine will always pair up with uracil during the protein synthesis process.",True,From DNA to RNA: Transcription,,,,
+fa061c15-8b04-4b34-8776-62561b409ff2,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Gene expression begins with the process called transcription, which is the synthesis of a strand of mRNA that is complementary to the gene of interest. This process is called transcription because the mRNA is like a transcript, or copy, of the gene’s DNA code. Transcription begins in a fashion somewhat like DNA replication, in that a region of DNA unwinds and the two strands separate, however, only that small portion of the DNA will be split apart. The triplets within the gene on this section of the DNA molecule are used as the template to transcribe the complementary strand of RNA (Figure 3.4.2). A codon is a three-base sequence of mRNA, so-called because they directly encode amino acids. Like DNA replication, there are three stages to transcription: initiation, elongation, and termination.",True,From DNA to RNA: Transcription,Figure 3.4.2,3.4 Protein Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0325_Transcription.jpg,"Figure 3.4.2 – Transcription: from DNA to mRNA: In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule."
+9c0dbcb6-0626-4334-adda-b124ef22f7e5,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule.",True,From DNA to RNA: Transcription,,,,
+f1bda863-fe5e-4765-a5d1-d7d29e5b5d7e,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,Stage 1: Initiation. A region at the beginning of the gene called a promoter—a particular sequence of nucleotides—triggers the start of transcription.,True,From DNA to RNA: Transcription,,,,
+2a69d593-7f59-4f41-a3fa-ed9127b6f87e,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Stage 2: Elongation. Transcription starts when RNA polymerase unwinds the DNA segment. One strand, referred to as the coding strand, becomes the template with the genes to be coded. The polymerase then aligns the correct nucleic acid (A, C, G, or U) with its complementary base on the coding strand of DNA. RNA polymerase is an enzyme that adds new nucleotides to a growing strand of RNA. This process builds a strand of mRNA.",True,From DNA to RNA: Transcription,,,,
+fd9dcde9-f55b-4c80-a165-af1739eded5c,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Stage 3: Termination. When the polymerase has reached the end of the gene, one of three specific triplets (UAA, UAG, or UGA) codes a “stop” signal, which triggers the enzymes to terminate transcription and release the mRNA transcript.",True,From DNA to RNA: Transcription,,,,
+021f52a2-4f78-4bf8-a3c7-9c97bf47ab21,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"The transcription process is regulated by a class of proteins called transcription factors, which bind to the gene sequence and either promote or inhibit their transcription.  (move Figure 3.35 here).",True,From DNA to RNA: Transcription,,,,
+1930210e-abff-423a-885b-30afa15e91ac,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Before the mRNA molecule leaves the nucleus and proceeds to protein synthesis, it is modified in a number of ways. For this reason, it is often called a pre-mRNA at this stage. For example, your DNA, and thus complementary mRNA, contains long regions called non-coding regions that do not code for amino acids. Their function is still a mystery, but the process called splicing removes these non-coding regions from the pre-mRNA transcript (Figure 3.4.3). A spliceosome—a structure composed of various proteins and other molecules—attaches to the mRNA and “splices” or cuts out the non-coding regions. The removed segment of the transcript is called an intron. The remaining exons are pasted together. An exon is a segment of RNA that remains after splicing. Interestingly, some introns that are removed from mRNA are not always non-coding. When different coding regions of mRNA are spliced out, different variations of the protein will eventually result, with differences in structure and function. This process results in a much larger variety of possible proteins and protein functions. When the mRNA transcript is ready, it travels out of the nucleus and into the cytoplasm.",True,From DNA to RNA: Transcription,Figure 3.4.3,3.4 Protein Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0326_Splicing.jpg,"Figure 3.4.3 – Splicing DNA: In the nucleus, a structure called a spliceosome cuts out introns (noncoding regions) within a pre-mRNA transcript and reconnects the exons."
+49eb4930-c237-449f-b1d7-1278cb19854a,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,From RNA to Protein: Translation,False,From RNA to Protein: Translation,,,,
+c10429ad-edee-4de0-8029-880b332dd621,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Like translating a book from one language into another, the codons on a strand of mRNA must be translated into the amino acid alphabet of proteins. Translation is the process of synthesizing a chain of amino acids called a polypeptide. Translation requires two major aids: first, a “translator,” the molecule that will conduct the translation, and second, a substrate on which the mRNA strand is translated into a new protein, like the translator’s “desk.” Both of these requirements are fulfilled by other types of RNA. The substrate on which translation takes place is the ribosome.",True,From RNA to Protein: Translation,,,,
+428bbbe0-9cd3-4f48-9d47-4e84b61edd3a,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Remember that many of a cell’s ribosomes are found associated with the rough ER, and carry out the synthesis of proteins destined for the Golgi apparatus. Ribosomal RNA (rRNA) is a type of RNA that, together with proteins, composes the structure of the ribosome. Ribosomes exist in the cytoplasm as two distinct components, a small and a large subunit. When an mRNA molecule is ready to be translated, the two subunits come together and attach to the mRNA. The ribosome provides a substrate for translation, bringing together and aligning the mRNA molecule with the molecular “translators” that must decipher its code.",True,From RNA to Protein: Translation,,,,
+96084e02-376c-4b79-818d-0626b462e212,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"The other major requirement for protein synthesis is the translator molecules that physically “read” the mRNA codons. Transfer RNA (tRNA) is a type of RNA that ferries the appropriate corresponding amino acids to the ribosome, and attaches each new amino acid to the last, building the polypeptide chain one-by-one. Thus tRNA transfers specific amino acids from the cytoplasm to a growing polypeptide. The tRNA molecules must be able to recognize the codons on mRNA and match them with the correct amino acid. The tRNA is modified for this function. On one end of its structure is a binding site for a specific amino acid. On the other end is a base sequence that matches the codon specifying its particular amino acid. This sequence of three bases on the tRNA molecule is called an anticodon. For example, a tRNA responsible for shuttling the amino acid glycine contains a binding site for glycine on one end. On the other end it contains an anticodon that complements the glycine codon (GGA is a codon for glycine, and so the tRNAs anticodon would read CCU). Equipped with its particular cargo and matching anticodon, a tRNA molecule can read its recognized mRNA codon and bring the corresponding amino acid to the growing chain (Figure 3.4.4).",True,From RNA to Protein: Translation,Figure 3.4.4,3.4 Protein Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0327_Translation.jpg,"Figure 3.4.4 – Translation from RNA to Protein: During translation, the mRNA transcript is “read” by a functional complex consisting of the ribosome and tRNA molecules. tRNAs bring the appropriate amino acids in sequence to the growing polypeptide chain by matching their anti-codons with codons on the mRNA strand."
+b28f8ce5-baf3-419b-8817-ef21469de035,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Much like the processes of DNA replication and transcription, translation consists of three main stages: initiation, elongation, and termination. Initiation takes place with the binding of a ribosome to an mRNA transcript. The elongation stage involves the recognition of a tRNA anticodon with the next mRNA codon in the sequence. Once the anticodon and codon sequences are bound (remember, they are complementary base pairs), the tRNA presents its amino acid cargo and the growing polypeptide strand is attached to this next amino acid. This attachment takes place with the assistance of various enzymes and requires energy. The tRNA molecule then releases the mRNA strand, the mRNA strand shifts one codon over in the ribosome, and the next appropriate tRNA arrives with its matching anticodon. This process continues until the final codon on the mRNA is reached which provides a “stop” message that signals termination of translation and triggers the release of the complete, newly synthesized protein. Thus, a gene within the DNA molecule is transcribed into mRNA, which is then translated into a protein product (Figure 3.4.5).",True,From RNA to Protein: Translation,Figure 3.4.5,3.4 Protein Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0328_Transcription-translation_Summary.jpg,"Figure 3.4.5 – From DNA to Protein: Transcription through Translation: Transcription within the cell nucleus produces an mRNA molecule, which is modified and then sent into the cytoplasm for translation. The transcript is decoded into a protein with the help of a ribosome and tRNA molecules."
+174d3acf-9392-4231-a8bf-f344f6895bea,https://open.oregonstate.education/aandp/,3.4 Protein Synthesis,https://open.oregonstate.education/aandp/chapter/3-4-protein-synthesis/,"Commonly, an mRNA transcription will be translated simultaneously by several adjacent ribosomes. This increases the efficiency of protein synthesis. A single ribosome might translate an mRNA molecule in approximately one minute; so multiple ribosomes aboard a single transcript could produce multiple times the number of the same protein in the same minute. A polyribosome is a string of ribosomes translating a single mRNA strand.",True,From RNA to Protein: Translation,,,,
+6ad17f3b-9d3d-4ba8-9f95-bb08f1915ef6,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"The nucleus is the largest and most prominent of a cell’s organelles (Figure 3.3.1). The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. Interestingly, some cells in the body, such as muscle cells, contain more than one nucleus (Figure 3.3.2), which is known as multinucleated. Other cells, such as mammalian red blood cells (RBCs), do not contain nuclei at all. RBCs eject their nuclei as they mature, making space for the large numbers of hemoglobin molecules that carry oxygen throughout the body (Figure 3.3.3). Without nuclei, the life span of RBCs is short, and so the body must produce new ones constantly.",True,From RNA to Protein: Translation,Figure 3.3.1,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0318_Nucleus.jpg,Figure 3.3.1 – The Nucleus: The nucleus is the control center of the cell. The nucleus of living cells contains the genetic material that determines the entire structure and function of that cell.
+81546f7b-8027-495f-a590-ed0ba736c768,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Inside the nucleus lies the blueprint that dictates everything a cell will do and all of the products it will make. This information is stored within DNA. The nucleus sends “commands” to the cell via molecular messengers that translate the information from the DNA. Each cell in your body (with the exception of germ cells) contains the complete set of your DNA. When a cell divides, the DNA must be duplicated so that each new cell receives a full complement of DNA. The following section will explore the structure of the nucleus and its contents, as well as the process of DNA replication.",True,From RNA to Protein: Translation,,,,
+5a80c242-7bc3-491a-bd57-21fc0ab7777b,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,Organization of the Nucleus and its DNA,False,Organization of the Nucleus and its DNA,,,,
+06efc7bd-03ac-4ecf-a4a2-8b8d68c571e7,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Like most other cellular organelles, the nucleus is surrounded by a membrane called the nuclear envelope. This membranous covering consists of two adjacent lipid bilayers with a thin fluid space in between them. Spanning these two bilayers are nuclear pores. A nuclear pore is a tiny passageway for the passage of proteins, RNA, and solutes between the nucleus and the cytoplasm. Proteins called pore complexes lining the nuclear pores regulate the passage of materials into and out of the nucleus.",True,Organization of the Nucleus and its DNA,,,,
+4f39f150-7c27-4f5c-afbf-9e5549c1f1cc,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Inside the nuclear envelope is a gel-like nucleoplasm with solutes that include the building blocks of nucleic acids. There also can be a dark-staining mass often visible under a simple light microscope, called a nucleolus (plural = nucleoli). The nucleolus is a region of the nucleus that is responsible for manufacturing the RNA necessary for construction of ribosomes. Once synthesized, newly made ribosomal subunits exit the cell’s nucleus through the nuclear pores.",True,Organization of the Nucleus and its DNA,,,,
+1d312cc6-0527-4dd3-9f80-01f668ac5a8b,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"The genetic instructions that are used to build and maintain an organism are arranged in an orderly manner in strands of DNA. Within the nucleus are threads of chromatin composed of DNA and associated proteins (Figure 3.3.4). Along the chromatin threads, the DNA is wrapped around a set of histone proteins. A nucleosome is a single, wrapped DNA-histone complex. Multiple nucleosomes along the entire molecule of DNA appear like a beaded necklace, in which the string is the DNA and the beads are the associated histones. When a cell is in the process of division, the chromatin condenses into chromosomes, so that the DNA can be safely transported to the “daughter cells.” The chromosome is composed of DNA and proteins; it is the condensed form of chromatin. It is estimated that humans have almost 22,000 genes distributed on 46 chromosomes.",True,Organization of the Nucleus and its DNA,Figure 3.3.4,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0321_DNA_Macrostructure.jpg,"Figure 3.3.4 – DNA Macrostructure: Strands of DNA are wrapped around supporting histones. These proteins are increasingly bundled and condensed into chromatin, which is packed tightly into chromosomes when the cell is ready to divide."
+9f772841-0839-4918-bde0-8c1e933a82ad,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,DNA Replication,False,DNA Replication,,,,
+c08336cf-687c-4a6c-af89-de773c29fbd4,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"In order for an organism to grow, develop, and maintain its health, cells must reproduce themselves by dividing to produce two new daughter cells, each with the full complement of DNA as found in the original cell. Billions of new cells are produced in an adult human every day. Only very few cell types in the body do not divide, including nerve cells, skeletal muscle fibers, and cardiac muscle cells. The division time of different cell types varies. Epithelial cells of the skin and gastrointestinal lining, for instance, divide very frequently to replace those that are constantly being rubbed off of the surface by friction.",True,DNA Replication,,,,
+96590628-3fa8-42c7-8cab-509422be2208,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"A DNA molecule is made of two strands that “complement” each other in the sense that the molecules that compose the strands fit together and bind to each other, creating a double-stranded molecule that looks much like a long, twisted ladder. Each side rail of the DNA ladder is composed of alternating sugar and phosphate groups (Figure 3.3.5). The two sides of the ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. The four DNA bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Because of their shape and charge, the two bases that compose a pair always bond together. Adenine always binds with thymine, and cytosine always binds with guanine. The particular sequence of bases along the DNA molecule determines the genetic code. Therefore, if the two complementary strands of DNA were pulled apart, you could infer the order of the bases in one strand from the bases in the other, complementary strand. For example, if one strand has a region with the sequence AGTGCCT, then the sequence of the complementary strand would be TCACGGA.",True,DNA Replication,Figure 3.3.5,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0322_DNA_Nucleotides.jpg,Figure 3.3.5 – Molecular Structure of DNA: The DNA double helix is composed of two complementary strands. The strands are bonded together via their nitrogenous base pairs using hydrogen bonds.
+25de5251-8a1c-47e9-affd-a2706b0cce3c,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"DNA replication is the copying of DNA that occurs before cell division can take place. After a great deal of debate and experimentation, the general method of DNA replication was deduced in 1958 by two scientists in California, Matthew Meselson and Franklin Stahl. This method is illustrated in Figure 3.3.6 and described below.",True,DNA Replication,Figure 3.3.6,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0323_DNA_Replication.jpg,"Figure 3.3.6 – DNA Replication: DNA replication faithfully duplicates the entire genome of the cell. During DNA replication, a number of different enzymes work together to pull apart the two strands so each strand can be used as a template to synthesize new complementary strands. The two new daughter DNA molecules each contain one pre-existing strand and one newly synthesized strand. Thus, DNA replication is said to be “semiconservative.”"
+6a9e8150-0eb5-4a5b-ba65-d0c34f2a358a,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Stage 1: Initiation. The two complementary strands are separated, much like unzipping a zipper. Special enzymes, including helicase, untwist and separate the two strands of DNA.",True,DNA Replication,,,,
+95430b4d-3b98-4693-8458-ab8ed52cbfeb,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. A DNA polymerase is an enzyme that adds free nucleotides to the end of a chain of DNA, making a new double strand. This growing strand continues to be built until it has fully complemented the template strand.",True,DNA Replication,,,,
+114594bc-2bc4-4600-aad6-4660f7ac1635,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Stage 3: Termination. Once the two original strands are bound to their own, finished, complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete.",True,DNA Replication,,,,
+eea2b449-4c8c-4c1b-8694-28cb307e4c18,https://open.oregonstate.education/aandp/,3.3 The Nucleus and DNA Replication,https://open.oregonstate.education/aandp/chapter/3-3-the-nucleus-and-dna-replication/,"Each new DNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is “semiconservative,” because half of the original DNA molecule is conserved in each new DNA molecule. This process continues until the cell’s entire genome, the entire complement of an organism’s DNA, is replicated. As you might imagine, it is very important that DNA replication take place precisely so that new cells in the body contain the exact same genetic material as their parent cells. Mistakes made during DNA replication, such as the accidental addition of an inappropriate nucleotide, have the potential to render a gene dysfunctional or useless. Fortunately, there are mechanisms in place to minimize such mistakes. A DNA proofreading process enlists the help of special enzymes that scan the newly synthesized molecule for mistakes and corrects them. Once the process of DNA replication is complete, the cell is ready to divide. You will explore the process of cell division later in the chapter.",True,DNA Replication,,,,
+34062ec2-d57d-4d7c-a3cb-bdd3112b0004,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Now that you have learned that the cell membrane surrounds all cells, you can dive inside of a prototypical human cell to learn about its internal components and their functions. All living cells in multicellular organisms contain an internal cytoplasmic compartment, and a nucleus within the cytoplasm. Cytosol, the jelly-like substance within the cell, provides the fluid medium necessary for biochemical reactions. Eukaryotic cells, including all animal cells, also contain various cellular organelles. An organelle (“little organ”) is one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. Just as the various bodily organs work together in harmony to perform all of a human’s functions, the many different cellular organelles work together to keep the cell healthy and performing all of its important functions. The organelles and cytosol, taken together, compose the cell’s cytoplasm. The nucleus is a cell’s central organelle, which contains the cell’s DNA (Figure 3.2.1).",True,DNA Replication,Figure 3.2.1,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0312_Animal_Cell_and_Components.jpg,"Figure 3.2.1 – Prototypical Human Cell: While this image is not indicative of any one particular human cell, it is a prototypical example of a cell containing the primary organelles and internal structures."
+8f587380-82c7-441b-8be1-095e072f7f6f,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Organelles of the Endomembrane System,False,Organelles of the Endomembrane System,,,,
+4956c288-945f-4d26-8057-3fd11be7994e,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"A set of three major organelles together form a system within the cell called the endomembrane system. These organelles work together to perform various cellular jobs, including the task of producing, packaging, and exporting certain cellular products. The organelles of the endomembrane system include the endoplasmic reticulum, Golgi apparatus, and vesicles.",True,Organelles of the Endomembrane System,,,,
+4c2ee27c-7074-496a-a039-4aea0f6bcf49,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Endoplasmic Reticulum,False,Endoplasmic Reticulum,,,,
+591ddddc-bcff-4fce-ac3c-bce4c8a4c08d,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"The endoplasmic reticulum (ER) is a system of channels that is continuous with the nuclear membrane (or “envelope”) covering the nucleus and composed of the same lipid bilayer material. The ER can be thought of as a series of winding thoroughfares similar to the waterway canals in Venice. The ER provides passages throughout much of the cell that function in transporting, synthesizing, and storing materials. The winding structure of the ER results in a large membranous surface area that supports its many functions (Figure 3.2.2).",True,Endoplasmic Reticulum,Figure 3.2.2,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0313_Endoplasmic_Reticulum.jpg,"Figure 3.2.2 – Endoplasmic Reticulum (ER): (a) The ER is a winding network of thin membranous sacs found in close association with the cell nucleus. The smooth and rough endoplasmic reticula are very different in appearance and function (source: mouse tissue). (b) Rough ER is studded with numerous ribosomes, which are sites of protein synthesis (source: mouse tissue, EM × 110,000). (c) Smooth ER synthesizes phospholipids, steroid hormones, regulates the concentration of cellular Ca++, metabolizes some carbohydrates, and breaks down certain toxins (source: mouse tissue, EM × 110,510). (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+ce99ba0c-28cb-4a39-ba38-4b726b0db653,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Endoplasmic reticulum can exist in two forms: rough ER and smooth ER. These two types of ER perform some very different functions and can be found in very different amounts depending on the type of cell. Rough ER (RER) is so-called because its membrane is dotted with embedded granules—organelles called ribosomes, giving the RER a bumpy appearance. A ribosome is an organelle that serves as the site of protein synthesis. It is composed of two ribosomal RNA subunits that wrap around mRNA to start the process of translation, followed by protein synthesis. Smooth ER (SER) lacks these ribosomes.",True,Endoplasmic Reticulum,,,,
+b63ee12e-4a97-41d7-a008-7ae5e57538b9,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"One of the main functions of the smooth ER is in the synthesis of lipids. The smooth ER synthesizes phospholipids, the main component of biological membranes, as well as steroid hormones. For this reason, cells that produce large quantities of such hormones, such as those of the female ovaries and male testes, contain large amounts of smooth ER. In addition to lipid synthesis, the smooth ER also sequesters (i.e., stores) and regulates the concentration of cellular Ca++, a function extremely important in cells of the nervous system where Ca++ is the trigger for neurotransmitter release. The smooth ER additionally metabolizes some carbohydrates and performs a detoxification role, breaking down certain toxins.",True,Endoplasmic Reticulum,,,,
+f9df5283-2e07-4906-b568-fd8568d65f67,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"In contrast with the smooth ER, the primary job of the rough ER is the synthesis and modification of proteins destined for the cell membrane or for export from the cell. For this protein synthesis, many ribosomes attach to the ER (giving it the studded appearance of rough ER). Typically, a protein is synthesized within the ribosome and released inside the channel of the rough ER, where sugars can be added to it (by a process called glycosylation) before it is transported within a vesicle to the next stage in the packaging and shipping process: the Golgi apparatus.",True,Endoplasmic Reticulum,,,,
+4b6d6212-a059-4990-92fa-f7fd95fd1eb9,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,The Golgi Apparatus,False,The Golgi Apparatus,,,,
+acc3f3e1-ddb3-45e8-a514-9b2943095779,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"The Golgi apparatus is responsible for sorting, modifying, and shipping off the products that come from the rough ER, much like a post-office. The Golgi apparatus looks like stacked flattened discs, almost like stacks of oddly shaped pancakes. Like the ER, these discs are membranous. The Golgi apparatus has two distinct sides, each with a different role. One side of the apparatus receives products in vesicles. These products are sorted through the apparatus and then they are released from the opposite side after being repackaged into new vesicles. If the product is to be exported from the cell, the vesicle migrates to the cell surface and fuses to the cell membrane, and the cargo is secreted (Figure 3.2.3).",True,The Golgi Apparatus,Figure 3.2.3,,,
+b63be08f-d87f-4733-b792-af86f808d54e,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Lysosomes,False,Lysosomes,,,,
+3f1e6893-3ed8-4c49-924c-2ee92d9cf5bf,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Some of the protein products packaged by the Golgi include digestive enzymes that are meant to remain inside the cell for use in breaking down certain materials. The enzyme-containing vesicles released by the Golgi may form new lysosomes, or fuse with existing, lysosomes. A lysosome is an organelle that contains enzymes that break down and digest unneeded cellular components, such as a damaged organelle. (A lysosome is similar to a wrecking crew that takes down old and unsound buildings in a neighborhood.) Autophagy (“self-eating”) is the process of a cell digesting its own structures. Lysosomes are also important for breaking down foreign material. For example, when certain immune defense cells (white blood cells) phagocytize bacteria, the bacterial cell is transported into a lysosome and digested by the enzymes inside. As one might imagine, such phagocytic defense cells contain large numbers of lysosomes.",True,Lysosomes,,,,
+d71fef3b-df9c-4aa9-bf6e-a95a99c6ab17,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Under certain circumstances, lysosomes perform a more grand and dire function. In the case of damaged or unhealthy cells, lysosomes can be triggered to open up and release their digestive enzymes into the cytoplasm of the cell, killing the cell. This “self-destruct” mechanism is called autolysis, and makes the process of cell death controlled (a mechanism called “apoptosis”).",True,Lysosomes,,,,
+4cb42c1c-07cf-4ddc-a9f2-9df84cdc4d2a,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Organelles for Energy Production and Detoxification,False,Organelles for Energy Production and Detoxification,,,,
+3a86a8a4-d906-4751-aa83-589661f378ce,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"In addition to the jobs performed by the endomembrane system, the cell has many other important functions. Just as you must consume nutrients to provide yourself with energy, so must each of your cells take in nutrients, some of which convert to chemical energy that can be used to power biochemical reactions. Another important function of the cell is detoxification. Humans take in all sorts of toxins from the environment and also produce harmful chemicals as byproducts of cellular processes. Cells called hepatocytes in the liver detoxify many of these toxins.",True,Organelles for Energy Production and Detoxification,,,,
+5f11127c-01e7-439f-90b9-ec19b0d24663,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Mitochondria,False,Mitochondria,,,,
+9c9dd03e-b29d-484f-91ae-1e553404f69c,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"A mitochondrion (plural = mitochondria) is a membranous, bean-shaped organelle that is the “energy transformer” of the cell. Mitochondria consist of an outer lipid bilayer membrane as well as an additional inner lipid bilayer membrane (Figure 3.2.4). The inner membrane is highly folded into winding structures with a great deal of surface area, called cristae. It is along this inner membrane that a series of proteins, enzymes, and other molecules perform the biochemical reactions of cellular respiration. These reactions convert energy stored in nutrient molecules (such as glucose) into adenosine triphosphate (ATP), which provides usable cellular energy to the cell. Cells use ATP constantly, and so the mitochondria are constantly at work. Oxygen molecules are required during cellular respiration, which is why you must constantly breathe it in. One of the organ systems in the body that uses huge amounts of ATP is the muscular system because ATP is required to sustain muscle contraction. As a result, muscle cells are packed full of mitochondria. Nerve cells also need large quantities of ATP to run their sodium-potassium pumps. Therefore, an individual neuron will be loaded with over a thousand mitochondria. On the other hand, a bone cell, which is not nearly as metabolically-active, might only have a couple hundred mitochondria.",True,Mitochondria,Figure 3.2.4,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0315_Mitochondrion_new.jpg,"Figure 3.2.4 – Mitochondrion: The mitochondria are the energy-conversion factories of the cell. (a) A mitochondrion is composed of two separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell’s major energy currency. (b) An electron micrograph of mitochondria (EM × 236,000). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+3c4f801a-de7e-4594-bd89-d2869541a844,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,Peroxisomes,False,Peroxisomes,,,,
+56774be0-1a8e-4a24-a373-61317ab4caf7,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Like lysosomes, a peroxisome is a membrane-bound cellular organelle that contains mostly enzymes (Figure 3.2.5). Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive enzymes found in lysosomes, the enzymes within peroxisomes serve to transfer hydrogen atoms from various molecules to oxygen, producing hydrogen peroxide (H2O2). In this way, peroxisomes neutralize poisons such as alcohol. In order to appreciate the importance of peroxisomes, it is necessary to understand the concept of reactive oxygen species.",True,Peroxisomes,Figure 3.2.5,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0316_Peroxisome.jpg,Figure 3.2.5 – Peroxisome: Peroxisomes are membrane-bound organelles that contain an abundance of enzymes for detoxifying harmful substances and lipid metabolism.
+013f9b4b-8172-47fb-b1b3-91df9261d7ba,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (O2−). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.
+
+Peroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but also contain enzymes that convert H2O2 into water and oxygen. These byproducts are safely released into the cytoplasm. Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells. The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.
+
+Defense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties. Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.
+
+Oxidative stress is the term used to describe damage to cellular components caused by ROS. Due to their distinctive unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive; they do the same to other molecules, causing a chain reaction. ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. Damaged DNA can lead to genetic mutations and even cancer. A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene. Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.",True,Peroxisomes,,,,
+7401e79b-3ac2-4de5-b644-e1074b36d144,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"The Cytoskeleton
+
+Much like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.
+
+The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.2.6). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.",True,Peroxisomes,Figure 3.2.6,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+bd291edf-f894-4d99-9f4a-2ef067f481f7,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"A very important function of microtubules is to set the paths (somewhat like railroad tracks) along where the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.",True,Peroxisomes,,,,
+90515d56-94db-482d-8fc7-b0c428e138ec,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.2.6b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.",True,Peroxisomes,Figure 3.2.6,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+a9944193-94ff-4059-8912-a5d9eb728a13,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.",True,Peroxisomes,,,,
+76043244-a898-4a0d-a7de-40f55e4bde62,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.2.6c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.",True,Peroxisomes,Figure 3.2.6,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+c386580a-d01f-4872-a78d-05dddafb0515,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,References,False,References,,,,
+2191ee67-abf3-48af-97b2-5cfed3d6c5cd,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,"Kolata, G. Severe diet doesn’t prolong life, at least in monkeys. New York Times [Internet]. 2012 Aug. 29 [cited 2013 Jan 21]; Available from:",True,References,,,,
+a747531b-0994-43f2-96a7-7de020a1fc6f,https://open.oregonstate.education/aandp/,3.2 The Cytoplasm and Cellular Organelles,https://open.oregonstate.education/aandp/chapter/3-2-the-cytoplasm-and-cellular-organelles/,http://www.nytimes.com/2012/08/30/science/low-calorie-diet-doesnt-prolong-life-study-of-monkeys-finds.html?_r=2&ref=caloricrestriction&,True,References,,,,
+178444bb-ff18-4f94-9d69-2cc777985045,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Despite differences in structure and function, all living cells in multicellular organisms have a surrounding cell membrane. Just as the outer layer of your skin separates your body from its environment, the cell membrane (also known as the plasma membrane) separates the inner contents of a cell from its exterior environment. This cell membrane provides a protective barrier around the cell and regulates which materials can pass in or out.",True,References,,,,
+43157622-7aea-4772-87e4-a99a6021e2e3,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Structure and Composition of the Cell Membrane,False,Structure and Composition of the Cell Membrane,,,,
+4b556f1f-0a59-4e61-8e07-cbb9b5e3626a,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,The cell membrane is an extremely pliable structure composed primarily of two layers of phospholipids (a “bilayer”). Cholesterol and various proteins are also embedded within the membrane giving the membrane a variety of functions described below.,True,Structure and Composition of the Cell Membrane,,,,
+4d1ea911-5bdf-46e4-98e0-2d594accc618,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"A single phospholipid molecule has a phosphate group on one end, called the “head,” and two side-by-side chains of fatty acids that make up the lipid “tails” (Figure 3.1.1). The lipid tails of one layer face the lipid tails of the other layer, meeting at the interface of the two layers. The phospholipid heads face outward, one layer exposed to the interior of the cell and one layer exposed to the exterior (Figure 3.1.1).",True,Structure and Composition of the Cell Membrane,Figure 3.1.1,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2019/07/phospholipid1-1024x669.png,"Figure 3.1.1 – Phospholipid Structure and Bilayer: A phospholipid molecule consists of a polar phosphate “head,” which is hydrophilic and a non-polar lipid “tail,” which is hydrophobic. Unsaturated fatty acids result in kinks in the hydrophobic tails. The phospholipid bilayer consists of two adjacent sheets of phospholipids, arranged tail to tail. The hydrophobic tails associate with one another, forming the interior of the membrane. The polar heads contact the fluid inside and outside of the cell."
+9f80a617-f594-4b85-8a91-98a38a87cc25,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"The phosphate group is negatively charged, making the head polar and hydrophilic—or “water loving.” A hydrophilic molecule (or region of a molecule) is one that is attracted to water. The phosphate heads are thus attracted to the water molecules of both the extracellular and intracellular environments. The lipid tails, on the other hand, are uncharged, or nonpolar, and are hydrophobic—or “water fearing.” A hydrophobic molecule (or region of a molecule) repels and is repelled by water. Phospholipids are thus amphipathic molecules. An amphipathic molecule is one that contains both a hydrophilic and a hydrophobic region. In fact, soap works to remove oil and grease stains because it has amphipathic properties. The hydrophilic portion can dissolve in the wash water while the hydrophobic portion can trap grease in stains that then can be washed away. A similar process occurs in your digestive system when bile salts (made from cholesterol, phospholipids and salt) help to break up ingested lipids.",True,Structure and Composition of the Cell Membrane,,,,
+6f611561-802f-4ba5-bd8f-01a1357a60e7,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Since the phosphate groups are polar and hydrophilic, they are attracted to water in the intracellular fluid. Intracellular fluid (ICF) is the fluid interior of the cell. The phosphate groups are also attracted to the extracellular fluid. Extracellular fluid (ECF) is the fluid environment outside the enclosure of the cell membrane (see above Figure). Since the lipid tails are hydrophobic, they meet in the inner region of the membrane, excluding watery intracellular and extracellular fluid from this space. In addition to phospholipids and cholesterol, the cell membrane has many proteins detailed in the next section.",True,Structure and Composition of the Cell Membrane,,,,
+5facc4e1-7152-43bc-89fe-e804fd013b5e,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Membrane Proteins,False,Membrane Proteins,,,,
+7ae9b4c5-b7ef-4c37-a54a-24a06a64d466,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"The lipid bilayer forms the basis of the cell membrane, but it is peppered throughout with various proteins. Two different types of proteins that are commonly associated with the cell membrane are the integral protein and peripheral protein (Figure 3.1.2). As its name suggests, an integral protein is a protein that is embedded in the membrane. Many different types of integral proteins exist, each with different functions. For example, an integral protein that extends an opening through the membrane for ions to enter or exit the cell is known as a channel protein. Peripheral proteins are typically found on the inner or outer surface of the lipid bilayer but can also be attached to the internal or external surface of an integral protein.",True,Membrane Proteins,Figure 3.1.2,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0303_Lipid_Bilayer_With_Various_Components.jpg,"Figure 3.1.2- Cell Membrane:  The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrate groups attached."
+ab518e89-05b3-47ea-9de4-8a1a3d8d014c,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Some integral proteins serve as cell recognition or surface identity proteins, which mark a cell’s identity so that it can be recognized by other cells. Some integral proteins act as enzymes, or in cell adhesion, between neighboring cells. A receptor is a type of recognition protein that can selectively bind a specific molecule outside the cell, and this binding induces a chemical reaction within the cell. Some integral proteins serve dual roles as both a receptor and an ion channel. One example of a receptor-channel interaction is the receptors on nerve cells that bind neurotransmitters, such as dopamine. When a dopamine molecule binds to a dopamine receptor protein, a channel within the transmembrane protein opens to allow certain ions to flow into the cell. Peripheral proteins are often associated with integral proteins along the inner cell membrane where they play a role in cell signaling or anchoring to internal cellular components (ie: cytoskeleton discussed later).",True,Membrane Proteins,,,,
+8ed327e9-f602-4e8e-b279-f40852305dec,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Some integral membrane proteins are glycoproteins. A glycoprotein is a protein that has carbohydrate molecules attached, which extend into the extracellular environment. The attached carbohydrate tags on glycoproteins aid in cell recognition. The carbohydrates that extend from membrane proteins and even from some membrane lipids collectively form the glycocalyx. The glycocalyx is a fuzzy-appearing coating around the cell formed from glycoproteins and other carbohydrates attached to the cell membrane. The glycocalyx can have various roles. For example, it may have molecules that allow the cell to bind to another cell, it may contain receptors for hormones, or it might have enzymes to break down nutrients. The glycocalyces found in a person’s body are products of that person’s genetic makeup. They give each of the individual’s trillions of cells the “identity” of belonging in the person’s body. This identity is the primary way that a person’s immune defense cells “know” not to attack the person’s own body cells, but it also is the reason organs donated by another person might be rejected.",True,Membrane Proteins,,,,
+9d4d5a89-510d-4047-971b-c8965df19d34,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Transport Across the Cell Membrane,False,Transport Across the Cell Membrane,,,,
+2bc5cb40-d59e-4ebd-a057-2bb6b6d5fa4f,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"One of the great wonders of the cell membrane is its ability to regulate the concentration of substances inside the cell. These substances include ions such as Ca++, Na+, K+, and Cl–, nutrients including sugars, fatty acids, and amino acids, and waste products, particularly carbon dioxide (CO2), which must leave the cell.",True,Transport Across the Cell Membrane,,,,
+ca40d03e-1cf4-4c01-9d99-7f21ba97da3b,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"The membrane’s lipid bilayer structure provides the first level of control. The phospholipids are tightly packed together, and the membrane has a hydrophobic interior. This structure causes the membrane to be selectively permeable. A membrane that has selective permeability allows only substances meeting certain criteria to pass through it unaided. In the case of the cell membrane, only relatively small, nonpolar materials can move through the lipid bilayer (remember, the lipid tails of the membrane are nonpolar). Some examples of these are other lipids, oxygen and carbon dioxide gases, and alcohol. However, water-soluble materials—like glucose, amino acids, and electrolytes—need some assistance to cross the membrane because they are repelled by the hydrophobic tails of the phospholipid bilayer. All substances that move through the membrane do so by one of two general methods, which are categorized based on whether or not energy is required. Passive transport is the movement of substances across the membrane without the expenditure of cellular energy. In contrast, active transport is the movement of substances across the membrane using energy from adenosine triphosphate (ATP).",True,Transport Across the Cell Membrane,,,,
+6220b7e1-cc05-4d8c-aaf2-d56fc34c1b9d,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Passive Transport,False,Passive Transport,,,,
+e5527054-d280-45f9-be22-2e7893caab5b,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"In order to understand how substances move passively across a cell membrane, it is necessary to understand concentration gradients and diffusion. A concentration gradient is the difference in concentration of a substance across a space. Molecules (or ions) will spread/diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space. (When molecules move in this way, they are said to move down their concentration gradient, from high concentration to low concentration.) Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. A couple of common examples will help to illustrate this concept. Imagine being inside a closed room. If a bottle of perfume were sprayed, the scent molecules would naturally diffuse from the spot where they left the bottle to all corners of the room, and this diffusion would go on until the molecules were equally distributed in the room. Another example is a spoonful of sugar placed in a cup of tea. Eventually the sugar will diffuse throughout the tea until no concentration gradient remains. In both cases, if the room is warmer or the tea hotter, diffusion occurs even faster as the molecules are bumping into each other and spreading out faster than at cooler temperatures.",True,Passive Transport,,,,
+a3006b94-266d-4544-99e4-6c610d9e6e9b,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Whenever a substance exists in greater concentration on one side of a semipermeable membrane, such as cell membranes, any substance that can move down its concentration gradient across the membrane will do so. If the substances can move across the cell membrane without the cell expending energy, the movement of molecules is called passive transport. Consider substances that can easily diffuse through the lipid bilayer of the cell membrane, such as the gases oxygen (O2) and carbon dioxide (CO2). These small, fat soluble gasses and other small lipid soluble molecules can dissolve in the membrane and enter or exit the cell following their concentration gradient. This mechanism of molecules moving across a cell membrane from the side where they are more concentrated to the side where they are less concentrated is a form of passive transport called simple diffusion. O2 generally diffuses into cells because it is more concentrated outside of them, and CO2 typically diffuses out of cells because it is more concentrated inside of them.",True,Passive Transport,,,,
+9ba1a9f6-e278-4a2a-814c-336846f5d765,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Before moving on, it is important to realize that the concentration gradients for oxygen and carbon dioxide will always exist across a living cell and never reach equal distribution. This is because cells rapidly use up oxygen during metabolism and so, there is typically a lower concentration of O2 inside the cell than outside. As a result, oxygen will diffuse from outside the cell directly through the lipid bilayer of the membrane and into the cytoplasm within the cell. On the other hand, because cells produce CO2 as a byproduct of metabolism, CO2 concentrations rise within the cytoplasm; therefore, CO2 will move from the cell through the lipid bilayer and into the extracellular fluid, where its concentration is lower. (Figure 3.1.3).",True,Passive Transport,Figure 3.1.3,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0305_Simple_Diffusion_Across_Plasma_Membrane-1.jpg,"Figure 3.1.3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion."
+cd7e17d4-d5c9-45e0-be22-23dbfd1c687d,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Large polar or ionic molecules, which are hydrophilic, cannot easily cross the phospholipid bilayer. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer. Solutes dissolved in water on either side of the cell membrane will tend to diffuse down their concentration gradients, but because most substances cannot pass freely through the lipid bilayer of the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane. Facilitated diffusion is the diffusion process used for those substances that cannot cross the lipid bilayer due to their size, charge, and/or polarity but do so down their concentration gradients (Figure 3.1.4). As an example, even though sodium ions (Na+) are highly concentrated outside of cells, these electrolytes are charged and cannot pass through the nonpolar lipid bilayer of the membrane. Their diffusion is facilitated by membrane proteins that form sodium channels (or “pores”), so that Na+ ions can move down their concentration gradient from outside the cells to inside the cells.  A common example of facilitated diffusion using a carrier protein is the movement of glucose into the cell, where it is used to make ATP. Although glucose can be more concentrated outside of a cell, it cannot cross the lipid bilayer via simple diffusion because it is both large and polar, and therefore, repelled by the phospholipid membrane. To resolve this, a specialized carrier protein called the glucose transporter will transfer glucose molecules into the cell to facilitate its inward diffusion. The difference between a channel and a carrier is that the carrier usually changes shape during the diffusion process, while the channel does not. There are many other solutes that must undergo facilitated diffusion to move into a cell, such as amino acids, or to move out of a cell, such as wastes.",True,Passive Transport,Figure 3.1.4,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Facilitated_Diffusion-804x1024.jpg,"Figure 3.1.4 – Facilitated Diffusion: (a) Facilitated diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carrier proteins. Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. (b) Carrier proteins are more selective, often only allowing one particular type of molecule to cross."
+58e9ff50-7dd8-4207-a5d3-3b1f3f970e7e,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Osmosis,False,Osmosis,,,,
+5d8a6ee4-b0ba-454c-8d9e-b99ea76750f5,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"A specialized example of facilitated transport is water moving across the cell membrane of all cells, through protein channels known as aquaporins. Osmosis is the diffusion of water through a semipermeable membrane from where there is more relative water to where there is less relative water (down its water concentration gradient) (Figure 3.1.5).",True,Osmosis,Figure 3.1.5,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0307_Osmosis.jpg,"Figure 3.1.5 – Osmosis: Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic."
+396d0ef5-7357-43ff-8b0d-3c5fa2753dea,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"On their own, cells cannot regulate the movement of water molecules across their membrane, so it is important that cells are exposed to an environment in which the concentration of solutes outside of the cells (in the extracellular fluid) is equal to the concentration of solutes inside the cells (in the cytoplasm). Two solutions that have the same concentration of solutes are said to be isotonic (equal tension). When cells and their extracellular environments are isotonic, the concentration of water molecules is the same outside and inside the cells, and the cells maintain their normal shape (and function).",True,Osmosis,,,,
+ec321808-a5ab-4860-892e-ce216bf70d3c,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution (Figure 3.1.6). Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution. Cells in a hypotonic solution will take on too much water and swell, with the risk of eventually bursting. A critical aspect of homeostasis in living things is to create an internal environment in which all of the body’s cells are in an isotonic solution. Various organ systems, particularly the kidneys, work to maintain this homeostasis.",True,Osmosis,Figure 3.1.6,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0346_Concentration_of_Solutions.jpg,Figure 3.1.6 – Concentration of Solution: A hypertonic solution has a solute concentration higher than another solution. An isotonic solution has a solute concentration equal to another solution. A hypotonic solution has a solute concentration lower than another solution.
+57c80571-69a9-4f05-addd-d24132e563ac,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Active Transport,False,Active Transport,,,,
+af07062f-bb04-4385-8635-5380cdcf8768,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"For all of the transport methods described above, the cell expends no energy. Membrane proteins that aid in the passive transport of substances do so without the use of ATP. During primary active transport, ATP is required to move a substance across a membrane, with the help of membrane protein, and against its concentration gradient.",True,Active Transport,,,,
+e733c6bf-aa90-4733-bca1-872fcab82cfb,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"One of the most common types of active transport involves proteins that serve as pumps. The word “pump” probably conjures up thoughts of using energy to pump up the tire of a bicycle or a basketball. Similarly, energy from ATP is required for these membrane proteins to transport substances—molecules or ions—across the membrane, against their concentration gradients (from an area of low concentration to an area of high concentration).",True,Active Transport,,,,
+7a2330e6-c20a-4d3f-8822-d58803e99838,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"The sodium-potassium pump, which is also called Na+/K+ ATPase, transports sodium out of a cell while moving potassium into the cell. The Na+/K+ pump is an important ion pump found in the membranes of all cells. The activity of these pumps in nerve cells is so great that it accounts for the majority of their ATP usage.",True,Active Transport,,,,
+d00388c6-0059-4367-bbd0-9d5601ff9b14,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Active transport pumps can also work together with other active or passive transport systems to move substances across the membrane. For example, the sodium-potassium pump maintains a high concentration of sodium ions outside of the cell. Therefore, if the cell needs sodium ions, all it has to do is open a passive sodium channel, as the concentration gradient of the sodium ions will drive them to diffuse into the cell. In this way, the action of an active transport pump (the sodium-potassium pump) powers the passive transport of sodium ions by creating a concentration gradient. When active transport powers the transport of another substance in this way, it is called secondary active transport.",True,Active Transport,,,,
+3f20666e-7a6a-430c-b7c6-927063c126bf,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Symporters are secondary active transporters that move two substances in the same direction. For example, the sodium-glucose symporter uses sodium ions to “pull” glucose molecules into the cell. Since cells store glucose for energy, glucose is typically at a higher concentration inside of the cell than outside; however, due to the action of the sodium-potassium pump, sodium ions will easily diffuse into the cell when the symporter is opened. The flood of sodium ions through the symporter provides the energy that allows glucose to move through the symporter and into the cell, against its concentration gradient.",True,Active Transport,,,,
+9f099ae0-7e00-43ea-85a1-801bb46b9444,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Conversely, antiporters are secondary active transport systems that transport substances in opposite directions. For example, the sodium-hydrogen ion antiporter uses the energy from the inward flood of sodium ions to move hydrogen ions (H+) out of the cell. The sodium-hydrogen antiporter is used to maintain the pH of the cell’s interior.",True,Active Transport,,,,
+6ed8782d-c469-46a5-a184-1d4522e3c96a,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Other Forms of Membrane Transport,False,Other Forms of Membrane Transport,,,,
+05905a4b-d7ef-48b1-8b62-da289d6eb6af,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Other forms of active transport do not involve membrane carriers. Endocytosis (bringing “into the cell”) is the process of a cell ingesting material by enveloping it in a portion of its cell membrane, and then pinching off that portion of membrane (Figure 3.1.8). Once pinched off, the portion of membrane and its contents becomes an independent, intracellular vesicle. A vesicle is a membranous sac—a spherical and hollow organelle bounded by a lipid bilayer membrane. Endocytosis often brings materials into the cell that must to be broken down or digested. Phagocytosis (“cell eating”) is the endocytosis of large particles. Many immune cells engage in phagocytosis of invading pathogens. Like little Pac-men, their job is to patrol body tissues for unwanted matter, such as invading bacterial cells, phagocytize them, and digest them. In contrast to phagocytosis, pinocytosis (“cell drinking”) brings fluid containing dissolved substances into a cell through membrane vesicles.",True,Other Forms of Membrane Transport,Figure 3.1.8,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0309_Three_Forms_of_Endocytosis.jpg,"Figure 3.1.8 – Three Forms of Endocytosis: Endocytosis is a form of active transport in which a cell envelopes extracellular materials using its cell membrane. (a) In phagocytosis, which is relatively nonselective, the cell takes in large particles into larger vesicles known as vacuoles. (b) In pinocytosis, the cell takes in small particles in fluid. (c) In contrast, receptor-mediated endocytosis is quite selective. When external receptors bind a specific ligand, the cell responds by endocytosing the ligand."
+630669b3-ed61-48b2-b77b-ab12297408b0,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"Phagocytosis and pinocytosis take in large portions of extracellular material, and they are typically not highly selective in the substances they bring in. Cells regulate the endocytosis of specific substances via receptor-mediated endocytosis. Receptor-mediated endocytosis is endocytosis by a portion of the cell membrane which contains many receptors that are specific for a certain substance. Once the surface receptors have bound sufficient amounts of the specific substance (the receptor’s ligand), the cell will endocytose the part of the cell membrane containing the receptor-ligand complexes. Iron, a required component of hemoglobin, is endocytosed by red blood cells in this way. Iron is bound to a protein called transferrin in the blood. Specific transferrin receptors on red blood cell surfaces bind the iron-transferrin molecules, and the cell endocytoses the receptor-ligand complexes.",True,Other Forms of Membrane Transport,,,,
+13d635e0-aae2-40e8-a0ac-7a64d214a0dc,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"In contrast with endocytosis, exocytosis (taking “out of the cell”) is the process of a cell exporting material using vesicular transport (Figure 3.1.9). Many cells manufacture substances that must be secreted, like a factory manufacturing a product for export. These substances are typically packaged into membrane-bound vesicles within the cell. When the vesicle membrane fuses with the cell membrane, the vesicle releases its contents into the interstitial fluid. The vesicle membrane then becomes part of the cell membrane.",True,Other Forms of Membrane Transport,Figure 3.1.9,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0310_Exocytosis.jpg,"Figure 3.1.9 – Exocytosis: Exocytosis is much like endocytosis in reverse. Material destined for export is packaged into a vesicle inside the cell. The membrane of the vesicle fuses with the cell membrane, and the contents are released into the extracellular space."
+039940cf-1296-464e-aff5-39b5cc3211a8,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,Specific examples of exocytosis include cells of the stomach and pancreas producing and secreting digestive enzymes through exocytosis (Figure 3.1.10) and endocrine cells producing and secreting hormones that are sent throughout the body.,True,Other Forms of Membrane Transport,Figure 3.1.10,3.1 The Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0311_Pancreatic_Cells_Micrograph.jpg,Figure 3.1.10 – Pancreatic Cells’ Enzyme Products: The pancreatic acinar cells produce and secrete many enzymes that digest food. The tiny black granules in this electron micrograph are secretory vesicles filled with enzymes that will be exported from the cells via exocytosis. LM × 2900. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+8f090f7d-63a5-443c-be2c-cc256afa42d9,https://open.oregonstate.education/aandp/,3.1 The Cell Membrane,https://open.oregonstate.education/aandp/chapter/3-1-the-cell-membrane/,"The addition of new membrane to the plasma membrane is usually coupled with endocytosis so that the cell is not constantly enlarging. Through these processes, the cell membrane is constantly renewing and changing as needed by the cell.",True,Other Forms of Membrane Transport,,,,
+e88fbfe1-43b6-4c58-84d2-b30bb2d8adc3,https://open.oregonstate.education/aandp/,3.0 Introduction,https://open.oregonstate.education/aandp/chapter/3-0-introduction/,"You developed from a single fertilized egg cell into the complex organism that you see when you look in a mirror, containing trillions of cells. During this developmental process, early, unspecialized cells become specialized in their structure and function (this is known as differentiation). These different cell types join to form specialized tissues that work in concert to perform all of the functions necessary for the living organism. Cellular and developmental biologists study how the continued division of a single cell leads to such complexity and differentiation.",True,Other Forms of Membrane Transport,,,,
+e6a2c1bd-4073-46fa-a54d-5364dba0fc4d,https://open.oregonstate.education/aandp/,3.0 Introduction,https://open.oregonstate.education/aandp/chapter/3-0-introduction/,"Consider the difference between a structural cell in the skin and a nerve cell. A structural skin cell may be shaped like a flat plate (squamous) and live only for a short time before it is shed and replaced. Packed tightly into rows and sheets, the squamous skin cells provide a protective barrier for the cells and tissues that lie beneath. A nerve cell, on the other hand, may be shaped something like a star, sending out long processes up to a meter in length and may live for the entire lifetime of the organism. With their long winding appendages, nerve cells can communicate with one another and with other types of body cells and send rapid signals that inform the organism about its environment and allow it to interact with that environment. These differences illustrate one very important theme that is consistent at all organizational levels of biology: the form of a structure is optimally suited to perform particular functions assigned to that structure. Keep this theme in mind as you tour the inside of a cell and are introduced to the various types of cells in the body.",True,Other Forms of Membrane Transport,,,,
+1e8d1e19-90d9-41b4-b0ed-34d5cd79674d,https://open.oregonstate.education/aandp/,3.0 Introduction,https://open.oregonstate.education/aandp/chapter/3-0-introduction/,"A primary responsibility of each cell is to contribute to homeostasis. Homeostasis is a term used in biology that refers to a dynamic state of balance within parameters that are compatible with life. For example, living cells require a water-based environment to survive in, and there are various physical (anatomical) and physiological mechanisms that keep all of the trillions of living cells in the human body moist. This is one aspect of homeostasis. When a particular parameter, such as blood pressure or blood oxygen content, moves far enough out of homeostasis (generally becoming too high or too low), illness or disease—and sometimes death—inevitably results.",True,Other Forms of Membrane Transport,,,,
+ee58bf7a-c34b-44b5-a156-0da95ada0eb6,https://open.oregonstate.education/aandp/,3.0 Introduction,https://open.oregonstate.education/aandp/chapter/3-0-introduction/,"The concept of a cell started with microscopic observations of dead cork tissue by scientist Robert Hooke in 1665. Without realizing their function or importance, Hooke coined the term “cell” based on the resemblance of the small subdivisions in the cork to the rooms that monks inhabited, called cells. About ten years later, Antonie van Leeuwenhoek became the first person to observe living and moving cells under a microscope. In the century that followed, the theory that cells represented the basic unit of life would develop. These tiny fluid-filled sacs house components responsible for the thousands of biochemical reactions necessary for an organism to grow and survive. In this chapter, you will learn about the major components and functions of cells and discover some of the different types of cells in the human body.",True,Other Forms of Membrane Transport,,,,
+1f2fcfa3-d3d8-4bd8-968a-5f6090b951a4,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, they are found throughout the world, in soils and seas, commercial products, and every cell of the human body. The four types most important to human structure and function are: carbohydrates, lipids, proteins, and nucleotides. Before exploring these compounds, you need to first understand the chemistry of carbon.",True,Other Forms of Membrane Transport,,,,
+f4d524b1-550e-47c5-9735-3a8b8b8a7279,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,The Chemistry of Carbon,False,The Chemistry of Carbon,,,,
+fc5a063f-bc4e-418d-8f95-b32042a082db,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"What makes organic compounds ubiquitous is the chemistry of their carbon core. Recall that carbon atoms have four electrons in their valence shell, and that the octet rule dictates that atoms tend to react in such a way as to complete their valence shell with eight electrons. Carbon atoms do not complete their valence shells by donating or accepting four electrons. Instead, they readily share electrons via covalent bonds.",True,The Chemistry of Carbon,,,,
+09a35eed-09ce-4a52-9c85-7fd34d0d47d1,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Normally, carbon atoms share with other carbon atoms, often forming a long carbon chain referred to as a carbon skeleton. When they share, however, they do not share all their electrons exclusively with each other. Rather, carbon atoms tend to share electrons with a variety of other elements, one of which is always hydrogen. Carbon and hydrogen groupings are called hydrocarbons. If you study the figures of organic compounds in the remainder of this chapter, you will see several with chains of hydrocarbons in one region of the compound.",True,The Chemistry of Carbon,,,,
+6ed03df1-ee8a-4850-9446-70c01231639d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Many combinations are possible to fill carbon’s four “vacancies.” Carbon may share electrons with oxygen or nitrogen or other atoms in a particular region of an organic compound. Moreover, the atoms to which carbon atoms bond may also be part of a functional group. A functional group is a group of atoms linked by strong covalent bonds and tend to function in chemical reactions as a single unit. You can think of functional groups as tightly knit “cliques” whose members are unlikely to be parted. Five functional groups are important in human physiology: the hydroxyl, carboxyl, amino, methyl and phosphate groups (Table 2.1).",True,The Chemistry of Carbon,,,,
+e3122472-c7fc-47de-8a09-f0d3678d91e6,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Carbon’s affinity for covalent bonding means that many distinct and relatively stable organic molecules readily form larger, more complex molecules. Any large molecule is referred to as macromolecule (macro- = “large”), and the organic compounds in this section all fit this description. However, some macromolecules are made up of several “copies” of single units called monomer (mono- = “one”; -mer = “part”). Like beads in a long necklace, these monomers link by covalent bonds to form long polymers (poly- = “many”). There are many examples of monomers and polymers among the organic compounds.",True,The Chemistry of Carbon,,,,
+951af231-0bf0-43e1-baa7-7fb0a9a78e69,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Monomers form polymers by engaging in dehydration synthesis (see Figure 2.4.1). As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes; one gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis (-lysis = “rupture”). The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.",True,The Chemistry of Carbon,Figure 2.4.1,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2019/07/213_Dehydration_Synthesis_and_Hydrolysis-01.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water."
+1b2632da-2e90-4d4d-b7c0-65b30d296925,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Carbohydrates,False,Carbohydrates,,,,
+17c59536-c04b-4c8e-af28-db3c97184ca4,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The term carbohydrate means “hydrated carbon.” Recall that the root hydro- indicates water. A carbohydrate is a molecule composed of carbon, hydrogen, and oxygen; in most carbohydrates, hydrogen and oxygen are found in the same two-to-one relative proportions they have in water. In fact, the chemical formula for a “generic” molecule of carbohydrate is (CH2O)n.",True,Carbohydrates,,,,
+6ae00a49-e15e-41a0-8df6-f3f5bef88c1d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Carbohydrates are referred to as saccharides, a word meaning “sugars.” Three forms are important in the body: monosaccharides, disaccharides, and polysaccharides. Monosaccharides are the monomers of carbohydrates. Disaccharides (di- = “two”) are made up of two monomers. Polysaccharides are the polymers, and can consist of hundreds to thousands of monomers.",True,Carbohydrates,,,,
+fe6fe6d4-6da3-4add-af4f-fed3b095be05,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Monosaccharides,False,Monosaccharides,,,,
+4491a0fd-d30a-4b01-9ffc-cf095085bcb2,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A monosaccharide is a monomer of carbohydrates. Five monosaccharides are important in the body. Three of these are the hexose sugars, so called because they each contain six atoms of carbon. These are glucose, fructose, and galactose, shown in Figure 2.5.1a. The remaining monosaccharides are the two pentose sugars, each of which contains five atoms of carbon. They are ribose and deoxyribose, shown in Figure 2.5.1b.",True,Monosaccharides,Figure 2.5.1,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2019/07/217_Five_Important_Monosaccharides-01.jpg,Figure 2.5.1 Five Important Monosaccharides
+6f422199-6ebd-464b-82a7-f509aaea94ce,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Disaccharides,False,Disaccharides,,,,
+a9a6b48d-4d5a-4cad-9392-95a2d19a5c5f,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A disaccharide is a pair of monosaccharides. Disaccharides are formed via dehydration synthesis, and the bond linking them is referred to as a glycosidic bond (glyco- = “sugar”). Three disaccharides (shown in Figure 2.5.2) are important to humans. These are sucrose, commonly referred to as table sugar, lactose, or milk sugar, and maltose, or malt sugar. As you can tell from their common names, you consume these in your diet, however, your body cannot use them directly. Instead, in the digestive tract, they are split into their component monosaccharides via hydrolysis.",True,Disaccharides,Figure 2.5.2,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/218_Three_Important_Disaccharides-01.jpg,Figure 2.5.2 – Three Important Disaccharides: All three important disaccharides form by dehydration synthesis.
+400268ec-9426-44c4-8001-e67340d8200a,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Polysaccharides,False,Polysaccharides,,,,
+c9e4dfed-3e32-491f-8364-7168e408c258,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Polysaccharides can contain a few to a thousand or more monosaccharides. Three are important to the body (Figure 2.5.3):,True,Polysaccharides,Figure 2.5.3,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/219_Three_Important_Polysaccharides-01.jpg,"Figure 2.5.3 – Three Important Polysaccharides: Three important polysaccharides are starches, glycogen, and fiber."
+7ab96ff3-3de3-4ff8-b18f-7f24e17109b9,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Starches are polymers of glucose. They occur in long chains called amylose or branched chains called amylopectin, both of which are stored in plant-based foods and are relatively easy to digest.",True,Polysaccharides,,,,
+5f4dd29c-8b59-4e16-abce-8aaa149e20d6,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Glycogen is also a polymer of glucose, but it is stored in the tissues of animals, especially in the muscles and liver. It is not considered a dietary carbohydrate because very little glycogen remains in animal tissues after slaughter, however, the human body stores excess glucose as glycogen, again, in the muscles and liver.",True,Polysaccharides,,,,
+4db57601-0ea9-4b15-8900-6e5e3ce0489a,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Cellulose, a polysaccharide that is the primary component of the cell wall of green plants, is the component of plant food referred to as “fiber”. In humans, cellulose/fiber is not digestible, however, dietary fiber has many health benefits. It helps you feel full so you eat less, it promotes a healthy digestive tract, and a diet high in fiber is thought to reduce the risk of heart disease and possibly some forms of cancer.",True,Polysaccharides,,,,
+6840400f-4731-4faa-b322-69e0a0b001d7,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Functions of Carbohydrates,False,Functions of Carbohydrates,,,,
+dea7428c-24b7-49f1-94a3-699c08df71f9,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The body obtains carbohydrates from plant-based foods. Grains, fruits, and legumes and other vegetables provide most of the carbohydrate in the human diet, although lactose is found in dairy products.",True,Functions of Carbohydrates,,,,
+d73948fc-008f-4ba0-af9f-117366d8a47e,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Although most body cells can break down other organic compounds for fuel, all body cells can use glucose. Moreover, nerve cells (neurons) in the brain, spinal cord, and through the peripheral nervous system, as well as red blood cells, can only use glucose for fuel. In the breakdown of glucose for energy, molecules of adenosine triphosphate, better known as ATP, are produced. Adenosine triphosphate (ATP) is composed of a ribose sugar, an adenine base, and three phosphate groups. ATP releases free energy when its phosphate bonds are broken, and thus supplies ready energy to the cell. More ATP is produced in the presence of oxygen (O2) than in pathways that do not use oxygen. The overall reaction for the conversion of the energy in glucose to energy stored in ATP can be written:",True,Functions of Carbohydrates,,,,
+6cb28ba2-395d-4b82-bb7c-7a0651b9b8e6,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP,True,Functions of Carbohydrates,,,,
+521008fa-f18f-4ba8-a741-94762873701d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"In addition to being a critical fuel source, carbohydrates are present in very small amounts in cells’ structure. For instance, some carbohydrate molecules bind with proteins to produce glycoproteins, and others combine with lipids to produce glycolipids, both of which are found in the membrane that encloses the contents of body cells.",True,Functions of Carbohydrates,,,,
+669cda8d-7752-4aa1-8b9e-e716914e06e1,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Lipids,False,Lipids,,,,
+b4618bb0-15f7-4411-be14-02e4b6fefca3,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A lipid is one of a highly diverse group of compounds made up mostly of hydrocarbons. The few oxygen atoms they contain are often at the periphery of the molecule. Their nonpolar hydrocarbons make all lipids hydrophobic. In water, lipids do not form a true solution, but they may form an emulsion, which is the term for a mixture of solutions that do not mix well.",True,Lipids,,,,
+93f97636-5c46-4d66-932d-940a1eb64c79,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Triglycerides,False,Triglycerides,,,,
+fdc882c6-15b6-441d-bf89-a7f1195a0648,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules (Figure 2.5.4):",True,Triglycerides,Figure 2.5.4,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/220_Triglycerides-01.jpg,"Figure 2.5.4 – Triglycerides: Triglycerides are composed of glycerol attached to three fatty acids via dehydration synthesis. Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group"
+210c3746-1f6a-4819-9e14-9faa2da74eab,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A glycerol backbone at the core of triglycerides, consisting of three carbon atoms.",True,Triglycerides,,,,
+7b8b6278-54d4-4856-88b4-2c5cc7fea360,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Three fatty acids, long chains of hydrocarbons with a carboxyl group and a methyl group at opposite ends, extending from each of the carbons of the glycerol.",True,Triglycerides,,,,
+54455327-3649-4d92-9053-3adad1b34280,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Triglycerides form via dehydration synthesis. Glycerol gives up hydrogen atoms from its hydroxyl groups at each bond, and the carboxyl group on each fatty acid chain gives up a hydroxyl group. A total of three water molecules are thereby released.",True,Triglycerides,,,,
+065d0793-3af0-4927-8213-834fa7b18fab,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature (Figure 2.5.5a). Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond (Figure 2.5.5b). These monounsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature. Polyunsaturated fatty acids contain two or more double carbon bonds, and are also liquid at room temperature. Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.",True,Triglycerides,Figure 2.5.5,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/221_Fatty_Acids_Shapes-01.jpg,Figure 2.5.5 – Fatty Acid Shapes: The level of saturation of a fatty acid affects its shape. (a) Saturated fatty acid chains are straight. (b) Unsaturated fatty acid chains are kinked.
+4dfcae0c-6409-4680-b0c3-1352e9dbb65b,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Whereas a diet high in saturated fatty acids increases the risk of heart disease, a diet high in unsaturated fatty acids is thought to reduce the risk. This is especially true for the omega-3 unsaturated fatty acids found in cold-water fish such as salmon. These fatty acids have their first double carbon bond at the third hydrocarbon from the methyl group (referred to as the omega end of the molecule).",True,Triglycerides,,,,
+7783ce3b-123c-49b0-9d10-b843749e3c6b,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Finally, trans fatty acids found in some processed foods, including some stick and tub margarines, are thought to be even more harmful to the heart and blood vessels than saturated fatty acids. Trans fats are created from unsaturated fatty acids (such as corn oil) when chemically treated to produce partially hydrogenated fats.",True,Triglycerides,,,,
+3c7ef0ca-fe0f-4899-9ad9-96579861abad,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"As a group, triglycerides are a major fuel source for the body. When you are resting or asleep, a majority of the energy used to keep you alive is derived from triglycerides stored in your fat (adipose) tissues. Triglycerides also fuel long, slow physical activity such as gardening or hiking, and contribute a modest percentage of energy for vigorous physical activity. Dietary fat also assists the absorption and transport of the nonpolar fat-soluble vitamins A, D, E, and K. Additionally, stored body fat protects and cushions the body’s bones and internal organs, and acts as insulation to retain body heat.",True,Triglycerides,,,,
+74f2c532-4c71-425e-8213-034f34ebdf0d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Fatty acids are also components of glycolipids, which are sugar-fat compounds found in the cell membrane. Lipoproteins are compounds in which the hydrophobic triglycerides are packaged in protein envelopes for transport in body fluids.",True,Triglycerides,,,,
+3f358bd9-7bb9-4674-bd57-6171686967cb,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Phospholipids,False,Phospholipids,,,,
+4150323d-609d-44c8-8054-84c055da3806,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.5.6). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, hydrophilic heads, the charged phosphate groups, and nitrogen atom.",True,Phospholipids,Figure 2.5.6,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+bd279195-1eb1-411c-9651-f212223e6028,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Steroids,False,Steroids,,,,
+5a32ea19-6365-4ae9-abfe-d14dfe77e24a,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"A steroid compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules (see Figure 2.5.6b). Although both plants and animals synthesize sterols, the type that makes the most important contribution to human structure and function is cholesterol, which is synthesized by the liver in humans and animals and is also present in most animal-based foods. Like other lipids, cholesterol’s hydrocarbons make it hydrophobic, however, it has a polar hydroxyl head that is hydrophilic. Cholesterol is an important component of bile acids and compounds that help emulsify dietary fats. In fact, the word’s root chole- refers to bile. Cholesterol is also a building block of many hormones, signaling molecules that the body releases to regulate processes at distant sites. Finally, like phospholipids, cholesterol molecules are found in the cell membrane, where their hydrophobic and hydrophilic regions help regulate the flow of substances into and out of the cell.",True,Steroids,Figure 2.5.6,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+c67c2917-44bf-44ed-8405-c95a51309fef,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Prostaglandins,False,Prostaglandins,,,,
+53207311-0e77-4c45-9423-9a492db4d88b,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Like a hormone, a prostaglandin is one of a group of signaling molecules, but prostaglandins are derived from unsaturated fatty acids (see Figure 2.5.6c). One reason that the omega-3 fatty acids found in fish are beneficial is that they stimulate the production of certain prostaglandins that help regulate aspects of blood pressure and inflammation, and thereby reduce the risk for heart disease. Prostaglandins also sensitize nerves to pain. One class of pain-relieving medications called nonsteroidal anti-inflammatory drugs (NSAIDs) works by reducing the effects of prostaglandins.",True,Prostaglandins,Figure 2.5.6,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+4bdb25e4-7c6b-4ac1-bb5d-afa9e925de3d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Proteins,False,Proteins,,,,
+71bd6cf0-40b0-4b45-af3b-852b6c8729dc,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"You might associate proteins with muscle tissue, but in fact, proteins are critical components of all tissues and organs. A protein is an organic molecule composed of amino acids linked by peptide bonds. Proteins include the keratin in the epidermis of skin that protects underlying tissues, and the collagen found in the dermis of skin, in bones, and in the meninges that cover the brain and spinal cord. Proteins are also components of many of the body’s functional chemicals, including digestive enzymes in the digestive tract, antibodies, the neurotransmitters that neurons use to communicate with other cells, and the peptide-based hormones that regulate certain body functions (for instance, growth hormone). While carbohydrates and lipids are composed of hydrocarbons and oxygen, all proteins also contain nitrogen (N), and many contain sulfur (S), in addition to carbon, hydrogen, and oxygen.",True,Proteins,,,,
+75f20f29-ebe3-4403-97a1-ccfe5472d543,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Microstructure of Proteins,False,Microstructure of Proteins,,,,
+0d03df70-341c-418b-b4a4-f10b792c69c5,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Proteins are polymers made up of nitrogen-containing monomers called amino acids. An amino acid is a molecule composed of an amino group and a carboxyl group, together with a variable side chain. Just 20 different amino acids contribute to nearly all of the thousands of different proteins important in human structure and function. Body proteins contain a unique combination of a few dozen to a few hundred of these 20 amino acid monomers. All 20 of these amino acids share a similar structure (Figure 2.5.7). All consist of a central carbon atom to which the following are bonded:",True,Microstructure of Proteins,Figure 2.5.7,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/223_Structure_of_an_Amino_Acid-01.jpg,Figure 2.5.7 Structure of an Amino Acid
+a2357771-9f42-4037-a2fc-58b1667b17bd,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,a hydrogen atom,False,a hydrogen atom,,,,
+b32d4c27-8d39-4249-a4cc-c79654306732,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,an alkaline (basic) amino group NH2 (see Table 2.1),True,a hydrogen atom,,,,
+5c2ec10f-5786-4129-89d8-81a631787ac3,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,an acidic carboxyl group COOH (see Table 2.1),True,a hydrogen atom,,,,
+e7d47791-ae27-4e64-bf37-c7deb428f892,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,a variable group,False,a variable group,,,,
+f47b1a51-f876-499b-ba84-2010086bd4c3,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Notice that all amino acids contain both an acid (the carboxyl group) and a base (the amino group) (amine = “nitrogen-containing”). For this reason, they make excellent buffers, helping the body regulate acid–base balance. What distinguishes the 20 amino acids from one another is their variable group, which is referred to as a side chain or an R-group. This group can vary in size and can be polar or nonpolar, giving each amino acid its unique characteristics. For example, the side chains of two amino acids—cysteine and methionine—contain sulfur. Sulfur does not readily participate in hydrogen bonds, whereas all other amino acids do. This variation influences the way that proteins containing cysteine and methionine are assembled.",True,a variable group,,,,
+60a56828-d2fc-41e6-9057-f4f451d6c330,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Amino acids join via dehydration synthesis to form protein polymers (Figure 2.5.8). The unique bond holding amino acids together is called a peptide bond. A peptide bond is a covalent bond between two amino acids that is formed by dehydration synthesis. A peptide, in fact, is a very short chain of amino acids. Strands containing fewer than about 100 amino acids are generally referred to as polypeptides rather than proteins.",True,a variable group,Figure 2.5.8,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/224_Peptide_Bond-01.jpg,"Figure 2.5.8 – Structure of an Amino Acid: Different amino acids join together to form peptides, polypeptides, or proteins via dehydration synthesis. The bonds between the amino acids are peptide bonds."
+c5d78337-10f4-4fa6-b4bd-cdce8773c17f,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The body is able to synthesize most of the amino acids from components of other molecules, however, nine cannot be synthesized and have to be consumed in the diet. These are known as the essential amino acids.",True,a variable group,,,,
+67256027-f88c-4971-9e39-5d9113181b0c,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Free amino acids available for protein construction are said to reside in the amino acid pool within cells. Structures within cells use these amino acids when assembling proteins. If a particular essential amino acid is not available in sufficient quantities in the amino acid pool, however, synthesis of proteins containing it can slow or even cease.",True,a variable group,,,,
+7cca7cfc-1c8d-41c1-b5ee-fc315774f067,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Shape of Proteins,False,Shape of Proteins,,,,
+6ff9dd51-dc58-442f-9733-b0d70ef11f16,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Just as a fork cannot be used to eat soup and a spoon cannot be used to spear meat, a protein’s shape is essential to its function. A protein’s shape is determined, most fundamentally, by the sequence of amino acids of which it is made (Figure 2.5.9a). The sequence is called the primary structure of the protein.",True,Shape of Proteins,Figure 2.5.9,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+a6b2257e-652f-4f8b-ad26-fa67f9fd8a47,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Although some polypeptides exist as linear chains, most are twisted or folded into more complex secondary structures that form when bonding occurs between amino acids with different properties at different regions of the polypeptide. The most common secondary structure is a spiral called an alpha-helix. If you were to take a length of string and simply twist it into a spiral, it would not hold the shape. Similarly, a strand of amino acids could not maintain a stable spiral shape without the help of hydrogen bonds, which create bridges between different regions of the same strand (see Figure 2.5.9b). Less commonly, a polypeptide chain can form a beta-pleated sheet, in which hydrogen bonds form bridges between different regions of a single polypeptide that has folded back upon itself, or between two or more adjacent polypeptide chains.",True,Shape of Proteins,Figure 2.5.9,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+49d95bf9-a593-4abb-8eaa-dcf14d40f45b,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The secondary structure of proteins further folds into a compact three-dimensional shape, referred to as the protein’s tertiary structure (see Figure 2.5.9c). In this configuration, amino acids that had been very distant in the primary chain can be brought quite close via hydrogen bonds or, in proteins containing cysteine, via disulfide bonds. A disulfide bond is a covalent bond between sulfur atoms in a polypeptide. Often, two or more separate polypeptides bond to form an even larger protein with a quaternary structure (see Figure 2.5.9d). The polypeptide subunits forming a quaternary structure can be identical or different. For instance, hemoglobin, the protein found in red blood cells is composed of four tertiary polypeptides, two of which are called alpha chains and two of which are called beta chains.",True,Shape of Proteins,Figure 2.5.9,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+19a14adc-aefa-4d27-b69e-86157a553e3c,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"When they are exposed to extreme heat, acids, bases, and certain other substances, proteins will denature. Denaturation is a change in the structure of a molecule through physical or chemical means. Denatured proteins lose their functional shape and are no longer able to carry out their jobs. An everyday example of protein denaturation is the curdling of milk when acidic lemon juice is added.",True,Shape of Proteins,,,,
+db63b94c-14c9-4878-84bf-90b6a6136634,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The contribution of the shape of a protein to its function can hardly be exaggerated. For example, the long, slender shape of protein strands that make up muscle tissue is essential to their ability to contract (shorten) and relax (lengthen). As another example, bones contain long threads of a protein called collagen that acts as scaffolding upon which bone minerals are deposited. These elongated proteins, called fibrous proteins, are strong and durable and typically hydrophobic.",True,Shape of Proteins,,,,
+e8b29d4d-0b3c-41e3-a07b-d6034cef26f7,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"In contrast, globular proteins are globes or spheres that tend to be highly reactive and are hydrophilic. The hemoglobin proteins packed into red blood cells are an example (see Figure 2.59d), however, globular proteins are abundant throughout the body, playing critical roles in most body functions. Enzymes, introduced earlier as protein catalysts, are examples of this. The next section takes a closer look at the action of enzymes.",True,Shape of Proteins,,,,
+58855bbe-225a-45b4-b032-ceed7121d7aa,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Proteins Function as Enzymes,False,Proteins Function as Enzymes,,,,
+cae76b48-5c1f-448d-beaf-4e5deeb983d4,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"If you were trying to type a paper, and every time you hit a key on your laptop there was a delay of six or seven minutes before you got a response, you would probably get a new laptop. In a similar way, without enzymes to catalyze chemical reactions, the human body would be nonfunctional. It functions only because enzymes function.",True,Proteins Function as Enzymes,,,,
+e66aa9fa-6f79-4488-aa65-37b26cf45f15,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Enzymatic reactions—chemical reactions catalyzed by enzymes—begin when substrates bind to the enzyme. A substrate is a reactant in an enzymatic reaction. This occurs on regions of the enzyme known as active sites (Figure 2.5.10). Any given enzyme catalyzes just one type of chemical reaction. This characteristic, called specificity, is due to the fact that a substrate with a particular shape and electrical charge can bind only to an active site corresponding to that substrate.",True,Proteins Function as Enzymes,Figure 2.5.10,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/227_Steps_in_an_Enzymatic_Reaction-01.jpg,"Figure 2.5.10 – Steps in an Enzymatic Reaction: (a) Substrates approach active sites on enzyme. (b) Substrates bind to active sites, producing an enzyme–substrate complex. (c) Changes internal to the enzyme–substrate complex facilitate interaction of the substrates. (d) Products are released and the enzyme returns to its original form, ready to facilitate another enzymatic reaction."
+53245d61-7aa2-463a-bde6-8bcb448c7396,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Binding of a substrate produces an enzyme–substrate complex. It is likely that enzymes speed up chemical reactions in part because the enzyme–substrate complex undergoes a set of temporary and reversible changes that cause the substrates to be oriented toward each other in an optimal position to facilitate their interaction. This promotes increased reaction speed. The enzyme then releases the product(s), and resumes its original shape. The enzyme is then free to engage in the process again, and will do so as long as substrate remains.",True,Proteins Function as Enzymes,,,,
+c379c821-730e-45cd-9205-ab27c10a699c,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Other Functions of Proteins,False,Other Functions of Proteins,,,,
+d2b6f850-d5e2-41ea-ba20-aa3f6b435fe5,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Advertisements for protein bars, powders, and shakes all say that protein is important in building, repairing, and maintaining muscle tissue, but the truth is that proteins contribute to all body tissues, from the skin to the brain cells. Also, certain proteins act as hormones and chemical messengers that help regulate body functions. For example, growth hormone is important for skeletal growth, among other roles.",True,Other Functions of Proteins,,,,
+eec7291f-06db-4120-9ba1-ea2984f8d13e,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"As was noted earlier, the basic and acidic components enable proteins to function as buffers in maintaining acid–base balance, but they also help regulate fluid–electrolyte balance. Proteins attract fluid, and a healthy concentration of proteins in the blood, the cells, and the spaces between cells helps ensure a balance of fluids in these various “compartments.” Moreover, proteins in the cell membrane help to transport electrolytes in and out of the cell, keeping these ions in a healthy balance. Like lipids, proteins can bind with carbohydrates. They can thereby produce glycoproteins or proteoglycans, both of which have many functions in the body.",True,Other Functions of Proteins,,,,
+5882250e-73b6-461e-9052-d3d1225ea408,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The body can use proteins for energy when carbohydrate and fat intake is inadequate, and stores of glycogen and adipose tissue become depleted. However, since there is no storage site for protein except functional tissues, using protein for energy causes tissue breakdown and results in body wasting.",True,Other Functions of Proteins,,,,
+00946b57-cb10-4d99-9570-20c7f131d780,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Nucleotides,False,Nucleotides,,,,
+e8679e48-9085-49e6-9eca-1db05ff4e0dd,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,The fourth type of organic compound important to human structure and function are the nucleotides (Figure 2.5.11). A nucleotide is one of a class of organic compounds composed of three subunits:,True,Nucleotides,Figure 2.5.11,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/228_Nucleotides-01.jpg,"Figure 2.5.11 – Nucleotides: (a) The building blocks of all nucleotides are one or more phosphate groups, a pentose sugar, and a nitrogen-containing base. (b) The nitrogen-containing bases of nucleotides. (c) The two pentose sugars of DNA and RNA."
+6a8b2b20-6092-4b11-9bbe-b22964bcd0ab,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,one or more phosphate groups,False,one or more phosphate groups,,,,
+7cf7fc5f-3262-4a2a-bfab-837fc0071c06,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,a pentose sugar: either deoxyribose or ribose,False,a pentose sugar: either deoxyribose or ribose,,,,
+b4b036f6-c5cf-420d-b228-b098204715aa,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"a nitrogen-containing base: adenine, cytosine, guanine, thymine, or uracil",False,"a nitrogen-containing base: adenine, cytosine, guanine, thymine, or uracil",,,,
+6f007f1f-3570-46d1-82e4-7bdad561189d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Nucleotides can be assembled into nucleic acids (DNA or RNA) or the energy compound adenosine triphosphate.,True,"a nitrogen-containing base: adenine, cytosine, guanine, thymine, or uracil",,,,
+a595cf9e-e271-4a4c-a49e-ecf091efcbcd,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Nucleic Acids,False,Nucleic Acids,,,,
+86d5af2c-e999-4f55-9eaf-cbac2aa5ed32,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The nucleic acids differ in their type of pentose sugar. Deoxyribonucleic acid (DNA) is nucleotide that stores genetic information. DNA contains deoxyribose (so-called because it has one less atom of oxygen than ribose) plus one phosphate group and one nitrogen-containing base. The “choices” of base for DNA are adenine, cytosine, guanine, and thymine. Ribonucleic acid (RNA) is a ribose-containing nucleotide that helps manifest the genetic code as protein. RNA contains ribose, one phosphate group, and one nitrogen-containing base, but the “choices” of base for RNA are adenine, cytosine, guanine, and uracil.",True,Nucleic Acids,,,,
+1b940302-508f-478f-8537-e166e082f921,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The nitrogen-containing bases adenine and guanine are classified as purines. A purine is a nitrogen-containing molecule with a double ring structure, which accommodates several nitrogen atoms. The bases cytosine, thymine (found in DNA only) and uracil (found in RNA only) are pyramidines. A pyramidine is a nitrogen-containing base with a single ring structure",True,Nucleic Acids,,,,
+188b388b-b317-4e7c-ba5a-d4d448d8493e,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Bonds formed by dehydration synthesis between the pentose sugar of one nucleic acid monomer and the phosphate group of another form a “backbone,” from which the components’ nitrogen-containing bases protrude. In DNA, two such backbones attach at their protruding bases via hydrogen bonds. These twist to form a shape known as a double helix (Figure 2.5.12). The sequence of nitrogen-containing bases within a strand of DNA form the genes that act as a molecular code instructing cells in the assembly of amino acids into proteins. Humans have almost 22,000 genes in their DNA, locked up in the 46 chromosomes inside the nucleus of each cell (except red blood cells which lose their nuclei during development). These genes carry the genetic code to build one’s body, and are unique for each individual except identical twins.",True,Nucleic Acids,Figure 2.5.12,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/229_Nucleotides-01.jpg,"Figure 2.5.12 – DNA: In the DNA double helix, two strands attach via hydrogen bonds between the bases of the component nucleotides."
+2f4223d6-3ca8-4efc-921c-1d3395091f84,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"In contrast, RNA consists of a single strand of sugar-phosphate backbone studded with bases. Messenger RNA (mRNA) is created during protein synthesis to carry the genetic instructions from the DNA to the cell’s protein manufacturing plants in the cytoplasm and the ribosomes.",True,Nucleic Acids,,,,
+82c3fdaf-2f38-4498-8f71-f3d6b124827e,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,Adenosine Triphosphate,False,Adenosine Triphosphate,,,,
+90acbf4c-5532-4d92-a565-669c28a871b8,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"The nucleotide adenosine triphosphate (ATP), is composed of a ribose sugar, an adenine base, and three phosphate groups (Figure 2.5.13). ATP is classified as a high energy compound because the two covalent bonds linking its three phosphates store a significant amount of potential energy. In the body, the energy released from these high energy bonds helps fuel the body’s activities, from muscle contraction to the transport of substances in and out of cells to anabolic chemical reactions.",True,Adenosine Triphosphate,Figure 2.5.13,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/230_Structure_of_Adenosine_Triphosphate_ATP-01.jpg,Figure 2.5.13 Structure of Adenosine Triphosphate (ATP)
+996b427b-145f-45f2-9d32-398d765e7d9d,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"When a phosphate group is cleaved from ATP, the products are adenosine diphosphate (ADP) and inorganic phosphate (Pi). This hydrolysis reaction can be written:",True,Adenosine Triphosphate,,,,
+32566f2f-ba62-4b8d-8486-bc6143b3cda2,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,ATP + H2O → ADP + Pi + energy,False,ATP + H2O → ADP + Pi + energy,,,,
+6e1e97a8-806c-4737-a981-0e5ea3b463d4,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Removal of a second phosphate leaves adenosine monophosphate (AMP) and two phosphate groups. Again, these reactions also liberate the energy that had been stored in the phosphate-phosphate bonds. They are reversible, too, as when ADP undergoes phosphorylation. Phosphorylation is the addition of a phosphate group to an organic compound, in this case, resulting in ATP. In such cases, the same level of energy that had been released during hydrolysis must be reinvested to power dehydration synthesis.",True,ATP + H2O → ADP + Pi + energy,,,,
+06d8f5b2-71fd-4076-ab0e-8dc83580c509,https://open.oregonstate.education/aandp/,2.5 Organic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-5-organic-compounds-essential-to-human-functioning/,"Cells can also transfer a phosphate group from ATP to another organic compound. For example, when glucose first enters a cell, a phosphate group is transferred from ATP, forming glucose phosphate (C6H12O6—P) and ADP. Once glucose is phosphorylated in this way, it can be stored as glycogen or metabolized for immediate energy.",True,ATP + H2O → ADP + Pi + energy,,,,
+34c0c53c-fb0d-44ad-ae17-a1d627067046,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"The concepts you have learned so far in this chapter govern all forms of matter, and would work as a foundation for geology as well as biology. This section of the chapter narrows the focus to the chemistry of human life; that is, the compounds important for the body’s structure and function. In general, these compounds are either inorganic or organic.",True,ATP + H2O → ADP + Pi + energy,,,,
+8a335909-0e85-46f1-9843-fceda8bb0189,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"An inorganic compound is a substance that does not contain both carbon and hydrogen. A great many inorganic compounds do contain hydrogen atoms, such as water (H2O) and the hydrochloric acid (HCl) produced by your stomach. In contrast, only a handful of inorganic compounds contain carbon atoms. Carbon dioxide (CO2) is one of the few examples.",True,ATP + H2O → ADP + Pi + energy,,,,
+e2d6f641-58ed-4582-a1b9-a947d64d7cfb,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"An organic compound is a substance that contains both carbon and hydrogen. Organic compounds are synthesized via covalent bonds within living organisms, including the human body. Recall that carbon and hydrogen are the second and third most abundant elements in your body. You will soon discover how these two elements combine in the foods you eat, in the compounds that make up your body structure, and in the chemicals that fuel your functioning.",True,ATP + H2O → ADP + Pi + energy,,,,
+94db92a9-ac54-40fd-aedc-461c54d8c088,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"The following section examines the four groups of inorganic compounds essential to life: water, salts, acids, and bases. Organic compounds are covered later in the chapter.",True,ATP + H2O → ADP + Pi + energy,,,,
+6a9efcc9-5c4d-40de-b3ee-05578403546e,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Water,False,Water,,,,
+cda8d0a4-99ff-486d-9f8b-25840100c7e6,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,As much as 70 percent of an adult’s body weight is water. This water is contained both within the cells and between the cells that make up tissues and organs. Its several roles make water indispensable to human functioning.,True,Water,,,,
+a24d55d9-b839-4247-9769-41f6e7c76d9c,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Water as a Lubricant and Cushion,False,Water as a Lubricant and Cushion,,,,
+0b8b7045-9cef-429b-9322-f7a45feb681e,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Water is a major component of many of the body’s lubricating fluids. Just as oil lubricates the hinge on a door, water in synovial fluid lubricates the actions of body joints, and water in pleural fluid helps the lungs expand and recoil with breathing. Watery fluids help keep food flowing through the digestive tract, and ensure that the movement of adjacent abdominal organs is friction free.",True,Water as a Lubricant and Cushion,,,,
+5215050e-4732-4585-bd5e-368886af11a2,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Water also protects cells and organs from physical trauma, cushioning the brain within the skull, for example, and protecting the delicate nerve tissue of the eyes. Water cushions a developing fetus in the mother’s womb as well.",True,Water as a Lubricant and Cushion,,,,
+ff9af189-0adb-44d7-a311-1583942c1cf6,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Water as a Heat Sink,False,Water as a Heat Sink,,,,
+40855d98-67c0-4c30-87ca-3ef3027f8bed,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A heat sink is a substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature. In the body, water absorbs the heat generated by chemical reactions without greatly increasing in temperature. Moreover, when the environmental temperature soars, the water stored in the body helps keep the body cool. This cooling effect happens as warm blood from the body’s core flows to the blood vessels just under the skin and is transferred to the environment. At the same time, sweat glands release warm water in sweat. As the water evaporates into the air, it carries away heat, and then the cooler blood from the periphery circulates back to the body core.",True,Water as a Heat Sink,,,,
+8cacf650-ff6e-4600-810f-0d482c43545b,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Water as a Component of Liquid Mixtures,False,Water as a Component of Liquid Mixtures,,,,
+f09b5660-f8e3-4212-8646-c4ed8d445b38,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A mixture is a combination of two or more substances, each of which maintains its own chemical identity. In other words, the constituent substances are not chemically bonded into a new, larger chemical compound. The concept is easy to imagine if you think of powdery substances such as flour and sugar; when you stir them together in a bowl, they obviously do not bond to form a new compound. The room air you breathe is a gaseous mixture, containing three discrete elements—nitrogen, oxygen, and argon—and one compound, carbon dioxide. There are three types of liquid mixtures, all of which contain water as a key component; these are solutions, colloids, and suspensions.",True,Water as a Component of Liquid Mixtures,,,,
+62a99cc0-9b18-4b52-b682-8c77125ee970,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"For cells in the body to survive, they must be kept moist in a water-based liquid called a solution. In chemistry, a liquid solution consists of a solvent that dissolves a substance called a solute. An important characteristic of solutions is that they are homogeneous; that is, the solute molecules are distributed evenly throughout the solution. If you were to stir a teaspoon of sugar into a glass of water, the sugar would dissolve into sugar molecules separated by water molecules. The ratio of sugar to water in the left side of the glass would be the same as the ratio of sugar to water in the right side of the glass. If you were to add more sugar, the ratio of sugar to water would change, but the distribution—provided you had stirred well—would still be even.",True,Water as a Component of Liquid Mixtures,,,,
+3aa05a88-10b4-4630-b4b1-856c854cc15e,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Water is considered the “universal solvent” and it is believed that life cannot exist without water because of this. Water is certainly the most abundant solvent in the body; essentially all of the body’s chemical reactions occur among compounds dissolved in water. Since water molecules are polar, with regions of positive and negative electrical charge, water readily dissolves ionic compounds and polar covalent compounds. Such compounds are referred to as hydrophilic, or “water-loving.” As mentioned above, sugar dissolves well in water. This is because sugar molecules contain regions of hydrogen-oxygen polar bonds, making it hydrophilic. Nonpolar molecules, which do not readily dissolve in water, are called hydrophobic, or “water-fearing.”",True,Water as a Component of Liquid Mixtures,,,,
+e4d4c2ac-ef91-4f61-832f-3dfd4e02d8da,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Concentrations of Solutes,False,Concentrations of Solutes,,,,
+f0514f52-3efb-49e0-800e-d55cd8de74c2,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Various mixtures of solutes and water are described in chemistry. The concentration of a given solute is the number of particles of that solute in a given space (oxygen makes up about 21 percent of atmospheric air). In the bloodstream of humans, glucose concentration is usually measured in milligram (mg) per deciliter (dL), and in a healthy adult averages about 100 mg/dL. Another method of measuring the concentration of a solute is by its molarilty—which is moles (M) of the molecules per liter (L). The mole of an element is its atomic weight, while a mole of a compound is the sum of the atomic weights of its components, called the molecular weight. An often-used example is calculating a mole of glucose, with the chemical formula C6H12O6. Using the periodic table, the atomic weight of carbon (C) is 12.011 grams (g), and there are six carbons in glucose, for a total atomic weight of 72.066 g. Doing the same calculations for hydrogen (H) and oxygen (O), the molecular weight equals 180.156g (the “gram molecular weight” of glucose). When water is added to make one liter of solution, you have one mole (1M) of glucose. This is particularly useful in chemistry because of the relationship of moles to “Avogadro’s number.” A mole of any solution has the same number of particles in it: 6.02 × 1023. Many substances in the bloodstream and other tissue of the body are measured in thousandths of a mole, or millimoles (mM).",True,Concentrations of Solutes,,,,
+183eec7a-2e3a-46c9-b23a-44ea43aaef2e,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A colloid is a mixture that is somewhat like a heavy solution. The solute particles consist of tiny clumps of molecules large enough to make the liquid mixture opaque (because the particles are large enough to scatter light). Familiar examples of colloids are milk and cream. In the thyroid glands, the thyroid hormone is stored as a thick protein mixture also called a colloid.",True,Concentrations of Solutes,,,,
+af01a5aa-cc4e-4786-8c95-f23bd9cef908,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A suspension is a liquid mixture in which a heavier substance is suspended temporarily in a liquid, but over time, settles out. This separation of particles from a suspension is called sedimentation. An example of sedimentation occurs in the blood test that establishes sedimentation rate, or sed rate. The test measures how quickly red blood cells in a test tube settle out of the watery portion of blood (known as plasma) over a set period of time. Rapid sedimentation of blood cells does not normally happen in the healthy body, but aspects of certain diseases can cause blood cells to clump together, and these heavy clumps of blood cells settle to the bottom of the test tube more quickly than do normal blood cells.",True,Concentrations of Solutes,,,,
+cc738192-5012-46bf-81de-cd1b8a498185,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,The Role of Water in Chemical Reactions,False,The Role of Water in Chemical Reactions,,,,
+aca7be7c-fbcb-4981-81fd-759a06d72906,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Two types of chemical reactions involve the creation or the consumption of water: dehydration synthesis and hydrolysis.,True,The Role of Water in Chemical Reactions,,,,
+2758d534-6987-4f43-8a10-66caa2ae9490,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"In dehydration synthesis, one reactant gives up an atom of hydrogen and another reactant gives up a hydroxyl group (OH) in the synthesis of a new product. In the formation of their covalent bond, a molecule of water is released as a byproduct (Figure 2.4.1). This is also sometimes referred to as a condensation reaction.",True,The Role of Water in Chemical Reactions,Figure 2.4.1,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2019/07/213_Dehydration_Synthesis_and_Hydrolysis-01.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water."
+f22bc758-65c8-4b37-b0d1-5a694e5ad5de,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"In hydrolysis, a molecule of water disrupts a compound, breaking its bonds. The water is itself split into H and OH. One portion of the severed compound then bonds with the hydrogen atom, and the other portion bonds with the hydroxyl group.",True,The Role of Water in Chemical Reactions,,,,
+d3b0e853-7013-4a41-afca-0efb311a8e2b,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"These reactions are reversible, and play an important role in the chemistry of organic compounds (which will be discussed shortly).",True,The Role of Water in Chemical Reactions,,,,
+b9c0d82d-999d-453a-8268-219458ffcd34,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Salts,False,Salts,,,,
+b2a29369-c0da-4161-bb7e-7a913aaa96f0,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Recall that salts are formed when ions form ionic bonds. In these reactions, one atom gives up one or more electrons, and thus becomes positively charged, whereas the other accepts one or more electrons and becomes negatively charged. You can now define a salt as a substance that, when dissolved in water, dissociates into ions other than H+ or OH–. This fact is important in distinguishing salts from acids and bases, discussed next.",True,Salts,,,,
+f7fb7745-0953-409b-9e99-c237f7d13b83,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A typical salt, NaCl, dissociates completely in water (Figure 2.4.2). The positive and negative regions on the water molecule (the hydrogen and oxygen ends respectively) attract the negative chloride and positive sodium ions, pulling them away from each other. Again, whereas nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions. These ions are electrolytes; they are capable of conducting an electrical current in solution. This property is critical to the function of ions in transmitting nerve impulses and prompting muscle contraction.",True,Salts,Figure 2.4.2,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/214_Dissociation_of_Sodium_Chloride_in_Water-01.jpg,"Figure 2.4.2 – Dissociation of Sodium Chloride in Water: Notice that the crystals of sodium chloride dissociate not into molecules of NaCl, but into Na+ cations and Cl– anions, each completely surrounded by water molecules."
+eb33d0c1-c616-4213-aea7-659502c53aac,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Many other salts are important in the body. For example, bile salts produced by the liver help break apart dietary fats, and calcium phosphate salts form the mineral portion of teeth and bones.",True,Salts,,,,
+0abce694-eecb-4a3b-93c6-99f7ba1fe5bf,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Acids and Bases,False,Acids and Bases,,,,
+c2f26743-cecf-42cd-9e09-6ef1184b4297,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Acids and bases, like salts, dissociate in water into electrolytes. Acids and bases can very much change the properties of the solutions in which they are dissolved.",True,Acids and Bases,,,,
+488740ec-1c6b-419e-bb41-c31b8c57d57c,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Acids,False,Acids,,,,
+63f01267-1039-4149-bbca-0fcffc88034b,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"An acid is a substance that releases hydrogen ions (H+) in solution (Figure 2.4.3a). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H+ in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H+ in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.",True,Acids,Figure 2.4.3,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/215_Acids_and_Bases-01.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–."
+d5f4f213-6eeb-4acb-a0b1-fcd3356ef46a,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Bases,False,Bases,,,,
+b0698cbb-eb1a-4f9a-ab4a-940271905891,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"A base is a substance that releases hydroxyl ions (OH–) in solution, or one that accepts H+ already present in solution (see Figure 2.4.3b). The hydroxyl ions (also known as hydroxide ions) or other basic substances combine with H+ present to form a water molecule, thereby removing H+ and reducing the solution’s acidity. Strong bases release most or all of their hydroxyl ions; weak bases release only some hydroxyl ions or absorb only a few H+. Food mixed with hydrochloric acid from the stomach would burn the small intestine (the next portion of the digestive tract after the stomach), if it were not for the release of bicarbonate (HCO3–), a weak base that attracts H+. Bicarbonate accepts some of the H+ protons, thereby reducing the acidity of the solution.",True,Bases,Figure 2.4.3,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/215_Acids_and_Bases-01.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–."
+9eb4d38d-a746-4167-b2c5-ce579ab3f4a7,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,The Concept of pH,False,The Concept of pH,,,,
+0c651b76-3bbd-4ebf-a1e1-be5ae599a8b5,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"The relative acidity or alkalinity of a solution can be indicated by its pH. A solution’s pH is the negative, base-10 logarithm of the hydrogen ion (H+) concentration of the solution. As an example, a pH 4 solution has an H+ concentration that is ten times greater than that of a pH 5 solution. That is, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5. The concept of pH will begin to make more sense when you study the pH scale, as shown in Figure 2.4.4. The scale consists of a series of increments ranging from 0 to 14. A solution with a pH of 7 is considered neutral—neither acidic nor basic. Pure water has a pH of 7. The lower the number below 7, the more acidic the solution, or the greater the concentration of H+. The concentration of hydrogen ions at each pH value is 10 times different than the next pH. For instance, a pH value of 4 corresponds to a proton concentration of 10–4 M, or 0.0001M, while a pH value of 5 corresponds to a proton concentration of 10–5 M, or 0.00001M. The higher the number above 7, the more basic (alkaline) the solution, or the lower the concentration of H+. Human urine, for example, is ten times more acidic than pure water, and HCl is 10,000,000 times more acidic than water.",True,The Concept of pH,Figure 2.4.4,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/app/uploads/sites/157/2021/02/216_pH_Scale-01.jpg,Figure 2.4.4 The pH Scale
+eb34bd6a-880f-4c4f-b3f2-3e8154d09ae3,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Buffers,False,Buffers,,,,
+095b42e3-9827-4e83-9dc9-b51ace3981a8,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"The pH of human blood normally ranges from 7.35 to 7.45, although it is typically identified as pH 7.4. At this slightly basic pH, blood can reduce the acidity resulting from the carbon dioxide (CO2) constantly being released into the bloodstream by the trillions of cells in the body. Homeostatic mechanisms (along with exhaling CO2 while breathing) normally keep the pH of blood within this narrow range. This is critical, because fluctuations—either too acidic or too alkaline—can lead to life-threatening disorders.",True,Buffers,,,,
+5de60e3a-0373-4472-a508-eb70adc943ba,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"All cells of the body depend on homeostatic regulation of acid–base balance at a pH of approximately 7.4. The body therefore has several mechanisms for this regulation, involving breathing, the excretion of chemicals in urine, and the internal release of chemicals collectively called buffers into body fluids. A buffer is a solution of a weak acid and its conjugate base. A buffer can neutralize small amounts of acids or bases in body fluids. For example, if there is even a slight decrease below 7.35 in the pH of a bodily fluid, the buffer in the fluid—in this case, acting as a weak base—will bind the excess hydrogen ions. In contrast, if pH rises above 7.45, the buffer will act as a weak acid and contribute hydrogen ions.",True,Buffers,,,,
+34fa0669-0eec-416c-aa41-242d15d76900,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,Homeostatic Imbalances,False,Homeostatic Imbalances,,,,
+982cba9e-9fe7-429e-90a8-0d43bffe2975,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"The excessive acidity of acids and bases, of the blood, and other body fluids is known as acidosis. Common causes of acidosis are situations and disorders that reduce the effectiveness of breathing, especially the person’s ability to exhale fully, which causes a buildup of CO2 (and H+) in the bloodstream. Acidosis can also be caused by metabolic problems that reduce the level or function of buffers that act as bases, or that promote the production of acids. For instance, with severe diarrhea, too much bicarbonate can be lost from the body, allowing acids to build up in body fluids. In people with poorly managed diabetes (ineffective regulation of blood sugar), acids called ketones are produced as a form of body fuel. These can build up in the blood, causing a serious condition called diabetic ketoacidosis. Kidney failure, liver failure, heart failure, cancer, and other disorders also can prompt metabolic acidosis.",True,Homeostatic Imbalances,,,,
+d6aacc08-94c3-4ccd-abe6-8d5948a4ef5a,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"In contrast, alkalosis is a condition in which the blood and other body fluids are too alkaline (basic). As with acidosis, respiratory disorders are a major cause; however, in respiratory alkalosis, carbon dioxide levels fall too low. Lung disease, aspirin overdose, shock, and ordinary anxiety can cause respiratory alkalosis, which reduces the normal concentration of H+.",True,Homeostatic Imbalances,,,,
+288a93ad-ccc8-4140-87cc-a4a196995047,https://open.oregonstate.education/aandp/,2.4 Inorganic Compounds Essential to Human Functioning,https://open.oregonstate.education/aandp/chapter/2-4-inorganic-compounds-essential-to-human-functioning/,"Metabolic alkalosis often results from prolonged, severe vomiting, which causes a loss of hydrogen and chloride ions (as components of HCl). Medications can also prompt alkalosis. These include diuretics that cause the body to lose potassium ions, as well as antacids when taken in excessive amounts, for instance by someone with persistent heartburn or an ulcer.",True,Homeostatic Imbalances,,,,
+13fe943d-f30b-4cac-af9a-8e97a8958d36,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"One characteristic of a living organism is metabolism, which is the sum total of all of the chemical reactions that go on to maintain that organism’s health and life. The bonding processes you have learned thus far are anabolic chemical reactions; they form larger molecules from smaller molecules or atoms. Recall that metabolism can proceed in another direction: in catabolic chemical reactions, when bonds between components of larger molecules break, releasing smaller molecules or atoms. Both types of reactions involve exchanges not only of matter, but of energy.",True,Homeostatic Imbalances,,,,
+f0f84e07-d849-4217-85b9-2346de0674b6,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,The Role of Energy in Chemical Reactions,False,The Role of Energy in Chemical Reactions,,,,
+ca549c41-8683-455e-97cb-bbeb954eff26,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Chemical reactions require a sufficient amount of energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ones formed. In general, kinetic energy is the form of energy powering any type of matter in motion. Imagine you are building a brick wall. The energy it takes to lift and place one brick atop another is kinetic energy—the energy matter possesses because of its motion. Once the wall is in place, it stores potential energy. Potential energy is the energy of position, or the energy matter possesses because of the positioning or structure of its components. If the brick wall collapses, the stored potential energy is released as kinetic energy when the bricks fall.",True,The Role of Energy in Chemical Reactions,,,,
+b360b3dd-deb3-4042-8d03-5b209f437646,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In the human body, potential energy is stored in the bonds between atoms and molecules. Chemical energy is the form of potential energy in which energy is stored in chemical bonds. When those bonds are formed, chemical energy is invested, and when they break, chemical energy is released. Notice that chemical energy, like all energy, is neither created nor destroyed, rather, it is converted from one form to another. When you eat an energy bar before heading out the door for a hike, the honey, nuts, and other foods the bar contains are broken down and rearranged by your body into molecules that your muscle cells convert to kinetic energy.",True,The Role of Energy in Chemical Reactions,,,,
+a7c25e8e-d7be-451f-a48f-30a7dbeedd00,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Chemical reactions that release more energy than they absorb are characterized as exergonic. The catabolism of the foods in your energy bar is an example. Some of the chemical energy stored in the bar is absorbed into molecules your body uses for fuel, but some of it is released—for example, as heat. In contrast, chemical reactions that absorb more energy than they release are endergonic. These reactions require energy input and the resulting molecule stores not only the chemical energy in the original components, but also the energy that fueled the reaction. Since energy is neither created nor destroyed, where does the energy needed for endergonic reactions come from? In many cases, it comes from exergonic reactions.",True,The Role of Energy in Chemical Reactions,,,,
+b63f9dd2-59e0-41f9-b3c1-792d740a51e1,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Forms of Energy Important in Human Functioning,False,Forms of Energy Important in Human Functioning,,,,
+99605ce9-16f2-44eb-9764-0757c4d46251,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"You have already learned that chemical energy is absorbed, stored, and released by chemical bonds. In addition to chemical energy, mechanical, radiant, and electrical energy are important in human functioning.",True,Forms of Energy Important in Human Functioning,,,,
+fe2a1d22-c5cc-49e0-a7e9-b421a572a762,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Mechanical energy, which is stored in physical systems such as machines, engines, or the human body, directly powers the movement of matter. When you lift a brick into place on a wall, your muscles provide the mechanical energy that moves the brick.",True,Forms of Energy Important in Human Functioning,,,,
+f04b953e-7b13-4778-8aed-9ad4c36c8bab,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Radiant energy is energy emitted and transmitted as waves rather than matter. These waves vary in length from long radio waves and microwaves to short gamma waves emitted from decaying atomic nuclei. The full spectrum of radiant energy is referred to as the electromagnetic spectrum. The body uses the ultraviolet energy of sunlight to convert a compound in skin cells to vitamin D, which is essential to human functioning. The human eye evolved to see the wavelengths that comprise the colors of the rainbow, from red to violet, so that range in the spectrum is called “visible light.”",True,Forms of Energy Important in Human Functioning,,,,
+692517a2-ec58-40eb-b796-4769a76db23f,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Electrical energy, supplied by electrolytes in cells and body fluids, contributes to the voltage changes that help transmit impulses in nerve and muscle cells.",True,Forms of Energy Important in Human Functioning,,,,
+1709f120-042a-409e-a8cd-9c901dd8aa48,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Characteristics of Chemical Reactions,False,Characteristics of Chemical Reactions,,,,
+29498fbf-c0e3-4ac0-a91b-d715bbf81375,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"All chemical reactions begin with a reactant, the general term for one or more substances that enter into the reaction. Sodium and chloride ions, for example, are the reactants in the production of table salt. One or more substances produced by a chemical reaction are called the product.",True,Characteristics of Chemical Reactions,,,,
+c3474cc6-9b9d-4686-878c-3307f6d0aeeb,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In chemical reactions, the components of the reactants—the elements involved and the number of atoms of each—are all present in the product(s). Similarly, there is nothing present in the products that are not present in the reactants. This is because chemical reactions are governed by the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.",True,Characteristics of Chemical Reactions,,,,
+14d45e8b-c381-49fa-979c-7f17da9247f2,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Just as you can express mathematical calculations in equations such as 2 + 7 = 9, you can use chemical equations to show how reactants become products. As in math, chemical equations proceed from left to right, but instead of an equal sign, they employ an arrow or arrows indicating the direction in which the chemical reaction proceeds. For example, the chemical reaction in which one atom of nitrogen and three atoms of hydrogen produce ammonia would be written as N + 3H→ NH3. Correspondingly, the breakdown of ammonia into its components would be written as NH3 →N + 3H.",True,Characteristics of Chemical Reactions,,,,
+aeac9423-3578-41ff-9b39-a744ec695e5c,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Notice that, in the first example, a nitrogen (N) atom and three hydrogen (H) atoms bond to form a compound. This anabolic reaction requires energy, which is then stored within the compound’s bonds. Such reactions are referred to as synthesis reactions. A synthesis reaction is a chemical reaction that results in the synthesis (joining) of components that were formerly separate (Figure 2.3.1a). Again, nitrogen and hydrogen are reactants in a synthesis reaction that yields ammonia as the product. The general equation for a synthesis reaction is A + B→AB.",True,Characteristics of Chemical Reactions,Figure 2.3.1,,,
+aaf5630b-6f6c-4b5f-ba8b-daab78db88fd,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In the second example, ammonia is catabolized into its smaller components, and the potential energy that had been stored in its bonds is released. Such reactions are referred to as decomposition reactions. A decomposition reaction is a chemical reaction that breaks down or “de-composes” something larger into its constituent parts (see Figure 2.3.1b). The general equation for a decomposition reaction is: AB→A+B.",True,Characteristics of Chemical Reactions,Figure 2.3.1,,,
+a60b9cf0-4bea-4201-890e-cf65ef2421c1,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"An exchange reaction is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both formed and broken, and chemical energy is absorbed, stored, and released (see Figure 2.3.1c). The simplest form of an exchange reaction might be: A+BC→AB+C. Notice that, to produce these products, B and C had to break apart in a decomposition reaction, whereas A and B had to bond in a synthesis reaction. A more complex exchange reaction might be: AB+CD→AC+B. Another example might be: AB+CD→AD+BC.",True,Characteristics of Chemical Reactions,Figure 2.3.1,,,
+e2db9d3e-8bb6-4291-8dd7-c12fa596f4a3,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In theory, any chemical reaction can proceed in either direction under the right conditions. Reactants may synthesize into a product that is later decomposed. Reversibility is also a quality of exchange reactions. For instance, A+BC→AB+C could then reverse to AB+C→A+BC. This reversibility of a chemical reaction is indicated with a double arrow: A+BC⇄AB+C. Still, in the human body, many chemical reactions do proceed in a predictable direction, either one way or the other. You can think of this more predictable path as the path of least resistance because, typically, the alternate direction requires more energy.",True,Characteristics of Chemical Reactions,,,,
+d5d710fc-87b5-4984-9640-510e79bb5765,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Factors Influencing the Rate of Chemical Reactions,False,Factors Influencing the Rate of Chemical Reactions,,,,
+8ed0138e-dba4-4745-ba75-a96a10a2d512,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"If you pour vinegar into baking soda, the reaction is instantaneous; the concoction will bubble and fizz, but many chemical reactions take time. A variety of factors influence the rate of chemical reactions. This section, however, will consider only the most important in human functioning.",True,Factors Influencing the Rate of Chemical Reactions,,,,
+8a02fab3-5070-4abe-9cf6-cb59112bf37a,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Properties of the Reactants,False,Properties of the Reactants,,,,
+706ceca4-8b21-4bc5-91f5-f136ca54844b,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"If chemical reactions are to occur quickly, the atoms in the reactants have to have easy access to one another. Thus, the greater the surface area of the reactants, the more readily they will interact. When you pop a cube of cheese into your mouth, you chew it before you swallow it. Among other things, chewing increases the surface area of the food so that digestive chemicals can more easily get at it. As a general rule, gases tend to react faster than liquids or solids, again because it takes energy to separate particles of a substance, and gases by definition already have space between their particles. Similarly, the larger the molecule, the greater the number of total bonds, so reactions involving smaller molecules, with fewer total bonds, would be expected to proceed faster.",True,Properties of the Reactants,,,,
+f6446b09-93f9-4a2e-844d-29980a8fd2aa,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In addition, recall that some elements are more reactive than others. Reactions that involve highly reactive elements like hydrogen proceed more quickly than reactions that involve less reactive elements. Reactions involving stable elements like helium are not likely to happen at all.",True,Properties of the Reactants,,,,
+d6f478d8-19dc-426f-9c08-04da89c8da8e,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Temperature,False,Temperature,,,,
+a939124c-e4e7-4fcb-8c75-d8742c5a304e,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Nearly all chemical reactions occur at a faster rate at higher temperatures. Recall that kinetic energy is the energy of matter in motion. The kinetic energy of subatomic particles increases in response to increases in thermal energy. The higher the temperature, the faster the particles move, and the more likely they are to come in contact and react.",True,Temperature,,,,
+9464067b-4711-4f29-b585-00e9dc819adb,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Concentration and Pressure,False,Concentration and Pressure,,,,
+ff0a742e-65f7-43d0-b39a-4db1eca0aa22,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"If just a few people are dancing at a club, they are unlikely to step on each other’s toes. As more and more people get up to dance—especially if the music is fast—collisions are likely to occur. It is the same with chemical reactions: the more particles present within a given space, the more likely those particles are to bump into one another. This means that chemists can speed up chemical reactions not only by increasing the concentration of particles—the number of particles in the space—but also by decreasing the volume of the space, which would correspondingly increase the pressure. If there were 100 dancers in that club, and the manager abruptly moved the party to a room half the size, the concentration of the dancers would double in the new space, and the likelihood of collisions would increase accordingly.",True,Concentration and Pressure,,,,
+89111e12-0d80-4654-a416-573780627f52,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,Enzymes and Other Catalysts,False,Enzymes and Other Catalysts,,,,
+0f27aa03-afe8-4ebb-87f2-4950e9176f58,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"For two chemicals in nature to react with each other they first have to come into contact, and this occurs through random collisions. Since heat helps increase the kinetic energy of atoms, ions, and molecules, it promotes their collision. However, in the body, extremely high heat—such as a very high fever—can damage body cells and be life-threatening. On the other hand, normal body temperature is not high enough to promote the chemical reactions that sustain life. That is where catalysts come in.",True,Enzymes and Other Catalysts,,,,
+f4dea024-6cf4-4270-8087-4e7136a1b63e,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"In chemistry, a catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any change. You can think of a catalyst as a chemical change agent. They help increase the rate and force at which atoms, ions, and molecules collide, thereby increasing the probability that their valence shell electrons will interact.",True,Enzymes and Other Catalysts,,,,
+a8669c84-eba6-41ae-8a6e-72d0215ea052,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"The most important catalysts in the human body are enzymes. An enzyme is a catalyst composed of protein or ribonucleic acid (RNA), both of which will be discussed later in this chapter. Like all catalysts, enzymes work by lowering the level of energy that needs to be invested in a chemical reaction. A chemical reaction’s activation energy is the “threshold” level of energy needed to break the bonds in the reactants. Once those bonds are broken, new arrangements can form. Without an enzyme to act as a catalyst, a much larger investment of energy is needed to ignite a chemical reaction (Figure 2.3.2).",True,Enzymes and Other Catalysts,Figure 2.3.2,2.3 Chemical Reactions,https://open.oregonstate.education/app/uploads/sites/157/2021/02/212_Enzymes-01.jpg,"Figure 2.3.2 – Enzymes:  Enzymes decrease the activation energy required for a given chemical reaction to occur. (a) Without an enzyme, the energy input needed for a reaction to begin is high. (b) With the help of an enzyme, less energy is needed for a reaction to begin."
+e5cd5791-6522-493c-80f2-4e8da0a3c298,https://open.oregonstate.education/aandp/,2.3 Chemical Reactions,https://open.oregonstate.education/aandp/chapter/2-3-chemical-reactions/,"Enzymes are critical to the body’s healthy functioning. They assist, for example, with the breakdown of food and its conversion to energy. In fact, most of the chemical reactions in the body are facilitated by enzymes.",True,Enzymes and Other Catalysts,,,,
+90140b00-e955-4fc3-8ebd-bdd43f06dbc9,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Atoms separated by a great distance cannot link; rather, they must come close enough for the electrons in their valence shells to interact. But do atoms ever actually touch one another? Most physicists would say no, because the negatively charged electrons in their valence shells repel one another. No force within the human body—or anywhere in the natural world—is strong enough to overcome this electrical repulsion. So when you read about atoms linking together or colliding, bear in mind that the atoms are not merging in a physical sense.",True,Enzymes and Other Catalysts,,,,
+5e38c418-56ee-4769-b788-07b5387101e1,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Instead, atoms link by forming a chemical bond. A bond is a weak or strong electrical attraction that holds atoms in the same vicinity. The new grouping is typically more stable—less likely to react again—than its component atoms were when they were separate. A more or less stable grouping of two or more atoms held together by chemical bonds is called a molecule. The bonded atoms may be of the same element, as in the case of H2, which is called molecular hydrogen or hydrogen gas. When a molecule is made up of two or more atoms of different elements, it is called a chemical compound. A unit of water, or H2O, is a compound, as is a single molecule of the gas methane, or CH4.",True,Enzymes and Other Catalysts,,,,
+6109ca19-ca1e-4931-9797-7e39e2c7ce17,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Three types of chemical bonds are important in human physiology, because they hold together substances that are used by the body for critical aspects of homeostasis, signaling, and energy production, to name just a few important processes. These are ionic bonds, covalent bonds, and hydrogen bonds.",True,Enzymes and Other Catalysts,,,,
+1f0f24e0-8250-46f4-8187-8773920e5300,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,Ions and Ionic Bonds,False,Ions and Ionic Bonds,,,,
+8e00930e-833d-46ff-ad90-45ea0f26d615,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Recall that an atom typically has the same number of positively charged protons and negatively charged electrons. As long as this situation remains, the atom is electrically neutral. When an atom participates in a chemical reaction that results in the donation or acceptance of one or more electrons, the atom will then become positively or negatively charged. This happens frequently for most atoms in order to have a full valence shell, as described previously. This can happen either by gaining electrons to fill a shell that is more than half-full, or by giving away electrons to empty a shell that is less than half-full, thereby leaving the next smaller electron shell as the new, full, valence shell. An atom that has an electrical charge—whether positive or negative—is an ion.",True,Ions and Ionic Bonds,,,,
+44d3b0d1-cda5-4b3a-b4ee-9e7222b7a168,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Potassium (K), for instance, is an important element in all body cells. Its atomic number is 19 and it has just one electron in its valence shell. This characteristic makes potassium highly likely to participate in chemical reactions in which it donates one electron (it is easier for potassium to donate one electron than to gain seven electrons). The loss will cause the positive charge of potassium’s protons to be more influential than the negative charge of potassium’s electrons. In other words, the resulting potassium ion will be slightly positive. A potassium ion is written K+, indicating that it has lost a single electron. A positively charged ion is known as a cation.",True,Ions and Ionic Bonds,,,,
+cd1c3f1b-5026-41e0-bd81-6b64422a06f6,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Now consider fluorine (F), a component of bones and teeth. Its atomic number is nine and it has seven electrons in its valence shell. Thus, it is highly likely to bond with other atoms in such a way that fluorine accepts one electron (it is easier for fluorine to gain one electron than to donate seven electrons). When it does, its electrons will outnumber its protons by one and it will have an overall negative charge. The ionized form of fluorine is called fluoride, and is written as F–. A negatively charged ion is known as an anion.",True,Ions and Ionic Bonds,,,,
+a8d21014-fc27-4bc5-a0af-99d793447851,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Atoms that have more than one electron to donate or accept will end up with stronger positive or negative charges. A cation that has donated two electrons has a net charge of +2. Using magnesium (Mg) as an example, this can be written as Mg++ or Mg2+. An anion that has accepted two electrons has a net charge of –2. The ionic form of selenium (Se), for example, is typically written Se2–.",True,Ions and Ionic Bonds,,,,
+c1a8528e-9a99-49d9-987b-ceff8237b55f,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"The opposite charges of cations and anions exert a moderately strong mutual attraction that keeps the atoms in close proximity forming an ionic bond. An ionic bond is an ongoing, close association between ions of opposite charge. The table salt you sprinkle on your food owes its existence to ionic bonding. As shown in Figure 2.2.1, sodium commonly donates an electron to chlorine, becoming the cation Na+. When chlorine accepts the electron, it becomes the chloride anion, Cl–. With their opposing charges, these two ions strongly attract each other.",True,Ions and Ionic Bonds,Figure 2.2.1,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/207_Ionic_Bonding-01.jpg,"Figure 2.2.1 – Ionic Bonding: (a) Sodium readily donates the solitary electron in its valence shell to chlorine, which needs only one electron to have a full valence shell. (b) The opposite electrical charges of the resulting sodium cation and chloride anion result in the formation of a bond of attraction called an ionic bond. (c) The attraction of many sodium and chloride ions results in the formation of large groupings called crystals."
+34043d67-c0af-48a9-9b3d-4851139d1427,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Water is an essential component of life because it is able to break the ionic bonds in salts to free the ions. In fact, in biological fluids, most individual atoms exist as ions. These dissolved ions produce electrical charges within the body. The behavior of these ions produces the tracings of heart and brain function observed as waves on an electrocardiogram (EKG or ECG) or an electroencephalogram (EEG). The electrical activity that derives from the interactions of the charged ions is why they are also called electrolytes.",True,Ions and Ionic Bonds,,,,
+1e31e3e7-aa68-46b0-bb4b-2dad64917055,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,Covalent Bonds,False,Covalent Bonds,,,,
+da005c71-808f-4889-b494-9001c42451e1,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Unlike ionic bonds formed by the attraction between a cation’s positive charge and an anion’s negative charge, molecules formed by a covalent bond which share electrons in a mutually stabilizing relationship. Like next-door neighbors whose kids hang out first at one home and then at the other, the atoms do not lose or gain electrons permanently. Instead, the electrons move back and forth between the elements. Because of the close sharing of pairs of electrons (one electron from each of two atoms), covalent bonds are stronger than ionic bonds.",True,Covalent Bonds,,,,
+dfbbbbb4-d4f8-4a04-93ab-9cef384c6bdf,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,Nonpolar Covalent Bonds,False,Nonpolar Covalent Bonds,,,,
+0103dac9-7173-4f9a-b28c-c3b7fd737d24,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Figure 2.2.2 shows several common types of covalent bonds. Notice that the two covalently bonded atoms typically share just one or two electron pairs, though larger sharings are possible. The important concept to take from this is that in covalent bonds, electrons in the outermost valence shell are shared to fill the valence shells of both atoms, ultimately stabilizing both of the atoms involved. In a single covalent bond, a single electron is shared between two atoms, while in a double covalent bond, two pairs of electrons are shared between two atoms. There are even triple covalent bonds, where three atoms are shared.",True,Nonpolar Covalent Bonds,Figure 2.2.2,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/208_Covalent_Bonding-01.jpg,Figure 2.2.2 Covalent Bonding
+69eb49c8-58a9-447b-9e08-b3739b0bded5,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"You can see that the covalent bonds shown in Figure 2.2.2 are balanced. The sharing of the negative electrons is relatively equal, as is the electrical pull of the positive protons in the nucleus of the atoms involved. This is why covalently bonded molecules that are electrically balanced in this way are described as nonpolar; that is, no region of the molecule is either more positive or more negative than any other.",True,Nonpolar Covalent Bonds,Figure 2.2.2,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/208_Covalent_Bonding-01.jpg,Figure 2.2.2 Covalent Bonding
+5036bf0b-66df-48d8-971e-965f8587afdf,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,Polar Covalent Bonds,False,Polar Covalent Bonds,,,,
+cd8772ca-cf76-4e5b-9027-1517429f839f,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Groups of legislators with completely opposite views on a particular issue are often described as “polarized” by news writers. In chemistry, a polar molecule is a molecule that contains regions that have opposite electrical charges. Polar molecules occur when atoms share electrons unequally, in polar covalent bonds.",True,Polar Covalent Bonds,,,,
+672d21cf-c415-4bff-bec0-dce12200ffb6,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"The most familiar example of a polar molecule is water (Figure 2.2.3). The molecule has three parts: one atom of oxygen, the nucleus of which contains eight protons, and two hydrogen atoms, whose nuclei each contain only one proton. Since every proton exerts an identical positive charge, a nucleus that contains eight protons exerts a charge eight times greater than a nucleus that contains one proton. This means that the negatively charged electrons present in the water molecule are more strongly attracted to the oxygen nucleus than to the hydrogen nuclei. Each hydrogen atom’s single negative electron, therefore, migrates toward the oxygen atom, making the oxygen end of their bond slightly more negative than the hydrogen end of their bond.",True,Polar Covalent Bonds,Figure 2.2.3,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+0b7025e5-2388-4c21-a4a0-8ed1839a98cd,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"What is true for the bonds is true for the water molecule as a whole; that is, the oxygen region has a slightly negative charge and the regions of the hydrogen atoms have a slightly positive charge. These charges are often referred to as “partial charges” because the strength of the charge is less than one full electron, as would occur in an ionic bond. As shown in Figure 2.2.3, regions of weak polarity are indicated with the Greek letter delta (∂) and a plus (+) or minus (–) sign.",True,Polar Covalent Bonds,Figure 2.2.3,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+096c443d-3514-4b12-b021-e2bc173d2764,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Even though a single water molecule is unimaginably tiny, it has mass, and the opposing electrical charges on the molecule pull that mass in such a way that it creates a shape somewhat like a triangular tent (see Figure 2.2.3b). This dipole, with the positive charges at one end formed by the hydrogen atoms at the “bottom” of the tent and the negative charge at the opposite end (the oxygen atom at the “top” of the tent) makes the charged regions highly likely to interact with charged regions of other polar molecules. For human physiology, the resulting bond, formed by water, is one of the most important—the hydrogen bond.",True,Polar Covalent Bonds,Figure 2.2.3,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+5c57848c-0224-4207-99c8-450d63376638,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,Hydrogen Bonds,False,Hydrogen Bonds,,,,
+8ee9e2fc-68eb-4809-b025-0fd2c7ff5474,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another molecule. In other words, hydrogen bonds always include hydrogen that is already part of a polar molecule.",True,Hydrogen Bonds,,,,
+a8446460-b31d-43ad-93e4-20ed7e7b010c,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"The most common example of hydrogen bonding in the natural world occurs between molecules of water. It happens before your eyes whenever two raindrops merge into a larger bead, or a creek spills into a river. Hydrogen bonding occurs because the weakly negative oxygen atom in one water molecule is attracted to the weakly positive hydrogen atoms of two other water molecules (Figure 2.2.4).",True,Hydrogen Bonds,Figure 2.2.4,2.2 Chemical Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/210_Hydrogen_Bonds_Between_Water_Molecules-01.jpg,"Figure 2.2.4 – Hydrogen Bonds between Water Molecules: Notice that the bonds occur between the weakly positive charge on the hydrogen atoms and the weakly negative charge on the oxygen atoms. Hydrogen bonds are relatively weak, and therefore are indicated with a dotted (rather than a solid) line."
+6f34d191-d706-4ae3-9c13-0f00743f7214,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Notice that the bonds occur between the weakly positive charge on the hydrogen atoms and the weakly negative charge on the oxygen atoms. Hydrogen bonds are relatively weak, and therefore are indicated with a dotted (rather than a solid) line.",True,Hydrogen Bonds,,,,
+96d62591-d626-41e5-ba31-cedab5eafe97,https://open.oregonstate.education/aandp/,2.2 Chemical Bonds,https://open.oregonstate.education/aandp/chapter/2-2-chemical-bonds/,"Water molecules also strongly attract other types of charged molecules as well as ions. This explains why “table salt,” for example, actually is a molecule called a “salt” in chemistry; it consists of equal numbers of positively-charged sodium (Na+) and negatively-charged chloride (Cl–), dissolves so readily in water, in this case, forming dipole-ion bonds between the water and the electrically-charged ions (electrolytes). Water molecules also repel molecules with nonpolar covalent bonds, like fats, lipids, and oils. You can demonstrate this with a simple kitchen experiment: pour a teaspoon of vegetable oil, a compound formed by nonpolar covalent bonds, into a glass of water. Instead of instantly dissolving in the water, the oil forms a distinct bead because the polar water molecules repel the nonpolar oil.",True,Hydrogen Bonds,,,,
+be2e2e42-0069-4cc0-9efa-2d70c2ca91e2,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"The substance of the universe—from a grain of sand to a star—is called matter. Scientists define matter as anything that occupies space and has mass. An object’s mass and its weight are related concepts, but not quite the same. An object’s mass is the amount of matter contained in the object, and is the same whether that object is on Earth or in the zero-gravity environment of outer space. An object’s weight, on the other hand, is its mass as affected by the pull of gravity. An object’s weight is greater where the pull of gravity is stronger than where the gravity is less strong. For example, an object of a certain mass weighs less on the moon than it does on Earth because the gravity of the moon is less than that of Earth. In other words, weight is variable, and is influenced by gravity. A piece of cheese that weighs a pound on Earth weighs only a few ounces on the moon.",True,Hydrogen Bonds,,,,
+4fd6ac21-fb1f-4ba8-91e3-659c22e436c8,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,Elements and Compounds,False,Elements and Compounds,,,,
+215ae162-cea0-4a6f-a385-4cfd3b15ec89,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"All matter in the natural world is composed of one or more of the 92 fundamental substances called elements. An element is a pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means. While your body can assemble many of the chemical compounds needed for life from their constituent elements, it cannot make elements. They must come from the environment. A familiar example of an element that you must take in is calcium (Ca++). Calcium is essential to the human body; it is absorbed and used for a number of processes, including strengthening bones. When you consume dairy products your digestive system breaks down the food into components small enough to cross into the bloodstream. Among these is calcium, which, because it is an element, cannot be broken down further. The elemental calcium in cheese, therefore, is the same as the calcium that forms your bones. Some other elements you might be familiar with are oxygen, sodium, and iron. The elements in the human body are shown in Figure 2.1.1, beginning with the most abundant: oxygen (O), carbon (C), hydrogen (H), and nitrogen (N). Each element’s name can be replaced by a one- or two-letter symbol; you will become familiar with some of these during this course. All the elements in your body are derived from the foods you eat and the air you breathe.",True,Elements and Compounds,Figure 2.1.1,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/app/uploads/sites/157/2019/07/201_Elements_of_the_Human_Body-01.jpg,Figure 2.1.1 – Elements of the Human Body: The main elements that compose the human body are shown from most abundant to least abundant.
+463b49e4-9620-4fe8-ad5c-07a5892f7641,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"In nature, elements rarely occur alone. Instead, they combine to form compounds. A compound is a substance composed of two or more elements joined by chemical bonds. For example, the compound glucose is an important body fuel. It is always composed of the same three elements: carbon, hydrogen, and oxygen. Moreover, the elements that make up any given compound always occur in the same relative amounts. In glucose, there are always six carbon and six oxygen units for every twelve hydrogen units. But what, exactly, are these “units” of elements?",True,Elements and Compounds,,,,
+e52ca509-1650-4966-9c94-eb71309d5ce5,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,Atoms and Subatomic Particles,False,Atoms and Subatomic Particles,,,,
+0e90e000-5811-4667-ab0d-f4f45fbac6c6,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"An atom is the smallest quantity of an element that retains the unique properties of that element. In other words, an atom of hydrogen is a unit of hydrogen—the smallest amount of hydrogen that can exist. As you might guess, atoms are almost unfathomably small. The period at the end of this sentence is millions of atoms wide.",True,Atoms and Subatomic Particles,,,,
+5cf49782-2f0a-4699-9f97-57014a8cfaeb,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,Atomic Structure and Energy,False,Atomic Structure and Energy,,,,
+801c37c5-219e-4259-96d6-58b653cd186e,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"Atoms are made up of even smaller subatomic particles, which include three important types: the proton, neutron, and electron. The number of positively-charged protons and non-charged (“neutral”) neutrons, gives mass to the atom, and the number of each in the nucleus of the atom determines the element. The number of negatively-charged electrons that “spin” around the nucleus at close to the speed of light equals the number of protons. An electron has about 1/2000th the mass of a proton or neutron.",True,Atomic Structure and Energy,,,,
+e50cf937-166d-472d-9ca5-eb673e005257,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"Figure 2.1.2 shows two models that can help you imagine the structure of an atom—in this case, helium (He). In the planetary model, helium’s two electrons are shown circling the nucleus in a fixed orbit depicted as a ring. Although this model is helpful in visualizing atomic structure, in reality, electrons do not travel in fixed orbits, but whiz around the nucleus erratically in a so-called electron cloud.",True,Atomic Structure and Energy,Figure 2.1.2,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/app/uploads/sites/157/2021/02/202_Two_Models_of_Atomic_Structure.jpg,"Figure 2.1.2 – Two Models of Atomic Structure: (a) In the planetary model, the electrons of helium are shown in fixed orbits, depicted as rings, at a precise distance from the nucleus, somewhat like planets orbiting the sun. (b) In the electron cloud model, the electrons of carbon are shown in the variety of locations they would have at different distances from the nucleus over time."
+f4cfb698-a9c6-43e7-83af-57d42d2ca026,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"An atom’s protons and electrons carry electrical charges. Protons, with their positive charge, are designated p+. Electrons, which have a negative charge, are designated e–. An atom’s neutrons have no charge: they are electrically neutral. Just as a magnet sticks to a steel refrigerator because their opposite charges attract, the positively charged protons attract the negatively charged electrons. This mutual attraction gives the atom some structural stability. The attraction by the positively charged nucleus helps keep electrons from straying far. The number of protons and electrons within a neutral atom are equal, thus, the atom’s overall charge is balanced.",True,Atomic Structure and Energy,,,,
+5b8a5213-a7ff-4a8e-82e5-fe3d0427ad1b,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,Atomic Number and Mass Number,False,Atomic Number and Mass Number,,,,
+f1d6775e-4b98-4c0d-b193-431c3bad60f4,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"An atom of carbon is unique to carbon, but a proton of carbon is not. One proton is the same as another, whether it is found in an atom of carbon, sodium (Na), or iron (Fe). The same is true for neutrons and electrons. So, what gives an element its distinctive properties—what makes carbon so different from sodium or iron? The answer is the unique quantity of protons each contains. Carbon by definition is an element whose atoms contain six protons. No other element has exactly six protons in its atoms. Moreover, all atoms of carbon, whether found in your liver or in a lump of coal, contain six protons. Thus, the atomic number, which is the number of protons in the nucleus of the atom, identifies the element. Since an atom usually has the same number of electrons as protons, the atomic number identifies the usual number of electrons as well.",True,Atomic Number and Mass Number,,,,
+3a7f3ee4-e695-42f6-84e9-84444dca5ace,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"In their most common form, many elements also contain the same number of neutrons as protons. The most common form of carbon, for example, has six neutrons as well as six protons, for a total of 12 subatomic particles in its nucleus. An element’s mass number is the sum of the number of protons and neutrons in its nucleus. So the most common form of carbon’s mass number is 12. Electrons have so little mass that they do not appreciably contribute to the mass of an atom. Carbon is a relatively light element; Uranium (U), in contrast, has a mass number of 238 and is referred to as a heavy metal. Its atomic number is 92 (it has 92 protons) but it contains 146 neutrons; it has the most mass of all the naturally occurring elements.",True,Atomic Number and Mass Number,,,,
+2d9c8413-90c1-4d7a-b8c1-cb01f4774c34,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"The periodic table of the elements, shown in Figure 2.1.3, is a chart identifying the 92 elements found in nature, as well as several larger, unstable elements discovered experimentally. The elements are arranged in order of their atomic number, with hydrogen and helium at the top of the table, and the more massive elements below. The periodic table is a useful device because for each element, it identifies the chemical symbol, the atomic number, and the mass number, while organizing elements according to their propensity to react with other elements. The number of protons and electrons in an element are equal. The number of protons and neutrons may be equal for some elements, but are not equal for all.",True,Atomic Number and Mass Number,Figure 2.1.3,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/app/uploads/sites/157/2021/02/203_Periodic_Table-02-scaled.jpg,"Figure 2.1.3 – The Periodic Table of the Elements (credit: R.A. Dragoset, A. Musgrove, C.W. Clark, W.C. Martin)"
+5826bf04-ccce-4562-ae4f-f01d8d3f34eb,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,Isotopes,False,Isotopes,,,,
+5e1055f3-fa26-436a-be1f-c29b7a01da2e,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"Although each element has a unique number of protons, it can exist as different isotopes. An isotope is one of the different forms of an element, distinguished from one another by different numbers of neutrons. The standard isotope of carbon is 12C, commonly called carbon twelve. 12C has six protons and six neutrons, for a mass number of twelve. All of the isotopes of carbon have the same number of protons; therefore, 13C has seven neutrons, and 14C has eight neutrons. The different isotopes of an element can also be indicated with the mass number hyphenated (for example, C-12 instead of 12C). Hydrogen has three common isotopes, shown in Figure 2.1.4.",True,Isotopes,Figure 2.1.4,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/app/uploads/sites/157/2021/02/204_Isotopes_of_Hydrogen-01.jpg,"Figure 2.1.4  -Isotopes of Hydrogen: Protium, designated 1H, has one proton and no neutrons. It is by far the most abundant isotope of hydrogen in nature. Deuterium, designated 2H, has one proton and one neutron. Tritium, designated 3H, has two neutrons."
+ae33c006-1fd9-40fa-b9ca-fba49eeb797b,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"An isotope that contains more than the usual number of neutrons is referred to as a heavy isotope. An example is 14C. Heavy isotopes tend to be unstable, and unstable isotopes are radioactive. A radioactive isotope is an isotope whose nucleus readily decays, giving off subatomic particles and electromagnetic energy. Different radioactive isotopes (also called radioisotopes) differ in their half-life, the time it takes for half of any size sample of an isotope to decay. For example, the half-life of tritium—a radioisotope of hydrogen—is about 12 years, indicating it takes 12 years for half of the tritium nuclei in a sample to decay. Excessive exposure to radioactive isotopes can damage human cells and even cause cancer and birth defects, but when exposure is controlled, some radioactive isotopes can be useful in medicine. For more information, see the Career Connections.",True,Isotopes,,,,
+5a5960a6-d352-4266-8a4d-58bd40378165,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,The Behavior of Electrons,False,The Behavior of Electrons,,,,
+3a174e8e-3a5d-4155-8543-508e39bd7cb3,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"In the human body, atoms do not exist as independent entities. Rather, they are constantly reacting with other atoms to form and to break down more complex substances. To fully understand anatomy and physiology you must grasp how atoms participate in such reactions. The key is understanding the behavior of electrons.",True,The Behavior of Electrons,,,,
+ffbca70d-7dc7-415d-8a63-923e50045b97,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"Although electrons do not follow rigid orbits a set distance away from the atom’s nucleus, they do tend to stay within certain regions of space called electron shells. An electron shell is a layer of electrons that encircle the nucleus at a distinct energy level.",True,The Behavior of Electrons,,,,
+d3446886-12a5-4be6-995d-20a3605bbd12,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"The atoms of the elements found in the human body have from one to five electron shells, and all electron shells hold eight electrons except the first shell, which can only hold two. This configuration of electron shells is the same for all atoms. The precise number of shells depends on the number of electrons in the atom. Hydrogen and helium have just one and two electrons, respectively. If you take a look at the periodic table of the elements, you will notice that hydrogen and helium are placed alone on either sides of the top row; they are the only elements that have just one electron shell (Figure 2.1.6). A second shell is necessary to hold the electrons in all elements larger than hydrogen and helium.",True,The Behavior of Electrons,Figure 2.1.6,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/app/uploads/sites/157/2021/02/206_Electron_Shells-01.jpg,"Figure 2.1.6 Electron Shells: Electrons orbit the atomic nucleus at distinct levels of energy called electron shells. (a) With one electron, hydrogen only half-fills its electron shell. Helium also has a single shell, but its two electrons completely fill it. (b) The electrons of carbon completely fill its first electron shell, but only half-fills its second. (c) Neon, an element that does not occur in the body, has 10 electrons, filling both of its electron shells."
+c165a4ad-1abf-454c-b5bf-0e14be886df2,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"Lithium (Li), whose atomic number is 3, has three electrons. Two of these fill the first electron shell, and the third spills over into a second shell. The second electron shell can accommodate as many as eight electrons. Carbon, with its six electrons, entirely fills its first shell, and half-fills its second. With ten electrons, neon (Ne) entirely fills its two electron shells. Again, a look at the periodic table reveals that all of the elements in the second row, from lithium to neon, have just two electron shells. Atoms with more than ten electrons require more than two shells. These elements occupy the third and subsequent rows of the periodic table.",True,The Behavior of Electrons,,,,
+8204706a-0ee8-49af-9eab-bfeab545d7d4,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"The factor that most strongly governs the tendency of an atom to participate in chemical reactions is the number of electrons in its valence shell. A valence shell is an atom’s outermost electron shell. If the valence shell is full, the atom is stable, meaning its electrons are unlikely to be pulled away from the nucleus by the electrical charge of other atoms. If the valence shell is not full, the atom is reactive, meaning it will tend to react with other atoms in ways that make the valence shell full. Consider hydrogen, with its one electron only half-filling its valence shell. This single electron is likely to be drawn into relationships with the atoms of other elements, so that hydrogen’s single valence shell can be stabilized.",True,The Behavior of Electrons,,,,
+b2f3784b-4e51-4043-bd25-516e307c1f00,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"All atoms (except hydrogen and helium with their single electron shells) are most stable when there are exactly eight electrons in their valence shell. This principle is referred to as the octet rule, and it states that an atom will give up, gain, or share electrons with another atom so that it ends up with eight electrons in its own valence shell. For example, oxygen, with six electrons in its valence shell, is likely to react with other atoms in a way that results in the addition of two electrons to oxygen’s valence shell, bringing the number to eight. When two hydrogen atoms each share their single electron with oxygen, covalent bonds are formed, resulting in a molecule of water, H2O.",True,The Behavior of Electrons,,,,
+7b8f9b0c-a65f-4890-8b6e-40bdf4beb8d2,https://open.oregonstate.education/aandp/,2.1 Elements and Atoms: The Building Blocks of Matter,https://open.oregonstate.education/aandp/chapter/2-1-elements-and-atoms-the-building-blocks-of-matter/,"In nature, atoms of one element tend to join with atoms of other elements in characteristic ways. For example, carbon commonly fills its valence shell by linking up with four atoms of hydrogen. In so doing, the two elements form the simplest of organic molecules—methane—which also is one of the most abundant and stable carbon-containing compounds on Earth. As stated above, another example is water; oxygen needs two electrons to fill its valence shell. It commonly interacts with two atoms of hydrogen, forming H2O. Incidentally, the name “hydrogen” reflects its contribution to water (hydro- = “water”; -gen = “maker”). Thus, hydrogen is the “water maker.”",True,The Behavior of Electrons,,,,
+e0b06513-da5b-40f9-b832-49be3e41a1df,https://open.oregonstate.education/aandp/,2.0 Introduction,https://open.oregonstate.education/aandp/chapter/2-0-introduction/,"The smallest, most fundamental material components of the human body are basic chemical elements. In fact, chemicals called nucleotide bases are the foundation of the genetic code with the instructions on how to build and maintain the human body from conception through old age. There are about three billion of these base pairs in human DNA.",True,The Behavior of Electrons,,,,
+7913d6ae-ee5d-4cb9-bb2d-84445d99fdb8,https://open.oregonstate.education/aandp/,2.0 Introduction,https://open.oregonstate.education/aandp/chapter/2-0-introduction/,"Human chemistry includes organic molecules (carbon-based) and biochemicals (those produced by the body). Human chemistry also includes elements. In fact, life cannot exist without many of the elements that are part of the earth. All of the elements that contribute to chemical reactions, to the transformation of energy, and to electrical activity and muscle contraction—elements that include phosphorus, carbon, sodium, and calcium, to name a few—originated in stars.",True,The Behavior of Electrons,,,,
+7e889b38-cbb8-4291-b662-698375ab69f7,https://open.oregonstate.education/aandp/,2.0 Introduction,https://open.oregonstate.education/aandp/chapter/2-0-introduction/,"These elements, in turn, can form both the inorganic and organic chemical compounds important to life, including, water, glucose, and proteins. This chapter begins by examining elements and how the structures of atoms, the basic units of matter, determine the characteristics of elements by the number of protons, neutrons, and electrons in the atoms. The chapter then builds the framework of life from there.",True,The Behavior of Electrons,,,,
+dd7a1898-24d5-48de-be31-1a0fced62efb,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"For thousands of years, fear of the dead and legal sanctions limited the ability of anatomists and physicians to study the internal structures of the human body. An inability to control bleeding, infection, and pain made surgeries infrequent, and those that were performed—such as wound suturing, amputations, tooth and tumor removals, skull drilling, and cesarean births—did not greatly advance knowledge about internal anatomy. Theories about the function of the body and about disease were therefore largely based on external observations and imagination. During the fourteenth and fifteenth centuries, however, the detailed anatomical drawings of Italian artist and anatomist Leonardo da Vinci and Flemish anatomist Andreas Vesalius were published, and interest in human anatomy began to increase. Medical schools began to teach anatomy using human dissection; some resorted to grave robbing to obtain corpses. Laws were eventually passed that enabled students to dissect the corpses of criminals and those who donated their bodies for research. Still, it was not until the late nineteenth century that medical researchers discovered non-surgical methods to look inside the living body.",True,The Behavior of Electrons,,,,
+05f8db45-468e-4b11-bbea-bcf3e1d2d752,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,X-Rays,False,X-Rays,,,,
+7c6bda9e-914e-431d-8434-3b69f902fbc8,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible “ray” would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an “X-ray” image (as it came to be called) of his wife’s hand. Scientists around the world quickly began their own experiments with X-rays, and by 1900, X-rays were widely used to detect a variety of injuries and diseases. In 1901, Röntgen was awarded the first Nobel Prize for physics for his work in this field.",True,X-Rays,,,,
+4bd0060a-a31e-4534-b7ea-17bc13ae2306,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"The X-ray is a form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases. As they are used in medicine, X-rays are emitted from an X-ray machine and directed toward a specially treated metallic plate placed behind the patient’s body. The beam of radiation results in darkening of the X-ray plate. X-rays are slightly impeded by soft tissues, which show up as gray on the X-ray plate, whereas hard tissues, such as bone, largely block the rays, producing a light-toned “shadow.” Thus, X-rays are best used to visualize hard body structures such as teeth and bones (Figure 1.5.1). Like many forms of high energy radiation, however, X-rays are capable of damaging cells and initiating changes that can lead to cancer. This danger of excessive exposure to X-rays was not fully appreciated for many years after their widespread use.",True,X-Rays,Figure 1.5.1,1.5 Medical Imaging,https://open.oregonstate.education/app/uploads/sites/157/2019/07/01_16_X-ray_of_Hand.jpg,"Figure 1.5.1 – X-Ray of a Hand:  High energy electromagnetic radiation allows the internal structures of the body, such as bones, to be seen in X-rays like these. (credit: Trace Meek/flickr)"
+fc9f539b-34a2-4094-a771-aa67c6750766,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Refinements and enhancements of X-ray techniques have continued throughout the twentieth and twenty-first centuries. Although often supplanted by more sophisticated imaging techniques, the X-ray remains a “workhorse” in medical imaging, especially for viewing fractures and for dentistry. The disadvantage of irradiation to the patient and the operator is now attenuated by proper shielding and by limiting exposure.",True,X-Rays,,,,
+e158dd22-bffe-42a4-b068-590eeca606fc,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Modern Medical Imaging,False,Modern Medical Imaging,,,,
+439672a1-3676-4142-b9c5-f3e9674f7a9c,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"X-rays can depict a two-dimensional image of a body region, and only from a single angle. In contrast, more recent medical imaging technologies produce data that is integrated and analyzed by computers to produce three-dimensional images or images that reveal aspects of the body functioning.",True,Modern Medical Imaging,,,,
+970c9c8e-03f6-4823-b045-fac26dc50191,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Computed Tomography,False,Computed Tomography,,,,
+a2adbef1-bfa5-4e92-b7c2-6aa988e3c0a5,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Tomography refers to imaging by sections. Computed tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal minute details about structures in the body (Figure 1.5.2a). The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images. A computer combines these images into a two-dimensional view of the scanned area, or “slice.”",True,Computed Tomography,Figure 1.5.2,1.5 Medical Imaging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+2746074e-cab6-414d-bea7-6bc2c68185fa,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Since 1970, the development of more powerful computers and more sophisticated software has made CT scanning routine for many types of diagnostic evaluations. It is especially useful for soft tissue scanning, such as of the brain and the thoracic and abdominal viscera. Its level of detail is so precise that it can allow physicians to measure the size of a mass down to a millimeter. The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. In fact, children who undergo CT scans are at increased risk of developing cancer, as are adults who have multiple CT scans.",True,Computed Tomography,,,,
+b128e55a-9d7a-4a8d-b7c5-6a6af2b7c1a2,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Magnetic Resonance Imaging,False,Magnetic Resonance Imaging,,,,
+75376e78-e424-457f-b0cc-2f612bfd4733,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device, which was in use clinically by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially to discover tumors. MRI also has the major advantage of not exposing patients to radiation.",True,Magnetic Resonance Imaging,,,,
+89a7dce4-b250-4f3f-bfc6-84cbf4969327,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan (see Figure 1.5.2b), sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, and so on) cannot undergo MRI scanning because it can dislodge these implants.",True,Magnetic Resonance Imaging,Figure 1.5.2,1.5 Medical Imaging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+97349173-edc2-4dae-86fd-f0d57af07192,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Functional MRIs (fMRIs), which detect the concentration of blood flow in certain parts of the body, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions, abnormalities, and diseases.",True,Magnetic Resonance Imaging,,,,
+1d7d1feb-cb02-4c6f-ac8a-e929f21ad383,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Positron Emission Tomography,False,Positron Emission Tomography,,,,
+05da35bc-47bc-4083-ba08-9c9855c3ca40,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Positron emission tomography (PET) is a medical imaging technique involving the use of so-called radiopharmaceuticals, substances that emit radiation that is short-lived and therefore relatively safe to administer to the body. Although the first PET scanner was introduced in 1961, it took 15 more years before radiopharmaceuticals were combined with the technique and revolutionized its potential. The main advantage is that PET (see Figure 1.5.2c) can illustrate physiologic activity—including nutrient metabolism and blood flow—of the organ or organs being targeted, whereas CT and MRI scans can only show static images. PET is widely used to diagnose a multitude of conditions, such as heart disease, the spread of cancer, certain forms of infection, brain abnormalities, bone disease, and thyroid disease.",True,Positron Emission Tomography,Figure 1.5.2,1.5 Medical Imaging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+94974f2d-18d0-4a57-b0fd-bb8083dfad81,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Ultrasonography,False,Ultrasonography,,,,
+43195399-ddc5-4a8a-a107-2fd854fa96fe,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Ultrasonography is an imaging technique that uses the transmission of high-frequency sound waves into the body to generate an echo signal that is converted by a computer into a real-time image of anatomy and physiology (see Figure 1.5.2d). Ultrasonography is the least invasive of all imaging techniques, and it is therefore used more freely in sensitive situations such as pregnancy. The technology was first developed in the 1940s and 1950s. Ultrasonography is used to study heart function, blood flow in the neck or extremities, certain conditions such as gallbladder disease, and fetal growth and development. The main disadvantages of ultrasonography are that the image quality is heavily operator-dependent and that it is unable to penetrate bone and gas.",True,Ultrasonography,Figure 1.5.2,1.5 Medical Imaging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+ae7ea320-e812-40f5-bf5f-35cf8bdb30f9,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,Microscopy,False,Microscopy,,,,
+8259daa0-ef45-4d65-8495-1c59e7b72217,https://open.oregonstate.education/aandp/,1.5 Medical Imaging,https://open.oregonstate.education/aandp/chapter/1-5-medical-imaging/,"Microscopy is not an imaging technique, but rather a way to view a small sample of tissue removed from the human body. When there is a problem in a specific body tissue, a physician can remove a sample of the tissue from the body and prepare it as a microscope slide. The physician can then view structures not visible with the naked eye. Commonly used microscope techniques include light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Tissue samples used in light microscopy are typically stained using colorful dyes to enhance contrast as various parts of the cells take up dye differently. Light microscopes typically magnify approximately 10x to 1000x. In contrast, SEM can magnify up to 500,000x and TEM can magnify up to 10,000,000x. Both SEM and TEM use electron waves rather than light to magnify a sample. SEM provides a 3D image of the sample surface, whereas TEM provides a high resolution image from an ultra-thin sample.",True,Microscopy,,,,
+ab594f5d-08ae-4eab-ae3b-4192fbaaf8be,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"Anatomists and health care providers use terminology that can be bewildering to the uninitiated; however, the purpose of this language is not to confuse, but rather to increase precision and reduce medical errors. For example, is a scar “above the wrist” located on the forearm two or three inches away from the hand? Or is it at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. For example, you might say a scar “on the anterior antebrachium 3 inches proximal to the carpus”. Anatomical terms are derived from ancient Greek and Latin words. Because these languages are no longer used in everyday conversation, the meaning of their words do not change.",True,Microscopy,,,,
+1a6080fa-dcae-4e91-895f-1cfd26bf87ec,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"Anatomical terms are made up of roots, prefixes, and suffixes. The root of a term often refers to an organ, tissue, or condition, whereas the prefix or suffix often describes the root. For example, in the disorder hypertension, the prefix “hyper-” means “high” or “over,” and the root word “tension” refers to pressure, so the word “hypertension” refers to abnormally high blood pressure.",True,Microscopy,,,,
+95c18630-1eda-4f59-a503-e92601f1c8f3,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Anatomical Position,False,Anatomical Position,,,,
+2f7fea39-44da-49eb-809f-95c79cc0452b,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated in Figure 1.4.1. Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.",True,Anatomical Position,Figure 1.4.1,1.4 Anatomical Terminology,https://open.oregonstate.education/app/uploads/sites/157/2019/07/107_Regions_of_Human_Body_new.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.
+7a6f3ce9-1cc6-4078-9bda-6da0fd750fe8,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Regional Terms,False,Regional Terms,,,,
+b956492f-1f54-41c1-ac70-0dc067ea1607,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"The human body’s numerous regions have specific terms to help increase precision (see Figure 1.4.1). Notice that the term “brachium” or “arm” is reserved for the “upper arm” and “antebrachium” or “forearm” is used rather than “lower arm.” Similarly, “femur” or “thigh” is correct, and “leg” or “crus” is reserved for the portion of the lower limb between the knee and the ankle. You will be able to describe the body’s regions using the terms from the figure.",True,Regional Terms,Figure 1.4.1,1.4 Anatomical Terminology,https://open.oregonstate.education/app/uploads/sites/157/2019/07/107_Regions_of_Human_Body_new.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.
+203de346-0a76-4cd6-a975-2320fffa99c7,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Directional Terms,False,Directional Terms,,,,
+b3f7b95d-afc6-44ad-97bb-8f419e759b36,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Directional Terms,False,Directional Terms,,,,
+7a2b8164-5049-4810-9f53-383c9ef75d02,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"Certain directional anatomical terms appear throughout this and any other anatomy textbook (Figure 1.4.2). These terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.",True,Directional Terms,Figure 1.4.2,1.4 Anatomical Terminology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/108_Directional_Terms.jpg,Figure 1.4.2 – Directional Terms Applied to the Human Body: Paired directional terms are shown as applied to the human body.
+0b490cf8-2b55-4dab-a9ad-be8910489c42,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Anterior (or ventral) describes the front or direction toward the front of the body. The toes are anterior to the foot.,True,Directional Terms,,,,
+075709c0-4fb5-4f3d-9eca-fb1005a8dc33,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Posterior (or dorsal) describes the back or direction toward the back of the body. The popliteus is posterior to the patella.,True,Directional Terms,,,,
+953f5365-0c0e-4112-afa4-3ecd97aaa9d5,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Superior (or cranial) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.,True,Directional Terms,,,,
+b0ce2bf7-a568-45ec-9279-8177b238efa2,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"Inferior (or caudal) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.",True,Directional Terms,,,,
+288a3f4e-265e-4d73-b636-51c02c640505,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Lateral describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.,True,Directional Terms,,,,
+17ed0547-c0ff-432a-8564-a400ee05a681,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe.,True,Directional Terms,,,,
+f2b70443-4484-4b2e-b03c-519072353db6,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.,True,Directional Terms,,,,
+a3a330e4-3990-480c-9750-2fdf01a71757,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.,True,Directional Terms,,,,
+5ce40270-2990-4898-baaa-e9ac51757348,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Superficial describes a position closer to the surface of the body. The skin is superficial to the bones.,True,Directional Terms,,,,
+5eb3e16e-6a34-4025-a0c5-290d4c06704f,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Deep describes a position farther from the surface of the body. The brain is deep to the skull.,True,Directional Terms,,,,
+06045922-7d28-4274-bf51-bdbf7fa923ea,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Body Planes,False,Body Planes,,,,
+2d56e886-8213-431d-a96b-33041619cd51,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Body Planes,False,Body Planes,,,,
+3325b3b8-99a0-4726-b239-a858e98af825,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"A section is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain “virtual sections” of living bodies. We call these scans. Body sections and scans can be correctly interpreted, only if the viewer understands the plane along which the section was made. A plane is an imaginary, two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure 1.4.3.",True,Body Planes,Figure 1.4.3,1.4 Anatomical Terminology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/109_Planes_of_Body.jpg,"Figure 1.4.3 – Planes of the Body: The three planes most commonly used in anatomical and medical imaging are the sagittal, frontal (or coronal), and transverse planes."
+4ac373b9-7d0c-4571-958d-23c46bbb68fa,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,section,False,section,,,,
+506749b1-dd27-421f-99f6-f3e174132dea,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"The sagittal plane divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section.",True,section,,,,
+507ec2b0-b875-4565-b0dd-190a964b0f96,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,The frontal plane divides the body or an organ into an anterior (front) portion and a posterior (rear) portion. The frontal plane is often referred to as a coronal plane. (“Corona” is Latin for “crown.”),True,section,,,,
+a4275891-6119-4301-8707-2cd83d943664,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,The transverse (or horizontal) plane divides the body or organ horizontally into upper and lower portions. Transverse planes produce images referred to as cross sections.,True,section,,,,
+b2c1b0f3-8b24-46b4-bb90-9bf5924aa362,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Body Cavities,False,Body Cavities,,,,
+2c13bd1d-3582-4035-86bc-294cb7ffd96a,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Body Cavities,False,Body Cavities,,,,
+ce929703-6dc1-4fd5-986b-7449540c174e,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The main cavities of the body include the cranial, thoracic and abdominopelvic (also known as the peritoneal) cavities. The cranial bones create the cranial cavity where the brain sits. The thoracic cavity is enclosed by the rib cage and contains the lungs and the heart, which is located in the mediastinum. The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic/peritoneal cavity. The abdominopelvic/peritoneal cavity is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, (the division that houses the digestive organs), and the pelvic cavity, (the division that houses the organs of reproduction).",True,Body Cavities,,,,
+0802a036-bef8-4e9a-85ab-811b73594ba8,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,cranial cavity,False,cranial cavity,,,,
+e6e50784-4a60-4f40-8d08-4d0f48b7cc06,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Abdominal Regions and Quadrants,False,Abdominal Regions and Quadrants,,,,
+d4618e00-6ca7-42f2-9676-d5d8827d054f,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,Abdominal Regions and Quadrants,False,Abdominal Regions and Quadrants,,,,
+846b8121-4f7a-4128-a8ac-7e8e70d48cd9,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"To promote clear communication, for instance, about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants (Figure 1.4.4).",True,Abdominal Regions and Quadrants,Figure 1.4.4,1.4 Anatomical Terminology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/111_Abdominal_Quadrant_Regions.jpg,Figure 1.4.4 – Regions and Quadrants of the Peritoneal Cavity: There are (a) nine abdominal regions and (b) four abdominal quadrants in the peritoneal cavity.
+abcdf987-860c-490a-8a20-b253c75df6f1,https://open.oregonstate.education/aandp/,1.4 Anatomical Terminology,https://open.oregonstate.education/aandp/chapter/1-4-anatomical-terminology/,"The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). There are nine resulting regions. The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersect at the patient’s umbilicus (navel).",True,Abdominal Regions and Quadrants,,,,
+65f8d785-acd2-4e9f-b377-f6092a7ff402,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"Maintaining a stable system requires the body to continuously monitor its internal conditions. Though certain physiological systems operate within frequently larger ranges, certain body parameters are tightly controlled homeostatically. For example, body temperature and blood pressure are controlled within a very narrow range. A set point is the physiological value around which the normal range fluctuates. For example, the set point for typical human body temperature is approximately 37°C (98.6°F). Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a range of a few degrees above and below that point. Receptors located in the body’s key places detect changes from this set point and relay information to the control centers located in the brain. The control centers monitor and send information to effector organs to control the body’s response. If these effectors reverse the original condition, the system is said to be regulated through negative feedback.",True,Abdominal Regions and Quadrants,,,,
+0bd5dffa-52d4-408a-a548-f33cb9f2c6fc,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"Control centers in the brain and other parts of the body monitor and react to deviations from this set point using negative feedback. Negative feedback is a mechanism that reverses a deviation from the set point, and in turn, maintains body parameters within their normal range. The maintenance of homeostasis by negative feedback goes on throughout the body at all times and an understanding of negative feedback is thus fundamental to an understanding of human physiology.",True,Abdominal Regions and Quadrants,,,,
+8dafcb7b-0756-445d-9345-aeba6c8f841f,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"A negative feedback system has three basic components: a sensor, control center and an effector. (Figure 1.3.2a). A sensor, also referred to a receptor, monitors a physiological value, which is then reported to the control center. The control center compares the value to the normal range. If the value deviates too much from the set point, then the control center activates an effector. An effector causes a change to reverse the situation and return the value to the normal range.",True,Abdominal Regions and Quadrants,Figure 1.3.2,1.3 Homeostasis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/105_Negative_Feedback_Loops.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback."
+bd96d4e5-6d63-4cf0-b511-7577f90dd506,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"In order to set the system in motion, a stimulus must drive a physiological parameter beyond its normal range (that is, beyond homeostasis). This stimulus is “heard” by a specific sensor. For example, in the control of blood glucose, specific endocrine cells in the pancreas detect excess glucose (the stimulus) in the bloodstream. These pancreatic beta cells respond to the increased level of blood glucose by releasing the hormone (insulin) into the bloodstream. The insulin signals skeletal muscle fibers, fat cells (adipocytes), and liver cells to take up the excess glucose, removing it from the bloodstream. As glucose concentration in the bloodstream drops, the decrease in concentration—the actual negative feedback—is detected by pancreatic alpha cells, and insulin release stops. This prevents blood sugar levels from continuing to drop below the normal range.",True,Abdominal Regions and Quadrants,,,,
+c8706d9f-e2d4-476f-afa1-c8457e4a531f,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"Humans have a similar temperature regulation feedback system that works by promoting either heat loss or heat gain (Figure 1.3.2b). When the brain’s temperature regulation center receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the “heat-loss center.” This stimulation has three major effects:",True,Abdominal Regions and Quadrants,Figure 1.3.2,1.3 Homeostasis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/105_Negative_Feedback_Loops.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback."
+45f3f158-b221-4d88-8182-30f3f3c11795,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,Blood vessels in the skin begin to dilate allowing more blood from the body core to flow to the surface of the skin allowing the heat to radiate into the environment.,True,Abdominal Regions and Quadrants,,,,
+da1d3cda-4eca-43e0-ace9-5b84595182ba,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"As blood flow to the skin increases, sweat glands are activated to increase their output. As the sweat evaporates from the skin surface into the surrounding air, it takes heat with it.",True,Abdominal Regions and Quadrants,,,,
+c0f48bf5-e340-485c-a77f-d6196cafd138,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the lungs.",True,Abdominal Regions and Quadrants,,,,
+0089ad1d-b980-4678-9a39-c408eb77167d,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"In contrast, activation of the brain’s heat-gain center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of deep veins. This arrangement traps heat closer to the body core and restricts heat loss. If heat loss is severe, the brain triggers an increase in random signals to skeletal muscles, causing them to contract, producing shivering. The muscle contractions of shivering release heat while using up ATP. The brain triggers the thyroid gland in the endocrine system to release thyroid hormone, which increases metabolic activity and heat production in cells throughout the body. The brain also signals the adrenal glands to release epinephrine (adrenaline), a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production.",True,Abdominal Regions and Quadrants,,,,
+b51f3796-55f9-4094-b233-3836c94f1c7f,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"Positive feedback intensifies a change in the body’s physiological condition rather than reversing it. A deviation from the normal range results in more change, and the system moves farther away from the normal range. Positive feedback in the body is normal only when there is a definite end point. Childbirth and the body’s response to blood loss are two examples of positive feedback loops that are normal but are activated only when needed.",True,Abdominal Regions and Quadrants,,,,
+02ba0313-acc4-443a-b377-864067a8a583,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"Childbirth at full term is an example of a situation in which the maintenance of the existing body state is not desired. Enormous changes in the mother’s body are required to expel the baby at the end of pregnancy. The events of childbirth, once begun, must progress rapidly to a conclusion or the life of the mother and the baby are at risk. The extreme muscular work of labor and delivery are the result of a positive feedback system (Figure 1.3.3).",True,Abdominal Regions and Quadrants,Figure 1.3.3,1.3 Homeostasis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/106_Pregnancy-Positive_Feedback.jpg,"Figure 1.3.3 – Positive Feedback Loop: Normal childbirth is driven by a positive feedback loop. A positive feedback loop results in a change in the body’s status, rather than a return to homeostasis."
+8a4b14f3-b3a7-4b52-aa04-f744896f22ce,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"The first contractions of labor (the stimulus) push the baby toward the cervix (the lowest part of the uterus). The cervix contains stretch-sensitive nerve cells that monitor the degree of stretching (the sensors). These nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain to release the hormone oxytocin into the bloodstream. Oxytocin causes stronger contractions of the smooth muscles in of the uterus (the effectors), pushing the baby further down the birth canal. This causes even greater stretching of the cervix. The cycle of stretching, oxytocin release, and increasingly more forceful contractions stops only when the baby is born. At this point, the stretching of the cervix halts, stopping the release of oxytocin.",True,Abdominal Regions and Quadrants,,,,
+f9b3238e-228c-4389-b578-7b611478be8b,https://open.oregonstate.education/aandp/,1.3 Homeostasis,https://open.oregonstate.education/aandp/chapter/1-3-homeostasis/,"A second example of positive feedback centers on reversing extreme damage to the body. Following a penetrating wound, the most immediate threat is excessive blood loss. Less blood circulating means reduced blood pressure and reduced perfusion (penetration of blood) to the brain and other vital organs. If perfusion is severely reduced, vital organs will shut down and the person will die. The body responds to this potential catastrophe by releasing substances in the injured blood vessel wall that begin the process of blood clotting. As each step of clotting occurs, it stimulates the release of more clotting substances. This accelerates the processes of clotting and sealing off the damaged area. Clotting is contained in a local area based on the tightly controlled availability of clotting proteins. This is an adaptive, life-saving cascade of events.",True,Abdominal Regions and Quadrants,,,,
+7595f975-1a68-4e72-9c86-434916c05ba6,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity, such as (from smallest to largest): chemicals, cells, tissues, organs, organ systems, and an organism.",True,Abdominal Regions and Quadrants,,,,
+6416f373-ee5f-4848-a60b-69cddb7afe29,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"The organization of the body often is discussed in terms of the distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.",True,Abdominal Regions and Quadrants,,,,
+9c33245f-3f18-4967-b154-ce0d4f1313b3,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,The Levels of Organization,False,The Levels of Organization,,,,
+e97bee57-ac0d-4038-8fb7-34b2dc2e293b,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements. Examples of these elements are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an atom. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a molecule, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures.",True,The Levels of Organization,,,,
+07ab2479-e16d-4fcf-9af4-7de5f591f94f,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"A cell is the smallest independently functioning unit of a living organism. Single celled organisms, like bacteria, are extremely small, independently-living organisms with a cellular structure. Humans are multicellular organisms with independent cells working in concert together. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells.",True,The Levels of Organization,,,,
+6cd4930c-ad56-4b24-a666-540437d45d56,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid, with a variety of tiny functioning units called organelles. In humans, as in all organisms, cells perform all functions of life.",True,The Levels of Organization,,,,
+b100e6a6-b4e3-45e4-9c72-877f58b05c28,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,A tissue is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. An organ is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions. An organ system is a group of organs that work together to perform major functions or meet physiological needs of the body.,True,The Levels of Organization,,,,
+bc65b489-5db0-42f8-a50e-c2edc6254049,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"This book covers eleven distinct organ systems in the human body (Figure 1.2.2). Assigning organs to organ systems can be imprecise since organs that “belong” to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.",True,The Levels of Organization,Figure 1.2.2,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/app/uploads/sites/157/2021/02/102_Organ_Systems_of_BodyPage2_revised-Recovered_modified.png,Figure 1.2.2 – Organ Systems of the Human Body: Organs that work together are grouped into organ systems.
+63d4f050-3d67-49d7-96ac-6aa99aa731e3,https://open.oregonstate.education/aandp/,1.2 Structural Organization of the Human Body,https://open.oregonstate.education/aandp/chapter/1-2-structural-organization-of-the-human-body/,"The organism level is the highest level of organization. An organism is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In multi-cellular organisms, including humans, all cells, tissues, organs, and organ systems of the body work together to maintain the life and health of the organism.",True,The Levels of Organization,,,,
+32e3acf5-411d-473c-bfbc-e953fd403a1c,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Human anatomy is the scientific study of the body’s structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope, while other, larger structures can readily be seen, manipulated, measured, and weighed. The word “anatomy” comes from the Greek root “ana” which means “to cut apart” and “tomia” which means “to cut.” Human anatomy was first studied by observing the exterior of the body, wounds of soldiers, and other injuries. Later, physicians were allowed to dissect bodies of the dead to augment their knowledge. When a body is dissected, its structures are cut apart in order to observe their physical attributes and their relationships to one another. Dissection is still used in medical schools, anatomy courses, and in pathology labs. In order to observe structures in living people, however, a number of imaging techniques have been developed. These techniques allow clinicians to visualize structures inside the living body such as a cancerous tumor or a fractured bone.",True,The Levels of Organization,,,,
+e28f50ec-cd69-4ee6-a2bf-0fdf166d193f,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Like most scientific disciplines, anatomy has areas of specialization. Gross anatomy is the study of the larger structures of the body, those visible without the aid of magnification (image below, Figure 1.1.1a). Gross and macro both mean “large,” thus, gross anatomy is also referred to as macroscopic anatomy. In contrast, micro means “small,” and microscopic anatomy is the study of structures that can be observed only with the use of a microscope or other magnification devices (image below, Figure 1.1.1b). Microscopic anatomy includes cytology, the study of cells, and histology, the study of tissues. As the technology of microscopes has advanced, anatomists have been able to observe smaller and smaller structures of the body, from slices of large structures like the heart, to the three-dimensional structures of large molecules in the body.",True,The Levels of Organization,Figure 1.1.1,1.1 How Structure Determines Function,https://open.oregonstate.education/app/uploads/sites/157/2019/07/01_01ab_Gross_and_Microscopic_Anatomy.jpg,"Figure 1.1.1 – Gross and Microscopic Anatomy: (a) Gross anatomy considers large structures such as the brain. (b) Microscopic anatomy can deal with the same structures, though at a different scale. This is a micrograph of nerve cells from the brain. LM × 1600. (credit a: “WriterHound”/Wikimedia Commons; credit b: Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+94b8d645-b89e-4e42-b66e-d549524c7606,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Anatomists take two general approaches to the study of the body’s structures: regional and systemic. Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. In contrast, systemic anatomy is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function. For example, a systemic anatomical study of the muscular system would consider all of the skeletal muscles of the body.",True,The Levels of Organization,,,,
+5262367e-e192-4b5f-ab66-14e824d40f9d,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Whereas anatomy is about structure, physiology is about function. Human physiology is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life. Much of the study of physiology centers on the body’s tendency toward homeostasis. Homeostasis is the state of steady internal conditions maintained by living things. The study of physiology certainly includes observation, both with the naked eye and with microscopes, as well as manipulations and measurements. Current advances in physiology usually depend on carefully designed laboratory experiments that reveal the functions of the many structures and chemical compounds that make up the human body.",True,The Levels of Organization,,,,
+713d3772-59d9-4216-a482-c3829cddae2a,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Like anatomists, physiologists typically specialize in a particular branch of physiology. For example, neurophysiology is the study of the brain, spinal cord, and nerves and how these work together to perform functions as complex and diverse as vision, movement, and thinking. Physiologists may work from the organ level (exploring, for example, what different parts of the brain does) to the molecular level (such as exploring how an electrochemical signal travels along nerves).",True,The Levels of Organization,,,,
+2fc53a39-e50d-46e4-a37e-4502c3a1f6da,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Form is closely related to function in all living things. For example, the thin flap of your eyelid can snap down to clear away dust particles and almost instantaneously slide back up to allow you to see again. At the microscopic level, the arrangement and function of the nerves and muscles that serve the eyelid allow for its quick action and retreat. At a smaller level of analysis, the function of these nerves and muscles likewise relies on the interactions of specific molecules and ions. Even the three-dimensional structure of certain molecules is essential to their function.",True,The Levels of Organization,,,,
+51af7b80-b238-4869-b0cf-bb52caafe957,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,"Your study of anatomy and physiology will make more sense if you continually relate the form of the structures you are studying to their function. In fact, it can be somewhat frustrating to attempt to study anatomy without an understanding of the physiology that a body structure supports. Imagine, for example, trying to appreciate the unique arrangement of the bones of the human hand if you had no conception of the function of the hand. Fortunately, your understanding of how the human hand manipulates tools—from pens to cell phones—helps you appreciate the unique alignment of the thumb in opposition to the four fingers, making your hand a structure that allows you to pinch and grasp objects and type text messages.",True,The Levels of Organization,,,,
+234a4244-d252-4060-9f0c-f734e1a250f3,https://open.oregonstate.education/aandp/,1.1 How Structure Determines Function,https://open.oregonstate.education/aandp/chapter/1-1-how-structure-determines-function/,Glossary,False,Glossary,,,,
+7dd09b14-f3b2-465f-9ee1-e214ad880f99,https://open.oregonstate.education/aandp/,1.0 Introduction,https://open.oregonstate.education/aandp/chapter/introduction/,"Though you may approach a course in anatomy and physiology strictly as a requirement for your field of study, the knowledge you gain in this course will serve you well in many aspects of your life. An understanding of anatomy and physiology is not only fundamental to any career in the health professions, but it can also benefit your own health. Familiarity with the human body can help you make healthful choices and prompt you to take appropriate action when signs of illness arise. Your knowledge in this field will help you understand news about nutrition, medications, medical devices, procedures and help you understand genetic or infectious diseases. At some point, everyone will have a problem with some aspect of his or her body and your knowledge can help you be a better parent, spouse, partner, friend, colleague, or caregiver.",True,Glossary,,,,
+373a591f-ad05-4b14-9543-faf7ac0be53e,https://open.oregonstate.education/aandp/,1.0 Introduction,https://open.oregonstate.education/aandp/chapter/introduction/,This chapter begins with an overview of anatomy and physiology and a preview of the body regions and functions. It then covers the characteristics of life and how the body works to maintain stable conditions. It introduces a set of standard terms for body structures and for planes and positions in the body that will serve as a foundation for more comprehensive information covered later in the text. It ends with examples of medical imaging used to see inside the living human body.,True,Glossary,,,,
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+fig_num,sub_section_headings,images-src,image_caption
+Figure 28.7.1,From Genotype to Phenotype,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2923_Male_Chromosomes.jpg,"Figure 28.7.1 – Chromosomal Complement of a Male: Each pair of chromosomes contains hundreds to thousands of genes. The banding patterns are nearly identical for the two chromosomes within each pair, indicating the same organization of genes. As is visible in this karyotype, the only exception to this is the XY sex chromosome pair in males. (credit: National Human Genome Research Institute)"
+Figure 28.7.2,Mendel’s Theory of Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2924_Mendelian_Pea_Plant_Cross.jpg,"Figure 28.7.2 – Random Segregation: In the formation of gametes, it is equally likely that either one of a pair alleles from one parent will be passed on to the offspring. This figure follows the possible combinations of alleles through two generations following a first-generation cross of homozygous dominant and homozygous recessive parents. The recessive phenotype, which is masked in the second generation, has a 1 in 4, or 25 percent, chance of reappearing in the third generation."
+Figure 28.7.3,Autosomal Dominant Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2925_Autosomal_Dominant_Inheritance.jpg,"Figure 28.7.3 – Autosomal Dominant Inheritance: Inheritance pattern of an autosomal dominant disorder, such as neurofibromatosis, is shown in a Punnett square."
+Figure 28.7.4,Autosomal Recessive Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2926_Autosomal_Recessive_Inheritance-new.jpg,Figure 28.7.4 – Autosomal Recessive Inheritance: The inheritance pattern of an autosomal recessive disorder with two carrier parents reflects a 3:1 probability of expression among offspring. (credit: U.S. National Library of Medicine)
+Figure 28.7.5,X-linked Dominant or Recessive Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2927_X-linked_Dominant_Inheritance-new.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine)
+Figure 28.7.5,X-linked Dominant or Recessive Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2927_X-linked_Dominant_Inheritance-new.jpg,Figure 28.7.5 – X-Linked Patterns of Inheritance: A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine)
+Figure 28.7.6,X-linked Dominant or Recessive Inheritance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2928_X-linked_Recessive_Inheritance-new.jpg,"Figure 28.7.6 – X-Linked Recessive Inheritance: Given two parents in which the father is normal and the mother is a carrier of an X-linked recessive disorder, a son would have a 50 percent probability of being affected with the disorder, whereas daughters would either be carriers or entirely unaffected. (credit: U.S. National Library of Medicine)"
+Figure 28.6.1,The Process of Lactation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2922_Let_Down_Reflex-new-scaled.jpg,Figure 28.6.1 – Let-Down Reflex: A positive feedback loop ensures continued milk production as long as the infant continues to breastfeed.
+Figure 28.5.1,Circulatory Adjustments,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2921_Neonatal_Circulatory_System.jpg,"Figure 28.5.1 – Neonatal Circulatory System: A newborn’s circulatory system reconfigures immediately after birth. The three fetal shunts have been closed permanently, facilitating blood flow to the liver and lungs."
+Figure 28.4.1,Gastrointestinal and Urinary Adjustments,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2917_Size_of_Uterus_Throughout_Pregnancy-02.jpg,Figure 28.4.1 – Size of Uterus throughout Pregnancy: The uterus grows throughout pregnancy to accommodate the fetus.
+Figure 28.4.3,Physiology of Labor,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2919_Hormones_Initiating_Labor-02.jpg,Figure 28.4.3 – Hormones Initiating Labor: A positive feedback loop of hormones works to initiate labor.
+Figure 28.4.4,Stages of Childbirth,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2920_Stages_of_Childbirth-02-scaled.jpg,"Figure 28.4.4 – Stages of Childbirth: The stages of childbirth include Stage 1, early cervical dilation; Stage 2, full dilation and expulsion of the newborn; and Stage 3, delivery of the placenta and associated fetal membranes. (The position of the newborn’s shoulder is described relative to the mother.)"
+Figure 28.3.1,Sexual Differentiation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2915_Sexual_Differentation-02.jpg,Figure 28.3.1 – Sexual Differentiation: Differentiation of the male and female reproductive systems does not occur until the fetal period of development.
+Figure 28.3.2,The Fetal Circulatory System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2916_Fetal_Circulatory_System-02.jpg,"Figure 28.3.2 – Fetal Circulatory System: The fetal circulatory system includes three shunts to divert blood from undeveloped and partially functioning organs, as well as blood supply to and from the placenta."
+Figure 28.2.1,Pre-implantation Embryonic Development,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2903_Preembryonic_Cleavages-02-1.jpg,Figure 28.2.1 – Pre-Embryonic Cleavages: Pre-embryonic cleavages make use of the abundant cytoplasm of the conceptus as the cells rapidly divide without changing the total volume.
+Figure 28.2.2,Implantation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2904_Preembryonic_Development-02-1.jpg,"Figure 28.2.2 – Pre-Embryonic Development: Ovulation, fertilization, pre-embryonic development, and implantation occur at specific locations within the female reproductive system in a time span of approximately 1 week."
+Figure 28.2.3,Implantation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2905_Implantation-1.jpg,"Figure 28.2.3 – Implantation: During implantation, the trophoblast cells of the blastocyst adhere to the endometrium and digest endometrial cells until it is attached securely."
+Figure 28.2.5,Embryonic Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2907_Embroyonic_Disc_Amniotic_Cavity_Yolk_Sac-02-1.jpg,Figure 28.2.5 – Development of the Embryonic Disc: Formation of the embryonic disc leaves spaces on either side that develop into the amniotic cavity and the yolk sac.
+Figure 28.2.6,Embryogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2908_Germ_Layers-02-1.jpg,Figure 28.2.6 – Germ Layers: Formation of the three primary germ layers occurs during the first 2 weeks of development. The embryo at this stage is only a few millimeters in length.
+Figure 28.2.7,Embryogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2909_Embryo_Week_3-02-1.jpg,"Figure 28.2.7 – Fates of Germ Layers in Embryo: Following gastrulation of the embryo in the third week, embryonic cells of the ectoderm, mesoderm, and endoderm begin to migrate and differentiate into the cell lineages that will give rise to mature organs and organ systems in the infant."
+Figure 28.2.8,Development of the Placenta,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2910_The_Placenta-02.jpg,"Figure 28.2.8 – Cross-Section of the Placenta: In the placenta, maternal and fetal blood components are conducted through the surface of the chorionic villi, but maternal and fetal bloodstreams never mix directly."
+Figure 28.2.9,Development of the Placenta,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2911_Photo_of_Placenta-02.jpg,Figure 28.2.9 – Placenta: This post-expulsion placenta and umbilical cord (white) are viewed from the fetal side.
+Figure 28.2.10,Organogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2912_Neurulation-02.jpg,Figure 28.2.10 – Neurulation: The embryonic process of neurulation establishes the rudiments of the future central nervous system and skeleton.
+Figure 28.2.11,Organogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2913_Embryonic_Folding.jpg,"Figure 28.2.11 – Embryonic Folding: Embryonic folding converts a flat sheet of cells into a hollow, tube-like structure."
+Figure 28.2.12,Organogenesis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2914_Photo_of_Embryo-02.jpg,"Figure 28.2.12 – Embryo at 7 Weeks: An embryo at the end of 7 weeks of development is only 10 mm in length, but its developing eyes, limb buds, and tail are already visible. (This embryo was derived from an ectopic pregnancy.) (credit: Ed Uthman)"
+Figure 28.1.1,Contact Between Sperm and Oocyte,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2901_Sperm_Fertilization.jpg,"Figure 28.1.1 – Sperm and the Process of Fertilization: Before fertilization, hundreds of capacitated sperm must break through the surrounding corona radiata and zona pellucida so that one can contact and fuse with the oocyte plasma membrane."
+Figure 27.3.1,Oogenesis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/cb3a51b134cfa417cf88f924fed1d8731ef8754f.jpeg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell."
+Figure 27.3.1,Oogenesis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/cb3a51b134cfa417cf88f924fed1d8731ef8754f.jpeg,"Figure 27.3.1 Oogenesis The unequal cell division of oogenesis produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell."
+Figure 27.3.2,Folliculogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 27.3.2,Folliculogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 27.3.3,Hormonal Control of the Ovarian Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0dbf6852b50fac8780909f0855e32e87bdc761af.jpeg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries."
+Figure 27.3.3,Hormonal Control of the Ovarian Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0dbf6852b50fac8780909f0855e32e87bdc761af.jpeg,"Figure 27.3.3 Hormonal Regulation of Ovulation The hypothalamus and pituitary gland regulate the ovarian cycle and ovulation. GnRH activates the anterior pituitary to produce LH and FSH, which stimulate the production of estrogen and progesterone by the ovaries."
+Figure 27.3.2,Hormonal Control of the Ovarian Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/b192057b57e4b471054c0d5a361f661824607e63.jpeg,"Figure 27.3.2 Folliculogenesis (a) The maturation of a follicle is shown in a clockwise direction proceeding from the primordial follicles. FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells. Once the follicle is mature, it ruptures and releases the oocyte. Cells remaining in the follicle then develop into the corpus luteum. (b) In this electron micrograph of a secondary follicle, the oocyte, theca cells (thecae folliculi), and developing antrum are clearly visible. EM × 1100. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 27.2.1,Onset of Puberty,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Figure_28_03_01.jpg,"Figure 27.2.1 – Hormones of Puberty: During puberty, the release of LH and FSH from the anterior pituitary stimulates the gonads to produce sex hormones in adolescents"
+Figure 27.1.1,Signs of Puberty,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Figure_28_02_02.jpg,"Figure 27.1.1 – Vulva: The mons pubis, labia minora, labia majora and vestibule are referred to collectively as the vulva."
+Figure 27.1.3,Vagina,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_01.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity"
+Figure 27.1.3,Ovaries,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_01.jpg,"Figure 27.1.3  Anatomy of a vagina, uterus, ovaries and pelvic cavity"
+Figure 27.1.4,Breasts,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_09.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple."
+Figure 27.1.4,Breasts,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_02_09.jpg,"Figure 27.1.4 – Anatomy of a Breast: During lactation, milk moves from the alveoli through the lactiferous ducts to the nipple."
+Figure 27.1.5,The Penis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+Figure 27.1.7,Testes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_02.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.
+Figure 27.1.6,Epididymis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_03.jpg,"Figure 27.1.6 – Anatomy of a Testis: This sagittal view shows seminiferous tubules, the site of sperm production. Formed sperm are transferred to the epididymis, where they mature. They leave the epididymis during an ejaculation via the ductus deferens."
+Figure 27.1.5,Scrotum,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+Figure 27.1.7,Scrotum,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_02.jpg,Figure 27.1.7 – Scrotum and Testes: This anterior view shows the structures of a scrotum and two testes.
+Figure 27.1.5,Duct System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+Figure 27.1.5,Seminal Vesicles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+Figure 27.1.5,Prostate Gland,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Figure_28_01_01.jpg,"Figure 27.1.5 – Penis and Testes: The structures of this reproductive system often include the testes, the epididymides, the penis, and the ducts and glands that produce and carry semen. Sperm exit the scrotum through the ductus deferens, which is bundled in the spermatic cord. The seminal vesicles and prostate gland add fluids to the sperm to create semen."
+Figure 26.5.1,Disorders of the Prostate gland,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2716_Symptoms_of_Acidosis_Alkalosis.jpg,Figure 26.5.1 – Symptoms of Acidosis and Alkalosis: Symptoms of acidosis affect several organ systems. Both acidosis and alkalosis can be diagnosed using a blood test.
+Figure 26.4.1,Compensation Mechanisms,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2713_pH_Scale-01.jpg,Figure 26.4.1 – The pH Scale: This chart shows where many common substances fall on the pH scale.
+Figure 26.4.3,Renal Regulation of Acid-Base Balance,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2715_Conservation_of_Bicarbonate_in_Kidney-01.jpg,"Figure 26.4.3 Conservation of Bicarbonate in the Kidney. Tubular cells are not permeable to bicarbonate; thus, bicarbonate is conserved rather than reabsorbed. Steps 1 and 2 of bicarbonate conservation are indicated."
+Figure 26.2.1,Regulation of Water Intake,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2708_Flowchart_of_Thirst_Response-01.jpg,Figure 26.2.1 – A Flowchart Showing the Thirst Response: The thirst response begins when osmoreceptors detect a decrease in water levels in the blood.
+Figure 26.2.2,Role of ADH,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2709_ADH.jpg,"Figure 26.2.2 – Antidiuretic Hormone (ADH): ADH is produced in the hypothalamus and released by the posterior pituitary gland. It causes the kidneys to retain water, constricts arterioles in the peripheral circulation, and affects some social behaviors in mammals."
+Figure 26.2.3,Role of ADH,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2710_Aquaporins-01.jpg,"Figure 26.2.3 – Aquaporins: The binding of ADH to receptors on the cells of the collecting tubule results in aquaporins being inserted into the plasma membrane, shown in the lower cell. This dramatically increases the flow of water out of the tubule and into the bloodstream."
+Figure 26.1.1,Body Water Content,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2701_Water_Content_in_the_Body-01.jpg,"Figure 26.1.1 – Water Content of the Body’s Organs and Tissues: Water content varies in different body organs and tissues, from as little as 8 percent in the teeth to as much as 85 percent in the brain."
+Figure 26.1.2,Fluid Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2702_Fluid_Compartments_ICF_ECF.jpg,Figure 26.1.2 – Fluid Compartments in the Human Body: The intracellular fluid (ICF) is the fluid within cells. The interstitial fluid (IF) is part of the extracellular fluid (ECF) between the cells. Blood plasma is the second part of the ECF. Materials travel between cells and the plasma in capillaries through the IF.
+Figure 26.1.4,Composition of Body Fluids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2704_Concentration_of_Elements_in_Body_Fluids.jpg,"Figure 26.1.4 – The Concentrations of Different Elements in Key Bodily Fluids: The graph shows the composition of the ICF, IF, and plasma. The compositions of plasma and IF are similar to one another but are quite different from the composition of the ICF."
+Figure 26.1.5,Composition of Body Fluids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2705_Sodium_Potassium_Pump.jpg,Figure 26.1.5 – The Sodium-Potassium Pump: The sodium-potassium pump is powered by ATP to transfer sodium out of the cytoplasm and into the ECF. The pump also transfers potassium out of the ECF and into the cytoplasm. (credit: modification of work by Mariana Ruiz Villarreal)
+Figure 26.1.6,Fluid Movement between Compartments,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2108_Capillary_Exchange.jpg,Figure 26.1.6 – Capillary Exchange: Net filtration occurs near the arterial end of the capillary since capillary hydrostatic pressure (CHP) is greater than blood colloidal osmotic pressure (BCOP). There is no net movement of fluid near the midpoint of the capillary since CHP = BCOP. Net reabsorption occurs near the venous end of the capillary since BCOP is greater than CHP.
+Figure 26.1.7,Solute Movement between Compartments,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2706_Facilitated_Diffusion.jpg,Figure 26.1.7 – Facilitated Diffusion: Glucose molecules use facilitated diffusion to move down a concentration gradient through the carrier protein channels in the membrane. (credit: modification of work by Mariana Ruiz Villarreal)
+Figure 25.4.2,Blood Pressure Regulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2626_Renin_Aldosterone_Angiotensin.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.
+Figure 25.8.1,Describe how the kidney modifies filtrate to influence urine production,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2601_Urine_Color_Chart.jpg,Figure 25.8.1 Urine Color can change due to degree of hydration.
+Figure 25.4.2,Regulation of Extracellular Na+,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2626_Renin_Aldosterone_Angiotensin.jpg,Figure 25.4.2 – Conversion of Angiotensin I to Angiotensin II: The enzyme renin converts the pro-enzyme angiotensin I; the lung-derived enzyme ACE converts angiotensin I into active angiotensin II.
+Figure 25.7.1,Regulation of Nitrogen Wastes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2627_Nitrogen_Wastes.jpg,Figure 25.7.1 Nitrogen Wastes.
+Figure 25.6.1,Elimination of Drugs and Hormones,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2621_Loop_of_Henle_Countercurrent_Multiplier_System.jpg,Figure 25.6.1 Countercurrent Multiplier System.
+Figure 25.5.1,Answers for Critical Thinking Questions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2618_Nephron_Secretion_Reabsorption.jpg,Figure 25.5.1 Locations of Secretion and Reabsorption in the Nephron.
+Figure 25.5.2,Reabsorption in the Proximal Convoluted Tubule,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2619_Substances_Reabsorbed_And_Secreted_By_The_PCT.jpg,Figure 25.5.2 Substances Reabsorbed and Secreted by the PCT.
+Figure 25.5.3,Reabsorption in the Proximal Convoluted Tubule,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2620_Reabsorption_of_Bicarbonate_from_the_PCT.jpg,Figure 25.5.3 Reabsorption of Bicarbonate from the PCT.
+Figure 25.4.1,Glomerular Filtration,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2617_Net_Filtration_Pressure_revised-e1568240504781.png,Figure 25.4.1 – Net Filtration Pressure: The NFP is the sum of osmotic and hydrostatic pressures.
+Figure 25.1.1,External Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2608_Kidney_Position_in_Abdomen_revised-e1568240294915.png,Figure 25.1.1 – Kidneys: The kidneys are slightly protected by the ribs and are surrounded by fat for protection. On the superior aspect of each kidney is an adrenal gland.
+Figure 25.1.2,External Anatomy,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2610_The_Kidney_revised.png,Figure 25.1.2 Left Kidney.
+Figure 24.7.1,Food and Metabolism,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2524_MyPlate.jpg,Figure 24.7.1 – MyPlate: The U.S. Department of Agriculture developed food guidelines called MyPlate to help demonstrate how to maintain a healthy lifestyle.
+Figure 24.6.1,Minerals,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2523_The-Hypothalamus_Controls_Thermoregulation-608x1024-1.jpg,Figure 24.6.1 – Hypothalamus Controls Thermoregulation: The hypothalamus controls thermoregulation.
+Figure 24.5.1,The Absorptive State,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2521_The_Absorptive_Stage-scaled.jpg,"Figure 24.5.1 – Absorptive State: During the absorptive state, the body digests food and absorbs the nutrients into cells."
+Figure 24.5.2,The Postabsorptive State,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2522_The_Postabsorptive_Stage-scaled.jpg,"Figure 24.5.2 – Postabsorptive State: During the postabsorptive state, the body must rely on stored glycogen for energy, breaking down glycogen in the cells and releasing it to cell (muscle) or the body (liver)."
+Figure 24.1.1,Starvation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2501_The_Structure_of_ATP_Molecules.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions."
+Figure 24.4.1,Starvation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2517_Protein-Digesting_EnzymesN.jpg,"Figure 24.4.1 – Digestive Enzymes and Hormones: Enzymes in the stomach and small intestine break down proteins into amino acids. HCl in the stomach aids in proteolysis by denaturing proteins, and hormones secreted by intestinal cells direct the digestive processes."
+Figure 24.4.2,Urea Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2518_Urea_Cycle-scaled.jpg,"Figure 24.4.2 – Urea Cycle: Nitrogen is transaminated, creating ammonia and intermediates of the Krebs cycle. Ammonia is processed in the urea cycle to produce urea that is eliminated through the kidneys."
+Figure 24.4.3,Urea Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2519_Energy_From_Amino_Acids.jpg,Figure 24.4.3 – Energy from Amino Acids: Amino acids can be broken down into precursors for glycolysis or the Krebs cycle. Amino acids (in bold) can enter the cycle through more than one pathway.
+Figure 24.3.1,Urea Cycle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2511_A_Triglyceride_Molecule_a_Is_Broken_Down_Into_Monoglycerides_b.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).
+Figure 24.3.1,Urea Cycle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2511_A_Triglyceride_Molecule_a_Is_Broken_Down_Into_Monoglycerides_b.jpg,Figure 24.3.1 – Triglyceride Broken Down into a Monoglyceride: A triglyceride molecule (a) breaks down into a monoglyceride and two free fatty acids (b).
+Figure 24.3.2,Urea Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2512_Chylomicrons_Contain_Triglycerides_Cholesterol_Molecules_and_Other_Lipids.jpg,"Figure 24.3.2 – Chylomicrons: Chylomicrons contain triglycerides, cholesterol molecules, and other apolipoproteins (protein molecules). They function to carry these water-insoluble molecules from the intestine, through the lymphatic system, and into the bloodstream, which carries the lipids to adipose tissue for storage."
+Figure 24.3.3,Lipolysis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2513_The_Breakdown_of_Fatty_Acids-scaled.jpg,"Figure 24.3.3 – Breakdown of Fatty Acids: During fatty acid oxidation, triglycerides can be broken down into acetyl CoA molecules and used for energy when glucose levels are low."
+Figure 24.3.4,Ketogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2514_Ketogenesis.jpg,"Figure 24.3.4 – Ketogenesis: Excess acetyl CoA is diverted from the Krebs cycle to the ketogenesis pathway. This reaction occurs in the mitochondria of liver cells. The result is the production of β-hydroxybutyrate, the primary ketone body found in the blood."
+Figure 24.3.5,Ketone Body Oxidation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2515_Ketone_Oxidation.jpg,"Figure 24.3.5 – Ketone Oxidation: When glucose is limited, ketone bodies can be oxidized to produce acetyl CoA to be used in the Krebs cycle to generate energy."
+Figure 24.3.6,Lipogenesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2516_Lipid_Metabolism.jpg,Figure 24.3.6 – Lipid Metabolism: Lipids may follow one of several pathways during metabolism. Glycerol and fatty acids follow different pathways.
+Figure 24.2.1,Lipogenesis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2503_Cellular_Respiration.jpg,"Figure 24.2.1 – Cellular Respiration: Cellular respiration oxidizes glucose molecules through glycolysis, the Krebs cycle, and oxidative phosphorylation to produce ATP."
+Figure 24.2.2,Glycolysis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2504_Glycosis_Overview-scaled.jpg,"Figure 24.2.2 – Glycolysis Overview: During the energy-consuming phase of glycolysis, two ATPs are consumed, transferring two phosphates to the glucose molecule. The glucose molecule then splits into two three-carbon compounds, each containing a phosphate. During the second phase, an additional phosphate is added to each of the three-carbon compounds. The energy for this endergonic reaction is provided by the removal (oxidation) of two electrons from each three-carbon compound. During the energy-releasing phase, the phosphates are removed from both three-carbon compounds and used to produce four ATP molecules."
+Figure 24.2.4,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2507_The_Krebs_Cycle.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules."
+Figure 24.2.4,Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2507_The_Krebs_Cycle.jpg,"Figure 24.2.4 – Krebs Cycle: During the Krebs cycle, each pyruvate that is generated by glycolysis is converted into a two-carbon acetyl CoA molecule. The acetyl CoA is systematically processed through the cycle and produces high-energy NADH, FADH2, and ATP molecules."
+Figure 24.2.5,Oxidative Phosphorylation and the Electron Transport Chain,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2508_The_Electron_Transport_Chain.jpg,Figure 24.2.5 – Electron Transport Chain: The electron transport chain is a series of electron carriers and ion pumps that are used to pump H+ ions out of the inner mitochondrial matrix.
+Figure 24.2.6,Oxidative Phosphorylation and the Electron Transport Chain,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2509_Carbohydrate_Metabolism-scaled.jpg,"Figure 24.2.6 – Carbohydrate Metabolism: Carbohydrate metabolism involves glycolysis, the Krebs cycle, and the electron transport chain."
+Figure 24.1.1,Catabolic Reactions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2501_The_Structure_of_ATP_Molecules.jpg,"Figure 24.1.1 – Structure of ATP Molecule: Adenosine triphosphate (ATP) is the energy molecule of the cell. During catabolic reactions, ATP is created and energy is stored until needed during anabolic reactions."
+Figure 24.1.2,Catabolic Reactions,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2502_Catabolic_Reactions.jpg,"Figure 24.1.2 – Sources of ATP: During catabolic reactions, proteins are broken down into amino acids, lipids are broken down into fatty acids, and polysaccharides are broken down into monosaccharides. These building blocks are then used for the synthesis of molecules in anabolic reactions."
+Figure 23.7.1,Oxidation-Reduction Reactions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2426_Mechanical_and_Chemical_DigestionN.jpg,Figure 23.7.1 – Digestion and Absorption: Digestion begins in the mouth and continues as food travels through the small intestine. Most absorption occurs in the small intestine.
+Figure 23.7.2,Carbohydrate Digestion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2427_Carbon_Digestion.jpg,Figure 23.7.2 – Carbohydrate Digestion Flow Chart: Carbohydrates are broken down into their monomers in a series of steps.
+Figure 23.7.3,Protein Digestion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2429_Digestion_of_Proteins_Physiology.jpg,Figure 23.7.3 – Digestion of Protein: The digestion of protein begins in the stomach and is completed in the small intestine.
+Figure 23.7.5,Absorption,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2430_Digestive_Secretions_Absorption_of_WaterN.jpg,"Figure 23.7.5 – Digestive Secretions and Absorption of Water: Absorption is a complex process, in which nutrients from digested food are harvested."
+Figure 23.7.6,Lipid Absorption,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2431_Lipid_Absorption.jpg,"Figure 23.7.6 – Lipid Absorption: Unlike amino acids and simple sugars, lipids are transformed as they are absorbed through epithelial cells."
+Figure 23.5.1,The Large Intestine,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2422_Accessory_Organs.jpg,"Figure 23.5.1 – Accessory Organs: The liver, pancreas, and gallbladder are considered accessory digestive organs, but their roles in the digestive system are vital."
+Figure 23.5.2,The Liver,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2423_Microscopic_Anatomy_of_Liver.jpg,Figure 23.5.2 – Microscopic Anatomy of the Liver: The liver is organized into repeating structures called lobules made up of hepatocytes. The liver receives oxygenated blood from the hepatic artery and nutrient-rich deoxygenated blood from the hepatic portal vein and drain the bile formed by the hepatocytes into the bile duct.
+Figure 23.5.3,The Pancreas,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2424_Exocrine_and_Endocrine_Pancreas.jpg,"Figure 23.5.3 – Exocrine and Endocrine Pancreas: The pancreas has a head, a body, and a tail. It delivers pancreatic juice to the duodenum through the pancreatic duct."
+Figure 23.5.4,The Gallbladder,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2425_Gallbladder.jpg,"Figure 23.5.4 – Gallbladder: The gallbladder stores and concentrates bile, and releases it into the two-way cystic duct when it is needed by the small intestine."
+Figure 23.4.1,Structure,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2414_Stomach.jpg,"Figure 23.4.1 – Stomach: The stomach has four major regions: the cardia, fundus, body, and pylorus. The addition of an inner oblique smooth muscle layer gives the muscularis the ability to vigorously churn and mix food."
+Figure 23.4.2,Histology,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2415_Histology_of_StomachN.jpg,"Figure 23.4.2 – Histology of the Stomach: The stomach wall is adapted for the functions of the stomach. In the epithelium, gastric pits lead to gastric glands that secrete gastric juice. The gastric glands (one gland is shown enlarged on the right) contain different types of cells that secrete a variety of enzymes, including hydrochloride acid, which activates the protein-digesting enzyme pepsin."
+Figure 23.4.3,Gastric Secretion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2416_Three_Phases_Gastric_Secretion.jpg,"Figure 23.4.3 – The Three Phases of Gastric Secretion: Gastric secretion occurs in three phases: cephalic, gastric, and intestinal. During each phase, the secretion of gastric juice can be stimulated or inhibited. EDITOR’S NOTE: Each place where figure says “Stimulates stomach secretory activity,” describe what that activity is and how much it is activated. In the section on the cephalic phase it could say something like: secretion of HCl and pepsin. In the section on the gastric phase it could say something like: increased secretion of HCl and pepsin and increased gastric motility. Etc."
+Figure 23.3.1,The Mouth,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2406_Structures_of_the_Mouth.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth."
+Figure 23.3.1,The Mouth,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2406_Structures_of_the_Mouth.jpg,"Figure 23.3.1 – Mouth: The mouth includes the lips, tongue, palate, gums, and teeth."
+Figure 23.3.2,The Tongue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2407_Tongue.jpg,Figure 23.3.2 – Tongue: This superior view of the tongue shows the locations and types of lingual papillae.
+Figure 23.3.6,The Pharynx,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2411_Pharynx.jpg,Figure 23.3.6 – Pharynx: The pharynx runs from the nostrils to the esophagus and the larynx.
+Figure 23.3.7,The Esophagus,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2412_The_Esophagus.jpg,Figure 23.3.7 – Esophagus: The upper esophageal sphincter controls the movement of food from the pharynx to the esophagus. The lower esophageal sphincter controls the movement of food from the esophagus to the stomach.
+Figure 23.3.8,Deglutition,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2413_Deglutition_revised.png,Figure 23.3.8 – Deglutition: Deglutition includes the voluntary phase and two involuntary phases: the pharyngeal phase and the esophageal phase.
+Figure 23.2.1,Digestive Processes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2404_PeristalsisN.jpg,Figure 23.2.1 – Peristalsis: Peristalsis moves food through the digestive tract with alternating waves of muscle contraction and relaxation.
+Figure 23.2.2,Digestive Processes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2405_Digestive_Process.jpg,"Figure 23.2.2 – Digestive Processes: The digestive processes are ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation."
+Figure 23.1.1,Regulatory Mechanisms,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2401_Components_of_the_Digestive_System_revised-e1568240853144.png,Figure 23.1.1 – Components of the Digestive System: All digestive organs play integral roles in the life-sustaining process of digestion.
+Figure 23.1.2,Histology of the Alimentary Canal,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2402_Layers_of_the_Gastrointestinal_Tract.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa."
+Figure 23.1.2,Nerve Supply,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2402_Layers_of_the_Gastrointestinal_Tract.jpg,"Figure 23.1.2 – Layers of the Alimentary Canal: The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa."
+Figure 23.1.3,The Peritoneum,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2403_The_PeritoneumN.jpg,"Figure 23.1.3 – The Peritoneum: A cross-section of the abdomen shows the relationship between abdominal organs and the peritoneum (darker lines). EDITOR’S NOTE: Please add an anterior and sagittal image showing the mesentery, mesocolon, greater omentum, and lesser omentum."
+Figure 22.5.1,Oxygen Transport in the Blood,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2322_Fig_23.22-a.jpg,"Figure 22.5.1 – Erythrocyte and Hemoglobin: Hemoglobin consists of four subunits, each of which contains one molecule of iron."
+Figure 22.5.4,Carbon Dioxide Transport in the Blood,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2325_Carbon_Dioxide_Transport.jpg,"Figure 22.5.4 – Carbon Dioxide Transport: Carbon dioxide is transported by three different methods: (a) in erythrocytes; (b) after forming carbonic acid (H2CO3 ), which is dissolved in plasma; (c) and in plasma."
+Figure 22.3.3,Pulmonary Ventilation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2316_Inspiration_and_Expiration.jpg,"Figure 22.3.3 – Inspiration and Expiration: Inspiration and expiration occur due to the expansion and contraction of the thoracic cavity, respectively."
+Figure 22.3.4,Respiratory Volumes and Capacities,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2317_Spirometry_and_Respiratory_Volumes.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.
+Figure 22.3.4,Respiratory Volumes and Capacities,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2317_Spirometry_and_Respiratory_Volumes.jpg,Figure 22.3.4 – Respiratory Volumes and Capacities: These two graphs show (a) respiratory volumes and (b) the combination of volumes that results in respiratory capacity.
+Figure 22.2.1,Gross Anatomy of the Lungs,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2312_Gross_Anatomy_of_the_Lungs.jpg,Figure 22.2.1 Gross Anatomy of the Lungs.
+Figure 22.2.2,Pleura of the Lungs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2313_The_Lung_Pleurea.jpg,Figure 22.2.2 Parietal and Visceral Pleurae of the Lungs.
+Figure 22.1.1,Pleura of the Lungs,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2301_Major_Respiratory_Organs.jpg,Figure 22.1.1 – Major Respiratory Structures: The major respiratory structures span the nasal cavity to the diaphragm.
+Figure 22.1.9,Respiratory Zone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2309_The_Respiratory_Zone.jpg,"Figure 22.1.9 – Respiratory Zone: Bronchioles lead to alveolar sacs in the respiratory zone, where gas exchange occurs."
+Figure 21.7.1,The Rh Factor,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2230_Erythroblastosis_Fetalis.jpg,"Figure 21.7.1 – Erythroblastosis Fetalis: Erythroblastosis fetalis (hemolytic disease of the newborn) is the result of an immune response in an Rh-negative mother who has multiple children with an Rh-positive father. During the first birth, fetal blood enters the mother’s circulatory system, and anti-Rh antibodies are made. During the gestation of the second child, these antibodies cross the placenta and attack the blood of the fetus. The treatment for this disease is to give the mother anti-Rh antibodies (RhoGAM) during the first pregnancy to destroy Rh-positive fetal red blood cells from entering her system and causing the anti-Rh antibody response in the first place."
+Figure 21.7.2,Immune Responses Against Cancer,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2231_Kaposis_Sacroma_Lesions.jpg,Figure 21.7.2 Karposi’s Sarcoma Lesions. (credit: National Cancer Institute)
+Figure 21.6.1,Hypersensitivities,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2228_Immune_Hypersensitivity_new-scaled.jpg,"Figure 21.6.1 – Immune Hypersensitivity: Components of the immune system cause four types of hypersensitivity. Notice that types I–III are B cell mediated, whereas type IV hypersensitivity is exclusively a T cell phenomenon."
+Figure 21.6.2,Autoimmune Responses,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2229_Autoimmune_Disorders_Rheumatoid_Arthritis_and_Lupus.jpg,Figure 21.6.2 – Autoimmune Disorders: Rheumatoid Arthritis and Lupus. (a) Extensive damage to the right hand of a rheumatoid arthritis sufferer is shown in the x-ray. (b) The diagram shows a variety of possible symptoms of systemic lupus erythematosus.
+Figure 21.4.5,T cell-dependent versus T cell-independent Antigens,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2224_T_and_B_Cell_Binding.jpg,"Figure 21.4.5 – T and B Cell Binding: To elicit a response to a T cell-dependent antigen, the B and T cells must come close together. To become fully activated, the B cell must receive two signals from the native antigen and the T cell’s cytokines."
+Figure 21.3.1,T Cell-Mediated Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2215_Alpha-Beta_T_Cell_Receptor.jpg,"Figure 21.3.1 – Alpha-beta T Cell Receptor: Notice the constant and variable regions of each chain, anchored by the transmembrane region."
+Figure 21.3.2,Antigens,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2214_Antigenic_Determinants.jpg,"Figure 21.3.2 – Antigenic Determinants: A typical protein antigen has multiple antigenic determinants, shown by the ability of T cells with three different specificities to bind to different parts of the same antigen."
+Figure 21.3.4,T Cell Development and Differentiation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2217_Differentiation_of_T_Cells_Within_the_Thymus.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.
+Figure 21.3.4,T Cell Development and Differentiation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2217_Differentiation_of_T_Cells_Within_the_Thymus.jpg,Figure 21.3.4 – Differentiation of T Cells within the Thymus: Thymocytes enter the thymus and go through a series of developmental stages that ensures both function and tolerance before they leave and become functional components of the adaptive immune response.
+Figure 21.3.5,Mechanisms of T Cell-mediated Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2218_Clonal_Selection_and_Expansion_of_T_Lymphocytes.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded."
+Figure 21.3.5,Clonal Selection and Expansion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2218_Clonal_Selection_and_Expansion_of_T_Lymphocytes.jpg,"Figure 21.3.5 – Clonal Selection and Expansion of T Lymphocytes: Stem cells differentiate into T cells with specific receptors, called clones. The clones with receptors specific for antigens on the pathogen are selected for and expanded."
+Figure 21.3.6,T Cell Types and their Functions,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2219_Pathogen_Presentation.jpg,"Figure 21.3.6 – Pathogen Presentation: (a) CD4 is associated with helper and regulatory T cells. An extracellular pathogen is processed and presented in the binding cleft of a class II MHC molecule, and this interaction is strengthened by the CD4 molecule. (b) CD8 is associated with cytotoxic T cells. An intracellular pathogen is presented by a class I MHC molecule, and CD8 interacts with it."
+Figure 21.2.1,T Cell Types and their Functions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2211_Cooperation_Between_Innate_and_Immune_Responses.jpg,Figure 21.2.1 – Cooperation between Innate and Adaptive Immune Responses: The innate immune system enhances adaptive immune responses so they can be more effective
+Figure 21.2.3,Inflammatory Response,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2213_Inflammatory_Process.jpg,Figure 21.2.3 Inflammatory Response.
+Figure 21.1.1,Structure of the Lymphatic System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2201_Anatomy_of_the_Lymphatic_System.jpg,Figure 21.1.1 – Anatomy of the Lymphatic System: Lymphatic vessels in the arms and legs convey lymph to the larger lymphatic vessels in the torso.
+Figure 21.1.4,The Organization of Immune Function,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2204_The_Hematopoietic_System_of_the_Bone_Marrow_new.jpg,Figure 21.1.4 – Hematopoietic System of the Bone Marrow: All the cells of the immune response as well as of the blood arise by differentiation from hematopoietic stem cells. Platelets are cell fragments involved in the clotting of blood.
+Figure 20.6.1,Secondary Lymphoid Organs and their Roles in Active Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2139_Fetal_Circulation.jpg,"Figure 20.6.1 – Fetal Shunts: The foramen ovale in the interatrial septum allows blood to flow from the right atrium to the left atrium. The ductus arteriosus is a temporary vessel, connecting the aorta to the pulmonary trunk. The ductus venosus links the umbilical vein to the inferior vena cava largely through the liver."
+Figure 20.5.1,Secondary Lymphoid Organs and their Roles in Active Immune Responses,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2141_CircSyst_vs_OtherSystemsN.jpg,Figure 20.5.1 Interaction of the Circulatory System with Other Body Systems
+Figure 20.5.2,Pulmonary Circulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+Figure 20.5.3,Overview of Systemic Arteries,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2120_Major_Systemic_Artery.jpg,Figure 20.5.3 – Systemic Arteries: The major systemic arteries shown here deliver oxygenated blood throughout the body.
+Figure 20.5.4,The Aorta,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2121_Aorta.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions."
+Figure 20.5.4,Coronary Circulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2121_Aorta.jpg,"Figure 20.5.4 – Aorta: The aorta has distinct regions, including the ascending aorta, aortic arch, and the descending aorta, which includes the thoracic and abdominal regions."
+Figure 20.5.2,Aortic Arch Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+Figure 20.5.2,Aortic Arch Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2119_Pulmonary_Circuit.jpg,"Figure 20.5.2 – Pulmonary Circuit: Blood exiting from the right ventricle flows into the pulmonary trunk, which bifurcates into the two pulmonary arteries. These vessels branch to supply blood to the pulmonary capillaries, where gas exchange occurs within the lung alveoli. Blood returns via the pulmonary veins to the left atrium."
+Figure 20.5.5,Aortic Arch Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2122_Common_Carotid_Artery.jpg,"Figure 20.5.5 – Arteries Supplying the Head and Neck: The common carotid artery gives rise to the external and internal carotid arteries. The external carotid artery remains superficial and gives rise to many arteries of the head. The internal carotid artery first forms the carotid sinus and then reaches the brain via the carotid canal and carotid foramen, emerging into the cranium via the foramen lacerum. The vertebral artery branches from the subclavian artery and passes through the transverse foramen in the cervical vertebrae, entering the base of the skull at the vertebral foramen. The subclavian artery continues toward the arm as the axillary artery."
+Figure 20.5.7,Thoracic Aorta and Major Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2124_Thoracic_Abdominal_Arteries.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.
+Figure 20.5.7,Abdominal Aorta and Major Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2124_Thoracic_Abdominal_Arteries.jpg,Figure 20.5.7 – Arteries of the Thoracic and Abdominal Regions: The thoracic aorta gives rise to the arteries of the visceral and parietal branches.
+Figure 20.5.8,Abdominal Aorta and Major Branches,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2125_Thoracic_Abdominal_Arteries_Chart-scaled.jpg,Figure 20.5.8 – Major Branches of the Aorta: The flow chart summarizes the distribution of the major branches of the aorta into the thoracic and abdominal regions.
+Figure 20.5.10,Arteries Serving the Upper Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2127_Thoracic_Upper_Limb_Arteries.jpg,Figure 20.5.10 – Major Arteries Serving the Thorax and Upper Limb: The arteries that supply blood to the arms and hands are extensions of the subclavian arteries.
+Figure 20.5.12,Arteries Serving the Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2129ab_Lower_Limb_Arteries_Anterior_Posterior.jpg,Figure 20.5.12 – Major Arteries Serving the Lower Limb: Major arteries serving the lower limb are shown in anterior and posterior views.
+Figure 20.5.13,Arteries Serving the Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2130_Lower_Limb_Arteries_Chart.jpg,Figure 20.5.13 – Systemic Arteries of the Lower Limb: The flow chart summarizes the distribution of the systemic arteries from the external iliac artery into the lower limb.
+Figure 20.5.14,Overview of Systemic Veins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2131_Major_Systematic_Veins.jpg,Figure 20.5.14 – Major Systemic Veins of the Body: The major systemic veins of the body are shown here in an anterior view.
+Figure 20.5.15,The Superior Vena Cava,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2132_Thoracic_Abdominal_Veins.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava."
+Figure 20.5.16,Veins of the Head and Neck,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2133_Head_and_Neck_Veins.jpg,"Figure 20.5.16 – Veins of the Head and Neck: This left lateral view shows the veins of the head and neck, including the intercranial sinuses."
+Figure 20.5.17,Veins Draining the Upper Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2134_Thoracic_Upper_Limb_Veins.jpg,Figure 20.5.17 – Veins of the Upper Limb: This anterior view shows the veins that drain the upper limb.
+Figure 20.5.18,Veins Draining the Upper Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2135_Veins_Draining_into_Superior_Vena_Cava_Chart.jpg,Figure 20.5.18 – Veins Flowing into the Superior Vena Cava: The flow chart summarizes the distribution of the veins flowing into the superior vena cava.
+Figure 20.5.15,The Inferior Vena Cava,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2132_Thoracic_Abdominal_Veins.jpg,"Figure 20.5.15 – Veins of the Thoracic and Abdominal Regions: Veins of the thoracic and abdominal regions drain blood from the area above the diaphragm, returning it to the right atrium via the superior vena cava."
+Figure 20.5.19,The Inferior Vena Cava,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2140_FlowChart_Veins_into_VenaCava.jpg,Figure 20.5.19 – Venous Flow into Inferior Vena Cava: The flow chart summarizes veins that deliver blood to the inferior vena cava.
+Figure 20.5.20,Veins Draining the Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2136ab_Lower_Limb_Veins_Anterior_Posterior.jpg,Figure 20.5.20 – Major Veins Serving the Lower Limbs: Anterior and posterior views show the major veins that drain the lower limb into the inferior vena cava.
+Figure 20.5.21,Veins Draining the Lower Limbs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2137_Lower_Limb_Veins_Chart.jpg,Figure 20.5.21 – Major Veins of the Lower Limb: The flow chart summarizes venous flow from the lower limb.
+Figure 20.5.22,Hepatic Portal System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2138_Hepatic_Portal_Vein_System.jpg,"Figure 20.5.22 – Hepatic Portal System: The liver receives blood from the normal systemic circulation via the hepatic artery. It also receives and processes blood from other organs, delivered via the veins of the hepatic portal system. All blood exits the liver via the hepatic vein, which delivers the blood to the inferior vena cava. (Different colors are used to help distinguish among the different vessels in the system.)"
+Figure 20.4.1,Hepatic Portal System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2115_Vascular_Homeostasis_Flow_Art-1-scaled.jpg,"Figure 20.4.1 – Summary of Factors Maintaining Vascular Homeostasis: Adequate blood flow, blood pressure, distribution, and perfusion involve autoregulatory, neural, and endocrine mechanisms."
+Figure 20.4.4,Effect of Exercise on Vascular Homeostasis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2143_Mechanism_Regulating_Arteries_and_Veins-1-scaled.jpg,Figure 20.4.4 Summary of Mechanisms Regulating Arteriole Smooth Muscle and Veins.
+Figure 20.2.1,Arterial Blood Pressure,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2109_Systemic_Blood_Pressure.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures."
+Figure 20.2.2,Pulse,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2110_Pulse_Sites.jpg,"Figure 20.2.2 – Pulse Sites: The pulse is most readily measured at the radial artery, but can be measured at any of the pulse points shown."
+Figure 20.2.3,Measurement of Blood Pressure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2111_Blood_Pressure_Graph.jpg,"Figure 20.2.3 – Blood Pressure Measurement: When pressure in a sphygmomanometer cuff is released, a clinician can hear the Korotkoff sounds. In this graph, a blood pressure tracing is aligned to a measurement of systolic and diastolic pressures."
+Figure 20.2.1,Four variables influence blood flow and blood pressure:,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2109_Systemic_Blood_Pressure.jpg,"Figure 20.2.1 – Systemic Blood Pressure: The graph shows blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures."
+Figure 20.1.1,Venous System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2101_Blood_Flow_Through_the_Heart.jpg,"Figure 20.1.1 – Cardiovascular Circulation: The pulmonary circuit moves blood from the right side of the heart to the lungs and back to the heart. The systemic circuit moves blood from the left side of the heart to the head and body and returns it to the right side of the heart to repeat the cycle. The arrows indicate the direction of blood flow, and the colors show the relative levels of oxygen concentration."
+Figure 20.1.3,Arteries,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2103_Muscular_and_Elastic_Artery_Arteriole.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries."
+Figure 20.1.3,Arterioles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2103_Muscular_and_Elastic_Artery_Arteriole.jpg,"Figure 20.1.3 – Types of Arteries and Arterioles: Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries."
+Figure 20.1.4,Capillaries,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2104_Three_Major_Capillary_Types.jpg,"Figure 20.1.4 – Types of Capillaries: The three major types of capillaries: continuous, fenestrated, and sinusoid."
+Figure 20.1.5,Metarterioles and Capillary Beds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2105_Capillary_Bed.jpg,"Figure 20.1.5 – Capillary Bed: In a capillary bed, arterioles give rise to metarterioles. Precapillary sphincters located at the junction of a metarteriole with a capillary regulate blood flow. A thoroughfare channel connects the metarteriole to a venule. An arteriovenous anastomosis, which directly connects the arteriole with the venule, is shown at the bottom."
+Figure 20.1.6,Venules,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2106_Large_Medium_Vein_Venule.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins."
+Figure 20.1.6,Veins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2106_Large_Medium_Vein_Venule.jpg,"Figure 20.1.6 – Comparison of Veins and Venules: Many veins have valves to prevent back flow of blood, whereas venules do not. In terms of scale, the diameter of a venule is measured in micrometers compared to millimeters for veins."
+Figure 20.1.8,Veins as Blood Reservoirs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2142_Distribution_of_Blood_Flow.jpg,Figure 20.1.8 Distribution of Blood Flow
+Figure 20.1.8,Veins as Blood Reservoirs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2142_Distribution_of_Blood_Flow.jpg,Figure 20.1.8 Distribution of Blood Flow
+Figure 19.5.1,Veins as Blood Reservoirs,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2037_Embryonic_Development_of_Heart.jpg,Figure 19.5.1 – Development of the Human Heart: This diagram outlines the embryological development of the human heart during the first eight weeks and the subsequent formation of the four heart chambers.
+Figure 19.4.1,CO = HR × SV,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2031_Factors_in_Cardiac_Output.jpg,"Figure 19.4.1 – Major Factors Influencing Cardiac Output: Cardiac output is influenced by heart rate and stroke volume, both of which are also variable."
+Figure 19.4.2,HRMax = 160 bpm,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2032_Automatic_Innervation.jpg,Figure 19.4.2 – Autonomic Innervation of the Heart: Cardioacceleratory and cardioinhibitory areas are components of the paired cardiac centers located in the medulla oblongata of the brain. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus (parasympathetic) nerves that slow cardiac activity.
+Figure 19.4.3,HRMax = 160 bpm,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2033_Depolarization_in_Sinus_Rhythm.jpg,"Figure 19.4.3 – Effects of Parasympathetic and Sympathetic Stimulation on Normal Sinus Rhythm: The wave of depolarization in a normal sinus rhythm shows a stable resting HR. Following parasympathetic stimulation, HR slows. Following sympathetic stimulation, HR increases."
+Figure 19.3.1,Stroke Volume,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2014_Phase_of_Cardiac_Cycle_revised.png,"Figure 19.3.1 – Overview of the Cardiac Cycle: The cardiac cycle begins with atrial systole and progresses to ventricular systole, atrial diastole, and ventricular diastole, when the cycle begins again. Correlations to the ECG are highlighted."
+Figure 19.3.3,Heart Sounds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2029_Cardiac_Cycle_vs_Heart_Sounds_revised.png,"Figure 19.3.3 – Heart Sounds and the Cardiac Cycle: In this illustration, the x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure."
+Figure 19.3.4,Heart Sounds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2030_Stethoscope_Placement.jpg,"Figure 19.3.4 – Stethoscope Placement for Auscultation: Proper placement of the bell of the stethoscope facilitates auscultation. At each of the four locations on the chest, a different valve can be heard."
+Figure 19.2.1,Structure of Cardiac Muscle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2017abc_Cardiac_Muscle.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)"
+Figure 19.2.1,Structure of Cardiac Muscle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2017abc_Cardiac_Muscle.jpg,"Figure 19.2.1 – Cardiac Muscle: (a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012)"
+Figure 19.2.2,Conduction System of the Heart,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2018_Conduction_System_of_Heart.jpg,"Figure 19.2.2 -Conduction System of the Heart: Specialized conducting components of the heart include the sinoatrial node, the internodal pathways, the atrioventricular node, the atrioventricular bundle, the right and left bundle branches, and the Purkinje fibers."
+Figure 19.2.6,Electrocardiogram,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2021_ECG_Placement_of_Electrodes.jpg,"Figure 19.2.6 – Standard Placement of ECG Leads: In a 12-lead ECG, six electrodes are placed on the chest, and four electrodes are placed on the limbs."
+Figure 19.2.7,Electrocardiogram,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2022_Electrocardiogram.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments."
+Figure 19.2.7,Electrocardiogram,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2022_Electrocardiogram.jpg,"Figure 19.2.7 – Electrocardiogram: A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments."
+Figure 19.1.1,Location and Size of the Heart,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2001_Heart_Position_in_Thorax_revised.png,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base."
+Figure 19.1.1,Shape and Size of the Heart,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2001_Heart_Position_in_Thorax_revised.png,"Figure 19.1.1 – Position of the Heart in the Thorax: The heart is located within the thoracic cavity, medially between the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base."
+Figure 19.1.2,Circulation through the Heart and Body,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2003_Dual_System_of_Human_Circulation_revised.png,"Figure 19.1.2 – Dual System of the Human Blood Circulation: Blood flows from the right atrium to the right ventricle, where it is pumped into the pulmonary circuit. The blood in the pulmonary artery branches is low in oxygen but relatively high in carbon dioxide. Gas exchange occurs in the pulmonary capillaries (oxygen into the blood, carbon dioxide out), and blood high in oxygen and low in carbon dioxide is returned to the left atrium. From here, blood enters the left ventricle, which pumps it into the systemic circuit. Following exchange in the systemic capillaries (oxygen and nutrients out of the capillaries and carbon dioxide and wastes in), blood returns to the right atrium and the cycle is repeated."
+Figure 19.1.8,Internal Structure of the Heart,https://open.oregonstate.education/app/uploads/sites/157/2021/02/2008_Internal_Anatomy_of_the_HeartN.jpg,"Figure 19.1.8 – Internal Structures of the Heart: This anterior view of the heart shows the four chambers, the major vessels and their early branches, as well as the four valves. The presence of the pulmonary trunk and aorta covers the interatrial septum, and the atrioventricular septum is cut away to show the atrioventricular valves."
+Figure 18.6.1,Rh Blood Groups,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1910_Erythroblastosis_Fetalis.jpg,"Figure 18.6.1 – Erythroblastosis Fetalis: The first exposure of an Rh− mother to Rh+ erythrocytes during pregnancy induces sensitization. Anti-Rh antibodies begin to circulate in the mother’s bloodstream. A second exposure occurs with a subsequent pregnancy with an Rh+ fetus in the uterus. Maternal anti-Rh antibodies may cross the placenta and enter the fetal bloodstream, causing agglutination and hemolysis of fetal erythrocytes."
+Figure 18.6.2,Determining ABO Blood Types,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1912_Cross_Matching_Blood_Types.jpg,"Figure 18.6.2 – Cross Matching Blood Types: This sample of a commercially produced “bedside” card enables quick typing of both a recipient’s and donor’s blood before transfusion. The card contains three reaction sites or wells. One is coated with an anti-A antibody, one with an anti-B antibody, and one with an anti-D antibody (tests for the presence of Rh factor D). Mixing a drop of blood and saline into each well enables the blood to interact with a preparation of type-specific antibodies. Agglutination of RBCs in a given site indicates a positive identification of the blood antigens, in this case A and Rh antigens for blood type A+. For the purpose of transfusion, the donor’s and recipient’s blood types must match."
+Figure 18.6.3,ABO Transfusion Protocols,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1913_ABO_Blood_Groups.jpg,Figure 18.6.3 – ABO Blood Group: This chart summarizes the characteristics of the blood types in the ABO blood group. See the text for more on the concept of a universal donor or recipient.
+Figure 18.5.1,Coagulation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1909_Blood_Clotting.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)"
+Figure 18.5.1,Fibrinolysis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1909_Blood_Clotting.jpg,"Figure 18.5.1 -Hemostasis: (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie)"
+Figure 18.4.1,Characteristics of Leukocytes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1906_Emigration.jpg,"Figure 18.4.1 – Emigration: Leukocytes exit the blood vessel and then move through the connective tissue of the dermis toward the site of a wound. Some leukocytes, such as the eosinophil and neutrophil, are characterized as granular leukocytes. They release chemicals from their granules that destroy pathogens; they are also capable of phagocytosis. The monocyte, an agranular leukocyte, differentiates into a macrophage that then phagocytizes the pathogens."
+Figure 18.4.3,Platelets,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1908_Platelet_Development.jpg,Figure 18.4.3 – Platelets: Platelets are derived from cells called megakaryocytes.
+Figure 18.3.1,Disorders of Platelets,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1914_Table_19_3_1-scaled.jpg,Figure 18.3.1 Summary of Formed Elements in Blood
+Figure 18.3.2,Shape and Structure of Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1903_Shape_of_Red_Blood_Cells.jpg,"Figure 18.3.2 – Shape of Red Blood Cells: Erythrocytes are biconcave discs with very shallow centers. This shape optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels."
+Figure 18.3.3,Hemoglobin,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1904_Hemoglobin.jpg,"Figure 18.3.3 – Hemoglobin: (a) A molecule of hemoglobin contains four globin proteins, each of which is bound to one molecule of the iron-containing pigment heme. (b) A single erythrocyte can contain 300 million hemoglobin molecules, and thus more than 1 billion oxygen molecules."
+Figure 18.3.4,Lifecycle of Erythrocytes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1905_Erythrocyte_Life_Cycle-scaled.jpg,"Figure 18.3.4 – Erythrocyte Lifecycle: Erythrocytes are produced in the bone marrow and sent into the circulation. At the end of their lifecycle, they are destroyed by macrophages, and their components are recycled."
+Figure 18.2.1,Differentiation of Formed Elements from Stem Cells,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2204_The_Hematopoietic_System_of_the_Bone_Marrow_new.jpg,"Figure 18.2.1. Hematopoietic System of Bone Marrow. Hemopoiesis is the proliferation and differentiation of the formed elements of blood. Lymphoid stem cells give rise to lymphocytes including T cells, B cells, and natural killer (NK) cells. Myeloid stem cells give rise to all the other formed elements."
+Figure 18.1.1,Composition of Blood,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1901_Composition_of_Blood.jpg,"Figure 18.1.1. Composition of Blood: The cellular elements of blood include a vast number of erythrocytes and comparatively fewer leukocytes and platelets. Plasma is the fluid in which the formed elements are suspended. A sample of blood spun in a centrifuge reveals that plasma is the least dense component. It floats at the top of the tube separated from the densest elements, the erythrocytes, which are separated by a buffy coat of leukocytes and platelets. Hematocrit is the percentage of the total sample that is comprised of erythrocytes. Depressed and elevated hematocrit levels are shown for comparison."
+Figure 17.9.1,Liver,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1820_The_Pancreas.jpg,Figure 17.9.1 – Pancreas   Pancreas endocrine function involves the secretion of insulin (produced by beta cells) and glucagon (produced by alpha cells) within the pancreatic islets. These two hormones regulate the rate of glucose metabolism in the body. The micrograph reveals pancreatic islets. LM × 760. Also shown are the exocrine acinar cells. (Micrograph provided by the Regents of University of Michigan Medical School © 2012.
+Figure 17.6.1,Discuss the hormonal regulation of the reproductive system,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1818_The_Adrenal_Glands.jpg,"Figure 17.6.1 – Adrenal Glands: Both adrenal glands sit atop the kidneys and are composed of an outer cortex and an inner medulla, all surrounded by a connective tissue capsule. The cortex can be subdivided into additional zones, all of which produce different types of hormones. LM × 204. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 17.5.1,Disorders Involving the Adrenal Glands,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1814_The_Parathyroid_Glands.jpg,Figure 17.5.1 – Parathyroid Glands: The small parathyroid glands are embedded in the posterior surface of the thyroid gland. LM × 760. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 17.5.2,Disorders Involving the Adrenal Glands,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1817_The_Role_of_Parathyroid_Hormone_in_Maintaining_Blood_Calcium_Homeostasis.jpg,"Figure 17.5.2 – Parathyroid Hormone in Maintaining Blood Calcium Homeostasis: Parathyroid hormone increases blood calcium levels when they drop too low. Conversely, calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too high. These two mechanisms constantly maintain blood calcium concentration at homeostasis."
+Figure 17.4.1,Disorders Involving the Adrenal Glands,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1811_The_Thyroid_Gland_revised-e1568244258246.png,Figure 17.4.1 – Thyroid Gland: The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 17.4.2,Regulation of TH Synthesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1813_A_Classic_Negative_Feedback_Loop.jpg,Figure 17.4.2 – Classic Negative Feedback Loop: A classic negative feedback loop controls the regulation of thyroid hormone levels.
+Figure 17.3.1,Calcitonin,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1806_The_Hypothalamus-Pituitary_Complex_revised-e1568244059979.png,"Figure 17.3.1 – Hypothalamus–Pituitary Complex: The hypothalamus region lies inferior and anterior to the thalamus. It connects to the pituitary gland by the stalk-like infundibulum. The pituitary gland consists of an anterior and posterior lobe, with each lobe secreting different hormones in response to signals from the hypothalamus."
+Figure 17.3.2,Posterior Pituitary,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1807_The_Posterior_Pituitary_Complex.jpg,Figure 17.3.2 – Posterior Pituitary: Neurosecretory cells in the hypothalamus release oxytocin (OT) or ADH into the posterior lobe of the pituitary gland. These hormones are stored or released into the blood via the capillary plexus.
+Figure 17.3.3,Anterior Pituitary,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1808_The_Anterior_Pituitary_Complex.jpg,Figure 17.3.3 – Anterior Pituitary: The anterior pituitary manufactures seven hormones. The hypothalamus produces separate hormones that stimulate or inhibit hormone production in the anterior pituitary. Hormones from the hypothalamus reach the anterior pituitary via the hypophyseal portal system.
+Figure 17.3.5,Intermediate Pituitary: Melanocyte-Stimulating Hormone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1810_Major_Pituitary_Hormones_revised.png,Figure 17.3.5 – Major Pituitary Hormones: Major pituitary hormones and their target organs.
+Figure 17.2.1,Types of Hormones,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1802_Examples_of_Amine_Peptide_Protein_and_Steroid_Hormone_Structure.jpg,"Figure 17.2.1:  Amine, Peptide, Protein, and Steroid Hormone Structure"
+Figure 17.1.1,Endocrine Organs,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1801_The_Endocrine_System.jpg,Figure 17.1.1 – Endocrine System: Endocrine glands and cells are located throughout the body and play an important role in homeostasis.
+Figure 16.4.1,Broad Autonomic Effects,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1512_Connections_to_Heart.jpg,"Figure 16.4.1 – Autonomic Connections to Heart and Blood Vessels: The nicotinic receptor is found on all autonomic ganglia, but the cardiovascular connections are particular, and do not conform to the usual competitive projections that would just cancel each other out when stimulated by nicotine. The opposing signals to the heart would both depolarize and hyperpolarize the heart cells that establish the rhythm of the heartbeat, likely causing arrhythmia. Only the sympathetic system governs systemic blood pressure so nicotine would cause an increase."
+Figure 16.4.3,Parasympathetic Effects,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1514_Belladona_Plant.jpg,"Figure 16.4.3 – Belladonna Plant: The plant from the genus Atropa, which is known as belladonna or deadly nightshade, was used cosmetically to dilate pupils, but can be fatal when ingested. The berries on the plant may seem attractive as a fruit, but they contain the same anticholinergic compounds as the rest of the plant."
+Figure 16.3.1,Parasympathetic Effects,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1509_Pupillary_Reflex_Pathways.jpg,"Figure 16.3.1 – Pupillary Reflex Pathways: The pupil is under competing autonomic control in response to light levels hitting the retina. The sympathetic system will dilate the pupil when the retina is not receiving enough light, and the parasympathetic system will constrict the pupil when too much light hits the retina."
+Figure 16.2.1,The Structure of Reflexes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1505_Comparison_of_Somatic_and_Visceral_Reflexes-scaled.jpg,"Figure 16.2.1 – Comparison of Somatic and Visceral Reflexes: The afferent inputs to somatic and visceral reflexes are essentially the same, whereas the efferent branches are different. Somatic reflexes, for instance, involve a direct connection from the ventral horn of the spinal cord to the skeletal muscle. Visceral reflexes involve a projection from the central neuron to a ganglion, followed by a second projection from the ganglion to the target effector."
+Figure 16.1.1,Sympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1501_Connections_of_the_Sympathetic_Nervous_System.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.
+Figure 16.1.2,Sympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+Figure 16.1.2,Sympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+Figure 16.1.2,Sympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1502_Symphatetic_Connections_and_the_Ganglia.jpg,"Figure 16.1.2 – Sympathetic Connections and Chain Ganglia: The axon from a central sympathetic neuron in the spinal cord can project to the periphery in a number of different ways. (a) The fiber can project out to the ganglion at the same level and synapse on a ganglionic neuron. (b) A branch can project to more superior or inferior ganglion in the chain. (c) A branch can project through the white ramus communicans, but not terminate on a ganglionic neuron in the chain. Instead, it projects through one of the splanchnic nerves to a collateral ganglion or the adrenal medulla (not pictured)."
+Figure 16.1.1,Sympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1501_Connections_of_the_Sympathetic_Nervous_System.jpg,Figure 16.1.1 – Connections of Sympathetic Division of the Autonomic Nervous System: Neurons from the lateral horn of the spinal cord (preganglionic nerve fibers – solid lines)) project to the chain ganglia on either side of the vertebral column or to collateral (prevertebral) ganglia that are anterior to the vertebral column in the abdominal cavity. Axons from these ganglionic neurons (postganglionic nerve fibers – dotted lines) then project to target effectors throughout the body.
+Figure 16.1.3,Parasympathetic Division of the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1503_Connections_of_the_Parasympathetic_Nervous_System-scaled.jpg,"Figure 16.1.3 – Connections of Parasympathetic Division of the Autonomic Nervous System: Neurons from brain-stem nuclei, or from the lateral horn of the sacral spinal cord, project to terminal ganglia near or within the various organs of the body. Axons from these ganglionic neurons then project the short distance to those target effectors."
+Figure 16.1.4,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1504_Autonomic_Varicosities.jpg,"Figure 16.1.4 – Autonomic Varicosities: The connection between autonomic fibers and target effectors is not the same as the typical synapse, such as the neuromuscular junction. Instead of a synaptic end bulb, a neurotransmitter is released from swellings along the length of a fiber that makes an extended network of connections in the target effector."
+Figure 15.5.1,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1411_Eye_in_The_Orbit.jpg,Figure 15.5.1 – The Eye in the Orbit: The eye is located within the orbit and surrounded by soft tissues that protect and support its function. The orbit is surrounded by cranial bones of the skull.
+Figure 15.5.2,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1412_Extraocular_Muscles.jpg,Figure 15.5.2 – Extraocular Muscles: The extraocular muscles move the eye within the orbit.
+Figure 15.5.3,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+Figure 15.5.3,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+Figure 15.5.3,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1413_Structure_of_the_Eye.jpg,"Figure 15.5.3 – Structure of the Eye: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea."
+Figure 15.5.4,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1414_Rods_and_Cones.jpg,"Figure 15.5.4 – Photoreceptor: (a) All photoreceptors have inner segments containing the nucleus and other important organelles and outer segments with membrane arrays containing the photosensitive opsin molecules. Rod outer segments are long columnar shapes with stacks of membrane-bound discs that contain the rhodopsin pigment. Cone outer segments are short, tapered shapes with folds of membrane in place of the discs in the rods. (b) Tissue of the retina shows a dense layer of nuclei of the rods and cones. LM × 800. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 15.5.5,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1415_Retinal_Isomers.jpg,"Figure 15.5.5 – Retinal Isomers: The retinal molecule has two isomers, (a) one before a photon interacts with it and (b) one that is altered through photoisomerization."
+Figure 15.5.6,Chemical Signaling in the Autonomic Nervous System,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1416_Color_Sensitivity.jpg,Figure 15.5.6 – Comparison of Color Sensitivity of Photopigments: Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths.
+Figure 15.4.1,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1409_Maculae_and_Equilibrium.jpg,"Figure 15.4.1 – Linear Acceleration Coding by Maculae: The maculae are specialized for sensing linear acceleration, such as when gravity acts on the tilting head, or if the head starts moving in a straight line. The difference in inertia between the hair cell stereocilia and the otolithic membrane in which they are embedded leads to a shearing force that causes the stereocilia to bend in the direction of that linear acceleration."
+Figure 15.4.2,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1410_Equilibrium_and_Semicircular_Canals.jpg,"Figure 15.4.2 – Rotational Coding by Semicircular Canals: Rotational movement of the head is encoded by the hair cells in the base of the semicircular canals. As one of the canals moves in an arc with the head, the internal fluid moves in the opposite direction, causing the cupula and stereocilia to bend. The movement of two canals within a plane results in information about the direction in which the head is moving, and activation of all six canals can give a very precise indication of head movement in three dimensions."
+Figure 15.4.3,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1419_Vestibulo-Ocular_Reflex.jpg,"Figure 15.4.3 – Vestibulo-ocular Reflex: Connections between the vestibular system and the cranial nerves controlling eye movement keep the eyes centered on a visual stimulus, even though the head is moving. During head movement, the eye muscles move the eyes in the opposite direction as the head movement, keeping the visual stimulus centered in the field of view."
+Figure 15.3.1,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1404_The_Structures_of_the_Ear.jpg,"Figure 15.3.1 – Structures of the Ear: The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively."
+Figure 15.3.2,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1405_Sound_Waves_and_the_Ear.jpg,"Figure 15.3.2 – Transmission of Sound Waves to Cochlea: A sound wave causes the tympanic membrane to vibrate. This vibration is amplified as it moves across the malleus, incus, and stapes. The amplified vibration is picked up by the oval window causing pressure waves in the fluid of the scala vestibuli and scala tympani. The complexity of the pressure waves is determined by the changes in amplitude and frequency of the sound waves entering the ear."
+Figure 15.3.3,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1406_Cochlea.jpg,"Figure 15.3.3 – Cross Section of the Cochlea: The three major spaces within the cochlea are highlighted. The scala tympani and scala vestibuli lie on either side of the cochlear duct. The organ of Corti, containing the mechanoreceptor hair cells, is adjacent to the scala tympani, where it sits atop the basilar membrane."
+Figure 15.3.4,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1407_The_Hair_Cell.jpg,"Figure 15.3.4 – Hair Cell: The hair cell is a mechanoreceptor with an array of stereocilia emerging from its apical surface. The stereocilia are tethered together by proteins that open ion channels when the array is bent toward the tallest member of their array, and closed when the array is bent toward the shortest member of their array."
+Figure 15.3.6,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1408_Frequency_Coding_in_The_Cochlea.jpg,"Figure 15.3.6 – Frequency Coding in the Cochlea: The standing sound wave generated in the cochlea by the movement of the oval window deflects the basilar membrane on the basis of the frequency of sound. Therefore, hair cells at the base of the cochlea are activated only by high frequencies, whereas those at the apex of the cochlea are activated only by low frequencies."
+Figure 15.3.7,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1418_Auditory_Brainstem_Mechanisms.jpg,Figure 15.3.7 – Auditory Brain Stem Mechanisms of Sound Localization: Localizing sound in the horizontal plane is achieved by processing in the medullary nuclei of the auditory system. Connections between neurons on either side are able to compare very slight differences in sound stimuli that arrive at either ear and represent interaural time and intensity differences.
+Figure 15.2.1,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1403_Olfaction.jpg,Figure 15.2.1 – The Olfactory System: (a) The olfactory system begins in the peripheral structures of the nasal cavity. (b) The olfactory receptor neurons are within the olfactory epithelium. (c) Axons of the olfactory receptor neurons project through the cribriform plate of the ethmoid bone and synapse with the neurons of the olfactory bulb (tissue source: simian). LM × 812. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 15.1.1,primary sensory cortex,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1402_The_Tongue.jpg,"Figure 15.1.1 – The Tongue: The tongue is covered with small bumps, called papillae, which contain taste buds that are sensitive to chemicals in ingested food or drink. Different types of papillae are found in different regions of the tongue. The taste buds contain specialized gustatory receptor cells that respond to chemical stimuli dissolved in the saliva. These receptor cells activate sensory neurons that are part of the facial and glossopharyngeal nerves. LM × 1600. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 14.5.2,Cortical Processing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1421_Sensory_Homunculus.jpg,Figure 14.5.2 – The Sensory Homunculus: A cartoon representation of the sensory homunculus arranged adjacent to the cortical region in which the processing takes place.
+Figure 14.5.3,Cortical Processing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Phineas_gage_-_1868_skull_diagram.jpg,"Figure 14.5.3 – Phineas Gage: The victim of an accident while working on a railroad in 1848, Phineas Gage had a large iron rod impaled through the prefrontal cortex of his frontal lobe. After the accident, his personality appeared to change, but he eventually learned to cope with the trauma and lived as a coach driver even after such a traumatic event. (credit b: John M. Harlow, MD)"
+Figure 14.2.5,Cortical Processing,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1317_CFS_Circulation.jpg,"Figure 14.2.5 – Cerebrospinal Fluid Circulation: The choroid plexus in the four ventricles produce CSF, which is circulated through the ventricular system and then enters the subarachnoid space through the median and lateral apertures. The CSF is then reabsorbed into the blood at the arachnoid granulations, where the arachnoid membrane emerges into the dural sinuses."
+Figure 14.5.4,Descending Pathways,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1426_Corticospinal_Pathway.jpg,"Figure 14.5.4 – Corticospinal Tract: The major descending tract that controls skeletal muscle movements is the corticospinal tract. It is composed of two neurons, the upper motor neuron and the lower motor neuron. The upper motor neuron has its cell body in the primary motor cortex of the frontal lobe and synapses on the lower motor neuron, which is in the ventral horn of the spinal cord and projects to the skeletal muscle in the periphery."
+Figure 14.5.5,The Sensory and Motor Exams,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1615_Locations_Spinal_Fiber_Tracts.jpg,Figure 14.5.5 Locations of Spinal Fiber Tracts
+Figure 14.4.1,check reflex,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1313_Spinal_Cord_Cross_Section.jpg,"Figure 14.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 14.3.1,The Cerebrum,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1305_CerebrumN-1.jpg,"Figure 14.3.1 – The Cerebrum: The cerebrum is a large component of the CNS in humans, and the most obvious aspect of it is the folded surface called the cerebral cortex."
+Figure 14.3.6,Cognitive Abilities,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1308_Frontal_Section_Basal_Nuclei-1.jpg,"Figure 14.3.6 – Frontal Section of Cerebral Cortex and Basal Nuclei: The major components of the basal nuclei, shown in a frontal section of the brain, are the caudate (just lateral to the lateral ventricle), the putamen (inferior to the caudate and separated by the large white-matter structure called the internal capsule), and the globus pallidus (medial to the putamen)."
+Figure 14.3.7,Cognitive Abilities,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1309_Basal_Nuclei_Connections-1.jpg,"Figure 14.3.7 – Connections of Basal Nuclei: Input to the basal nuclei is from the cerebral cortex, which is an excitatory connection releasing glutamate as a neurotransmitter. This input is to the striatum, or the caudate and putamen. In the direct pathway, the striatum projects to the internal segment of the globus pallidus and the substantia nigra pars reticulata (GPi/SNr). This is an inhibitory pathway, in which GABA is released at the synapse, and the target cells are hyperpolarized and less likely to fire. The output from the basal nuclei is to the thalamus, which is an inhibitory projection using GABA."
+Figure 14.3.8,The Diencephalon,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1310_Diencephalon.jpg,"Figure 14.3.8 – The Diencephalon: The diencephalon is composed primarily of the thalamus and hypothalamus, which together define the walls of the third ventricle. The thalami are two elongated, ovoid structures on either side of the midline that make contact in the middle. The hypothalamus is inferior and anterior to the thalamus, culminating in a sharp angle to which the pituitary gland is attached."
+Figure 14.3.9,Brain Stem,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1311_Brain_Stem.jpg,"Figure 14.3.9 – The Brain Stem: The brain stem comprises three regions: the midbrain, the pons, and the medulla."
+Figure 14.3.10,The Cerebellum,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1312_CerebellumN.jpg,"Figure 14.3.10 – The Cerebellum: The cerebellum is situated on the posterior surface of the brain stem. Descending input from the cerebellum enters through the large white matter structure of the pons. Ascending input from the periphery and spinal cord enters through the fibers of the inferior olive. Output goes to the midbrain, which sends a descending signal to the spinal cord."
+Figure 14.2.3,Blood Supply to the Brain,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1602_The_Hemorrhagic_Stroke-02.jpg,Figure 14.2.3 – Hemorrhagic Stroke: (a) A hemorrhage into the tissue of the cerebrum results in a large accumulation of blood with an additional edema in the adjacent tissue. The hemorrhagic area causes the entire brain to be disfigured as suggested here by the lateral ventricles being squeezed into the opposite hemisphere. (b) A CT scan shows an intraparenchymal hemorrhage within the parietal lobe. (credit b: James Heilman)
+Figure 14.2.4,Protective Coverings of the Brain and Spinal Cord,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1316_Meningeal_LayersN.jpg,"Figure 14.2.4 – Meningeal Layers of Superior Sagittal Sinus: The layers of the meninges in the longitudinal fissure of the superior sagittal sinus are shown, with the dura mater adjacent to the inner surface of the cranium, the pia mater adjacent to the surface of the brain, and the arachnoid and subarachnoid space between them. An arachnoid villus is shown emerging into the dural sinus to allow CSF to filter back into the blood for drainage."
+Figure 14.1.1,The Neural Tube,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1301_Neural_Tube_Dev.jpg,"Figure 14.1.1 – Early Embryonic Development of Nervous System: The neuroectoderm begins to fold inward to form the neural groove. As the two sides of the neural groove converge, they form the neural tube, which lies beneath the ectoderm. The anterior end of the neural tube will develop into the brain, and the posterior portion will become the spinal cord. The neural crest develops into peripheral structures."
+Figure 14.1.2,Primary Vesicles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1302_Brain_Vesicle_DevN.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions."
+Figure 14.1.2,Secondary Vesicles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1302_Brain_Vesicle_DevN.jpg,"Figure 14.1.2 – Primary and Secondary Vesicle Stages of Development: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions."
+Figure 14.1.3,Relating Embryonic Development to the Adult Brain,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1303_Human_Neuroaxis.jpg,"Figure 14.1.3 – Human Neuraxis: The mammalian nervous system is arranged with the neural tube running along an anterior to posterior axis, from nose to tail for a four-legged animal like a dog. Humans, as two-legged animals, have a bend in the neuraxis between the brain stem and the diencephalon, along with a bend in the neck, so that the eyes and the face are oriented forward."
+Figure 13.7.1,Sensory Nerves,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1606_Snellen_Chart-02.jpg,"Figure 13.7.1 – The Snellen Chart: The Snellen chart for visual acuity presents a limited number of Roman letters in lines of decreasing size. The line with letters that subtend 5 minutes of an arc from 20 feet represents the smallest letters that a person with normal acuity should be able to read at that distance. The different sizes of letters in the other lines represent rough approximations of what a person of normal acuity can read at different distances. For example, the line that represents 20/200 vision would have larger letters so that they are legible to the person with normal acuity at 200 feet."
+Figure 13.7.2,Sensory Nerves,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1614_Pituitary_Tumor-02.jpg,"Figure 13.7.2 – Pituitary Tumor: The pituitary gland is located in the sella turcica of the sphenoid bone within the cranial floor, placing it immediately inferior to the optic chiasm. If the pituitary gland develops a tumor, it can press against the fibers crossing in the chiasm. Those fibers are conveying peripheral visual information to the opposite side of the brain, so the patient will experience “tunnel vision”—meaning that only the central visual field will be perceived."
+Figure 13.7.3,Gaze Control,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1607_Saccadic_Movements.jpg,"Figure 13.7.3 – Saccadic Eye Movements: Saccades are rapid, conjugate movements of the eyes to survey a complicated visual stimulus, or to follow a moving visual stimulus. This image represents the shifts in gaze typical of a person studying a face. Notice the concentration of gaze on the major features of the face and the large number of paths traced between the eyes or around the mouth."
+Figure 13.7.4,Gaze Control,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1608_Vestibulo-Ocular_Reflex-02.jpg,"Figure 13.7.4 – Vestibulo-ocular Reflex: If the head is turned in one direction, the coordination of that movement with the fixation of the eyes on a visual stimulus involves a circuit that ties the vestibular sense with the eye movement nuclei through the MLF."
+Figure 13.7.5,Motor Nerves of the Neck,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1610_Muscles_Controlled_by_the_Accessory_Nerve-02.jpg,"Figure 13.7.5 – Muscles Controlled by the Accessory Nerve: The accessory nerve innervates the sternocleidomastoid and trapezius muscles, both of which attach to the head and to the trunk and shoulders. They can act as antagonists in head flexion and extension, and as synergists in lateral flexion toward the shoulder."
+Figure 13.6.1,The Cranial Nerve Exam,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1615_Locations_Spinal_Fiber_Tracts.jpg,Figure 13.6.1 Locations of Spinal Fiber Tracts
+Figure 13.6.2,Sensory Modalities and Location,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1611_Dermatomes-02.jpg,Figure 13.6.2 – Dermatomes: The surface of the skin can be divided into topographic regions that relate to the location of sensory endings in the skin based on the spinal nerve that contains those fibers. (credit: modification of work by Mikael Häggström)
+Figure 13.4.1,Reflexes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1313_Spinal_Cord_Cross_Section.jpg,"Figure 13.4.1 – Cross-section of Spinal Cord: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 13.3.1,Reflexes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1321_Spinal_Nerve_Plexuses.jpg,"Figure 13.3.1 – Nerve Plexuses of the Body: There are four main nerve plexuses in the human body. The cervical plexus supplies nerves to the posterior head and neck, as well as to the diaphragm. The brachial plexus supplies nerves to the arm. The lumbar plexus supplies nerves to the anterior leg. The sacral plexus supplies nerves to the posterior leg."
+Figure 13.2.1,Ganglia,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1318b_Dorsal_Root_Ganglion.jpg,"Figure 13.2.1 – Dorsal Root Ganglion: The cell bodies of sensory neurons, which are unipolar neurons by shape, are seen in this photomicrograph. Also, the fibrous region is composed of the axons of these neurons that are passing through the ganglion to be part of the dorsal nerve root (tissue source: canine). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 13.2.3,Nerves,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1319_Nerve_Structure.jpg,"Figure 13.2.3 – Nerve Structure. The structure of a nerve is organized by the layers of connective tissue on the outside, around each fascicle, and surrounding the individual nerve fibers (tissue source: simian). LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 12.5.1,Electrically Active Cell Membranes,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1215_Cell_Membrane_Channels.jpg,"Figure 12.5.1 – Cell Membrane and Transmembrane Proteins: The cell membrane is composed of a phospholipid bilayer and has many transmembrane proteins, including different types of channel proteins that serve as ion channels."
+Figure 12.5.2,Electrically Active Cell Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1216_Ligand-gated_Channels.jpg,"Figure 12.5.2 – Ligand-Gated Channels: When the ligand, in this case the neurotransmitter acetylcholine, binds to a specific location on the extracellular surface of the channel protein, the pore opens to allow select ions through. The ions, in this case, are cations of sodium, calcium, and potassium."
+Figure 12.5.3,Electrically Active Cell Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1217_Mechanically-gated_Channels-02.jpg,"Figure 12.5.3 – Mechanically-Gated Channels: When a mechanical change occurs in the surrounding tissue (such as pressure or stretch) the channel is physically opened, and ions can move through the channel, down their concentration gradient."
+Figure 12.5.4,Electrically Active Cell Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1218_Voltage-gated_Channels_revised-e1568245968412.png,Figure 12.5.4 – Voltage-Gated Channels: Voltage-gated channels open when the transmembrane voltage changes around them. Amino acids in the structure of the protein are sensitive to charge and cause the pore to open to the selected ion.
+Figure 12.5.5,Electrically Active Cell Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1219_Leakage_Channels.jpg,"Figure 12.5.5 – Leak Channels: These channels open and close at random, allowing ions to pass through when they are open."
+Figure 12.5.6,The Membrane Potential,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1220_Resting_Membrane_Potential.jpg,"Figure 12.5.6 – Measuring Charge across a Membrane with a Voltmeter: A recording electrode is inserted into the cell and a reference electrode is outside the cell. By comparing the charge measured by these two electrodes, the transmembrane voltage is determined. It is conventional to express that value for the cytosol relative to the outside."
+Figure 12.4.1,Synapses,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1225_Chemical_Synapse.jpg,"Figure 12.4.1 – The Synapse: The synapse is a connection between a neuron and its target cell (which is not necessarily a neuron). The presynaptic element is the synaptic end bulb of the axon where Ca2+ enters the bulb to cause vesicle fusion and neurotransmitter release. The neurotransmitter diffuses across the synaptic cleft to bind to its receptor. The neurotransmitter is cleared from the synapse either by enzymatic degradation, neuronal reuptake, or glial reuptake."
+Figure 12.4.2,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1226_Receptor_Types.jpg,"Figure 12.4.2 – Receptor Types: (a) An ionotropic receptor is a channel that opens when the neurotransmitter binds to it. (b) A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in gene transcription."
+Figure 12.4.3,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1223_Graded_Potentials_revised.png,"Figure 12.4.3 – Graded Potentials: Graded potentials are temporary changes in the membrane voltage, the characteristics of which depend on the size of the stimulus. Some types of stimuli cause depolarization of the membrane, whereas others cause hyperpolarization. It depends on the specific ion channels that are activated in the cell membrane."
+Figure 12.4.4,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1224_Post_Synaptic_Potential_Summation.jpg,"Figure 12.4.4 – Postsynaptic Potential Summation: The result of summation of postsynaptic potentials is the overall change in the membrane potential. At point A, several different excitatory postsynaptic potentials add up to a large depolarization. At point B, a mix of excitatory and inhibitory postsynaptic potentials result in a different end result for the membrane potential."
+Figure 12.3.1,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+Figure 12.3.1,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+Figure 12.3.1,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1212_Sensory_Neuron_Test_Water_revised-copy-e1568245696709.png,Figure 12.3.1 Testing the Water. Use the text below with this figure to describe signal transmission in the body.
+Figure 12.3.3,Neurotransmitter and Receptor Systems,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1214_Motor_Response_Test_Water.jpg,"Figure 12.3.3 – The Motor Response: On the basis of the sensory input and the integration in the CNS, a motor response is formulated and executed."
+Figure 12.1.1,The Central and Peripheral Nervous Systems,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1201_Overview_of_Nervous_System_revised.png,"Figure 12.1.1 – Central and Peripheral Nervous System: The CNS contains the brain and spinal cord, the PNS includes nerves."
+Figure 11.4.22,Gluteal Region Muscles That Move the Thigh,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1122_Gluteal_Muscles_that_Move_the_Femur.jpg,"Figure 11.4.22 – Hip and Thigh Muscles: The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. The muscles that move the lower leg typically originate on the femur and insert into the bones of the knee joint. The anterior muscles of the femur extend the lower leg but also aid in flexing the thigh. The posterior muscles of the femur flex the lower leg but also aid in extending the thigh. A combination of gluteal and thigh muscles also adduct, abduct, and rotate the thigh and lower leg."
+Figure 11.4.27,Muscles That Move the Feet and Toes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1124_Intrinsic_Muscles_of_the_Foot.jpg,"Figure 11.4.27 – Intrinsic Muscles of the Foot: The muscles along the dorsal side of the foot (a) generally extend the toes while the muscles of the plantar side of the foot (b, c, d) generally flex the toes. The plantar muscles exist in three layers, providing the foot the strength to counterbalance the weight of the body. In this diagram, these three layers are shown from a plantar view beginning with the bottom-most layer just under the plantar skin of the foot (b) and ending with the top-most layer (d) located just inferior to the foot and toe bones."
+Figure 11.4.1,Muscles of Facial Expression,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1106_Front_and_Side_Views_of_the_Muscles_of_Facial_Expressions.jpg,"Figure 11.4.1 – Muscles of Facial Expression: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones."
+Figure 11.4.2,Muscles of Facial Expression,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1125_Muscles_in_Facial_Expression_revised.png,Figure 11.4.2 Muscles in Facial Expression
+Figure 11.4.7,Muscles of the Anterior Neck,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1110_Muscle_of_the_Anterior_Neck_revised.png,Figure 11.4.7 – Muscles of the Anterior Neck: The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.
+Figure 11.4.8,Muscles That Move the Head,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1117_Muscles_of_the_Neck_and_Back-scaled.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column."
+Figure 11.4.8,Muscles of the Posterior Neck and the Back,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1117_Muscles_of_the_Neck_and_Back-scaled.jpg,"Figure 11.4.8 – Muscles of the Neck and Back: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column."
+Figure 11.3.1,Muscles of the Posterior Neck and the Back,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1105_Anterior_and_Posterior_Views_of_Muscles-scaled.jpg,"Figure 11.3.1 – Overview of the Muscular System: On the anterior and posterior views of the muscular system above, superficial muscles (those at the surface) are shown on the right side of the body while deep muscles (those underneath the superficial muscles) are shown on the left half of the body. For the legs, superficial muscles are shown in the anterior view while the posterior view shows both superficial and deep muscles."
+Figure 10.2.1,Patterns of Fascicle Organization,https://open.oregonstate.education/app/uploads/sites/156/2019/07/1001_Muscle_Tissue_revised.png,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium."
+Figure 11.2.1,Patterns of Fascicle Organization,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1102_Fascicle_Muscle_Shapes.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.
+Figure 11.2.1,Patterns of Fascicle Organization,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1102_Fascicle_Muscle_Shapes.jpg,Figure 11.2.1 – Muscle Shapes and Fiber Alignment: The skeletal muscles of the body typically come in seven different general shapes.
+Figure 11.1.1,Compare and contrast agonist and antagonist muscles,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1101_Biceps_Muscle.jpg,"Figure 11.1.1 – Prime Movers and Synergists: The biceps brachii flex the lower arm. The brachoradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion."
+Figure 10.7.2,Explain the criteria used to name skeletal muscles,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1028_Smooth_Muscle_Contraction.jpg,"Figure 10.7.2 – Muscle Contraction: The dense bodies and intermediate filaments are networked through the sarcoplasm, which cause the muscle fiber to contract."
+Figure 10.6.1,Endurance Exercise,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1026_Marathoners.jpg,Figure 10.6.1 – Marathoners: Long-distance runners have a large number of slow oxidative fibers and relatively few fast oxidative and fast glycolytic fibers. (credit: “Tseo2”/Wikimedia Commons)
+Figure 10.6.2,Resistance Exercise,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1027_Hypertrophy.jpg,Figure 10.6.2 – Muscle hypertrophy: Body builders work on increasing the size of the fast glycolytic fibers through resistance training. (credit: Lin Mei/flickr)
+Figure 10.4.1,Resistance Exercise,https://open.oregonstate.education/app/uploads/sites/157/2019/07/1015_Types_of_Contraction_new.jpg,"Figure 10.4.1- Types of Muscle Contractions: During isotonic contractions (concentric and eccentric contractions), muscle length changes to move a load. During isometric contractions, muscle length does not change because the load equals the tension the muscle generates."
+Figure 10.4.2,Motor Units,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.2.-new.png,Figure 10.4.2 – Skeletal Muscle Contractions
+Figure 10.4.2,Motor Units,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1029_Smooth_Muscle_Motor_Units_noLeaders.png,Figure 10.4.2b
+Figure 10.4.4,The Length-Tension Range of a Sarcomere,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1012_Muscle_Twitch_Myogram.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops."
+Figure 10.4.4,The Frequency of Motor Neuron Stimulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1012_Muscle_Twitch_Myogram.jpg,"Figure 10.4.4 – A Myogram of a Muscle Twitch: A single muscle twitch has a latent period, a contraction phase when tension increases, and a relaxation phase when tension decreases. During the latent period, the action potential is being propagated along the sarcolemma. During the contraction phase, Ca++ ions in the sarcoplasm bind to troponin, tropomyosin moves from actin-binding sites, cross-bridges form, and sarcomeres shorten. During the relaxation phase, tension decreases as Ca++ ions are pumped out of the sarcoplasm and cross-bridge cycling stops."
+Figure 10.4.5,The Frequency of Motor Neuron Stimulation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+Figure 10.4.5,The Frequency of Motor Neuron Stimulation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+Figure 10.4.5,Treppe,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.4.4-replacement.png,"Figure 10.4.5 – Wave Summation and Tetanus: (a) The excitation-contraction coupling effects of successive motor neuron signaling is added together which is referred to as wave summation. The peaks in the lower portion of the image represent stimuli to the muscle cell. (b) When the stimulus frequency is so high that the relaxation phase disappears completely, the contractions become continuous; this is called tetanus."
+Figure 10.3.1,Excitation-Contraction Coupling,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1009_Motor_End_Plate_and_Innervation_revised-1024x735.png,"Figure 10.3.1 – Motor End-Plate and Innervation: At the NMJ, the axon terminal releases acetylcholine (ACh). The motor end-plate is the location of the ACh-receptors in the muscle fiber sarcolemma. When ACh molecules are released, they diffuse across a minute space called the synaptic cleft and bind to the receptors."
+Figure 10.3.2,Excitation-Contraction Coupling,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1023_T-tubule.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them."
+Figure 10.3.5,Contraction and Relaxation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1010a_Contraction-and-Relaxation-1024x751.png,"Figure 10.3.5 – Contraction of a Muscle Fiber: A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten. Relaxation of a Muscle Fiber: Ca++ ions are pumped back into the SR, which causes the tropomyosin to reshield the binding sites on the actin strands. A muscle may also stop contracting when it runs out of ATP and becomes fatigued."
+Figure 10.3.2,Contraction and Relaxation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/1023_T-tubule.jpg,"Figure 10.3.2 – The T-tubule: Narrow T-tubules permit the conduction of electrical impulses. The sarcoplasmic reticulum (SR) functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them."
+Figure 10.2.1,Muscle Strength,https://open.oregonstate.education/app/uploads/sites/156/2019/07/1001_Muscle_Tissue_revised.png,"Figure 10.2.1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium."
+Figure 10.2.2,Skeletal Muscle Fibers,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+Figure 10.2.2,The Sarcomere,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+Figure 10.2.2,The Sarcomere,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1022_Muscle_Fibers_small_revised-1.png,"Figure 10.2.2 – Muscle Fiber: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many myofibrils, which contain sarcomeres with light and dark regions that give the cell its striated appearance."
+Figure 10.2.3,The Sarcomere,https://open.oregonstate.education/app/uploads/sites/156/2021/02/1003_Thick_and_Thin_Filaments_revised.png,"Figure 10.2.3 – The Sarcomere: The sarcomere, the region from one Z-disc to the next Z-disc, is the functional unit of a skeletal muscle fiber."
+Figure 10.2.4,The Sliding Filament Model of Contraction,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.2.4-replacement.png,"Figure 10.2.4 – The Sliding Filament Model of Muscle Contraction: When a sarcomere shortens, the Z-discs move closer together, and the I band becomes smaller. The A band stays the same width. At full contraction, the thin and thick filaments have the most amount of overlap."
+Figure 10.1.1,Answers for Critical Thinking Questions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.1.1.-replacement.png,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 10.1.1,Answers for Critical Thinking Questions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/10.1.1.-replacement.png,"Figure 10.1.1 – The Three Types of Muscle Tissue: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 9.1.2,Articulations of the Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2021/02/902_Intervertebral_Disk-02.jpg,Figure 9.1.2 – Intervertebral Disc: An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint.
+Figure 9.6.1,Articulations of the Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2019/07/912_Atlantoaxial_Joint.jpg,"Figure 9.6.1 – Atlantoaxial Joint: The atlantoaxial joint is a pivot type of joint between the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament."
+Figure 9.6.2,Temporomandibular Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/913_Tempomandibular_Joint.jpg,"Figure 9.6.2 – Temporomandibular Joint: The temporomandibular joint is the articulation between the temporal bone of the skull and the condyle of the mandible, with an articular disc located between these bones. During depression of the mandible (opening of the mouth), the mandibular condyle moves both forward and hinges downward as it travels from the mandibular fossa onto the articular tubercle."
+Figure 9.6.3,Shoulder Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0914_Shoulder_Joint_revised-1024x757.png,Figure 9.6.3 – Glenohumeral Joint: The glenohumeral (shoulder) joint is a ball-and-socket joint that provides the widest range of motions. It has a loose articular capsule and is supported by ligaments and the rotator cuff muscles.
+Figure 9.6.4,Elbow Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0915_Elbow_Joint_revised-1024x842.png,"Figure 9.6.4 – Elbow Joint: (a) The elbow is a hinge joint that allows only for flexion and extension of the forearm. (b) It is supported by the ulnar and radial collateral ligaments. (c) The annular ligament supports the head of the radius at the proximal radioulnar joint, the pivot joint that allows for rotation of the radius"
+Figure 9.6.5,Hip Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0916_Hip_Joint_revised-761x1024.png,"Figure 9.6.5 – Hip Joint: (a) The ball-and-socket joint of the hip is a multiaxial joint that provides both stability and a wide range of motion. (b–c) When standing, the supporting ligaments are tight, pulling the head of the femur into the acetabulum."
+Figure 9.6.6,Knee Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+Figure 9.6.6,Knee Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+Figure 9.6.6,Knee Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0917_Knee_Joint_revised-1024x879.png,"Figure 9.6.6 – Knee Joint: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles."
+Figure 9.6.8,Ankle and Foot Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/919_Ankle_Feet_Joints.jpg,"Figure 9.6.8 – Ankle Joint: The talocrural (ankle) joint is a uniaxial hinge joint that only allows for dorsiflexion or plantar flexion of the foot. Movements at the subtalar joint, between the talus and calcaneus bones, combined with motions at other intertarsal joints, enables eversion/inversion movements of the foot. Ligaments that unite the medial or lateral malleolus with the talus and calcaneus bones serve to support the talocrural joint and to resist excess eversion or inversion of the foot."
+Figure 9.5.1,Define and identify the different body movements,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+Figure 9.5.1,Flexion and Extension,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+Figure 9.5.1,Abduction and Adduction,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+Figure 9.5.1,Circumduction,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+Figure 9.5.1,Rotation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-1-865x1024-1.jpg,"Figure 9.5.1 – Movements of the Body, Part 1: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation)."
+Figure 9.5.2,Supination and Pronation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.5.2,Dorsiflexion and Plantar Flexion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.5.2,Inversion and Eversion,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.5.2,Protraction and Retraction,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.5.2,Depression and Elevation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.5.2,Opposition and Reposition,https://open.oregonstate.education/app/uploads/sites/157/2021/02/911_Body_MovementsPage-2-948x1024-1.jpg,"Figure 9.5.2 – Movements of the Body, Part 2: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an “X.” (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger."
+Figure 9.4.1,Describe the characteristic features for synovial joints and give examples,https://open.oregonstate.education/app/uploads/sites/157/2019/07/907_Synovial_Joints.jpg,Figure 9.4.1 – Synovial Joints: Synovial joints allow for smooth movements between the adjacent bones. The joint is surrounded by an articular capsule that defines a joint cavity filled with synovial fluid. The articulating surfaces of the bones are covered by a thin layer of articular cartilage. Ligaments support the joint by holding the bones together and resisting excess or abnormal joint motions.
+Figure 9.4.2,Additional Structures Associated with Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/908_Bursa_revised-e1568231910936.png,"Figure 9.4.2 – Bursae: Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg"
+Figure 9.4.3,Types of Synovial Joints,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Pivot Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Hinge Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Condyloid Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Saddle Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Plane Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.4.3,Ball-and-Socket Joint,https://open.oregonstate.education/app/uploads/sites/157/2021/02/909_Types_of_Synovial_Joints-scaled.jpg,"Figure 9.4.3 – Types of Synovial Joints: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body."
+Figure 9.3.1,Describe the characteristic features for fibrous joints and give examples,https://open.oregonstate.education/app/uploads/sites/157/2019/07/906_Cartiliginous_Joints.jpg,"Figure 9.3.1 – Cartiliginous Joints: At cartilaginous joints, bones are united by hyaline cartilage to form a synchondrosis or by fibrocartilage to form a symphysis. (a) The hyaline cartilage of the epiphyseal plate (growth plate) forms a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length. (b) The pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage, forming the pubic symphysis."
+Figure 9.2.1,Describe the characteristic features for fibrous joints and give examples,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+Figure 9.2.1,Suture,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+Figure 9.2.2,Suture,https://open.oregonstate.education/app/uploads/sites/157/2021/02/905_The_Newborn_Skull.jpg,Figure 9.2.2 – The Newborn Skull: The fontanelles of a newborn’s skull are broad areas of fibrous connective tissue that form fibrous joints between the bones of the skull.
+Figure 9.2.1,Syndesmosis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+Figure 9.2.1,Gomphosis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/904_Fibrous_Joints_revised-1024x772.png,Figure 9.2.1 – Fibrous Joints: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
+Figure 8.5.1,Limb Growth,https://open.oregonstate.education/app/uploads/sites/157/2019/07/2914_Photo_of_Embryo-02.jpg,Figure 8.5.1 – Embryo at Seven Weeks: Limb buds are visible in an embryo at the end of the seventh week of development (embryo derived from an ectopic pregnancy). (credit: Ed Uthman/flickr)
+Figure 8.4.1,Femur,https://open.oregonstate.education/app/uploads/sites/157/2019/07/810_Femur_and_Patella.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur."
+Figure 8.4.1,Patella,https://open.oregonstate.education/app/uploads/sites/157/2019/07/810_Femur_and_Patella.jpg,"Figure 8.4.1 – Femur and Patella: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur."
+Figure 8.4.3,Tibia,https://open.oregonstate.education/app/uploads/sites/157/2021/02/811_Tibia_and_fibula_revised-793x1024.png,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight."
+Figure 8.4.3,Fibula,https://open.oregonstate.education/app/uploads/sites/157/2021/02/811_Tibia_and_fibula_revised-793x1024.png,"Figure 8.4.3 – Tibia and Fibula: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight."
+Figure 8.4.4,Tarsal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+Figure 8.4.4,Metatarsal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+Figure 8.4.4,Phalanges,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+Figure 8.4.4,Arches of the Foot,https://open.oregonstate.education/app/uploads/sites/157/2021/02/812_Bones_of_the_Foot.jpg,Figure 8.4.4 – Bones of the Foot: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
+Figure 8.3.1,Arches of the Foot,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+Figure 8.3.2,Hip Bone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/808_Hip_Bone.jpg,"Figure 8.3.2 – The Hip Bone: Each adult hip bone consists of three regions. The ilium forms the large, fan-shaped superior portion, the ischium forms the posteroinferior portion, and the pubis forms the anteromedial portion."
+Figure 8.3.1,Hip Bone,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+Figure 8.3.1,Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2019/07/807_Pelvis.jpg,"Figure 8.3.1 – Pelvis: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis."
+Figure 8.3.3,Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/817_Ligaments_of_Pelvis.jpg,"Figure 8.3.3 – Ligaments of the Pelvis: The posterior sacroiliac ligament supports the sacroiliac joint. The sacrospinous ligament spans the sacrum to the ischial spine, and the sacrotuberous ligament spans the sacrum to the ischial tuberosity. The sacrospinous and sacrotuberous ligaments contribute to the formation of the greater and lesser sciatic foramens."
+Figure 8.3.4,Pelvis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/809_Male_Female_Pelvic_Girdle.jpg,"Figure 8.3.4 – Male and Female Pelvis: The female pelvis is adapted for childbirth and is broader, with a larger subpubic angle, a rounder pelvic brim, and a wider and more shallow lesser pelvic cavity than the male pelvis."
+Figure 8.2.1,Humerus,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Humerus__elbow_joint-872x1024.png,Figure 8.2.1 – Humerus and Elbow Joint: The humerus is the single bone of the arm region. It articulates with the radius and ulna bones of the forearm to form the elbow joint.
+Figure 8.2.2,Ulna,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Forearm_-1024x989.png,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane."
+Figure 8.2.2,Radius,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Forearm_-1024x989.png,"Figure 8.2.2 – Ulna and Radius: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane."
+Figure 8.2.3,Carpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+Figure 8.2.4,Carpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/814_Radiograph_of_Hand.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek
+Figure 8.2.4,Carpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/814_Radiograph_of_Hand.jpg,Figure 8.2.4 – Bones of the Hand: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand. (credit: modification of work by Trace Meek
+Figure 8.2.5,Carpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/815_The_Carpal_Tunnel.jpg,"Figure 8.2.5 – Carpal Tunnel: The carpal tunnel is the passageway by which nine muscle tendons and the median nerve enter the hand from the anterior forearm. The walls and floor of the carpal tunnel are formed by the U-shaped grouping of the carpal bones, and the roof is formed by the flexor retinaculum, a strong ligament that anteriorly unites the bones."
+Figure 8.2.3,Metacarpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+Figure 8.2.6,Metacarpal Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/816_Hand_Gripping.jpg,"Figure 8.2.6 – Hand During Gripping: During tight gripping—compare (b) to (a)—the fourth and, particularly, the fifth metatarsal bones are pulled anteriorly. This increases the contact between the object and the medial side of the hand, thus improving the firmness of the grip."
+Figure 8.2.3,Phalanx Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/806_Hand_and_Wrist.jpg,Figure 8.2.3 – Bones of the Wrist and Hand: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
+Figure 8.1.1,Phalanx Bones,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+Figure 8.1.1,Clavicle,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+Figure 8.1.2,Scapula,https://open.oregonstate.education/app/uploads/sites/157/2021/02/803_The_Scapula_revised-1024x438.png,"Figure 8.1.2 – Scapula: The isolated scapula is shown here from its anterior (deep) side, lateral side and its posterior (superficial) side."
+Figure 8.1.1,Scapula,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+Figure 8.1.1,Scapula,https://open.oregonstate.education/app/uploads/sites/157/2019/07/802_Pectoral_Girdle.jpg,"Figure 8.1.1 – Pectoral Girdle: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton."
+Figure 8.0.2,Scapula,https://open.oregonstate.education/app/uploads/sites/157/2021/02/801_Appendicular_Skeleton.jpg,"Figure 8.0.2 – Axial and Appendicular Skeletons: The axial skeleton forms the central axis of the body and consists of the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of the pectoral and pelvic girdles, the limb bones, and the bones of the hands and feet."
+Figure 7.6.1,Development of the Skull,https://open.oregonstate.education/app/uploads/sites/157/2019/07/702_Newborn_Skull-01.jpg,"Figure 7.6.1 – Newborn Skull: The bones of the newborn skull are not fully ossified and are separated by large areas called fontanelles, which are filled with fibrous connective tissue. The fontanelles allow for continued growth of the brain and skull after birth. At the time of birth, the facial bones are small and underdeveloped, and the mastoid process has not yet formed."
+Figure 7.5.1,Describe the components of the thoracic cage,https://open.oregonstate.education/app/uploads/sites/157/2019/07/721_Rib_Cage.jpg,"Figure 7.5.1 – Thoracic Cage: The thoracic cage is formed by the (a) sternum and (b) 12 pairs of ribs with their costal cartilages. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The ribs are classified as true ribs (1–7) and false ribs (8–12). The last two pairs of false ribs are also known as floating ribs (11–12)."
+Figure 7.4.1,Ribs,https://open.oregonstate.education/app/uploads/sites/157/2019/07/715_Vertebral_Column.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves)."
+Figure 7.4.1,Curvatures of the Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2019/07/715_Vertebral_Column.jpg,"Figure 7.4.1 – Vertebral Column: The adult vertebral column consists of 24 vertebrae, plus the fused vertebrae of the sacrum and coccyx. The vertebrae are divided into three regions: cervical C1–C7 vertebrae, thoracic T1–T12 vertebrae, and lumbar L1–L5 vertebrae. The vertebral column is curved, with two primary curvatures (thoracic and sacrococcygeal curves) and two secondary curvatures (cervical and lumbar curves)."
+Figure 7.4.4,General Structure of a Vertebra,https://open.oregonstate.education/app/uploads/sites/157/2021/02/718_Vertebra.jpg,"Figure 7.4.4 – Parts of a Typical Vertebra: A typical vertebra consists of a body and a vertebral arch. The arch is formed by the paired pedicles and paired laminae. Arising from the vertebral arch are the transverse, spinous, superior articular, and inferior articular processes. The vertebral foramen provides for passage of the spinal cord. Each spinal nerve exits through an intervertebral foramen, located between adjacent vertebrae. Intervertebral discs unite the bodies of adjacent vertebrae."
+Figure 7.4.5,General Structure of a Vertebra,https://open.oregonstate.education/app/uploads/sites/157/2021/02/716_Intervertebral_Disk.jpg,"Figure 7.4.5 – Intervertebral Disc: The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The intervertebral foramen is the opening formed between adjacent vertebrae for the exit of a spinal nerve."
+Figure 7.3.1,Intervertebral Discs and Ligaments of the Vertebral Column,https://open.oregonstate.education/app/uploads/sites/157/2019/07/703_Parts_of_Skull_revised-1024x842.png,"Figure 7.3.1 – Parts of the Skull: The skull consists of the rounded cranium that houses the brain and the facial bones that form the upper and lower jaws, nose, orbits, and other facial structures."
+Figure 7.3.2,Anterior View of Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/704_Skull-01.jpg,"Figure 7.3.2 – Anterior View of Skull: An anterior view of the skull shows the bones that form the forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws."
+Figure 7.3.3,Lateral View of Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lateral-sagittal_skull-795x1024.png,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum."
+Figure 7.3.4,Bones of the Cranium,https://open.oregonstate.education/app/uploads/sites/157/2021/02/727_Cranial_Fossae_revised.png,"Figure 7.3.4 – Cranial Fossae: The bones of the brain case surround and protect the brain, which occupies the cranial cavity. The base of the brain case, which forms the floor of cranial cavity, is subdivided into the shallow anterior cranial fossa, the middle cranial fossa, and the deep posterior cranial fossa."
+Figure 7.3.3,Sutures of the Skull,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lateral-sagittal_skull-795x1024.png,"Figure 7.3.3 – Lateral View and Sagittal Section of Skull:  (a) Lateral View of Skull. The lateral skull shows the large rounded brain case, zygomatic arch, and the upper and lower jaws. The zygomatic arch is formed jointly by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The shallow space above the zygomatic arch is the temporal fossa. (b) Sagittal Section of Skull. This midline view of the sagittally sectioned skull shows the nasal septum."
+Figure 7.3.15,The Orbit,https://open.oregonstate.education/app/uploads/sites/157/2021/02/713_Bones_Forming_Orbit.jpg,Figure 7.3.15 – Bones of the Orbit: Seven skull bones contribute to the walls of the orbit. Opening into the posterior orbit from the cranial cavity are the optic canal and superior orbital fissure.
+Figure 7.3.16,The Nasal Septum and Nasal Conchae,https://open.oregonstate.education/app/uploads/sites/157/2021/02/714_Bone_of_Nasal_Cavity.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.
+Figure 7.3.12,The Nasal Septum and Nasal Conchae,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Sutures_of_the_skull-1009x1024.png,Figure 7.3.12 Sutures of the skull
+Figure 7.3.17,Paranasal Sinuses,https://open.oregonstate.education/app/uploads/sites/157/2021/02/724_Paranasal_Sinuses.jpg,"Figure 7.3.17 – Paranasal Sinuses: The air-filled paranasal sinuses, each named for the bone in which it is found, drain into the nasal cavity."
+Figure 7.3.16,Paranasal Sinuses,https://open.oregonstate.education/app/uploads/sites/157/2021/02/714_Bone_of_Nasal_Cavity.jpg,Figure 7.3.16 – Nasal Septum: The nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer bone. The septal cartilage fills the gap between these bones and extends into the nose.
+Figure 7.3.18,Hyoid Bone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/712_Hyoid_Bone_revised-805x1024.png,"Figure 7.3.18 – Hyoid Bone: The hyoid bone is located in the upper neck and does not join with any other bone. It provides attachments for muscles that act on the tongue, larynx, and pharynx."
+Figure 7.2.1,Bone Markings,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 7.2.1 – Bone Features: The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+Figure 7.1.1,The Axial Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/Ventral_skeleton_app-1024x803.png,"Figure 7.1.1 – Axial and Appendicular Skeleton: The axial skeleton supports the head, neck, back, and chest and thus forms the vertical axis of the body. It consists of the skull, vertebral column (including the sacrum and coccyx), and the thoracic cage, formed by the ribs and sternum. The appendicular skeleton is made up of all bones of the upper and lower limbs and the girdles which attach them to the axial skeleton."
+Figure 6.7.1,The Appendicular Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+Figure 6.7.1,The Appendicular Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+Figure 6.7.1,The Appendicular Skeleton,https://open.oregonstate.education/app/uploads/sites/157/2019/07/625_Calcium_Homeostasis.jpg,Figure 6.7.1 – Pathways in Calcium Homeostasis: The body regulates calcium homeostasis with two pathways; one is signaled to turn on when blood calcium levels drop below normal and one is the pathway that is signaled to turn on when blood calcium levels are elevated.
+Figure 6.6.1,Calcium and Vitamin D,https://open.oregonstate.education/app/uploads/sites/157/2019/07/614_Synthesis_of_Vitamin_D.jpg,Figure 6.6.1 – Synthesis of Vitamin D: Sunlight is one source of vitamin D.
+Figure 6.5.1,Types of Fractures,https://open.oregonstate.education/app/uploads/sites/157/2019/07/612_Types_of_Fractures_revised-475x1024.png,"Figure 6.5.1 – Types of Fractures: Compare healthy bone with different types of fractures: (a) open fracture, (b) closed fracture, (c) oblique fracture, (d) comminuted fracture, (e) spiral fracture , (f) impacted fracture, (g) greenstick fracture, and (h) transverse fracture."
+Figure 6.5.2,Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+Figure 6.5.2,Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+Figure 6.5.2,Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+Figure 6.5.2,Bone Repair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/613_Stages_of_Fracture_Repair.jpg,"Figure 6.5.2 – Stages in Fracture Repair: The healing of a bone fracture follows a series of progressive steps: (a) Broken blood vessels leak blood that clots into a fracture hematoma. (b) Internal and external calluses form made of cartilage and bone. (c) Cartilage of the calluses is gradually eroded and replaced by trabecular bone, forming the hard callus. (d) Remodeling occurs to replace immature bone with mature bone."
+Figure 6.4.1,Intramembranous Ossification,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+Figure 6.4.1,Intramembranous Ossification,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+Figure 6.4.1,Intramembranous Ossification,https://open.oregonstate.education/app/uploads/sites/157/2019/07/611_Intramembraneous_Ossification_revised.png,"Figure 6.4.1 – Intramembranous Ossification: Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, differentiate into osteoblasts, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red bone marrow."
+Figure 6.4.2,Endochondral Ossification,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+Figure 6.4.2,Endochondral Ossification,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+Figure 6.4.2,Endochondral Ossification,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+Figure 6.4.2,Endochondral Ossification,https://open.oregonstate.education/app/uploads/sites/157/2021/02/608_Endochrondal_Ossification_revised.png,"Figure 6.4.2 – Endochondral Ossification: Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes that produce a cartilage model of the future bony skeleton. (b) Blood vessels on the edge of the cartilage model bring osteoblasts that deposit a bony collar. (c) Capillaries penetrate cartilage and deposit bone inside cartilage model, forming primary ossification center. (d) Cartilage and chondrocytes continue to grow at ends of the bone while medullary cavity expands and remodels. (e) Secondary ossification centers develop after birth. (f) Hyaline cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage."
+Figure 6.4.3,How Bones Grow in Length,https://open.oregonstate.education/app/uploads/sites/157/2021/02/622_Longitudinal_Bone_Growth_revised-657x1024.png,Figure 6.4.3 – Longitudinal Bone Growth: The epiphyseal plate is responsible for longitudinal bone growth.
+Figure 6.4.4,How Bones Grow in Length,https://open.oregonstate.education/app/uploads/sites/157/2021/02/623_Epiphyseal_Plate-Line.jpg,"Figure 6.4.4 – Progression from Epiphyseal Plate to Epiphyseal Line: As a bone matures, the epiphyseal plate progresses to an epiphyseal line. (a) Epiphyseal plates are visible in a growing bone. (b) Epiphyseal lines are the remnants of epiphyseal plates in a mature bone."
+Figure 6.3.1,Gross Anatomy of Bones,https://open.oregonstate.education/app/uploads/sites/157/2019/07/603_Anatomy_of_a_Long_Bone_revised-606x1024.png,Figure 6.3.1 – Anatomy of a Long Bone: A typical long bone showing gross anatomical features.
+Figure 6.3.4,Gross Anatomy of Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lossy-page1-1280px-Bertazzo_S_-_SEM_deproteined_bone_-_wistar_rat_-_x10k.tif_-300x225-1.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)"
+Figure 6.3.4,Gross Anatomy of Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Bone-matrices-300x146-1.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson"
+Figure 6.3.4,Gross Anatomy of Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+Figure 6.3.3,Gross Anatomy of Bones,https://open.oregonstate.education/app/uploads/sites/157/2021/02/621_Anatomy_of_a_Flat_Bone.jpg,Figure 6.3.3 – Anatomy of a Flat Bone: This cross-section of a flat bone shows the spongy bone (diploë) covered on either side by a layer of compact bone.
+Figure 6.3.5,Bone Cells,https://open.oregonstate.education/app/uploads/sites/157/2021/02/604_Bone_cells_revised.png,"Figure 6.3.5 – Bone Cells: Four types of cells are found within bone tissue. Osteogenic cells are undifferentiated and develop into osteoblasts. Osteoblasts deposit bone matrix. When osteoblasts get trapped within the calcified matrix, they become osteocytes. Osteoclasts develop from a different cell lineage and act to resorb bone."
+Figure 6.3.6,Compact Bone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/624_Diagram_of_Compact_Bone_revised.png,"Figure 6.3.6 – Diagram of Compact Bone: (a) This cross-sectional view of compact bone shows several osteons, the basic structural unit of compact bone. (b) In this micrograph of the osteon, you can see the concentric lamellae around the central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 6.3.8,Spongy (Cancellous) Bone,https://open.oregonstate.education/app/uploads/sites/157/2021/02/606_Spongy_Bone.jpg,Figure 6.3.8 – Diagram of Spongy Bone: Spongy bone is composed of trabeculae that contain the osteocytes. Red marrow fills the spaces in some bones.
+Figure 6.3.10,Blood and Nerve Supply,https://open.oregonstate.education/app/uploads/sites/157/2021/02/609_Body_Supply_to_the_Bone.jpg,Figure 6.3.10 – Diagram of Blood and Nerve Supply to Bone: Blood vessels and nerves enter the bone through the nutrient foramen.
+Figure 6.3.4,Define and list examples of bone markings,https://open.oregonstate.education/app/uploads/sites/157/2021/02/lossy-page1-1280px-Bertazzo_S_-_SEM_deproteined_bone_-_wistar_rat_-_x10k.tif_-300x225-1.jpg,"Figure 6.3.4a Calcified collagen fibers from bone (scanning electron micrograph, 10,000 X, By Sbertazzo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20904735)"
+Figure 6.3.4,Define and list examples of bone markings,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Bone-matrices-300x146-1.jpg,"Figure 6.3.4b Contributions of the organic and inorganic matrices of bone. Image from Ammerman figure 6-5, Pearson"
+Figure 6.3.4,Define and list examples of bone markings,https://open.oregonstate.education/app/uploads/sites/157/2021/02/602_Bone_Markings.jpg,"Figure 6.3.4 Bone Features The surface features of bones depend on their function, location, attachment of ligaments and tendons, or the penetration of blood vessels and nerves."
+Figure 6.2.1,Describe the classes of bones.,https://open.oregonstate.education/app/uploads/sites/157/2019/07/601_Bone_Classification_revised-874x1024.png,Figure 6.2.1 – Classifications of Bones: Bones are classified according to their shape.
+Figure 6.1.1,"Support, Movement, and Protection",https://open.oregonstate.education/app/uploads/sites/157/2019/07/mineral_storage_revised-838x1024.png,Figure 6.1.1 Functions of the skeletal system.
+Figure 6.1.2,"Mineral and Fat Storage, Blood Cell Formation",https://open.oregonstate.education/app/uploads/sites/157/2021/02/marrow_skele-1024x920.png,Figure 6.1.2 – Bone Marrow: Bones contain variable amounts of yellow and/or red bone marrow. Yellow bone marrow stores fat and red bone marrow is responsible for producing blood cells (hematopoiesis).
+Figure 6.1.3,bone marrow,https://open.oregonstate.education/app/uploads/sites/157/2021/02/620_Arms_Brace.jpg,Figure 6.1.3 – Arm Brace: An orthopedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support. (credit: Juhan Sonin)
+Figure 5.3.1,Sensory Function,https://open.oregonstate.education/app/uploads/sites/157/2021/02/514_Light_Micrograph_of_a_Meissner_Corpuscle.jpg,"Figure 5.3.1 – Light Micrograph of a Meissner Corpuscle: In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM × 100. (credit: “Wbensmith”/Wikimedia Commons)"
+Figure 5.3.2,Thermoregulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/515_Thermoregulation.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)"
+Figure 5.3.2,Thermoregulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/515_Thermoregulation.jpg,"Figure 5.3.2 – Thermoregulation: During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). (credit a: “Trysil”/flickr; credit c: Ralph Daily)"
+Figure 5.3.3,Thermoregulation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/516_Aging.jpg,"Figure 5.3.3 – Aging: Generally, skin, especially on the face and hands, starts to display the first noticeable signs of aging, as it loses its elasticity over time. (credit: Janet Ramsden)"
+Figure 5.2.1,Hair,https://open.oregonstate.education/app/uploads/sites/157/2019/07/506_Hair.jpg,Figure 5.2.1 – Hair: Hair follicles originate in the epidermis and have many different parts.
+Figure 5.2.2,Hair,https://open.oregonstate.education/app/uploads/sites/157/2021/02/511_Hair_Follicle.jpg,Figure 5.2.2 – Hair Follicle: The slide shows a cross-section of a hair follicle. Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath. Basal cells at the base of the hair root form the outer root sheath. LM × 4. (credit: modification of work by “kilbad”/Wikimedia Commons)
+Figure 5.2.3,Nails,https://open.oregonstate.education/app/uploads/sites/157/2021/02/507_Nails.jpg,Figure 5.2.3 – Nails: The nail is an accessory structure of the integumentary system.
+Figure 5.2.4,Sweat Glands,https://open.oregonstate.education/app/uploads/sites/157/2021/02/508_Eccrine_gland.jpg,Figure 5.2.4 – Eccrine Gland: Eccrine glands are coiled glands in the dermis that release sweat that is mostly water.
+Figure 5.1.1,Sebaceous Glands,https://open.oregonstate.education/app/uploads/sites/157/2019/07/501_Structure_of_the_skin.jpg,"Figure 5.1.1 – Layers of Skin: The skin is composed of two main layers: the epidermis, made of closely packed epithelial cells, and the dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures. Beneath the dermis lies the hypodermis, which is composed mainly of loose connective and fatty tissues."
+Figure 5.1.2,The Epidermis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/502ab_Thin_Skin_versus_Thick_Skin.jpg,"Figure 5.1.2 – Thin Skin versus Thick Skin: These slides show cross-sections of the epidermis and dermis of (a) thin and (b) thick skin. Note the significant difference in the thickness of the epithelial layer of the thick skin. From top, LM × 40, LM × 40. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 5.1.3,The Epidermis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/503_Epidermis.jpg,"Figure 5.1.3 – Epidermis: The epidermis is epithelium composed of multiple layers of cells. The basal layer consists of cuboidal cells, whereas the outer layers are squamous, keratinized cells, so the whole epithelium is often described as being keratinized stratified squamous epithelium. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 5.1.6,Dermis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/506_Layers_of_the_Dermis.jpg,"Figure 5.1.6 – Layers of the Dermis: This stained slide shows the two components of the dermis—the papillary layer and the reticular layer. Both are made of connective tissue with fibers of collagen extending from one to the other, making the border between the two somewhat indistinct. The dermal papillae extending into the epidermis belong to the papillary layer, whereas the dense collagen fiber bundles below belong to the reticular layer. LM × 10. (credit: modification of work by “kilbad”/Wikimedia Commons)"
+Figure 5.1.7,Pigmentation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/504_Melanocytes.jpg,Figure 5.1.7 – Skin Pigmentation: The relative coloration of the skin depends of the amount of melanin produced by melanocytes in the stratum basale and taken up by keratinocytes.
+Figure 4.6.1,Tissue Injury and Repair,https://open.oregonstate.education/app/uploads/sites/157/2019/07/417_Tissue_Repair.jpg,"Figure 4.6.1 – Tissue Healing: During wound repair, collagen fibers are laid down randomly by fibroblasts that move into repair the area."
+Figure 4.6.2,Homeostatic Imbalances: Tissues and Cancer,https://open.oregonstate.education/app/uploads/sites/157/2021/02/418_Development_of_Cancer.png,"Figure 4.6.2 – Development of Cancer: Note the change in cell size, nucleus size, and organization in the tissue."
+Figure 4.5.1,References,https://open.oregonstate.education/app/uploads/sites/157/2019/07/415_Neuron.jpg,"Figure 4.5.1 – The Neuron: The cell body of a neuron, also called the soma, contains the nucleus and mitochondria. The dendrites transfer the nerve impulse to the soma. The axon carries the action potential away to another excitable cell (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 4.5.2,References,https://open.oregonstate.education/app/uploads/sites/157/2021/02/416_Nervous_Tissue-new.jpg,Figure 4.5.2 – Nervous Tissue: Nervous tissue is made up of neurons and neuroglia. The cells of nervous tissue are specialized to transmit and receive impulses (LM × 872). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 4.4.1,References,https://open.oregonstate.education/app/uploads/sites/157/2019/07/414_Skeletal_Smooth_Cardiac.jpg,"Figure 4.4.1 – Muscle Tissue: (a) Skeletal muscle cells have prominent striation and nuclei on their periphery. (b) Smooth muscle cells have a single nucleus and no visible striations. (c) Cardiac muscle cells appear striated and have a single nucleus. From top, LM × 1600, LM × 1600, LM × 1600. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 4.2.2,Embryonic Connective Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+Figure 4.3.1,Connective Tissue Proper,https://open.oregonstate.education/app/uploads/sites/157/2019/07/408_Connective_Tissue-1.jpg,"Figure 4.3.1 – Connective Tissue Proper: Fibroblasts produce this fibrous tissue. Connective tissue proper includes the fixed cells fibrocytes, adipocytes, and mesenchymal cells (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 4.3.2,Loose Connective Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/409_Adipose_Tissue-1.jpg,Figure 4.3.2 – Adipose Tissue: This is a loose connective tissue that consists of fat cells with little extracellular matrix. It stores fat for energy and provides insulation (LM × 800). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 4.3.2,Loose Connective Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/areolar1_enhanced.png,Figure 4.3.2a – Areolar tissue
+Figure 4.3.5,Cartilage,https://open.oregonstate.education/app/uploads/sites/157/2021/02/412_Types_of_Cartilage-new-1.jpg,"Figure 4.3.5 – Types of Cartilage: Cartilage is a connective tissue consisting of collagenous fibers embedded in a firm matrix of chondroitin sulfates. (a) Hyaline cartilage provides support with some flexibility. The example is from dog tissue. (b) Fibrocartilage provides some compressibility and can absorb pressure. (c) Elastic cartilage provides firm but elastic support. From top, LM × 300, LM × 1200, LM × 1016. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 4.3.6,Fluid Connective Tissue,https://open.oregonstate.education/app/uploads/sites/157/2021/02/424_Blood_A_Fluid_Connective_Tissue-new-1024x541-1.jpg,Figure 4.3.6 – Blood: A Fluid Connective Tissue: Blood is a fluid connective tissue containing erythrocytes and various types of leukocytes that circulate in a liquid extracellular matrix (LM × 1600). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 4.2.1,The Epithelial Cell,https://open.oregonstate.education/app/uploads/sites/157/2019/07/402_Types_of_Cell_Junctions_new-scaled.jpg,"Figure 4.2.1 – Types of Cell Junctions: The three basic types of cell-to-cell junctions are tight junctions, gap junctions, and anchoring junctions."
+Figure 4.2.2,Classification of Epithelial Tissues,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+Figure 4.2.2,Classification of Epithelial Tissues,https://open.oregonstate.education/app/uploads/sites/157/2021/02/403_Epithelial_Tissue.jpg,Figure 4.2.2 – Cells of Epithelial Tissue: Simple epithelial tissue is organized as a single layer of cells and stratified epithelial tissue is formed by several layers of cells.
+Figure 4.2.4,Glandular Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/406_Types_of_Glands.jpg,Figure 4.2.4 – Types of Exocrine Glands: Exocrine glands are classified by their structure.
+Figure 4.2.5,Glandular Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/405_Modes_of_Secretion_by_Glands_updated.jpg,"Figure 4.2.5 – Modes of Glandular Secretion: (a) In merocrine secretion, the cell remains intact. (b) In apocrine secretion, the apical portion of the cell is released, as well. (c) In holocrine secretion, the cell is destroyed as it releases its product and the cell itself becomes part of the secretion."
+Figure 4.2.6,Glandular Structure,https://open.oregonstate.education/app/uploads/sites/157/2021/02/407_Sebaceous_Glands.jpg,Figure 4.2.6 – Sebaceous Glands: These glands secrete oils that lubricate and protect the skin. They are holocrine glands and they are destroyed after releasing their contents. New glandular cells form to replace the cells that are lost (LM × 400). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 4.1.1,The Four Primary Tissue Types,https://open.oregonstate.education/app/uploads/sites/157/2019/07/401_Types_of_Tissue.jpg,"Figure 4.1.1 – The Four Primary Tissue Types: Examples of nervous tissue, epithelial tissue, muscle tissue, and connective tissue found throughout the human body. Clockwise from nervous tissue, LM × 872, LM × 282, LM × 460, LM × 800. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 4.1.2,Embryonic Origin of Tissues,https://open.oregonstate.education/app/uploads/sites/157/2021/02/04-13_EmbryoTissue_1-copy-1024x777.png,Figure 4.1.2 – Embryonic Origin of Tissues and Major Organs: Embryonic germ layers and the resulting primary tissue types formed by each.
+Figure 4.1.3,Tissue Membranes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/413_Types_of_Membranes.jpg,"Figure 4.1.3 – Tissue Membranes: The two broad categories of tissue membranes in the body are (1) connective tissue membranes, which include synovial membranes, and (2) epithelial membranes, which include mucous membranes, serous membranes, and the cutaneous membrane, in other words, the skin."
+Figure 3.5.1,Interphase,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0329_Cell_Cycle.jpg,"Figure 3.5.1 – Cell Cycle: The two major phases of the cell cycle include mitosis (cell division), and interphase, when the cell grows and performs all of its normal functions. Interphase is further subdivided into G1, S, and G2 phases."
+Figure 3.5.3,Mitosis and Cytokinesis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0331_Stages_of-_Mitosis_and_Cytokinesis.jpg,"Figure 3.5.3 – Cell Division: Mitosis Followed by Cytokinesis: The stages of cell division oversee the separation of identical genetic material into two new nuclei, followed by the division of the cytoplasm."
+Figure 3.5.4,Mechanisms of Cell Cycle Control,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0332_Cell_Cycle_With_Cyclins_and_Checkpoints.jpg,"Figure 3.5.4 – Control of the Cell Cycle: Cells proceed through the cell cycle under the control of a variety of molecules, such as cyclins and cyclin-dependent kinases. These control molecules determine whether or not the cell is prepared to move into the following stage."
+Figure 3.4.1,Homeostatic Imbalances: Cancer Arises from Homeostatic Imbalances,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0324_DNA_Translation_and_Codons.jpg,Figure 3.4.1 – The Genetic Code: DNA holds all of the genetic information necessary to build a cell’s proteins. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein.
+Figure 3.4.2,From DNA to RNA: Transcription,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0325_Transcription.jpg,"Figure 3.4.2 – Transcription: from DNA to mRNA: In the first of the two stages of making protein from DNA, a gene on the DNA molecule is transcribed into a complementary mRNA molecule."
+Figure 3.4.3,From DNA to RNA: Transcription,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0326_Splicing.jpg,"Figure 3.4.3 – Splicing DNA: In the nucleus, a structure called a spliceosome cuts out introns (noncoding regions) within a pre-mRNA transcript and reconnects the exons."
+Figure 3.4.4,From RNA to Protein: Translation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0327_Translation.jpg,"Figure 3.4.4 – Translation from RNA to Protein: During translation, the mRNA transcript is “read” by a functional complex consisting of the ribosome and tRNA molecules. tRNAs bring the appropriate amino acids in sequence to the growing polypeptide chain by matching their anti-codons with codons on the mRNA strand."
+Figure 3.4.5,From RNA to Protein: Translation,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0328_Transcription-translation_Summary.jpg,"Figure 3.4.5 – From DNA to Protein: Transcription through Translation: Transcription within the cell nucleus produces an mRNA molecule, which is modified and then sent into the cytoplasm for translation. The transcript is decoded into a protein with the help of a ribosome and tRNA molecules."
+Figure 3.3.1,From RNA to Protein: Translation,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0318_Nucleus.jpg,Figure 3.3.1 – The Nucleus: The nucleus is the control center of the cell. The nucleus of living cells contains the genetic material that determines the entire structure and function of that cell.
+Figure 3.3.4,Organization of the Nucleus and its DNA,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0321_DNA_Macrostructure.jpg,"Figure 3.3.4 – DNA Macrostructure: Strands of DNA are wrapped around supporting histones. These proteins are increasingly bundled and condensed into chromatin, which is packed tightly into chromosomes when the cell is ready to divide."
+Figure 3.3.5,DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0322_DNA_Nucleotides.jpg,Figure 3.3.5 – Molecular Structure of DNA: The DNA double helix is composed of two complementary strands. The strands are bonded together via their nitrogenous base pairs using hydrogen bonds.
+Figure 3.3.6,DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0323_DNA_Replication.jpg,"Figure 3.3.6 – DNA Replication: DNA replication faithfully duplicates the entire genome of the cell. During DNA replication, a number of different enzymes work together to pull apart the two strands so each strand can be used as a template to synthesize new complementary strands. The two new daughter DNA molecules each contain one pre-existing strand and one newly synthesized strand. Thus, DNA replication is said to be “semiconservative.”"
+Figure 3.2.1,DNA Replication,https://open.oregonstate.education/app/uploads/sites/157/2019/07/0312_Animal_Cell_and_Components.jpg,"Figure 3.2.1 – Prototypical Human Cell: While this image is not indicative of any one particular human cell, it is a prototypical example of a cell containing the primary organelles and internal structures."
+Figure 3.2.2,Endoplasmic Reticulum,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0313_Endoplasmic_Reticulum.jpg,"Figure 3.2.2 – Endoplasmic Reticulum (ER): (a) The ER is a winding network of thin membranous sacs found in close association with the cell nucleus. The smooth and rough endoplasmic reticula are very different in appearance and function (source: mouse tissue). (b) Rough ER is studded with numerous ribosomes, which are sites of protein synthesis (source: mouse tissue, EM × 110,000). (c) Smooth ER synthesizes phospholipids, steroid hormones, regulates the concentration of cellular Ca++, metabolizes some carbohydrates, and breaks down certain toxins (source: mouse tissue, EM × 110,510). (Micrographs provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 3.2.4,Mitochondria,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0315_Mitochondrion_new.jpg,"Figure 3.2.4 – Mitochondrion: The mitochondria are the energy-conversion factories of the cell. (a) A mitochondrion is composed of two separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell’s major energy currency. (b) An electron micrograph of mitochondria (EM × 236,000). (Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
+Figure 3.2.5,Peroxisomes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0316_Peroxisome.jpg,Figure 3.2.5 – Peroxisome: Peroxisomes are membrane-bound organelles that contain an abundance of enzymes for detoxifying harmful substances and lipid metabolism.
+Figure 3.2.6,Peroxisomes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+Figure 3.2.6,Peroxisomes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+Figure 3.2.6,Peroxisomes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0317_Cytoskeletal_Components.jpg,"Figure 3.2.6 – The Three Components of the Cytoskeleton: The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division."
+Figure 3.1.1,Structure and Composition of the Cell Membrane,https://open.oregonstate.education/app/uploads/sites/157/2019/07/phospholipid1-1024x669.png,"Figure 3.1.1 – Phospholipid Structure and Bilayer: A phospholipid molecule consists of a polar phosphate “head,” which is hydrophilic and a non-polar lipid “tail,” which is hydrophobic. Unsaturated fatty acids result in kinks in the hydrophobic tails. The phospholipid bilayer consists of two adjacent sheets of phospholipids, arranged tail to tail. The hydrophobic tails associate with one another, forming the interior of the membrane. The polar heads contact the fluid inside and outside of the cell."
+Figure 3.1.2,Membrane Proteins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0303_Lipid_Bilayer_With_Various_Components.jpg,"Figure 3.1.2- Cell Membrane:  The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrate groups attached."
+Figure 3.1.3,Passive Transport,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0305_Simple_Diffusion_Across_Plasma_Membrane-1.jpg,"Figure 3.1.3 – Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion."
+Figure 3.1.4,Passive Transport,https://open.oregonstate.education/app/uploads/sites/157/2021/02/Facilitated_Diffusion-804x1024.jpg,"Figure 3.1.4 – Facilitated Diffusion: (a) Facilitated diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carrier proteins. Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. (b) Carrier proteins are more selective, often only allowing one particular type of molecule to cross."
+Figure 3.1.5,Osmosis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0307_Osmosis.jpg,"Figure 3.1.5 – Osmosis: Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic."
+Figure 3.1.6,Osmosis,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0346_Concentration_of_Solutions.jpg,Figure 3.1.6 – Concentration of Solution: A hypertonic solution has a solute concentration higher than another solution. An isotonic solution has a solute concentration equal to another solution. A hypotonic solution has a solute concentration lower than another solution.
+Figure 3.1.8,Other Forms of Membrane Transport,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0309_Three_Forms_of_Endocytosis.jpg,"Figure 3.1.8 – Three Forms of Endocytosis: Endocytosis is a form of active transport in which a cell envelopes extracellular materials using its cell membrane. (a) In phagocytosis, which is relatively nonselective, the cell takes in large particles into larger vesicles known as vacuoles. (b) In pinocytosis, the cell takes in small particles in fluid. (c) In contrast, receptor-mediated endocytosis is quite selective. When external receptors bind a specific ligand, the cell responds by endocytosing the ligand."
+Figure 3.1.9,Other Forms of Membrane Transport,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0310_Exocytosis.jpg,"Figure 3.1.9 – Exocytosis: Exocytosis is much like endocytosis in reverse. Material destined for export is packaged into a vesicle inside the cell. The membrane of the vesicle fuses with the cell membrane, and the contents are released into the extracellular space."
+Figure 3.1.10,Other Forms of Membrane Transport,https://open.oregonstate.education/app/uploads/sites/157/2021/02/0311_Pancreatic_Cells_Micrograph.jpg,Figure 3.1.10 – Pancreatic Cells’ Enzyme Products: The pancreatic acinar cells produce and secrete many enzymes that digest food. The tiny black granules in this electron micrograph are secretory vesicles filled with enzymes that will be exported from the cells via exocytosis. LM × 2900. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
+Figure 2.4.1,The Chemistry of Carbon,https://open.oregonstate.education/app/uploads/sites/157/2019/07/213_Dehydration_Synthesis_and_Hydrolysis-01.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water."
+Figure 2.5.1,Monosaccharides,https://open.oregonstate.education/app/uploads/sites/157/2019/07/217_Five_Important_Monosaccharides-01.jpg,Figure 2.5.1 Five Important Monosaccharides
+Figure 2.5.2,Disaccharides,https://open.oregonstate.education/app/uploads/sites/157/2021/02/218_Three_Important_Disaccharides-01.jpg,Figure 2.5.2 – Three Important Disaccharides: All three important disaccharides form by dehydration synthesis.
+Figure 2.5.3,Polysaccharides,https://open.oregonstate.education/app/uploads/sites/157/2021/02/219_Three_Important_Polysaccharides-01.jpg,"Figure 2.5.3 – Three Important Polysaccharides: Three important polysaccharides are starches, glycogen, and fiber."
+Figure 2.5.4,Triglycerides,https://open.oregonstate.education/app/uploads/sites/157/2021/02/220_Triglycerides-01.jpg,"Figure 2.5.4 – Triglycerides: Triglycerides are composed of glycerol attached to three fatty acids via dehydration synthesis. Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group"
+Figure 2.5.5,Triglycerides,https://open.oregonstate.education/app/uploads/sites/157/2021/02/221_Fatty_Acids_Shapes-01.jpg,Figure 2.5.5 – Fatty Acid Shapes: The level of saturation of a fatty acid affects its shape. (a) Saturated fatty acid chains are straight. (b) Unsaturated fatty acid chains are kinked.
+Figure 2.5.6,Phospholipids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+Figure 2.5.6,Steroids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+Figure 2.5.6,Prostaglandins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/222_Other_Important_Lipids-01.jpg,"Figure 2.5.6 – Other Important Lipids: (a) Phospholipids are composed of two fatty acids, glycerol, and a phosphate group. (b) Sterols are ring-shaped lipids. Shown here is cholesterol. (c) Prostaglandins are derived from unsaturated fatty acids. Prostaglandin E2 (PGE2) includes hydroxyl and carboxyl groups."
+Figure 2.5.7,Microstructure of Proteins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/223_Structure_of_an_Amino_Acid-01.jpg,Figure 2.5.7 Structure of an Amino Acid
+Figure 2.5.8,a variable group,https://open.oregonstate.education/app/uploads/sites/157/2021/02/224_Peptide_Bond-01.jpg,"Figure 2.5.8 – Structure of an Amino Acid: Different amino acids join together to form peptides, polypeptides, or proteins via dehydration synthesis. The bonds between the amino acids are peptide bonds."
+Figure 2.5.9,Shape of Proteins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+Figure 2.5.9,Shape of Proteins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+Figure 2.5.9,Shape of Proteins,https://open.oregonstate.education/app/uploads/sites/157/2021/02/225_Peptide_Bond-01-1024x870-1.jpg,"Figure 2.5.9 – The Shape of Proteins: (a) The primary structure is the sequence of amino acids that make up the polypeptide chain. (b) The secondary structure, which can take the form of an alpha-helix or a beta-pleated sheet, is maintained by hydrogen bonds between amino acids in different regions of the original polypeptide strand. (c) The tertiary structure occurs as a result of further folding and bonding of the secondary structure. (d) The quaternary structure occurs as a result of interactions between two or more tertiary subunits. The example shown here is hemoglobin, a protein in red blood cells which transports oxygen to body tissues."
+Figure 2.5.10,Proteins Function as Enzymes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/227_Steps_in_an_Enzymatic_Reaction-01.jpg,"Figure 2.5.10 – Steps in an Enzymatic Reaction: (a) Substrates approach active sites on enzyme. (b) Substrates bind to active sites, producing an enzyme–substrate complex. (c) Changes internal to the enzyme–substrate complex facilitate interaction of the substrates. (d) Products are released and the enzyme returns to its original form, ready to facilitate another enzymatic reaction."
+Figure 2.5.11,Nucleotides,https://open.oregonstate.education/app/uploads/sites/157/2021/02/228_Nucleotides-01.jpg,"Figure 2.5.11 – Nucleotides: (a) The building blocks of all nucleotides are one or more phosphate groups, a pentose sugar, and a nitrogen-containing base. (b) The nitrogen-containing bases of nucleotides. (c) The two pentose sugars of DNA and RNA."
+Figure 2.5.12,Nucleic Acids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/229_Nucleotides-01.jpg,"Figure 2.5.12 – DNA: In the DNA double helix, two strands attach via hydrogen bonds between the bases of the component nucleotides."
+Figure 2.5.13,Adenosine Triphosphate,https://open.oregonstate.education/app/uploads/sites/157/2021/02/230_Structure_of_Adenosine_Triphosphate_ATP-01.jpg,Figure 2.5.13 Structure of Adenosine Triphosphate (ATP)
+Figure 2.4.1,The Role of Water in Chemical Reactions,https://open.oregonstate.education/app/uploads/sites/157/2019/07/213_Dehydration_Synthesis_and_Hydrolysis-01.jpg,"Figure 2.4.1 – Dehydration Synthesis and Hydrolysis: Monomers, the basic units for building larger molecules, form polymers (two or more chemically-bonded monomers). (a) In dehydration synthesis, two monomers are covalently bonded in a reaction in which one gives up a hydroxyl group and the other a hydrogen atom. A molecule of water is released as a byproduct during dehydration reactions. (b) In hydrolysis, the covalent bond between two monomers is split by the addition of a hydrogen atom to one and a hydroxyl group to the other, which requires the contribution of one molecule of water."
+Figure 2.4.2,Salts,https://open.oregonstate.education/app/uploads/sites/157/2021/02/214_Dissociation_of_Sodium_Chloride_in_Water-01.jpg,"Figure 2.4.2 – Dissociation of Sodium Chloride in Water: Notice that the crystals of sodium chloride dissociate not into molecules of NaCl, but into Na+ cations and Cl– anions, each completely surrounded by water molecules."
+Figure 2.4.3,Acids,https://open.oregonstate.education/app/uploads/sites/157/2021/02/215_Acids_and_Bases-01.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–."
+Figure 2.4.3,Bases,https://open.oregonstate.education/app/uploads/sites/157/2021/02/215_Acids_and_Bases-01.jpg,"Figure 2.4.3 – Acids and Bases: (a) In aqueous solution, an acid dissociates into hydrogen ions (H+) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H+. (b) In aqueous solution, a base dissociates into hydroxyl ions (OH–) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH–."
+Figure 2.4.4,The Concept of pH,https://open.oregonstate.education/app/uploads/sites/157/2021/02/216_pH_Scale-01.jpg,Figure 2.4.4 The pH Scale
+Figure 2.3.2,Enzymes and Other Catalysts,https://open.oregonstate.education/app/uploads/sites/157/2021/02/212_Enzymes-01.jpg,"Figure 2.3.2 – Enzymes:  Enzymes decrease the activation energy required for a given chemical reaction to occur. (a) Without an enzyme, the energy input needed for a reaction to begin is high. (b) With the help of an enzyme, less energy is needed for a reaction to begin."
+Figure 2.2.1,Ions and Ionic Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/207_Ionic_Bonding-01.jpg,"Figure 2.2.1 – Ionic Bonding: (a) Sodium readily donates the solitary electron in its valence shell to chlorine, which needs only one electron to have a full valence shell. (b) The opposite electrical charges of the resulting sodium cation and chloride anion result in the formation of a bond of attraction called an ionic bond. (c) The attraction of many sodium and chloride ions results in the formation of large groupings called crystals."
+Figure 2.2.2,Nonpolar Covalent Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/208_Covalent_Bonding-01.jpg,Figure 2.2.2 Covalent Bonding
+Figure 2.2.2,Nonpolar Covalent Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/208_Covalent_Bonding-01.jpg,Figure 2.2.2 Covalent Bonding
+Figure 2.2.3,Polar Covalent Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+Figure 2.2.3,Polar Covalent Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+Figure 2.2.3,Polar Covalent Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/209_Polar_Covalent_Bonds_in_a_Water_Molecule.jpg,Figure 2.2.3 Polar Covalent Bonds in a Water Molecule
+Figure 2.2.4,Hydrogen Bonds,https://open.oregonstate.education/app/uploads/sites/157/2021/02/210_Hydrogen_Bonds_Between_Water_Molecules-01.jpg,"Figure 2.2.4 – Hydrogen Bonds between Water Molecules: Notice that the bonds occur between the weakly positive charge on the hydrogen atoms and the weakly negative charge on the oxygen atoms. Hydrogen bonds are relatively weak, and therefore are indicated with a dotted (rather than a solid) line."
+Figure 2.1.1,Elements and Compounds,https://open.oregonstate.education/app/uploads/sites/157/2019/07/201_Elements_of_the_Human_Body-01.jpg,Figure 2.1.1 – Elements of the Human Body: The main elements that compose the human body are shown from most abundant to least abundant.
+Figure 2.1.2,Atomic Structure and Energy,https://open.oregonstate.education/app/uploads/sites/157/2021/02/202_Two_Models_of_Atomic_Structure.jpg,"Figure 2.1.2 – Two Models of Atomic Structure: (a) In the planetary model, the electrons of helium are shown in fixed orbits, depicted as rings, at a precise distance from the nucleus, somewhat like planets orbiting the sun. (b) In the electron cloud model, the electrons of carbon are shown in the variety of locations they would have at different distances from the nucleus over time."
+Figure 2.1.3,Atomic Number and Mass Number,https://open.oregonstate.education/app/uploads/sites/157/2021/02/203_Periodic_Table-02-scaled.jpg,"Figure 2.1.3 – The Periodic Table of the Elements (credit: R.A. Dragoset, A. Musgrove, C.W. Clark, W.C. Martin)"
+Figure 2.1.4,Isotopes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/204_Isotopes_of_Hydrogen-01.jpg,"Figure 2.1.4  -Isotopes of Hydrogen: Protium, designated 1H, has one proton and no neutrons. It is by far the most abundant isotope of hydrogen in nature. Deuterium, designated 2H, has one proton and one neutron. Tritium, designated 3H, has two neutrons."
+Figure 2.1.6,The Behavior of Electrons,https://open.oregonstate.education/app/uploads/sites/157/2021/02/206_Electron_Shells-01.jpg,"Figure 2.1.6 Electron Shells: Electrons orbit the atomic nucleus at distinct levels of energy called electron shells. (a) With one electron, hydrogen only half-fills its electron shell. Helium also has a single shell, but its two electrons completely fill it. (b) The electrons of carbon completely fill its first electron shell, but only half-fills its second. (c) Neon, an element that does not occur in the body, has 10 electrons, filling both of its electron shells."
+Figure 1.5.1,X-Rays,https://open.oregonstate.education/app/uploads/sites/157/2019/07/01_16_X-ray_of_Hand.jpg,"Figure 1.5.1 – X-Ray of a Hand:  High energy electromagnetic radiation allows the internal structures of the body, such as bones, to be seen in X-rays like these. (credit: Trace Meek/flickr)"
+Figure 1.5.2,Computed Tomography,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+Figure 1.5.2,Magnetic Resonance Imaging,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+Figure 1.5.2,Positron Emission Tomography,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+Figure 1.5.2,Ultrasonography,https://open.oregonstate.education/app/uploads/sites/157/2021/02/113abcd_Medical_Imaging_Techniques.jpg,Figure 1.5.2 – Medical Imaging Techniques: (a) The results of a CT scan of the head are shown as successive transverse sections. (b) An MRI machine generates a magnetic field around a patient. (c) PET scans use radiopharmaceuticals to create images of active blood flow and physiologic activity of the organ or organs being targeted. (d) Ultrasound technology is used to monitor pregnancies because it is the least invasive of imaging techniques and uses no electromagnetic radiation. (credit a: Akira Ohgaki/flickr; credit b: “Digital Cate”/flickr; credit c: “Raziel”/Wikimedia Commons; credit d: “Isis”/Wikimedia Commons)
+Figure 1.4.1,Anatomical Position,https://open.oregonstate.education/app/uploads/sites/157/2019/07/107_Regions_of_Human_Body_new.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.
+Figure 1.4.1,Regional Terms,https://open.oregonstate.education/app/uploads/sites/157/2019/07/107_Regions_of_Human_Body_new.jpg,Figure 1.4.1 – Regions of the Human Body: The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface.
+Figure 1.4.2,Directional Terms,https://open.oregonstate.education/app/uploads/sites/157/2021/02/108_Directional_Terms.jpg,Figure 1.4.2 – Directional Terms Applied to the Human Body: Paired directional terms are shown as applied to the human body.
+Figure 1.4.3,Body Planes,https://open.oregonstate.education/app/uploads/sites/157/2021/02/109_Planes_of_Body.jpg,"Figure 1.4.3 – Planes of the Body: The three planes most commonly used in anatomical and medical imaging are the sagittal, frontal (or coronal), and transverse planes."
+Figure 1.4.4,Abdominal Regions and Quadrants,https://open.oregonstate.education/app/uploads/sites/157/2021/02/111_Abdominal_Quadrant_Regions.jpg,Figure 1.4.4 – Regions and Quadrants of the Peritoneal Cavity: There are (a) nine abdominal regions and (b) four abdominal quadrants in the peritoneal cavity.
+Figure 1.3.2,Abdominal Regions and Quadrants,https://open.oregonstate.education/app/uploads/sites/157/2019/07/105_Negative_Feedback_Loops.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback."
+Figure 1.3.2,Abdominal Regions and Quadrants,https://open.oregonstate.education/app/uploads/sites/157/2019/07/105_Negative_Feedback_Loops.jpg,"Figure 1.3.2 – Negative Feedback Loop: In a negative feedback loop, a stimulus—a deviation from a set point—is resisted through a physiological process that returns the body to homeostasis. (a) A negative feedback loop has four basic parts. (b) Body temperature is regulated by negative feedback."
+Figure 1.3.3,Abdominal Regions and Quadrants,https://open.oregonstate.education/app/uploads/sites/157/2021/02/106_Pregnancy-Positive_Feedback.jpg,"Figure 1.3.3 – Positive Feedback Loop: Normal childbirth is driven by a positive feedback loop. A positive feedback loop results in a change in the body’s status, rather than a return to homeostasis."
+Figure 1.2.2,The Levels of Organization,https://open.oregonstate.education/app/uploads/sites/157/2021/02/102_Organ_Systems_of_BodyPage2_revised-Recovered_modified.png,Figure 1.2.2 – Organ Systems of the Human Body: Organs that work together are grouped into organ systems.
+Figure 1.1.1,The Levels of Organization,https://open.oregonstate.education/app/uploads/sites/157/2019/07/01_01ab_Gross_and_Microscopic_Anatomy.jpg,"Figure 1.1.1 – Gross and Microscopic Anatomy: (a) Gross anatomy considers large structures such as the brain. (b) Microscopic anatomy can deal with the same structures, though at a different scale. This is a micrograph of nerve cells from the brain. LM × 1600. (credit a: “WriterHound”/Wikimedia Commons; credit b: Micrograph provided by the Regents of University of Michigan Medical School © 2012)"
diff --git a/Anatomy_And_Physio/scores.csv b/Anatomy_And_Physio/scores.csv
new file mode 100644
index 0000000000000000000000000000000000000000..37e7b98d46fde91d189154c519a77b146b62da19
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